COMPOUNDS AND METHODS FOR THE SELECTIVE TREATMENT OF CANCER AND BACTERIAL INFECTIONS

FIELD OF THE INVENTION

The present invention relates to a new class of glucuronides, esters, and glycosides whose aglycone activity is more highly toxic than normally found for such compounds, as well as to methods of preparation of such glucuronides, esters, and glycosides The present invention also relates to the treatment of tumors with an ester, or glucuronide and/or glycoside and optionally an enzyme such as an esterase, glucuronidase and/or glycosidase The enzvme at the site of the tumor is either (i) a property of the tumor or (n) is delivered there (targeted), or a combination of the two The targeting is accomplished via a binding species or an organism The invention further relates to the treatment of bacterial infections, in particular, infections having esterase, glucuronidase and/or glycosidase activity

BACKGROUND OF THE INVENTION

The selectivity of anti-cancer drugs ts poor and most of the drugs used for treatment have dose limiting toxicity (typically bone marrow toxicity but other tissues are affected depending on the anti-cancer drug) The use of doxorubicin, for example, is dose limited due to its cardiac toxicity and its mvelosuppressive effect Numerous attempts have been made to isolate related anthracychne drugs which show improved properties but doxorubicin and daunorubicin remain two of the most useful drugs for treatment of cancers and leukemias (Young, RC et al, New England J Medicine 19S 1 , 305, 139- 153, Zunino F and Capranico G, Anti-Cancer Drugs Design 1990, 5, 307-3 17, EP 0 441 218 A2)

The most interesting drugs for use as prodrugs are those which are toxic at low levels with IC50 (inhibitory concentration causing 50% inhibition of growth) <10° M. Examples of such agents include morpholinyl anthracyclines (Streeter DG et al, Cancer Chemother Pharmacol 1985, 14, 160- 164; US 4,301,277), barminomycins (Uchida T, et al, The J of Antibiotics, 1988, XLI, 404-408) actinomycin D, and anthracycline analogs bearing latent alkylating substituents (US Patent 5, 196,522). ^' Morpholinyl anthracyclines such as compound 1 (see below) can dissociate in solution to form the reactive iminium compound 2; and compound 3. an anthracycline analog bearing a latent aldehyde, can undergo hydrolysis of the diacεtoxy group by esterases in vivo followed bv cyclization to form the analogous iminium compound 4.

3 4

Reactive iminium ions are formed by the reaction of amines with carbonyl groups such as aldehydes and ketones.

The need for more toxic agents as prodrugs has been suggested by a number of workers in this area (Henle KJ. et al Radiation Res, 19S8, 1 15, 373-

386) Attempts have also been made to improve the properties of the anthracycline cancer drugs by making glycoside modifications to generate activatable prodrugs (EP 0 441 218 A2, Leenders Ruben GG et ai Tet Lett 1995, 36, 1701 - 1704, EP 0 565 133 A2, WO 92/19639) These anthracycline glycosides do not make use of the more potent anthracyclines resulting in less desirable anthracycline prodrugs due to the clinical problems of large doses and increased cost of synthesis

Antibodies which are specific for tumors are well known in the art Tumor specific antibodies have been used to target toxins in attempts to develop cancer therapies

The production of drug antibody conjugates has been achiev ed with some success /// v/t/o but with disappointing results in tumor bearing mice and clinical studies (Garnett MC, et al Int J Cancer 1983, 3 1 661 -670, Embleton MJ et al Br J Cancer 1983, 47 43-49)

Attempts hav e been made to improv e selective delivery of cvtotoxic agents to tumors using antibodies coupled to enzymes Conjugation of enzymes such as ricin and other ribosome inactivating proteins to antibodies has been used to target enzymes to tumors In these studies, the enzyme is also the active toxin entering the cell and catalytically inactiv ating it bv modification of the ribosomes (Moller G, Immunol Rev 1982,62)

In other studies, attempts have been made to use the activ mes of enzymes conjugated to targeting antibodies to generate cvtotoxic agents for targeted tumor killing The early work on this principle used glucose oxidase as the enzv me (Philpott GD, et al J Immunology 1973, 1 1 1 921 -929) See also Parker et al, 1975 Proc Nat Acad Sci USA 72, 338-342

WO 87/03205 discloses enzvme-coupled antibody, in which the enzyme is characteπzed by its ability to catah ze reactions which result in the death of cells bearing antigenic sites which the antibody can bind See also US Patent 4975278 In animal studies tumor regressions were seen with the targeting of the CC 49 anti tag 72 antibodv as a conjugate to beta-1 actam ase to tumors followed by the treatment of the animals with a vinblastine prodrug substrate for beta-lactamase, Mev er et al (Cancer Res 1993 53, 3956-3963) In these studies, in addition to the antibodv -enzyme conjugates, the drug antibody conjugates were ev aluated and shown to be relatively ineffective and required very large doses of antibodv when compared to enzvme activation

Targeting of glycosidic enzv mes has also been successfully used In one example a tumor specific antibodv was chemically cross linked to the enzyme E colt beta-glucuronidase and used to target a rat hepatoma cell line This targeted beta-glucuronidase w as used to activate p-dι-2- chloroethv laminophenv l-beta-D-glucuronide prodrug to its active drug N,N-dι- (2-chloroethvl) 4-hvdrow aniline (W ang SM et al Cancer Res 1992 Aug 15,52( 16) 4484-91 )

In a further demonstration of this approach, a pan carcinoma antibody was chemically linked to £ coli beta-glucuronidase generating a conjugate which was able to specificallv target v arious carcinoma cells The prodrug used in this studv was a glucuronide of epirubicin which resulted in a detoxification of the parent drug up to 1000 fold This glucuronide was isolated from the urine of patients treated w ith epirubicin The /// viti o data demonstrated good levels of activ ation and cv totoxiαtv using these conjugates (Haisma HJ et al Br J Cancer 1992 Sep 66(3) 474-8)

In another studv making use of (I) a conjugate of E coli beta galactosidase to an antι-CE \ antibody Col l and (π) a galactoside of 5-

fluorouridine, targeted activation was also demonstrated (Abraham R et al 1994 Cell Biophysics 24/25, 127- 133)

Prodrug approaches have also been used clinically making use of the prokaryotic enzyme carboxypeptidase-G2 fused to anti CEA antibodies (Bagshawe KD et al Br J Cancer 1988 58700-703) In a study aimed at producing a less immunogenic antibody fusion, which may have advantages over mouse antibodies and bacterial enzymes, a fusion with the human beta glucuronidase was made to a humanized anti CEA antibody This vvas achieved by making a genetic construction allowing reproducible production of the therapeutic antibody (Bosslet K et al Br J Cancer 1992 65 234-23 S. EP 0501215 A2) This humanized anti CEA antibody human beta glucuronidase fusion protein has been demonstrated to activate a glucuronide of doxopjbicin (see WO 92/19639) in tumor bearing mice to achieve some reduction in tumor growth and 10 fold higher levels of doxorubicin in the tumor (Bosslet K et al, 1994 Cancer Res 54, 2151 -2159) In an approach similar to that described by Bosslet et al . the use of human antibodies and human lysozyme has also been proposed to reduce the potential problems associated w ith immunogenic antibodies and enzymes (WO 90/07929)

The potential for the use of exogenous glycosidic enzymes in a non targeted format has been investigated (Tshiersch B, Schwabe K, Svdovv G. and Graffi A Cancer Treat Rep 1977 61 1489- 1493) In this study a combination of alpha-L-arabinofuranosidase from Aspergillus niger was used in combination with a prodrug form of beta-peltatin A, beta-peltatin A-alpha-L- arabinofuranoside The aim of this approach vvas to make use of the lower pH optimum for the alpha-L-arabinofuranosidase to develop selectiv e activation in tumors based on the lower pH found in tumors This group also made use of the ability to affect the tumor pH by glucose infusion

The potential for the use of endogenous glycosidic enzymes m a non targeted format has been inv estigated US Patents 4,327,074, 4,337,760, 4,481, 195, 4,584,368, and 5 005,588 describe the potential of using beta- glucuronidase activ ity present in rumors The inventors note that the effect can be enhanced by the use of glucose and alkalinization to increase the differences in pH between the tumor and the normal tissues The use of glucose allows the tumor pH to be lowered significantlv and the use of a base such as sodium bicarbonate allows the urine pH and other areas of normal tissue to remain at pH in the range of 7 4 The low eπng of the tumor pH can be as much as 0 5 pH unit m some cases (Cancer Res 4 ^Q 4373-4384, 1989) US Patent 4,248,999 discloses the use of 5-fluorouracil as a glucuronide (and other glv cosides) by linking it to the C6 position of the αracil πng Protocols for the improvement of therapv with glucuronide prodrugs have also been suggested which make use of the potential for endogenous ^, glucuronidase activ itv increasing the whole bodv pH and lowering the tumor pH

The potential of using v ιrus and or nucleic acid targeted prodrug activ ation has also been inv estigated In an example of this approach the enzv me cvtosine deaminase has been targeted using a retroviral v ector to achieve the selectiv e deliv er* and activ ation of the prodrug 5-fluorocytosιne This has been demonstrated w ith the generation of retrov iral vectors which have incorporated the cytosine deaminase gene from yeast under control of the CEA promoter (Huber BE et al 1993 Cancer Res 53, 4619-4626) In a similar approach the herpes simplex v irus thvmidine kinase (HSV-tk) has been incorporated into retrov iral v ectors to activate ganciclov ιr to its toxic phosphorylated form (J Michae' DΛIaio et al 1994, Surgery 1 16, 205-213) Other viruses mav be used in this targeting approach such as adenov irus fowlpox, newcastles disease These v iruses are being explored in the treatment of cancer The c ¹ >lιv er\ of the v irus mav be direct through the use of an infectious particle which opnonalh has been engineered to have a selective

tissue tropism (1 e , by inclusion of antibody binding domains (Chu et al _, J Virol 1995, 69 2659-63)) In an alternative method the virus is targeted by the use of other vehicles such as liposomes in either a targeted (by binding moieties, ₁ e antibodies) or untargeted fashion (Bichko V et al 1994, J Virology 68, 5247- 5 5252) The targeting and delivery of genes to activate prodrugs can also occur via the delivery of DNA (not in the form of a virus) An encapsulation method can be used for delivery either via liposomes or through the use of viral like particles to package the DNA as has been demonstrated with a number of E coli viruses

SUMMARY OF THE INVENTION

The present invention relates to compounds containing an anthracychnone group such as doxorubicin, daunorubicin or a derivative thereof The compounds of the invention also contain ester, glycoside or glucuronide structures which are hydrolyzed by the corresponding esterase, glycosidase or glucuronidase These compounds possess potent cvtotoxic activ ity which is developed after the hydrolysis of the ester or glycoside group of the compound and are effective in the inhibition of tumor cells and bacterial growth, after activation Included are compounds having the formula

R ^:

R' Y B R ^; Z

where

R ¹ is a radical of an anthracychnone where the point of attachment is the 3' nitrogen of the daunosamine sugar,

R ² is H, alkyl having from 1 to 6 carbon atoms, phenyl or aromatic or

heteroaromatic having from 1 to 10 carbon atoms substituted with NO ₂ , CN, F,

Cl, OH, OMe, or alkoxy having from 1 to 6 carbon atoms, COMe, CF ₃ , COOH,

COO(alkyl or aryl) having from 1 to 10 carbon atoms,

R ^" is cyano. methoxy, ethoxv . alkoxy having from 3 to 18 carbon atoms,

phenyloxy or aryloxy having from 1 - 10 carbon atoms substituted with NO-,,

CN, F, Cl, OH, alkoxy having from 1 to 6 carbon atoms, COMe, CF ₃ , COOH,

or COO (alkyl or aryl) having from 1 to 10 carbon atoms, acetoxy,

propionyloxy, trimethylacetoxy. or benzoyloxy,

X = CH ₂ , O. S, or N substituted by H. alkyl or acyl having from 1 to 6

carbon atoms, phenyl, or aromatic or heteroaromatic having from 1 to 10 carbon

atoms substituted w ith methyl, ethv 1 acetyl or benzoyl,

n = 2 if X = O. S, or substituted N,

n = l or 2 if X = CH _; .

B is O, NHCOO. or one of the following substituted aromatics

0 O

.-

where M is H, NO _: . CN, F, Cl OH. alkoxy having from 1 to 18 carbon atoms, COMe, CF _{3 ,} COOH. COO(alkv l or aryl) having from 1 to 10 carbon atoms,

phenyl, aromatic or heteroaromatic having from 1 to 10 carbon atoms, methyl or

alkyl having from 2 to 18 carbon atoms, and

Z is a glycosyl, or substituted aliphatic or aromatic acyl having from 1 to

18 carbon atoms attached to the aromatic or carbamoyl 0 of B at the anomeric

carbon of Z,

provided that where R ³ is aryloxy or acyloxy, BZ cannot be the same as

R ³

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates the mechanisms by which two compounds of claim 1

can break down to form an amino aldehyde, which spontaneously forms the

reactive iminium ion

Figure 2 illustrates the breakdown of an inactivated amino prodrug

incorporating a self-immolative linker

Figure 3 illustrates another version of a self-immolative linker

Figure 4 illustrates breakdown of the prodrug to form an unsaturated

ketone

Figure 5 schematically illustrates the potential mechanism of action of

one example of the anthracyclines class of prodrugs This prodrug is structured

to be activated by the enzyme glucuronidase

Figure 6 is a schematic illustration of a synthetic route to a glucuronide

of doxorubicin and daunorubicin ⁽ Example 2)

Figure 7 is a schematic illustration of a synthetic route to a glucuronide

of doxorubicin (Example 3)

The invention, as w ell as other objects, features and advantages thereof

will be understood more clearly and fully from the following detailed

description when read with reference to the accompanying Figures.

ΠFTAΠ,ED DESCRIPTION OF THE INVENTION

The subject invention relates to a novel family of prodrugs for the

treatment of cancer and bacterial infections which are based on the site specific

activation of the prodrugs by various methods involving enzymes. Upon

activation, the prodrugs are capable of undergoing spontaneous reactions

leading to the formation of reactive iminium ions In particular, the compounds

of the present invention are activatable by glycosidases including

glucuronidases, and esterases

Advantageous anticancer drugs which can be modified according to the

subject invention include anthracyclinones such as doxorubicin,

deoxydoxorubicin and daunorubicin, epirubicin and idarubicin, or derivatives

thereof

The compounds of the invention are activated by enzymatic removal of

glycoside structure to yield active intermediates, see Figure 5 An example of

activation using a glucuronide and glucuronidase is shown in Figure 5

The compounds of the invention are effective in the inhibition of human

tumor growth and bacterial growth The compounds may be divided into three

classes based on the strategy of inactivation by glycosylation or esterification

1 Glycosylation and esterification serves to mask a latent aldehyde or

ketone from reaction with the amino group of the anthracycline Figure 1

illustrates the mechanisms by which two compounds of claim 1 can break down

to form an amino aldehyde, which spontaneously forms the reactive iminium

ion The sugar can be directly attached to the latent aldehyde, or can be

connected indirectly through a self-immolative linker Figure 3 illustrates

another version of a self-immolative linker

2 Glycosylation and esterification serves to mask the reactivity of the

amino group of the anthracycline The reactivity of the aldehyde or ketone is

temporarily reduced as well, in order to inhibit undesirable intermolecular

reactions with proteins, for example Figure 2 illustrates the breakdown of an

inactivated amino prodrug incorporating a self-immolative linker After the

latent aldehyde is unmasked (hv drolysis at the acidic tumor pH), the amino aldehyde spontaneously forms the reactiv e iminium ion

3 Glycosylation and esterification serves to mask a latent aldehyde or

ketone which is reactiv e w ith the ammo group of the anthracycline at the a or b

position (as well as at the carbonv l ) in a manner designed to give a reactive

imminium ion Figure 4 illustrates breakdown of the prodrug to form an

unsaturated ketone Michael addition giv es the a-halo amine, which

dehalogenates spontaneous! v to form a reactive iminium ion

I_ Definitions

Organism means anv bacteria, virus, parasite, or other living thing

with a size less than lOOμM in anv dimension

Binding species means anv molecule which has an affinity or avidity for

another molecule greater than ImM Examples of such molecules are usually

defined as pairs w here one binds to another of different or the same structure

Examples are avidin/biotin antibody/antigen, receptor/ligand, metal lon/ligand.

protein/protein, lectin/carbohydrate. and nucleic acid ^/ protein

Humanized antibody means an antibody which has been modified to

incorporate human sequences into it resulting in an antibody which is more like

a human antibody The term also includes antibodies which have been mutated to reduce immunogenicity

Glycosyl group is a single molecular moiety added to another molecule Examples of glvcosyl groups which can be added to the molecules of the

invention are galactosyl, glucuronyl, deoxy-glucosyl, lduronvl glucosy l _, N-

acetyl glucosammosyl, fructosyl, sialosyl, h>aluronosvl sedoheptulosvl _,

xylulosyl ribulosyl πbosyl, xylitosyl, daunosaminosy l arabinosvl fucosy l deoxy-πbosv l, mannosyl, N-acetyl-galactosvJ, rhamnosv l, 3 6-anhvdro-

galactosvl, sialv lfucosyl, and xylosyl Molecules containing these glv cosv 1

moieties are called gl ^y cosides Molecules containing these glycosyl moieties

the glvcosides are substrates for the respectiv e glycosidase

Antlv acychnones are molecular moieties characterized by the presence

of four fused six-membrered rings forming a substituted tetrahydronaphthacene quinone (aglv cone) moiety conjugated via glvcosidic linkages to a side chain

containing one or more glycosyl groups Most clinically important

anthracyclines contain an amino glycosyl attached to the aglycone portion The

number and or distribution of hydroxyls or methoxvls in the aglycone v ary and semisynthetic anthracychnones can contain functional groups not found in the

natural products Examples of compounds which form the anthracychnones of

the present invention are adπamvcin, daunomycin, carminomycin, aibidazone,

carminomycin, zorubicin, epirubicin idarubicin, deoxydoxorubicin, 4'-

demethoxydaunorubicin, ditnsarubicms, betaclamycins, 2-

hydroxyaclacinomycins, 4'-0-tetrahv dropyranyladπamycin, barminomycins,

baumvcins, annamycin, pirarubicm THP-doxorubicin, pirarubicin, aclarubicin,

zorubicin, lododoxorubicin AD-32 detorubicin, esorubicin, marcellomycin,

quelamvcin, rodorubicin menogaπl and nogalomycin Examples are also

presented in US 4,41 1 ,834 herebv incorporated by reference

Heteroaromatics are πng structures having from ^ to 8 atoms in the ring

which contain in addition to carbon atoms, other atom tv pes in the ring These

other atoms "hetero-atoms ' can be S 0 N, P Si In addition to these hetero¬

atoms the πng structure can also contain at least two double bonds as part of the

ring structure The number of heteroatoms in a ring can be from 1 to 4 Also

multiple rings can be fused to form a heteroaromatic as in the case of adenine

Examples of such heteroaromatics are furan, pyridine, indole, guanine, adenine

thiophene These heteroaromatics can be derivatized with NO _: CN, F, Cl, OH

alkoxv hav ing from 1 to 6 carbon atoms COMe, CF-,, COOH, or COO (alkyl or

aryl) hav ing from 1 to 10 carbon atoms acetox>, propionyloxy, tπmethv lacetoxv or benzov loxv attached to the ring structure

Glycosidase means a molecular species which is able to effect the

removal of a glvcoside or glucuronide from a molecular species containing a

glycoside or glucuronide. Examples of glycosidases are glucuronidase,

galactosidase, glucosidase, iduronidase, lysozyme, amylase, N-acetyl

glucosaminidase, fructosidase, sialidase, hyaluronidase, etc., these being defined

by the activity which each possess Glycosidase activity is not a property solely

of proteins Synthetic chemistry can also generate similar activities (ability to

hydrolyse the glycosidic bond). Examples of substrates for such glycosidases

are lactose, glycogen, starch, cellulose, sucrose, nitrophenyl-maltohexoside _, maltotriose, bromo-chloro-indolyl galactoside, methylumbelliferyl-N-

acetylneuraminic acid, nitrophenyl glucoside

A latent aldehyde or ketone is a functional group that can undergo

conversion to form an aldehyde or ketone For example, diacetoxv acetals such

as CH(OCOCMe ₃ ) ₂ can undergo hydrolysis of the ester groups to form CH=0,

the group C=NNHCOCH ₂ CH ₂ SS(2-pyridvϊ) is very stable at pH 7 4 _, but has a

half life of 1 8 hours at pH 5 0 and hydrolyzes to form C=0 (Biυconjugate

Chem , Vol 2, 133- 141 , 1991 ); and the hydrolysis of silyl enol ethers such as

CH=CHOSiR ₃ to form CH ₂ CH=0 is well precedented in the literature

39007 P T/US97/05920

16

l_ Synthesis of the Compounds of the Invention

A Synthesis of Glucurony I Prodrugs of Anthracychnone Drugs

In general, synthesis is as follows acetyl protected bromoglucuronic

acid methyl esters are convened to the beta-benzyl glucuronates At low

temperature, the benzv l groups are cleaved to give the beta-alcohol anomer,

which is quickly silv lated to giv e the beta-tπmethylsilyl glucuronide

Alternativelv acetv l protected glucuronic acid esters with a free hvdroxyl at the

anomeric position are reacted w ith tπmethylsilyldialkylamines to give the β-

trimethylsilyl glucuronide w ith high selectiv itv The silyl glycoside is reacted at

low temperature w ith an alkenv 1 acetal to give the glucuronyl mixed acetal

Ozonolvsis of the alkene produces an aldehyde which is used for the reductive

alkyla _t ion of the anthracv chnes The ester protecting groups are removed bv

saponification to giv e the prodrugs

B Synthesis ofDiacyloxy Prodrugs of Anthracychnone Drugs

In general sv nthesis is as follows alkenyl alcohols are oxidized to

the aldehydes using an oxidant such as catalytic tetra-n-propγlammonιum

perruthena _t e and N-methv lmorphohne-N-oxide The alkenyl aldehydes are

reacted with carbow lic acid anhvdrides using a Lewis acid activator such as

boron trifluoride etherate to giv e the diacvloxy alkenes Ozonolvsis of the

alkenes produces diacv loxv aldehv des, which are used for the reeductive

alkylation of the anthracyclines

HI Treatment of Cancer

Treatment of cancer in paπents, 1 e , mammals including humans, is

achieved by administering the compounds and compositions of the invention

Examples of cancers which are treatable according to the invention are lung

colon, breast, pancreatic, ovarian, melanoma, and stomach cancers Solid

tumors offer the best opportunity for the use of the compounds of the present

invention These allow the generation of necrotic regions more readily able to activate the esters, glucuronides or glycosides of the present invention

A Activation of Prodi ug by Endogenous Enzymes

In one embodiment of the invention, activation of the prodrug occurs due to endogenous enzyme in the tumor such as glucurionidase Tumor pH is modulated using glucose and bicarbonate infusions which lower the tumor pH allowing the endogenous lysosomal enzymes to be more active than in normal tissue The prodrug is then injected at doses from 1 miligram to 50 grams and at dosing intervals based on the response to the therapv and levels of prodrug products in the serum The prodrug dose is advantageously in the range of 50 μg-5000 mg/m ^: with dose cvcles of tumor pH modulation and prodrug administration each day for up to 20 days, depending on the level of non¬ specific activation as measured by the appearance of prodrug products in the serum During the course of treatment patients are monitored for adverse cardiac toxicitv , myelosuppression, liver and kidnev function This cycle of therapy is repeated a number of times (3- 10 times) as required

B Glucuronide Therapy

In order to prepare the patient for glucuronide therapy, the tumor pH is lowered to improve the therapeutic effect of the glucuronidase activation The patient is typically first given juices and asked to empty his bladder This is followed by a dose of 100 g of glucose After 30 min to 2 hrs, the patient then receives a drip which deliv ers 10° o glucose and 60 milhequivalents of sodium bicarbonate This drip deliv ers up to 1 liter ov er one hour At 30 mm into the drip the patient empties his bladder to determine the effectiveness of the therapy in causing alkalanization of the urine Alkalanization is also achieved bv the use of inhibitors of carbonic anhv drase (I e , acetazolamide) in combination w ith bicarbonate to achiev e a more prolonged affect

The treatment with the glucuronide drug is initiated when it has been determined that the glucose and bicarbonate drip has achieved alkamzation of the urine The analv sis of the 30 mm urine sample should show a pH above 7 4 The glucuronide prodrug is tv picalK giv en as an infusion in order to maintain a sustained lev el of drug in the blood for a period of one hour or more Alternativ eiv the prodrug is giv en as a bolus IV The dose of the prodrug is a maximum of 500 mg'm2 per treatment round but can be fractionated into multiple doses Patients mav be eligible for further treatment based on the indications of toxic side effects Treatment rounds occur at intervals of 3-6 weeks

Patients are monitored for adequate organ function including hematological function (white cell count, platelet count), hepatic function (bilirubin aspartate amino transferase alanine aminotransferase). renal functions (creatinme lev els) and pulmonarv function (carbon monoxide diffusing capaαtv ) This data is useful as a basis for controlling dose and interv als during treatment

In one embodiment of the invention activation at a desired target is accomplished by causing the target to synthesize the activating species For example, it is possible to direct tumor cells to synthesize enzymes which are able to activate prodrugs For example, a retroviral vector which contains a glycosidic enzyme activity is generated which is capable of activating a compound of the invention This viral vector is then targeted via the selective nature of the infectious agent for dividing cells or via the selective expression systems within the cell Other viruses can be used in this targeting approach such as adenovirus, fowlpox, newcastles disease The delivery of the virus can be direct through the use of an infectious particle which optionally has been engineered to have a selectiv e tissue tropism (I e , by inclusion of antibody binding domains (cf Winters)) In an alternative method, the virus is targeted by the use of other vehicles such as liposomes in either a targeted (bv binding moieties, I e , antibodies) or untargeted fashion (Bichko V et al 1994 _, J Virology 68, 5247-5252)

The targeting and deliv ery of genes to activ ate prodrugs can also occur via the delivery of DNA (not in the form of a virus) An encapsulation method is used for delivery either via liposomes or through the use of viral like panicles to package the DNA, as has been demonstrated with a number of E coli viruses Thus, this type of system can be used to target the prodrug activation of the compounds of the invention Targeting the ex ression is accomplished either via the targeting or the selectiv e expression of glucuronidases or other glycosidases which then activate the prodrugs of the invention This viral targeting of the activating agent gene to achieve the selective activation of the prodrugs of the invention can also be achieved using other organisms which show tropisms for tissues and organs In an advantageous embodiment, the glucuronidase and/or glycosidase are expressed in these virally or organism based targeted systems in a form which does not diffuse away from the tumor or other target site, by making use of, for example, transmembrane domains of

membrane binding proteins the binding domains of antibodies, etc known in the an

Also the use of transformed cells may be used to target the delivery of enzyme activ ity to the site of therap ^y See Cancer Immunol Immunother 1994 Maj, 38(5) 299-303, Cancer 1994 Mar 15, 73(6)1731-7

C Actnation ofPiodiug b\ Exogeneous Enzymes In another embodiment activation of the prodrug is accomplished bv the administration of a dose of enzv me Examples of glycosidase enzymes which are useful in the subject inv ention are glucuronidase, lysozyme, beta- galactosidase, alpha-galactosidase beta-glucosidase or other lvsosomal enzvmes which are able to hv drolv ze glv cosides Ideally these enzvmes should hav e a low pH optimum I e below pH6 For example from 1 - 100 mg of glucuronidase is administered followed bv a clearance period during which the level of glucuronidase in the serum is monitored At a time point after the injection of the enzv me the lev el of enzvme reaches a level where the potential for activ ation of the prodrug is not significant This time point will ty pically be from 12 hrs to 90 hrs after injection of the enzvme At this time, when the level of enzvme has reached a lev el in serum not to cause over activation of the prodrug, the prodrug is miected at doses from 100 μg to 50 grams and at dosing interv als based on the patients response to the therapy, and/or levels of prodrug products in the serum Adv antageouslv the prodrug dose is in the range of 50 μg-5000 mg ^/ m ^~ of prodrug w ith doses each day for up to 20 days depending on the level of non-specific activ ation (measured bv the appearance of prodrug products in the serum)

Optionallv tumor pH is modulated using glucose and bicarbonate as described in the section abov e on activ ation by endogenous enzymes This

allows the tumor pH to be lowered permitting the accumulated glucuronidase to be more active than in normal tissues

Adverse cardiac toxicity, myelosuppression, liver and kidney function 5 are monitored duπng treament This cycle of therapy is repeated a number of times (3- 10 times) as required

D Activation of Prodi ug by an Antibodx -Enzyme Fusion

In the case of targeted glucuronidase and glycosidases, examples of

10 targeting antibodies which can be used are OncoScmt® (Cytogen Corp

Princeton NJ) which is capable of achieving in some cases tumor normal tissue ratios of greater than 20 1 (Stern H, et al Cancer Investigation 1993, 1 1 (2) 129- 134), CA 125 BR96, B72 3, CC49, Col 1, 17- 1 A, and 16 88, which include both mouse, humanized and human antibodies (Siddiki B et al Int J Cancer 1993 54,

15 467-474, W erner LM et al J Immunotherapv 13, 1 10-1 16 Muraro R et al Cancer Res 1985 45, 5769-5780, Colcher D et al Cancer Res 19S8 48, 459 ^" '- 4603, Jager RD et al Seminars in Nuclear Medicine 1993 XXIII 165- 179) See also U S Patent application Ser Nos 07/773 042 and 07/919,85 1 each of which is hereby incorporated in its entirety bv reference These antibodies are linked 0 by a chemical linkage or via the construction of genetic fusions These molecules are dosed prior to the administration of compounds of the invention

An antibody -enzyme fusion is administered at up to 1 gm in various dosing schedules, but typically in the range 1-200 mg per dose as a single dose 5 which mav be infused over a period of time from 10 min to 24 hr The dose of antibody-enzyme can also be given in multiple dose injections After antibodv- enzvme infusion periodically the levels of enzvme are measured and the antibody titers The typical time allowed for this clearance is from 1 to 14 days When the lev els of prodrug activating enzvme have reached a lev el at which 0 little toxic activation can occur, the prodrug is administered The prodrug is

injected at doses up to 5 grams and at dosing intervals based on the response to therapy and levels of prodrug products in the serum Advantageously, the prodrug dose is in the range of 50 μg-5000 mg/m of prodrug with doses each day for up to 20 days The rate of administration will vary depending on the level of non-specific activation as measured by the appearance of prodrug products in the serum and monitoring of the dose limiting toxicity using HPLC analysis of extracted blood samples and serum chemistry analysis

In addition, tumor pH modulation using glucose and bicarbonate to lower the pH within the tumor is optionally used in this embodiment This increases the activity of the prodrug activ ating enzy mes if these had pH optima which were lower than the normal leading to the delivery of more drug to the tumor

During the course of treatment patients are monitored for adverse cardiac toxicitv and myelosuppression The cvcle of therapy is repeated a number of times

This targeting of the prodrug activ ating glv cosidase activ ity is achieved using a number of binding species which hav e been shown to have selectivity for the tumors or tissues where selectiv e activ ation is desired Examples of targeting agents are growth factors lectins, amino acids, vitamins for which there are receptors and/or transporters able to act as binding species for targeting These targeting agents are linked to the glycosidase activ lty to allow selective accumulation of the activ ating enzvme mediated via these binding species

IV. Use of Glycoside Prodrugs as Antibiotics

The glycoside prodrugs of the invention are useful in the treatment of bacterial infections where the bacteria involved have a specific glycosidase activity Examples of such bacteria are streptococci, staphylococci, and E coli Treatment is similar to that described above for cancer but there is no need for hyperacidification The alkalinization of the urine is carried out to reduce the non-specific activation in the bladder as described abov e Bicarbonate drips or drug treatments (e g , acetazolamide) can be used Having established this alkalinization, the prodrug is given via the bicarbonate drip or by intravenous injection in a suitable vehicle Alkalinization can also be achiev ed by oral bicarbonate

In one embodiment of the invention, the prodrugs are used without alkahzation due to the stability of the glycoside pro- group to the conditions present in the bladder

Y_ Formulation and Administration

The present invention also encompasses pharmaceutical compositions, combinations and methods for treating cancers and other tumors More particularly, the invention includes combinations comprising immunocon _j ugates (targeting protein and catalytic protein, or targeting antibody and catalytic antibodv (bispecific antibodies)) and the corresponding prodrug or prodrugs for use in a method for treating tumors wherein a mammalian host is treated m a pharmaceutically acceptable manner with a pharmaceutically jffective amount of a targeting protem catal ^y tic protein conjugate or conjugates or bispecific antibody or antibodies and a pharmaceutically effective amount of a prodru« or prodrugs In addition the invention includes combinations comprising immunoconjugates (targeting protein and catalytic protein, or targeting antibodv

and catalytic antibody (bispecific antibodies)) and the corresponding prodrug or prodrugs for use in a method for treating tumors wherein a mammalian host is treated in a pharmaceutically acceptable manner with a pharmaceutically effective amount of a targeting protein catalytic protein conjugate or conjugates or bispecific antibody or antibodies and a pharmaceutically effective amount of a prodrug or prodrugs The combination and methods of this invention are useful in treating humans and animals

The prodrugs and/or the binding species or organism is administered by any suitable route, preferably parenterally. e.g., by injection or infusion. These compounds are administered using conv entional modes of administration including, but not limited to, intravenous, intraperitioneal, oral, intralymphatic, or administration directly into the tumor. Intravenous administration is particularly advantageous.

The compositions of the invention— comprising the binding species or organism or prodrugs— can be in a variety of dosage forms which include, but are not limited to, liquid solutions or suspensions, tablets, pills, powders, suppositories, polymeric microcapsules or microvesicles. liposomes, and injectable or infusible solutions. The preferred form depends upon the mode of administration and the therapeutic application. For example, oral administration of the antibody-enzyme conjugate or bispecific antibody may be disfavored because the conjugate proteins tend to be degraded in the stomach if taken orally, e.g., in tablet form

Suitable formulations of the binding species or organisms or prodrug for parenteral administration include suspensions, solutions or emulsions of each component in oily or aqueous vehicles and optionally contain formulatory agents such as suspending, establishing and/or dispersing agents. Alternatively, the binding species or organism or prodrug is in powder form for reconstituting

with a suitable vehicle, e g , sterile pyrogen-free water before use If desired, the immunoconjugate antibody and/or prodrug is presented in unit dosage form Formulations are conveniently prepared in isotonic saline for in _j ection

The most effective mode of administration and dosage regimen for the compositions of this invention depends upon the severity and course of the disease, the patient's health and response to treatment and the _j udgement of the treating physician Accordingly, the dosages of the binding species, organisms and prodrugs should be titrated to the individual patient

Nev ertheless, an effective dose of the binding species or organisms of this invention is in the range of from about 1 0 to about 100 mg/m ² An effectiv e dose of the prodrug of the invention will range from 100 μg - 100 g/m- the precise doses at which the immunoconjugate and prodrug will be administered will depend on the route of administration, body weight and pathology of the patient, the nature of the prodrug, and the catalytic properties of the immunoconjugate Since the prodrug is less cytotoxic than the parent drug dosa ^g es in excess of those recognized in the art for the parent drug mav be used

EXAMPLES

Example 1 : Synthesis of Methyl 2,3,4-Tri-O-acetyl-l-O-trimethyIsilyl-β-D- glucuronate 3.

The compounds referred to in this synthesis are shown in Figure 7 1 he numbered intermediates of the Figure are cross-referenced in the text below in bold

Methyl 2,3,4-tri-O-acetv l- l-O-tπmethylsιlyl-β-D-glucuronate 3 can be prepared following a published three-reaction procedure (see compounds 1-4 in Figure 2, L F Tietze, et al , Carbohydrate Res., Vol 148 ( 1986), 349-352), however, this procedure is technically demanding because it requires careful control of temperature A simpler and more direct synthesis (compounds 1-3 in Figure 7) has been developed the commercially available tetraacetate 1 was converted to a mixture of the α and β pyranoses 2 using a mixture of hydrazine and acetic acid in DMF The anomeric mixture was treated with N- tπmethylsilyldiethylamine in acetone at room temperature to give the desired β- silyl glucuronide 3 highly selectiv eh (β a > 98 2 by NMR)

The stereoselectivitv of this reaction can be attributed to three factors 1 Under the reaction conditions, the a and β pyranoses undergo facile anomeπzation 2 Despite the fact that the a anomer is favored thermodynamicallv , the β-alkoxv anion is more reactive kinetically (Schmidt, et al Tetrahedron Lett , Vol 25 ( 1984) 821 Liebigs Ann Chem , ( 1984), 1343) 3 Unfavorable 1 ,3-dιaxιal interactions with the glucuronvl H3 and H5 disfavor reaction between the bulkv sih lating reagent and the a alkoxide

In detail, the synthesis is as follows

Methyl 2,3,4-trι-O-acety l-D-ghtcιιronate 2

Methyl 1 ,2,3,4-tetra-O-acetv l-D-glucuronate 1 (2 50 g, 6 7 mmol) was added in one portion to a solution of hv drazine hydrate (380 mL, 8 0 mmol) and acetic acid (460 mL. S 0 mmol) in 20 mL of DMF at room temperature After 1 h, the mixture was partitioned betw een ethv l acetate (3 x 100 mL) and water (100 mL), 5% KHCO- (100 mL) and 0 1 M HCl ( 100 mL), and the organic phases were washed with brine (50 mL). dried over anhydrous MgSO ₄ and concentrated in vacuo The residue vvas purified by flash chromatography (40.

50, and 60% ethyl acetate/hexane) to give 0 21 g of recovered starting material (8%) and 1.66 g of the product as a colorless foam (74%), a 3 6. 1 mixture of α and β anomers by NMR Crystallization from ether/hexane gave the pure α anomer R _f 0.26 (50% ethyl acetate/hexane), mp 104 5-109 5 °C, ^] H NMR 5 (CDC1 ₃ ) 6 2 01 (s, 3), 2 02 (s, 3), 2 06 (s, 3), 3 72 (s, 3), 4.56 (d, 1, J=10 1, H5), 4.87 (dd, 1 , J=3 6, 10.2, H2), 5.1 1-5. 18 (m, 1, H4), 5 51 (d, 1 , J=3 6, HI), 5 52- 5 58 (m, 1, H3); ¹³ C NMR (CDC1 ₃ ) δ 20 47, 20 60, 52.88, 67 89, 69 06, 69.45, 70 70, 90 14, 168.50, 169.68, 170 04, 170 17

10 Methyl 2, 3, 4-tri-0-acetyl-l-0-irimethylsilyl-$-D-ghtcw -onate 3

Four mL of N-trimethylsilyldiethylamine was added to a solution of glucuronate 2 (700 mg, 2 0 mmol) in 4 mL of acetone After 40 h at room temperature, the volatile components were evaporated in vacuo The resultant

15 brown solid, greater than 98% the b-silyl glucuronide 3 by NMR, was sufficiently pure to be used without further purification The residue can be crystallized from ether and hexane 1H NMR (CDC1 ₃ ) 6 0 15 (s, 9), 2 01 (s, 6), 2 03 (s, 3), 3 74 (s, 3), 4 00-4 07 (m, 1 , H5). 4 79 (d, 1, J=7 4, H I ), 4 90-4 95 (m, 1), 5 18-5.26 (m, 2), ^{I 3} C NMR (CDC1 ₃ ) δ -0 06, 20 47, 20 60, 52 76, 69 44,

20 72 06, 72.66, 73. 1 1, 95.56, 167 15, 169 17, 169 30, 170 14

\

Example 2: Synthesis of Glucuronide Prodrugs of the Invention.

The compounds referred to in this synthesis are shown in Figure 6 The 25 numbered intermediates of the Figure are cross-referenced in the text below in bold

Compounds 9b and 10b are glucuronide prodrugs of doxorubicin and daunorubicin, respectively Compound 9b will undergo esterase hydrolysis of 30 the methvl ester in vivo before glucuronidase catalyzed removal of the

39007 7 05920

28

glucuronic acid to give the drug Compound 10b will undergo glucuronidase catalyzed removal of the glucuronic acid to give the drug without prior transformation.

Compounds 9b and 10b were made starting from methyl 2,3,4-tri-O- acetyl-1-O-trimethylsilyl-β-D-glucuronate 4 (see Example 1 for its preparation) Compound 4 was reacted with the readily available compound 5 using a Lewis acid catalyst at low temperature following the method described by Tietze, et al (Carbohydrate Res., Vol 180 ( 1988). 253-262) Working carefully, the β- glucuronide 6 can be obtained selectively , but acid catalyzed equilibration of compound 4 to the more stable a anomer pπor to coupling, which will give the α-glucuronide, can be problematic Compound 6 was reacted with ozone to give compound 8a Alternativ ely the acetate protecting groups of compound 6 were removed by methanolv sis to giv e compound 7, which was reacted with ozone to give aldehyde 8b Compound 8b underwent reductive amination with doxorubicin to give the prodrug 9b Compound 8a underwent reductive amination with daunorubicin to giv e compound 10a. and the ester groups of compound 10a were saponified to giv e prodrug 10b

In detail, the synthesis is as follows

4-Pentenal diethyl acetal 5

Boron trifluoride diethvl etherate (0 2 mL) was added, with stirring, to a solution of 4-pentenal (Cheπf, A , Farquhar. D N-(5,5-dιacetoxypent-l - yljdoxorubicin A new intensely potent doxorubicin analogue J Med Chem 35 3208-3214 (1992)) (2 5 g. 29 8 mmol) in ethanol ( 150 mL) The mixture was refluxed for 10 min under nitrogen, then the ethanol was removed under reduced pressure The residue vvas taken up in dichloromethane (25 mL), and the solution was washed with 10% sodium acetate solution (15 mL) and water

7/

29

(2 x 10 mL) The organic layers were combined, dried over anhydrous sodium sulfate, and evaporated The residue was chromatographed on a column of silica gel using chloroform/methanol (97 3) as eluent. 4-Pentenal diethyl acetal was obtained as an oil (4.5 g, 96%). 1H NMR (CDC1 ₃ ) δ 5 88-5 61 (m, 1 H _, 5 H4), 5 03-4 87 (m, 2 H, H5), 4.38 (t, 1 H, J=7, HI), 3 30-3 61 (m, 4 H, 2 x CH ₂ ), 2.07- 1 96 (m, 2 H, H2), 1.64-1.53 (m. 2 H, H3), 1 09 (t, 6 H, J=7 _, 2 x CH ₃ )

Methyl I-0-[(l "RSJ-1 "-ethoxypent-4"-enyl]-2, 3, 4-tri-O-acetyl-^-D- 10 glucopyranuronate 6

Trimethylsilyl trifluoromethanesulfonate (0 2 mL of a 0 1 M solution in chloroform. 0 02 mmol) was added, with stirring, to a solution of 5 (100 mg, 0 63 mmol) and methyl 2,3,4-tri-O-acetyl- l -O-tπmethylsιlyl-β-D-

15 glucopyranuronate 4 (L F. Tietze and R Seele, Stereoselective synthesis of 1 - O-trimethylsilyl α- and β-D-glucopyranuronate Carbohydrate Res 148, 349- 352 ( 1986)) (90 5 mg, 0 22 mmol) in dry dichloromethane (3 mL) at -70 °C under a dry nitrogen atmosphere The mixture was kept at -70 °C for 2 days, then triethylamine (0 I mL) was added to quench the reaction The solvent was

20 evaporated, and the residue was taken up in chloroform ( 10 mL) and washed with saturated sodium bicarbonate (10 mL) and sodium chloride ( 10 mL) The organic extract was dried (MgSO ₄ ) and evaporated, and the residual solid was chromatographed on a column of silica (25 cm x 2 cm ) using a stepwise gradient of hexane-ethyl acetate ( 10 0, 20 mL. 7 3, 100 mL, 6 4, 100 mL, 5 5 _,

25 150 mL) The eluted fractions were monitored by TLC using iodine vapor to visualize the products The title compound was obtained as a solid 1H NMR (CDC1 ₃ ) δ 5 63-5 86 (m, 1 H, H4"), 5 24-5 18 (m. 2 H, H3,4), 5 05-4 99 (m, 1 H, H2), 4 96-4 89 (m, 2 H, H5"), 4.83-4 74 (m, 1 5 H. HI (S), HI (R), H I " (5)), 4 65 (t, 0 5 H, J=6 0, H I " (/?)), 4.02-3 97 (m. 1 H, H5), 3 71 (s, 3 H, CO ₂ Me),

30 3 68-3 43 (m, 2 H, CH ₂ ), 1 99, 1 98, 1 96 (3 s, 9 H, 3 Ac), 1.74- 1 67 (m, 2 H _,

H3 "), 2 09-2 01 (m, 2 H, H2"), 1 15 (t. 3 H, J=7, CH ₃ ), MS (FAB) m/z 447 (M + H) ^T .

Methyl l-0-[(l "RS)-1 "-ethoxypent-4 ^" -enyl]-$-D-glucopyranuronate 7

5

Compound 6 (72 mg, 0 167 mmol) was dissolved in dry methanol (2 mL). and 0 4 mL of a solution of sodium methoxide (42 mg, 0 78 mmol) in methanol ( 10 ml) was added The reaction mixture was maintained at ambient temperature for 3 h, then evaporated under reduced pressure The residue was

10 purified on a thick layer of silica to giv e the title compound, 7, as a white solid 1H NMR δ 5 88-5 74 (m, 1 H, H4"). 5 07-4 90 (m, 2 H. H5"), 4 8 1 (t, 0.5 H, J=6 0, H I , (S)), 4 70 (t. 0 5 H, J=6 0. H I . (R)), 4 60 (d. 0 5 H, J=7 5, H i ", (S)), 4 53 (d. 0 5 H, J=7 5, H I ", (R)). 3 84 ( s 3 H, CO _; Me). 3 91 -3 47 (m. 6 H, H2, H3. H4, H5, OCH ₂ CH-J. 2 13-2 05 (m. 2 H. H2"), 1 79-1 70 (m, 2 H, H3"),

15 1 19 (t. 3 H, CH ₃ )

Methy I J-O-ffl "RSJ- 1 "-ethoxy -4"~axohuty 1-2.3, 4-tri-O-atery !-β-D-g htcopyranuronate 8a

2 ₀ A solution of compound 6 (79 6 mg. 0 185 mmol) in dichloromethane (5 mL) was placed in a cylindrical gas absorption vessel w ith an inlet dispersion tube extending to the base. The vessel was cooled to -70 °C in a dry ice/acetone mixture, and ozone was introduced Ozomzation vvas continued until the reaction w as complete (until the mixture turned blue as a result of formation of

25 the ozonide, approximately 20 min) Dimethyl sulfide (54 μL, 0 74 mmol, 4 equiv) vv as added, and the mixture was stirred overnight to reduce the ozonide to the corresponding aldehyde The excess dimethyl sulfide vvas evaporated, and the residue was chromatographed on a column of silica (23 cm x 2 cm) using a stepwise gradient of hexane-ethyl acetate ( 10 0. 50 mL, 7 3, 150 mL;

30 6 4. 100 mL) 100 fractions of approx 3 mL each were collected The major

product (fractions 62-67) was identified by NMR as the title compound ^l H NMR (CDCI ₃ ) δ 9 72 (s, 1 H, CHO), 5.25-5 18 (m, 2 H, H3,4), 5 09-5 01 (m, I H, H2), 4 85-4.75 (m, 2 H, HI (R,S), HI " (R,S)), 4 02-3 97 (m, 1 H, H5), 3 73 (s, 3 H, CO ₂ Me), 3 65-3.39 (ra, 2 H, CH ₂ ), 2 57-2 5 1 (m, 2 H, H3 "), 1 98- 1 92 5 (m, 2 H, H2"), 2.03, 2 02, 2.00 (3 s, 9 H, 3 Ac), 1 16 (t, 3 H, J=7, CH ₃ )

Methyl l-0-[(l "RSJ-1 "-ethoxy-4"-oxobutyl]-$-D-ghtcopyτωmrυ,ιate 8b

A solution of compound 7 (56 3 mg , 0 185 mmol) in dichloromethane 10 ( 15 mL) was ozonized for 20 minutes, as described for 8a The intermediate ozonide was reduced with dimethyl sulfide (54 μL, 0 74 mmol, 4 equiv) The product was purified by preparative chromatograpy on silica

A ^' -f(4"RS)-4"-Ethoxy-4"-(methy/ 2 ', 3 \ 4 -tn-O-acetyl-β-D-

15 glucopyranuronyloxy)butylf doxorubicin hydrochloride 9a

A solution of sodium cyanoborohydride ( 1 M m tetrahydrofuran, 1 1 3 μL ^, 0 01 13 mmc') was added to a stirred solution of doxorubicin hydrochlonde ( 10 mg, 0 017 mmol) and compound 8a ( 15 mg, 0 035 mmol) in acetonitrile-

20 water (2 1 ) (5 mL). The mixture was stirred under a nitrogen atmosphere at room temperature in the dark for 1 h When reaction was complete (as evidenced by TLC of a 5 μL aliquot), the solution was diluted with water (8 mL), and extracted repeatedly (10 x 10 mL) with chloroform- methanol (5 1 ) The combined extracts were dried and ev aporated to give a red amorphous solid

25 which was purified by preparative TLC (chloroform-mefhanol, 10 1 ) The yield was 8 2 mg (5 1%) The product was suspended in water ( 1 mL) _, and acidified to pH 5 by dropwise addition of 0 05 N hydrochloric acid The solution was lyophilized to afford the title compound which was stored under nitrogen in a tightly stoppered vessel at -78 °C in the dark ^] H NMR. (CDCI ₃ ) (free base) δ 3 ⁰ 7 90 (m, 1 H, H I ), 7 71 (t, J=8, 1 H, H2). 7.34 (m, 1 H, H3), 5 53-5 10 (m, 5 H _,

H7, HI ", H2"", H3 , H4 ). 4 87-4 30 (m 4 H, H4" (R,S), HI (R,S),

H14), 4 05-3 90 (m, 1 H, H5 ), 4 02 (s. 3 H 4-CH ₃ ), 3 75-3 36 (m, 4 H, H4",

H5", OCH ₂ CH ₃ ), 3 71 (s, 3 H, C0 _; Me), 3 25-2 50 (m, 5 H, HlOa, HlOb, H3", HI "), 2 4-2 2 (m, 2 H, H8a. H8b), 2 04-2 02 (3 s, 9 H, 3 Ac), 2 0-1 5 (m, 6 H, 5 H2", H3", H2"a, H2"b), 1 36 (d J=6 3 H, H6"), 1 13-1 05 (m, 3 H, OCH ₂ CH ₃ )

N-[(4 "RSj-4 "-Ethoxy -4 "-(me thy I $-D-glιιcopy ramιronylυxy)butyl]doxorubιcιn hydrochlonde 9b

0 1 M sodium cv anoborohv dπde (20 uL 0 02 mmol) was added to a solution of compound 8b ( 12 mg 0 039 mmol) and doxorubicin hydrochlonde (22 mg, 0 038 mmol) in acetonitπle-water (2 1 ) (5 mL) under nitrogen The mixture was stirred at room temperature in the dark for 2 h When reaction was complete [as ev idenced bv TLC of a 5 μL aliquot using chloroform-methanol 5 (9 2) as eluent or HPLC on a C- l S column using 0 05 M ammonium acetate- acetonitπle (6 4) as mobile phase], the solution vvas diluted with water (8 mL), and then extracted repeatedly ( 10 x 10 mL) w ith chloroform- methanol (5 1) The combined extracts were dried and ev aporated to give a red amorphous solid Preparative TLC of this solid (chloroform-methanol, 7 3) afforded three bands 0 The fastest moving band vvas shown by NMR and MS to be the desired product Yield 16 8 mg (53%) The compound was suspended in water ( 1 mL), and acidified to pH 5 by dropwise addition of 0 05 N hydrochloric acid The solution was lyophilized to afford the title compound Η NMR (CD ₃ OD) (free base) δ 7 86 (m 1 H H I ), 7 82 (t 1 H H2) 7 57 (m, 1 H, H3), 5 49-5 44 (m, 1 5 H, HI "), 5 07-5 03 (m 1 H, H7). 4 9-4 2 (m, 4 H, H4" (R,S), HI (R,S)

H 14). 4 03 (s, 3 H 4-CH ₃ ) 3 85-3 65 (m 7 H, H2 , H3 , H4 , H5"" ,

CO _: Me). 3 65-3 15 (m, 4 H H4", H5", OCH ₂ CH ₃ ), 3 15-2 55 (m, 5 H, H l Oa. H l Ob _, H3", H I "), 2 4- 1 9 ι,m 6 H, H8a, H8b, H2"a, H2"b, H3"), 1 8- 1 6 (m. 2 H, H2"), 1 30 (d, J=6 3 H, H6") 1 1 S- 1 08 (m 3 H, OCH ₂ CH ₃ ) MS (F.AB) m z

30 850 (M + H) ⁺ .

N-[(4"RS)-4"-Ethoxy-4"-(methyl 2 ', 3""",4' -tri-O-acetyl-p-D- glucopyranuronyloxyjbutyljdaunorubicin hydrochloride 1 Oa

5 A solution of sodium cyanoborohydride (1 M in tetrahydrofuran, 1 1 3 μL, 0 01 13 mmol) was added to a stirred solution of daunomycin hydrochloride (9 6 mg, 0 017 mmol) and compound 8a ( 15 mg, 0 035 mmol) in acetonitrile- water (2 1) (5 mL) The mixture was stirred under a nitrogen atmosphere at room temperature in the dark for 1 h. When reaction was complete, the solution

10 was diluted with water (8 mL), and extracted repeatedly ( 10 x 10 mL) with chloroform-methanol (5 1) The μ oduct was purified bv thick layer chromatography using chloroform-methanol (9 1 ) as eluent Yield, 9 0 mg (55%) 1H NMR (CDC1 ₃ ) (free base) δ 8 92 (d, 1 H, J=8. HI ), 7 76 (t. J=8. 1 H, H2), 7 37 (d, 1 H, J=8, H3), 5 53 (br s, 1 H, HI "), 5 35-4 93 (m, 4 H, H2"",

15 H3 , H4 , H7), 4 82-4 40 (m, 2 H, H4" (R.S), H I (R,S)), 4 20-4 0 (m, 1

H, H5 ), 4 03 (s, 3 H, 4-CH ₃ ), 3 8-3 3 (m, 4 H, H4", H5", OCH ₂ CH ₃ ), 3 69

(s, 3 H, CO ₂ Me), 3 3-2 6 (m, 5 H, HlOa, Hl Ob, H3 ", H I "), 2 40 (s, 3 H, 14- CH ₃ ), 2 00- 1 9S (3 s, 9 H, 3 Ac), 2 5-1 9 (m, 4 H, HSa. H8b, H3 "), 1 9- 1 5 (m, 4 H. H2", H2"a. H2"b), 1 32 (d, J=6, 3 H. H6"), 1 19-1 09 (m, 3 H, OCH ₂ CH ₃ )

20

N-[(4 "RS)-4 "-Ethoxy-4 "-(Q-D-glucopyraniironyloxyjbitty 1] daunorubicin (Sodium salt) 10b

0 1 N NaOH solution (2 0 mL) was added to a solution of compound 25 10a (8 mg, 8 0 μmol) in methanol (2 0 mL) The reaction mixture was maintained for 1 h at ambient temperature It vvas then added to a column of Amberhte IRC-50 CP cation exchange resin in the H ⁺ form (500 mg, 1 1 3 meq/g) The column was washed with water and the eluent was collected in a flask containing 0 1 M triethylammonium acetate (3 mL, pH 7) that was 30 maintained at 0 °C After all the colored material had eluted, the contents of the

flask were frozen and lyophilized The residual red powder was taken up in water, and the solution was applied to a column of weakly basic cation exchange resin (Biorex 70-Na ⁺ , 235 mg) The product was eluted with water The eluent was frozen and lyophilized to afford the title compound which was characterized by mass spectrometπ. Yield, 4 5 mg (67%) MS (FAB, glycerol) nXz 886 [M - 2H - 3Na] ^~ . 864 [\1 - H + 2Naf, 842 [M + Na] ⁺ , 820 [M + H] ⁺

Example 3: Synthesis of Glucuronide Prodrugs of the Invention.

The compounds referred to in this sy nthesis are shown in Figure 7 The numbered intermediates of the Figure are cross-referenced in the text below in bold

Acetal 6 w as prepared in two unexceptional steps from alcohol 4, and was reacted with si IN 1 gh co≤ide 3 to give compound 7 using the method described bv Tietze. et al (Cai bolndrate Res , Vol 180 ( 1988), 253-262) Alkenes such as 7 can be reacted w ith anthracyclines such as 10 to form the prodrugs following published procedures inv olv ing ozonolvsis, reductive amination. and deacety lation ( A Cheπf, D Farquhar J Med Chem , Vol 3 S ( 1992), 3208-3214) The glucuronv l hydroxyls were deprotected before ozonolvsis and reductiv e amination methanolysis using catalytic NaOMe gave alkene 8 in good yield Reductiv e alkylation of the amino group of 10 by aldehyde 9 (obtained by ozonolv sis of alkene 8) using NaBH ₄ or NaBH ₃ CN as a reducing agent giv es the prodrug 11 Finally, mild enzvmatic hv drolysis of the me _t hvl es _t er of compound 1 1 affords prodrug 12 Deesteπfication can be carried out in vitro, and compound 12 should be stored as the salt of the acid, the acid form is expected to undergo autocatalyzed decomposition Al _t ernativ elv _, compound 1 1 can be used as a pre-prodrug and esterase- catalyzed hydrolysis will occur in v ivo

9007

35

In detail, the synthesis is as follows

6, 6-Dιmethoxy- 1-hexene 6

A solution of 5-hexen-l-ol 4 (5 0 g, 50 mmol) in 25 mL of CH ₇ C1 ₂ was added dropwise to a rapidly stirred suspension of PCC (21 5 g, 100 mmol) in 200 mL of CH ₂ C1 ₂ cooled by an ice bath. After the addition was complete, the mixture was allowed to warm to room temperature After 3 h, approximately 20 g of silica gel was added to the dark, tarry mixture, and then the mixture was diluted with 200 mL of ether Then, the mixture was filtered through a pad of silica gel, eluting with an additional 400 mL of ether The solvents were removed by distillation to leave 5 7 g of a pale yellow liquid, which contained residual ether, CH ₂ C1 ₂ , 5-hexenyl 5-hexenoate as well as 5-hexenal, compound 5 1H NMR (CDC1 ₃ ) 6 1 69- 1 79 (m, 2, CH ₂ CH ₂ CH ₂ ), 2 04-2 14 (m, 2, CH ₂ CH=CH ₂ ), 2 45 (dt, 2, J=l 6, 7 3, CH ₂ CHO), 4 97-5 06 (m, 2, CH=CH ₂ ), 5 77 (dddd, 1, J=6 7, 6 7, 10.2, 17 0, CH=CH ₂ ), 9 77 (t, 1, J=l 6, CHO), ¹³ C NMR (CDCl ₃ ) δ 21 15, 32 92, 43 07, 1 15 53, 137 52, 202 46

The above oxidation can also be carried out using N-methvlmorpholine N-oxide (NMO) and catalytic tetrapropylammonium perruthenate (TPAP) in CH ₂ C1 ₂ . moderating the vigorous reaction by cooling with an ice bath

The crude product containing compound 5 was taken up in 30 mL of MeOH, and camphorsulfonic acid (596 mg, 2.5 mmol) and trimethyl orthoformate (5 46 mL, 50 mmol) were added The mixture was heated at reflux for 3 h, then allowed to stand at room temperature overnight The acid was neutralized by the addition of 0 70 mL of triethylamine, and most of the solvent vvas removed by distillation The residue was partitioned between water and hexane, the hexane layer was dried over anhydrous Na ₂ SO ₄ , and the solution was filtered through a 3 in column of silica gel, eluting vvith additional

hexane The solvent was removed bv distillation to leave 5 0 g of the product, compound 6, as a colorless liquid Η NMR (CDC1 ₃ ) δ 1 39-1 49 (m, 2), 1 58- 1 65 (m, 2), 2.03-2 1 1 (m, 2), 3 3 1 (s. 6, CH(OCH ₃ ) ₂ ), 4.37 (t, 1, J=5 7, CH(OCH ₃ ) ₂ ), 4 93-5 05 (m, 2, CH=CH ₂ ), 5 80 (dddd, 1, J=6 6, 6 6, 10 3, 16 9, CH=CH ₂ ), ¹³ C NMR (CDC1 ₃ ) δ 23 79, 3 1 83, 33 42, 52 49, 104 33, 1 14 64, 138 38

Methyl 2, 3, 4-tri-0-acetyl-l-0- ⁽ R,S-l-methoxy-5-hexenyl)-$-D-glucuronate 7

A O l M solution of trimethv Isilyl trifluoromethanesulfonate in CH ₂ CU

(0 1 equiv ) was added to a mixture of crude silyl ether 3 (1 equiv , see Example 1 for its preparation) and l, l -dιmethoxy-5-hexene 6 ( 1 equiv ) in CH ₂ C1 ₂ (0 1 M) cooled to -78 °C After three dav s. the trimethylsilyl trifluoromethanesulfonate was neutralized by adding triethylamine ( 1 equiv ), one volume of ether was added, the solution vvas warmed to room temperature, filtered through a pad of silica gel with ether, and the filtrate vvas concentrated in vacuo Purification by flash chromatography (2% tnethylamine in 30-40- 70% ethvl acetate 'hexane) resulted in the elution of, in order, recovered alkene, α-silyl glucuronide. desilylated glucuronate, and the product 6 as a 2 5 1 mixture of diastereoisomers >H NMR (CDC1 ₃ ) δ 1 26- 1 37 (m, 2), 1 45- 1 57 (m, 2), 1 87-2 00 (m, 1 1), 3 16 (s. 3, CHOCH. ₃ of major isomer), 3 24 (s, 3, CHOCH ₃ of minor isomer), 3 60 (s. 3. COOCH ₃ of minor isomer), 3 60 (s, 3, COOCH ₃ of major isomer), 3 96 (d. 1. J=9 4, H5), 4 45 (t, 1 , J=5 5, CHOCH ₃ of minor isomer). 4 65 (t, 1, J=5 5. CHOCH ₃ of major isomer), 4 65-4 67 (H I of minor isomer partially obscured). 4 74 (d, 1 , J=7 8, H I of major isomer),

4 78-4 83 (m, 2. CH=CH ₂ ), 4 86-4 92 (m. 1 , H2), 5 03-5 10 (m, 1, H4). 5 10-

517 (m, 1, H3).563 (dddd.1. J=30.99, 140, 168, CH=CH _; ), ^1: T NMR (CDCl-0 δ 2015.229S.2320.3215.3291, 3299, 3360.5174, 5232.5448, 6912, 7097, 7209.9612, 10212.10528, 11441, 13800, 16673.16682, 16863, 16891, 16962

Methyl l-0-(R,S-l-melhoxy-5-hexenyl)-$-D-glucιtronate 8

To a solution of triacetate 7 (474 mg, 1.06 mmol) in 10 mL of MeOH was added 25 wt % NaOMe in MeOH (0 03 mL) After 1 h, excess ammonium acetate was added to neutralize the mixture The volatile components were evaporated in vacuo, and the residue was purified by flash chromatography (2% triethylamine in ethyl acetate) to give 304 mg of the product as a colorless oil (89%) R _f O 28 (2% triethylamine/ethy! acetate), ^l H NMR (CDC1 ₃ ) δ 1 39- 1 59 (m, 2, H3') 1 61 -1 68 (m, 2, H2'), 2 00-2 07 (m, 2. H4'), 3 23-3 28 (m, 1 , H2) _, 3 34-3 42 (m, 1, H3), 3 37 (s, 3, CHOCH ₃ of major isomer), 3 38 (s, 3,

CHOCH ₃ of minor isomer), 3 50-3 57 (m, 1, H4). 3 75 (s, 3, COOCH ₃ of minor isomer), 3 76 (s, 3, COOCH ₃ of major isomer), 3 83 (d. 1 , J=9 7, H5 of minor isomer), 3 84 (d, 1, J=9 7, H5 of major isomer), 4 46 (d, 1 , J=7 8, HI of minor isomer). 4 56 (d. 1 , J=7 8, HI of major isomer), 4 56-4 60 (m, 1. CHOCH ₃ of minor isomer), 4 72 (t, 1 , J=5 6, CHOCH ₃ of major isomer), 4 90-5 01 (m. 2, CH=CH ₂ ). 5 78 (dddd, 1, J=6 7, 6 7, 10 2, 16 9, CH=CH ₂ ), ¹³ C NMR (CDC1 ₃ ) δ 24 59 (C3' major), 24 75 (C3' minor), 34 44 (C4 ¹ major), 34 56 (C2 ¹ ma _j or, C4' minor). 35 36 (C2 ¹ minor), 52 78 (COOCH ₃ ). 53 48 (CHOCH ₃ ma _j or). 55 72 (CHOC _. H ₃ minor), 73 06 (C4), 74 71 (C2 minor), 74 76 (C2 ma _j or). 76 74 (C5). 77 34 (C3 major), 77 39 (C3 minor), 100 82 (C l minor), 101 73 (C l major). 104 49 (Cl' major), 106 99 (C L minor), 1 15 02 (C6'), 139 75 (C5')_ 171 1 1 (COOCH ₃ )

Methyl 1-0-/R, S-l-methoxy-5-oxopenty!)-$-D-ghιcuronate 9

Ozone was bubbled through a solution of alkene 8 (45 mg) in 20 mL of MeOH cooled by a dry ice/acetone bath until a persistent blue color was observed Excess ozone was purged by bubbling nitrogen through the mixαire, and 3 mL of dimethyl sulfide was added to the mixture After 5 h, the volatile components were evaporated in vacuo Examination of the residue by ^[ K NMR

indicated that the vinyl protons were absent, but no aldehydic protons were observed The residue was taken up in 10 mL of 1 1 ethyl acetate and and 100 mg of anhydrous Na ₂ S0 ₄ and 2 mL of dimethyl sulfide were added After standing at room temperature for 3 days, the mixture was filtered through 5 a pad of silica gel, eluting further with ethyl acetate The volatile components were evaporated in vacuo, and examination of the ^l H NλDΛ spectrum indicated the presence of the aldehydic protons Partial Η NMR (CDC1 ₃ ) d 1.61-1 71 (m _. 4, CH ₂ CH ₂ CH ₂ CHO), 2.41 (CH _; CHO of major isomer), 2 56 (CH ₂ CHO of minor isomer), 3 38 (s, 3, CHOCH; of major isomer), 3 45-3 50 (m, 1, H2),

10 3 58-3 64 (m, 1 , H3), 3 71 -3 77 (m 1. H4), 3 79 (s, 3, COOCH ₃ of minor isomer), 3 80 (s, 3, COOCH-, of major isomer), 3 90 (d, 1 , J=9 6, H5), 4 52 (d. 1, J=7 8, HI of minor isomer). 4 60 (d. 1, J=7 7, HI of major isomer), 4 75 (bs. 1, CHOCH ₃ of major isomer). 9 74 (s. 1, CH=0 of major isomer), 9 77 (s, 1 , CH=0 of minor isomer)

15

Reductive alkylation of doxorubicin 10 by aldehyde 9

Solid NaBH ₄ (0 7 equiv ) is added to a 0 01 M solution of doxorubicin hydrochloride 10 in 2 1 MeOHH _: 0 containing aldehyde 9 (2 equiv ) The 0 mixture is stirred in the dark under argon at room temperature until the starting material is consumed as observed by TLC The solution is diluted with 1 5 volumes of H ₂ O and extracted repeatedly vvith 5 1 CHCl ₃ /MeOH The organic phases are dried over anhydrous Na _: S0 ₄ and concentrated in vacuo The product, compound 11, is purified by reverse phase HPLC ( 125 mM Et ₃ N- 5 HOAc in H-iO (pH 7)/MeOH), repeated lyophilization to remove excess buffer salts, and ion exchange on DE.AE-Sepharose (HCl form)

Hydrolysis of compoimd 11 to give compound 12

Pig liver esterase (130 U) is added to a 0 1 M solution of ester 11 in 0 1 M sodium phosphate buffer (pH 7 5) at 33 °C After 5 h, the mixture is filtered through a membrane filter, and the product 12 is purified from the filtrate chromatographically

Example 4: Prodrug Enzyme Activation.

Enzymes. β-Glucuronidase (E Coli) (EC 3 2 1 31) vvas purchased from Sigma Chemical Co , St Louis, MO and was used as received The specific activity of the preparation vvas 16,000 units/mg protein where 1 unit is defined as the amount of enzyme that will liberate 1 0 ug of phenolphthalein from phenolphthalein β-glucuronide per hour at pH 6 8 and 37°C

Stability Studies of N-[(4"RS)-4"-Ethoxy-4"-(B-D- glucυpyranuronglυxy) butyl] daunorubicin (sodium salt) 10b in the presence of β-glucuronidase. The title compound (in the form of its sodium salt) ( 16 8 ug, 0 02 μmol) was dissolved in 0 05 M potassium phosphate buffer, pH 7 4 (200 μL) contained in a 2 0-mL glass vial (final drug concentration 10 ^"4 M) The solution was incubated at 37°C for 50 h At selected time intervals ( 1 , 4, 8, 12, 24, 30, and 50 h) aliquots ( 10 μL) were withdrawn and analyzed for parent drug by HPLC on a C-18 reverse-phase column (Waters Associates, Milford, MA, μ-Bondapak C-18, 200 x 4 6 mm i d ) A solution of CH ₃ CN-0 05M acetate buffer, pH 4 0 (2 3, v/v), at a flow rate of 1 0 mL/min, was used as mobile phase (retention time = 3 91 min)

For the enzyme studies, 10b (33 6 μg, 0 04 μmol) and sodium cyanide (9 8 μg. 0 2 μmol) were dissolved in 0 05 M potassium phosphate buffer, pH 7 4 (380 μL) contained in a 2 0-mL glass vial (final drug concentration 10' ⁴ M) The reaction was initiated by the addition of 28 units of β-glucuronidase (2 2 units of enzyme per μmole of substrate) in the same buffer (20 μL) At

intervals of 0 25, 0 5, 2, 5, 8. 24 and 32 h, aliquots (20 μL) of the mixture were withdrawn and added to 4 volumes of MeOH contained in 1 5-mL centrifuge tubes The tubes were agitated on a Vortex shaker for 20 s and then centrifuged for 4 min at 1000 rpm Aliquots (25 μL) of the clear supernatant were analyzed by HPLC as described above The peak corresponding to the parent compound gradually disappeared and vvas replaced by two peaks with retention times of 6 58 and 7 08, respectively The experiment was repeated in the presence of 10 units and 20 units of the enzv me per μmol of substrate The half-lives for the disappearance of 10b, determined by linear least-square regression analysis of the pseudo first-order reactions were

2-fold enzyme excess 8 1 h. 10-fold enzyme excess, 6 9 h, 20-fold enzyme excess, 2 0 h

Growth Inhibition Studies Six cell lines A-375 (human melanoma), LS 174T (colon carcinoma), ME 180 (cerv ical carcinoma), SK-OY-3 (ovarian carcinoma), and BT-474 (breast carcinoma) were routinely grown in Hank's Minimal Essential Medium (MEM. Gibco Inc ) containing 10 % fetal bovine serum albumin (Atlanta Biologies ) Cells were passaged weekly by trypsinization (Gibco) followed bv plating at reduced density (50,000 cells/ml) They were routinely tested and found to be free of mycoplasma contamination Cells were harvested by trypsinization and plated in 96 well plates at a density of 5,000 per well in 100 μl of MΞM culture media Cells were allowed to adhere by incubation for 24 hr at 37°C in humidified 5% C0 ₂ The wells containing log-phase cells w ere treated with complete MEM containing serial dilutions daunorubicin (sodium salt) 10b at concentrations ranging from 10 ^"5 to 10 ^{" 14} M Each well also contained a 50-fold unit excess of β-glucuronidase (1 e , 50 units of enzyme per μmole of substrate) Control actions were run with 10b in the absence of β-glucuronidase. daunomyαn alone, and daunomycin in the presence β-glucuronidase The cells were then incubated for a further 72 hr at

9007

41

37°C in a humidified CO? incubator The wells were emptied and the remaining cells were stained by the addition of 100 μl of 0 5% Crystal Violet (Fischer Scientific) in 20% methanol (Fischer Scientific) After incubation for 20 min, the dye was removed, and the wells were washed were with deionized water Cell-bound dye was solubilized with Sorenson's Buffer (0 1 M sodium citrate, pH 4 2-ethaπol, 1.1 , v/v) and the wells were read on an ELISA microplate autoreader at 540 nm Dose-response curves were constructed and the IC ₅₀ values (the drug concentrations that inhibited cell growth by 50%) determined

With the A375 cell line the IC50 for the glucuronide was 2x 10 ^~7 g ml In the presence of glucuronidase, the IC50 was 2x 10 ^" ' ' g ml demonstrating the potency of these compounds as prodrugs on specific activation

Example 5: Endogenous Enzyme Activation of Prodrugs in Animal Models.

The studies in animals followed protocols similar to those seen with the cell lines used for in vivo studies are colon carcinoma cell lines LS 174T (ATCC

CL 18S), Colo 205 (ATCC CCL 222), Lovo (ATCC CCL 229), Cx i , Mx l, B 16, CU38, and H Tumor cells were implanted as sub-cutaneous injection of 3X10 ⁶ for LS 174T and allowed to grow to desired size typically a tumor volume of 20- 100 mm (L X W ² /2) in about 4-8 days from sub-cutaneous injection of the tumor cell lines into the nude mice (NCr nude mice female 6-9 week, Taconic Farms Inc or Jackson Labs) The Cxi, and Mxl tumors were transplanted bv insertion of l- 10mm ³ subcutaneously The mouse tumors LL (lewis lung) and Cu38 colon C-38 were carried in BDF1 mice The tumor volumes were calculated based on caliper measurements In any given study there are 10 animals in the control group and 5-10 in the treatment groups Animals were treated with prodrug in the range of 0 5-50 mg/kg/day w ith treatment schedules from 3 to 12 days of consecutive IV treatments

α Tumor size was monitored also at 2-4 day intervals In a parallel set of animals, the pH of the tumor was also modified by the use of IP injections of D-glucose (4 5mg/g) and Na HCO ₃ (0 33 mg/g) these were then dosed with prodrug after 40 mm with 0 5-50 mg/kg/day This cycle of glucose/NaHCO ₃ followed by prodrug would be repeated daily for 3- 12 days of treatment as in the prodrug only group

The animals in the studv after final prodrug treatment were monitored for up to 60 days The results demonstrated significant reduction of tumor growth for treated animals At the end of the experiment the tumor mass was also measured by excision of the tumor mass

Example 6: Exogenous Enzy me Activ ation of Prodrugs in Animal Models.

The studies in animals basically followed those of Meyer DL et al (Cancer Res 1993 53 3956-3963) The cell lines used for the in vivo studies were colon carcinoma cell lines LS P4T (ATCC CL 188), Colo 205 (ATCC CCL 2221 and Lov o (ATCC CCL 229) Tumor cells were implanted as sub- cutaneous injection of 3X10 ⁶ for LS I 74T and allowed to grow to the desired size typically a tumor volume of 20-100 mm ³ (L X W/2) in about 4-8 days from sub-cutaneous injection of the tumor cell lines into the nude mice (NCr nude mice female 6-9 week, Taconic Farms Inc or Jackson Labs) The tumor volumes w ere calculated based on caliper measurements In any given study, there were 10 animals in the control group, and 5- 10 in the treatment group Animals were treated enzyme doses at 35-500 μg per mouse some with repeated doses of up to three separate treatments Typically , enzv me vvas dosed at day 4- 81 with a time interv al of 4-12 day s between the enzyme doses The prodrug treatment was normally applied at 3- 10 dav s after the enzyme injection Prodrug doses were in the range of 0 5-50 mg/kg/day

Tumor size was monitored also at 2-4 day intervals In a parallel set of animals, the pH of the tumor was also modified by the use of IP injections of D- glucose (4 5 mg/g) and Na HCO ₃ (0 33 mg/g) these were then dosed with prodrug after 40 min with 0 5-50 mg/kg/day This cycle of glucose/NaHCO ₃ followed by prodrug was repeated daily for 3-10 days of treatment The animals in the study were monitored for up to 60 days at 7 day intervals

The results demonstrated significant reduction of tumor growth for animals treated with the enzyme followed by prodrug both with pH modulation by the glucose infusion protocol At the end of the experiment the tumor mass was also measured by excision of the tumor mass

Example 7: Targeted Antibody-Enzyme Activation of Prodrugs in Animal Models.

The studies in animals basically followed those of Meyer DL et al (Cancer Res 1993 53, 3956-3963) The cell lines used for in vivo studies were colon carcinoma cell lines LS 174T (ATCC CL 188), Colo 205 (ATCC CCL 222) and Lovo (ATCC CCL 229) Tumor cells were implanted by sub- cutaneous injection of 3X10 ⁶ for LS 174T and allowed to grow to the desired size, typically, a tumor volume of 20-100 mm (L X W ² /2) in about 4-8 days from sub-cutaneous injection of the tumor cell lines into the nude mice (NCr nude mice female 6-9 week, Taconic Farms Inc or Jackson Labs ) The tumor volumes were calculated based on caliper measurements In any given study 10 animals were the control group, and 5 in treatment group Animals were treated with specific (anti-TAG-72, anti CEA antibody fusions) and also non-specific (anti NP antibody fusion) at various time points with antibody-enzyme doses at 35-280 μg per mouse some with repeated doses up to three separate treatments Typically, antibody was dosed at day 4-81, with a time interval of 4-12 days between the antibody doses The prodrug treatment vvas normally applied at 3-

10 days after the antibody injection Prodrug doses were in the range of 0 5-50 mg/kg/day

Tumor size was monitored also at 2 day intervals In a parallel set of animals the pH of the tumor w as also modified by the use of IP injections of D- glucose (4 5 mg/g) and Na HCOXO 33 mg/g) these were then dosed with prodrug after 40 min vvith 0 5-50 mg/kg/day This cycle of glucose/NaHCO ₃ followed by prodrug was repeated daily for 3-10 days of treatment

The animals in the study were monitored for up to 60 days at 7 day intervals The results demonstrated significant reduction of tumor growth for animals treated with the specific antibody followed by prodrug both with and without pH modulation by the glucose infusion protocol At the end of the experiment the tumor mass w as also measured by excision of the tumor mass

The foregoing is intended as illustrative of the present invention but not limiting Numerous variations and modifications may be effected without departing from the true spirit and scope of the invention