The present application claims priority to U.S. Provisional Patent Application Serial No. 62/456,816, filed on February 9, 2017, the contents of which is incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Technical Field This invention relates to the use of highly purified eicosapentaenoic acid as free fatty acids (EPA-FFA) for reducing fecal calprotectin levels and relapses in subjects with ulcerative colitis.

Related Art

Ulcerative colitis (UC) is a chronic inflammatory condition affecting the colon, characterized by alternating periods of activity and remission. ¹ Clinical activity is frequently preceded by a progressive asymptomatic mucosal inflammation. Effective treatment of the pre-clinical condition may prevent clinical relapses and can potentially play a key role in the management of UC.

Fecal calprotectin (FC), a 36-kilodalton calcium- and zinc-binding protein, comprises up to 60% of the total cytosolic protein in granulocytes. It is stable in feces for up to 7 days, correlates well with fecal granulocyte excretion and is a useful marker of mucosal inflammation in inflammatory bowel disease (IBD) patients. ² Specifically, in patients with UC, FC levels higher than 150 μg/g is associated with endoscopic ³ and histological activity ⁴ and can predict clinical relapse ^5"7 .

The long chain dietary n-3 polyunsaturated fatty acids (PUFAs), in particular eicosapentaenoic acid (EPA, the major component of n-3 fish oil), are beneficial in several chronic inflammatory disorders. ⁸ EPA is involved in the regulation of immunological and inflammatory responses. It modulates the composition of cell membranes by displacing n-6 PUFAs, influences lipid raft formation in cell signaling, ⁹ and leads to the production of anti-inflammatory mediators, such as resolvins, defensins and maresins. ⁸

Despite the experimental evidence implying biological plausibility for the role of n-3 PUFAs in inflammatory bowel disease (IBD), the clinical data about the effectiveness of n-3 PUFAs in IBD are still controversial and conflicting, especially in Crohn's disease (CD). ^10"12 Notably, recent epidemiological studies suggest that n-3 PUFAs may protect against the development of UC. ^13-15 but the results are contradictory.

Accordingly, there is a need for a more potent and active omega-3 PUFA which also exhibits greater in vivo stability and purity. Specifically there is the need for the use of an isolated and purified omega-3 PUFA in free fatty acid form that has the ability to reduce levels of fecal calprotectin and relapses in subjects with ulcerative colitis.

SUMMARY OF THE INVENTION The present invention relates to showing the effectiveness of highly purified eicosapentaenoic acid as free-fatty acid (EPA-FFA) in reducing fecal calprotectin levels and preventing recurrence in a group of asymptomatic UC patients at risk of clinical relapse, defined as fecal calprotectin level >150 μ^. Preferably, the eicosapentaenoic acid in the free fatty acid (EPA-FFA) form has a purity of at least 90%, and more preferably at least 95% and most preferred at least 99%.

In one aspect, the present invention provides a method of reducing fecal calprotectin levels and relapses in subjects with ulcerative colitis in a subject by administering to the subject EPA-FFA having a purity of at least 90%, and more preferably at least 95% and most preferred at least 99%, in an amount effective to reduce levels of fecal calprotectin below 150 μg/g and more preferably below 110 ug/g of fecal matter and most preferably a reduction of FC of about 100 μg/g or greater over a six month period. Importantly the present invention has shown a reduction of at least 100 μg/g of FC over a six month period of administering highly purified EPA-FFA as shown in the results. The purified EPA-FFA can be administered with or without a pharmaceutically acceptable carrier.

In another aspect, the present provides a method of reducing fecal calprotectin levels and relapses in subjects with ulcerative colitis in a subject by administering to the subject EPA-FFA having a purity of at least 90%, and more preferably at least 95% and most preferred at least 99%, in a therapeutic amount effective to reduce levels of fecal calprotectin below 150 μg/g and more preferably below 110 ug/g and most preferably below 85 ug/g of fecal matter over a six month period alone or in combination with another therapeutic agent used to treat UC. The therapeutic agent that may be combined with the EPA-FFA may include aminosalicylates (5-ASA), such as, sulfasalazine, mesalamine, olsalazine, and balsalazide; corticosteroids, such as, prednisone, methylprednisolone and budesonide; immunomodulators; antibiotics such as, metronidazole, ampicillin, ciprofloxacin, and etc.; and biologic therapies such as antibodies.

In yet another aspect, the present invention provides for a composition comprising EPA-FFA having a purity of at least 90%, and more preferably at least 95% and most preferred at least 99%, in a therapeutic amount effective to reduce levels of fecal calprotectin below 150 μg/g and more preferably below 110 ug/g of fecal matter alone or in combination with another therapeutic agent used to treat UC. The therapeutic agent that may be combined with the EPA-FFA may include aminosalicylates (5-ASA), such as, sulfasalazine, mesalamine, olsalazine, and balsalazide; corticosteroids, such as, prednisone, methylprednisolone and budesonide; immunomodulators; antibiotics such as, metronidazole, ampicillin, ciprofloxacin, and etc.; and biologic therapies such as antibodies.

In a still further aspect, the present invention provides for use of a composition comprising EPA-FFA having a purity of at least 90%, and more preferably at least 95% and most preferred at least 99%, in a therapeutic amount effective to reduce levels of fecal calprotectin below 150 μg/g and more preferably below 110 ug/g of fecal matter. Preferably the therapeutic amount is from about 250 mg per day to 4 grams per day and more preferably from about 1000 mg to about 2 g daily. Additionally, the EPA-FFA can be combined with aminosalicylates (5-ASA), such as, sulfasalazine, mesalamine, olsalazine, and balsalazide; corticosteroids, such as, prednisone, methylprednisolone and budesonide; immunomodulators; antibiotics such as, metronidazole, ampicillin, ciprofloxacin, and etc.; and biologic therapies such as antibodies. In another aspect, the present invention provides a method to reduce the amount of Fecal calprotectin (FC) by about 100 μg/g or more over a period of six month period relative to the amount of FC determined in a patient having a level of FC greater than about 150 μg/g to about 200 μg/g before administering highly purified EPA-FFA. The EPA-FFA having a purity of at least 90%, and more preferably at least 95% and most preferred at least 99% and in a therapeutic amount from about 250 mg per day to 4 grams per day and more preferably from about 1000 mg to about 2 g daily.

Still further, the present invention provides for the use of highly purified EPA-FFA to reduce the amount of Fecal calprotectin (FC) by about 100 μg/g or more over a period of six month period relative to the amount of FC determined in a patient having a level of FC greater than about 150 μg/g to about 200 μg/g before administering highly purified EPA-FFA. The EPA-FFA having a purity of at least 90%, and more preferably at least 95% and most preferred at least 99% and in a therapeutic amount from about 250 mg per day to 4 grams per day and more preferably from about 1000 mg to about 2 g daily.

These and other advantages and features of the present invention will be described more fully in a detailed description of the preferred embodiments which follows. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 shows the Trial profile. EPA-FFA=Eicosapentaenoic acid - free fatty acid.

Figure 2 shows the proportion of patients achieving the primary (A) and secondary endpoints (B). CI= confidence interval; EPA-FFA=Eicosapentaenoic acid - free fatty acid; OR=odds ratio.

Figure 3 shows the cumulative 3- and 6-month relapse-free survival rate (Kaplan-Meier method). EPA-FFA=Eicosapentaenoic acid - free fatty acid. Figure 4 shows the median fecal calprotectin levels at baseline, 3 and 6 months according to treatment type. EPA-FFA = Eicosapentaenoic acid - free fatty acid.

DETAILED DESCRIPTION OF THE INVENTION

The prevention of clinical relapse represents the major outcome in the treatment of ulcerative colitis (UC) patients. High fecal calprotectin levels indicate mucosal inflammation and have been shown to predict clinical relapse in many groups of UC patients. Recent epidemiological studies suggest that n-3 polyunsaturated fatty acids protect against the development of UC. Eicosapentaenoic acid, the major component of n-3 fish oil, has shown to have anti-inflammatory properties in chronic inflammatory disorders. The aim of this present invention was to define the effectiveness of highly purified eicosapentaenoic acid as free-fatty acid (EPA-FFA) in reducing fecal calprotectin levels and preventing recurrence in a group of asymptomatic UC patients at risk of clinical relapse, defined as fecal calprotectin level >150 μ^.

It was found, as shown herein, that a placebo-controlled trial of 60 patients with UC treated for 6 months with the administration of highly purified EPA-FFA reduced fecal levels of calprotectin with no serious adverse events. As such, highly purified EPA- FFA is effective in reducing the amount of fecal calprotectin FC in treated patients and such use may also have the ability to test for effectiveness and to identify symptom-free remission in patients with UC using the highly purified EPA-FFA.

The present invention is based on the findings that administration of EPA-FFA is effective in vivo in inhibiting or reducing levels of fecal calprotectin.

Preferably, the EPA-FFA used for making the medical preparations, medicaments or compositions in accordance with the invention is of at least about 90% purity and will contain no more than minimal or pharmaceutically insignificant amounts of any other polyunsaturated fatty acids. A purity of more than 95% is recommended with the highest commercially available grade (about 99% purity), which is substantially free of any other polyunsaturated fatty acids, being the most preferred material. Thus, according to one aspect of the present invention, highly purified eicosapentaenoic acid as a free fatty acid is used to make a medical preparation or medicament for the reduction of fecal calprotectin in a treated subject. EPA may be found in fish oil, plants or microorganisms as free fatty acids or in conjugated forms such as acyl glycerols, phospholipids, sulfolipids or glycolipids, and may be extracted through a variety of means well-known in the art. Such means may include extraction with organic solvents, such as methanol and chloroform, sonication, supercritical fluid extraction using for example carbon dioxide, and physical means such as presses, or combinations thereof. Where desirable, the aqueous layer can be acidified to protonate negatively charged moieties and thereby increase partitioning of desired products into the organic layer. After extraction, the organic solvents can be removed by evaporation under a stream of nitrogen. When isolated in conjugated forms, the products may be enzymatically or chemically cleaved to release the free fatty acid or a less complex conjugate of interest, and can then be subject to further manipulations to produce a desired end product.

If further purification is necessary, standard methods can be employed. Such methods may include extraction, treatment with urea, fractional crystallization, HPLC, fractional distillation, silica gel chromatography, high speed centrifugation or distillation, or combinations of these techniques. Protection of reactive groups, such as the acid or alkenyl groups, may be done at any step through known techniques, for example alkylation or iodination. Protecting groups may be removed at any step. Desirably, purification of fractions containing EPA may be accomplished by initial esterfication, treatment with urea, supercritical fluid extraction and chromatography with the subsequent isolation of the free fatty acid.

In order to isolate EPA from the triglyceride it is necessary to free the fatty acids by hydrolysis or ester exchange in order that purification can be effected. Purification can be achieved by techniques such as fractional distillation, molecular distillation and chromatography. A particularly desirable chromatographic method employs supercritical fluids using, for example, carbon dioxide as the mobile phase, such as described in European Patent EP 0 712 651. It has been found that using such techniques EPA may be purified to levels approaching 100 per cent. For practical reasons the EPA may be purified as its ethyl or methyl ester and hydrolyzed back to the free fatty acid form. Purification enables a product to be prepared which is highly concentrated and free from other fatty acids that are less desirable in the finished product. In addition other chemicals entities such as mono- and di-glycerides, hydrocarbons, pesticide residues and the like can be removed. The highly purified EPA is thus suitable for human ingestion as it contains substantially reduced levels of toxins, compounds contributing to unpalatability or undesirable fatty acids such as saturated fatty acids. The free fatty acid form of EPA can be absorbed in the gut easily without need of prior enzymatic conversion. Using this method about 150 kg of unpure EPA can be converted into 50 kg of essentially pure EPA-FFA, that being at least 90% purity.

If further purification is necessary, standard methods can be employed. Such methods may include extraction, treatment with urea, fractional crystallization, UPLC, fractional distillation, silica gel chromatography, high speed centrifugation or distillation, or combinations of these techniques. Protection of reactive groups, such as the acid or alkenyl groups, may be done at any step through known techniques, for example alkylation or iodination. Protecting groups may be removed at any step. Desirably, purification of fractions containing EPA may be accomplished by initial esterfication, treatment with urea, supercritical fluid extraction and chromatography with the subsequent isolation of the free fatty acid.

A preferred EPA free fatty acid is commercially available under the tradename ALFA™ (S.L.A. Pharma, UK). This PUFA is 99% pure EPA, in a free fatty acid form and formulated into a pH-dependent, enteric-coated capsules designed to ensure release of the contents in the small intestine at pH 5.5. Other constituents include AA (<0.5%) and trace amounts of other fatty acids. Key advantages of this preparation of EPA are its high degree of purity compared with many fish oil products, its presentation as the free fatty acid maximizing systemic bioavailability, ease of dosage in 500 mg capsules and a delayed-release profile, which minimizes gastro-intestinal side-effects.

Preferably the 99% pure EPA-FFA is administered in an amount from about 250 mg to 4 g per day and more preferably from about 1000 mg to about 2 g daily. The dosage may be preferably administered daily, but depending on the dosage may be extended to every other day, weekly or longer for about 1 to 8 months. Notably, the tolerability of 99% pure EPA as ALFA™ capsules is excellent and the predominant small bowel delivery of EPA minimized any unpleasant taste and smell sensations that have previously hampered therapy with other fish oil preparations. The EPA-FFA alone or in combination with another therapeutic agent used to treat UC may be formulated in multiple delivery modes. The active agent can be administered orally either in liquid or solid composition form. Compositions suitable for oral administration include solid forms, such as pills, capsules, granules, tablets, and powders, and liquid forms, such as solutions, syrups, elixirs, and suspensions. Forms useful for parenteral administration include sterile solutions, emulsions, and suspensions.

A solid composition form may include a solid carrier and one or more substances which may also act as flavoring agents, lubricants, solubilizers, suspending agents, fillers, glidants, compression aids, binders or tablet-disintegrating agents; it can also be an encapsulating material. In powders, the carrier is a finely divided solid which is in admixture with the finely divided active ingredients. In tablets, the active ingredients are mixed with a carrier having the necessary compression properties in suitable proportions and compacted in the shape and size desired. Suitable solid carriers include, for example, calcium phosphate, magnesium stearate, talc, sugars, lactose, dextrin, starch, gelatin, cellulose, polyvinylpyrrolidine, low melting waxes and ion exchange resins.

Liquid carriers are used in preparing solutions, suspensions, emulsions, syrups, elixirs and pressurized compositions. The active ingredient can be dissolved or suspended in a pharmaceutically acceptable liquid carrier such as water, an organic solvent, a mixture of both or pharmaceutically acceptable oils or fats. The liquid carrier can contain other suitable pharmaceutical additives such as solubilizers, emulsifiers, buffers, preservatives, sweeteners, flavoring agents, suspending agents, thickening agents, colors, viscosity regulators, stabilizers or osmo-regulators. Suitable examples of liquid carriers for oral and parenteral administration include water (partially containing additives as above, e.g. cellulose derivatives, preferably sodium carboxymethyl cellulose solution); alcohols (including monohydric alcohols and polyhydric alcohols, e.g. glycols) and their derivatives, and oils (e.g. fractionated coconut oil and arachis oil). For parenteral administration, the carrier can also be an oily ester such as ethyl oleate and isopropyl myristate. Sterile liquid carriers are useful in sterile liquid form compositions for parenteral administration. The liquid carrier for pressurized compositions can be halogenated hydrocarbon or other pharmaceutically acceptable propellent.

Having described the invention in detail, it will be apparent that modifications and variations are possible without departing the scope of the invention defined in the appended claims. Furthermore, it should be appreciated that the following examples are provided as non-limiting examples.

The present invention provides for a double-blind, randomized, placebo-controlled study. Sixty UC patients with fecal calprotectin level >150 μg/g and in stable therapy for at least the 3 previous months, were randomized 1 : 1 to receive either 2 grams daily of EPA-FFA (2 dosages of 500 mg sustained-release capsules, twice a day) or placebo (2 dosages of 500 mg sustained-release capsules of capric and caprylic acids, twice daily) for a 6 month period. At baseline, the patients underwent a total colonoscopy. Fecal calprotectin levels, clinical and laboratory assessments were performed at baseline, 3 and 6 months or at the time of clinical relapse, which has been defined as the occurrence of symptoms accompanied by an increase in the partial Mayo score > 2 and/or requiring a change in therapy. Patients who relapsed were referred for endoscopic evaluation.

It was found that the cohort groups did not differ in clinical and demographic characteristics. However, fecal calprotectin levels surprisingly and significantly decreased in the EPA-FFA group in comparison to the placebo group (p = 0.004). At intention to treat analysis, 76.7% of patients in the EPA-FFA group and 50% of patients in the placebo group maintained a clinical remission at 6 months treatment (χ ² p=0.03). Binary logistic regression analysis showed that EPA-FFA treatment was the only factor affecting the number of patients who relapsed (HR 0.30, 95% CI 0.10 - 0.92, p=0.03). The cumulative 3 and 6 month relapse-free survival was 86.7 and 76.7%), respectively, in the EPA-FFA group, compared to 80%> and 50%>, respectively, in the placebo group (Log-Rank test p = 0.04). Both treatments were safe and well tolerated, with no major side effects. Thus, surprisingly and unexpectedly it was found that EPA-FFA decreases fecal calprotectin levels and is a safe and acceptable treatment to maintain symptom-free remission in UC patients. Materials and Methods

Study Design and patients

Eligible patients were individuals 18 years and older with a diagnosis of UC based on clinical, endoscopic and histological criteria, in stable clinical remission, defined as partial Mayo score <2 for at least the last 3 months, ¹⁶ with a degree of mucosal activity defined as FC levels >150 μ^. Use of concomitant therapies for UC (such as oral mesalazine, immunomodulators and/or biological drugs) without modification in the previous 3 months was allowed. Exclusion criteria were: 1) recent use of steroids (<3 months), topical mesalazine (<3 months) or other experimental drugs (<3 months); 2) concomitant use of non-steroidal anti-inflammatory drugs and/or anticoagulants; 3) proctitis; 4) pregnancy or breast feeding; 5) known or suspected hypersensitivity to EPA or n-3 PUFAs; and 6) severe comorbidities (serious cardiopulmonary, hepatic, renal, neurological, psychiatric disease, diabetes or hemorrhagic disorders). All patients provided written informed consent.

Patients who satisfied the inclusion criteria underwent blood tests, including C-reactive protein (CRP) (normal upper limit 5 mg/L) and a total colonoscopy with multiple biopsies at baseline. They were then randomized 1 : 1 to receive either 2 g daily of EPA-FFA (2 x 500 mg gastro-resistant sustained-release capsules, twice-daily) or 2 g of placebo (2 x 500 mg gastro-resistant sustained-release capsules of capric and caprylic acids that are triglycerides of the fractionated plant fatty acids, twice-daily) for a 6-month period. The randomization list was computer-generated by the Investigational Drug Service Unit (IDS) of the Hospital, and all patients, investigators and the entire study team were blinded to the treatment assignment.

The primary endpoint was the proportion of patients achieving a 100-point reduction (100 μg/g or greater) from baseline in FC level at 6 months. The secondary endpoint was the number of patients achieving maintenance of clinical remission at 6 months, defined as a stable partial Mayo score <2 without any change in therapy. A combined endpoint consisting of the number of patients achieving the primary and secondary endpoints was also calculated. Clinical assessments, FC measurement and blood tests were repeated at 3 and 6 months, or at the time of clinical relapse, which was defined as the occurrence of symptoms accompanied by an increase in the partial Mayo score >2 and requiring a change in therapy. Change in therapy was defined as escalation of ongoing therapy with the introduction of steroids and/or immunosuppressive biological drugs. Only patients with clinical relapse were referred for a second endoscopic evaluation. Any change in dietary habits (including change to vegans or vegetarian diet) was verified at each study visit. Adherence to treatment was evaluated by capsule count: an acceptable level of adherence was achieved if 80-100% of the prescribed capsules were not returned to the outpatient clinic.

Fecal calprotectin quantification

Fecal calprotectin analyses were performed during the screening phase, and at 3 and 6 months, or at the time of clinical relapse (24 h before colonoscopy). A FC cut-off level >150 μg/g was considered indicative of endoscopic and/or histological activity, as well as of early clinical relapse, as previously demonstrated. ^4"7 Following these assumptions, it is considered that a 100-point drop ^g/g) of FC as a clinically meaningful change. Endoscopic and histological evaluation

Colonoscopy with multiple colonic biopsies was performed at baseline and if a clinical relapse occurred. The grade of endoscopic mucosal inflammation was recorded according to the Mayo endoscopic sub-score. ¹⁶ Endoscopic activity was defined as a Mayo endoscopic sub-score >0. ¹⁷ Biopsy samples were scored according to the Geboes grading system, with a cut-off score >3.1 indicating active histological inflammation ¹⁸ .

Fecal calprotectin quantification A fecal sample from the first bowel movement in the morning was stored in a refrigerator at 2-8 ^° C for a maximum of 24 h before performing the analysis. Quantification of FC levels was carried out using a quantitative, enzyme-linked immunosorbent assay (Calprest; Eurospital, Trieste, Italy), according to the manufacturers' instructions. Standards with known concentrations of calprotectin were used as reference. Measurements ranged from 15 to 3000 μ^.

Endoscopic and histological evaluation When biopsy showed different degrees of activity, the highest degree of inflammation was considered. The endoscopist and pathologist were both blinded to the time point under evaluation (baseline vs relapse).

Statistical analysis

Assuming a 100-point reduction of FC from baseline in at least 70% of patients in the EPA-FFA group and 30% of patients in the placebo group (40% difference), 5% significance level, 80% power, two-sided Fisher's exact test, the number of patients to be enrolled was 56. Assuming a 7% drop-out rate, it was necessary to enrol 60 patients. All patients randomized to treatment who received at least 1 dose of the study drug were included in the intention-to-treat (ITT) analysis. Patients who discontinued the study because of adverse events (AEs) or other reasons were considered as non- responders. Descriptive statistics were reported for each group (mean with standard deviation [SD] or median with interquartile range [IQR]); binary logistic regression analysis was performed to evaluate the primary, secondary and combined aims. Because a normal distribution of FC could not be presumed, a non-parametric Mann- Whitney U-test was used to compare differences in FC levels between groups at each time point, while analysis of variance with the Friedman test was used to assess FC changes from baseline to 3 and 6 months within each group. A post-hoc Wilcoxon signed-rank test with Bonferroni correction was performed if the Friedman test achieved significance. The Kaplan-Meier method was used to estimate the relapse-free survival (RES) for each treatment group at 3 and 6 months, and a Log-rank test was used to compare them. A p value less than 0.05 was considered significant. IBM SPSS version 23.0 (Chicago, Illinois, USA) was used to perform statistical analysis. RESULTS

Study population

Sixty patients satisfied the inclusion criteria and were enrolled and included in the ITT population, 30 in the active group and 30 in the placebo group. (Figure 1) The two treatment groups were well matched for baseline demographics and clinical characteristics (Table 1). The median FC level at baseline was 177.5 (IQR 161.5- 210.3) μg/g and 181 (IQR 154.5-208.3) μg/g in the proposed EPA-FFA and proposed placebo groups, respectively. At the baseline colonoscopy, all patients showed a Mayo endoscopic subscore <1; 24 out of 30 (80%) and 19 out of 30 (63.3%) patients had a Mayo endoscopic subscore = 1 in the EPA-FFA and placebo groups, respectively. All patients had a histological Geboes score between 3.1 and 4.1.

Primary endpoint: 100-point reduction in FC level at 6 months

At 3 months, 16 out of 30 (53.3%) patients in the EPA-FFA achieved a 100-point reduction in the FC level compared to 4 out of 30 (13.3%) patients in the placebo group (odds ratio [OR] 7.59, 95% confidence interval [CI] 2.04-28.15, p=0.002). At 6 months, 19 out of 30 (63.3%) and 4 out of 30 (13.3%) patients in the EPA-FFA and placebo groups, respectively, achieved a 100-point reduction in FC level (OR 12.0, 95% CI 3.12-46.24, p<0.001) (Figure 2A). Secondary endpoint: maintenance of clinical remission at 6 months

At 6 months, 38 out of 60 patients maintained clinical remission: 23 of 30 (76.7%) in the EPA-FFA and 15 of 30 (50%) patients in the placebo groups (OR 3.29, 95% CI 1.08-9.95, p=0.035) (Figure 2B). The cumulative 3- and 6-month RFS was 86.7% and 76.7%) in the EPA-FFA group compared to 80% and 50%, respectively in the placebo group (Log-rank p=0.04) (Figure 3).

Combined endpoint: 100-point reduction in FC level and maintenance of clinical remission at 6 months At 6 months, 19 of 30 (63.3%) and 4 of 30 (13.3%) patients achieved both a 100-point reduction in FC level and maintenance of clinical remission in the EPA-FFA and placebo groups, respectively (OR 13, 95% CI 2.71-62.9, p=0.001). Comparison of FC levels between and within treatment groups

Considering only patients who achieved the secondary endpoint, in which 3 FC measurements were available (n=23 and n=15 in EPA-FFA and placebo group, respectively), median FC levels in EPA-FFA group were significantly lower than in the placebo group at both 3 and 6 months (Mann-Whitney p=0.002 and p<0.001, respectively). FC levels decreased significantly from baseline at 3 and 6 months within the EPA-FFA group only (Friedman: χ2 (df 2) = 24.02, p=0.001). A post-hoc Wilcoxon signed rank-test conducted with a Bonferroni correction resulted in a significance level set at p<0.017 (3 comparisons). Median (IQR) FC levels in the EPA- FFA group at baseline, 3 and 6 months were 176 (160-207) μ^, 53 (40-117) μg/g and 40 (16-64) μ^, respectively. There was a statistically significant reduction in median FC levels from baseline to 3 months (Z = -3.362; p=0.001) and from baseline to 6 months (Z = -3.711; p<0.001); no statistically significant reduction was observed in the FC levels between 3 and 6 months (Z = -1.429; p=0.153). However, within the placebo group, there was no statistically significant difference between FC levels at baseline, 3 and 6 months (Friedman: χ2 (df 2) = 3.73; p=0.155) (Figure 4).

Comparison of CRP levels between treatment groups Median CRP levels were not significantly different between the two treatment groups at 3 and 6 months (Mann-Whitney p=0.8 and p=0.55, respectively) and did not change significantly within each group during the study (Friedman: χ2 (df 2) = 0.44, p=0.80 and χ2 (df 2) = 0, p = 1, for EPA-FFA and placebo, respectively). Characteristics of patients who experienced a relapse

Excluding 4 patients who dropped out (1 for pregnancy and 3 for mild AEs), 18 patients experienced a clinical relapse (mean follow-up 4.78 months 95% CI 4.11- 5.45). Median (IQR) FC levels at the time of relapse were significantly lower in the EPA-FFA group (n=5) than the placebo group (n=13): 412 μg/g (374-495) and 535 μg/g (476.5-738), respectively (Mann-Whitney p=0.01). No between-group differences were observed in the partial Mayo score, Mayo endoscopic subscore and Geboes score at relapse (Table 2).

Safety and compliance

Three patients discontinued the study because of mild AEs: 2 (one in each treatment group) because of diarrhea after 1 and 3 months of treatment respectively, and 1 (in the EPA-FFA group) because of bloating after 3 months. No serious AEs were reported in either treatment group. All patients who completed the study satisfied the adherence criteria, with 80-100% of the prescribed capsules not returned to our outpatient clinic.

DISCUSSION This is the first clinical study demonstrating the beneficial effects of highly purified EPA-FFA in reducing mucosal inflammation, as indicated by FC levels, and in preventing symptomatic relapses in UC patients. The chosen primary endpoint was a decrease in FC level, as a marker of reduction of tissue inflammation suggestive of clinical remission. Being the first randomized, placebo-controlled study with such an endpoint the choice of a 100-point reduction in FC level was arbitrary; however, data in the published literature suggest that FC values <150 μg/g are indicative of low-grade histological activity. ⁴

Recent epidemiological data indicate a potential beneficial effect of n-3 PUFAs in reducing the incidence of UC. Ananthakrishnan et al. prospectively analyzed cases of UC in a large cohort study conducted over 26 years (Nurses' Health Study) and found that a high intake of n-3 PUFAs was associated with a reduced risk of incident UC. ¹⁴ Moreover, consumption of a high ratio of pro-inflammatory n-6 PUFAs to n-3 PUFAs has been associated with an increased risk of UC. ^{15 19}

However, previous clinical trials of fish oil derivatives in UC have reported mixed results. ^{20 21} Despite some beneficial effects, such as a reduction of inflammation and a decreased need for steroid use, these studies failed to demonstrate a clear protective effect of fish oil derivatives in preventing clinical relapse. Possible explanations for these disparate results could be related to different study design, the formula of n-3 PUFAs used, too broad a range of dosages, poor patient adherence, the wrong time of administration, or the use of olive oil or other PUFAs as placebo. ²² In the present study, active n-3 PUFAs were formulated as 2 g of highly purified EPA (>95%) in a free fatty acid (FFA) form, in gastric-resistant capsules. Previously, it has been demonstrated ^23-25 that the FFA form of n-3 PUFAs provides the most favourable pharmacokinetic profile in comparison to ethyl ester and triglyceride preparations. Moreover, in a study of patients with IBD and healthy volunteers who received EPA- FFA 2 g daily for 8 weeks, EPA was consistently incorporated into plasma phospholipids and red blood cell membranes. EPA-FFA is quickly converted into docosahexaenoic acid via docosapentaenoic acid and EPA can be considered the "universal donor" of n-3 PUFAs. ²⁶ This is the first study in which FC was used as a surrogate of impending clinical relapse to select patients who are eligible for preventative treatment. Previously published robust data have already established that FC is a very reliable marker of mucosal inflammation, with a good correlation with endoscopic score ³ ' ⁵ and histological inflammation grade, ⁴ and ability to predict clinical relapse. ^5"7 FC is increasingly being included in high-quality, well-designed clinical trials as a predictor of response to new treatments. ²⁷ Although, the optimal FC cut-off level to identify patients at high risk of developing symptomatic relapse in the short term is still under debate, previous experience, ⁵ supported by others' published data, ^{6 7} indicated that 150 μg/g is a reasonable cut-off value for such purpose. It is believed that it is important to accurately identify patients at risk of relapse. FC and the results shown herein provides a method to identify and treat this subgroup of patients before symptoms occurrence, reducing episodes of acute flares, hospitalization, need of more toxic drugs and patient's disability. The negative impact of a less than optimal marker (to identify at- risk patients) can be seen in the EPIC 1 trial. ²⁸ In a large study investigating the use of n-3 PUFAs in preventing CD relapse, ²⁸ 363 patients with CD in clinical remission were included, with previous time in remission (between 3 and 12 months) the only criterion for risk of relapse. ²⁹ Results showed comparably low rates of relapse in patients in the active (31.6%) and placebo (35.7%) groups after 1 year of follow up. A possible explanation for this failure is the low sensitivity of the criterion for identifying patients at high risk of relapse. The use of a reliable inflammatory marker in CD, such as CRP, at entry into the study could have better stratified patients at high risk of relapse.

Mucosal and histological inflammation are predictors of a worsening UC course, whereas low levels of FC predict sustained clinical remission. ³¹ In line with these findings, it is shown herein that a significant reduction of FC level is an important endpoint to reach in order to prolong a symptomless disease course. The data herein support the concept that adding EPA-FFA to ongoing UC treatment could reduce mild mucosal inflammation and stabilize clinical activity of the disease. Furthermore in a pilot study conducted in 20 patients with long-standing UC, the same EPA-FFA dosage improved endoscopic and histological inflammation and stimulated goblet cells differentiation. ³²

It was determined in the present invention that the relapse rate in the placebo arm was high (50% at 6 months) supporting the capability of FC to identify patients at high risk of relapse. ⁵ According to other studies in which FC was tested as a predictor of clinical course ⁶ ' ⁷ and of the disease pattern, CRP did not change significantly throughout the period of the study, confirming its poor sensitivity in monitoring UC disease activity compared to FC. ³³

There were several limitations to the results of the present testing, such as the small number of patients enrolled, the single-center design and the relatively short follow-up period. However, the majority of cases of clinical relapse in patients with elevated FC occur during the first 6 months of follow-up. ³⁴ Although, FC is a reliable marker to assess mucosal inflammation in UC, a colonoscopy was additionally performed with multiple biopsies at baseline and at the time of clinical relapse, in order to provide unquestionable evidence of disease activity. While it is reasonable to assume that patients who remained asymptomatic at the end of the study, with stable FC levels compared to the screening phase, had an unchanged Mayo endoscopic subscore, the absence of a second colonoscopy with biopsies at the end of the treatment is a relevant limitation of the study. The chosen primary endpoint was a decrease in FC level, as a marker of reduction of tissue inflammation suggestive of clinical remission. Being the first randomized, placebo-controlled study with such an endpoint the choice of a 100- point reduction in FC level was arbitrary; however, data in the published literature suggest that FC values <150 μg/g are indicative of low-grade histological activity. ⁴

In conclusion, these encouraging data demonstrate that the use of EPA-FFA decreases fecal calprotectin level, an important inflammatory marker in UC, and is a safe and promising treatment to maintain symptom-free remission in UC patients.

References

1 Langholz E, Munkholm P, Davidsen M, et al. Course of ulcerative colitis: Analysis of changes in disease activity over years. Gastroenterology 1994; 107: 3-11.

2 Sipponen T, Kolho K-L. Fecal calprotectin in diagnosis and clinical assessment of inflammatory bowel disease. Scand J Gastroenterol 2015; 50: 74-80.

3 Lobaton T, Rodriguez -Moranta F, Lopez A, et al. A New Rapid Quantitative Test for Fecal Calprotectin Predicts Endoscopic Activity in Ulcerative Colitis. Inflamm Bowel Dis 2013; 19: 1034-1042.

4 Guardiola J, Lobaton T, Rodriguez -Alonso L, et al. Fecal Level of Calprotectin Identifies Histologic Inflammation in Patients With Ulcerative Colitis in Clinical and

Endoscopic Remission. Clin Gastroenterol Hepatol 2014; 12: 1865-1870.

5 Scaioli E, Scagliarini M, Cardamone C, et al. Clinical application of faecal calprotectin in ulcerative colitis patients. Eur J Gastroenterol Hepatol 2015; 27: 1418— 1424. 6 Costa F, Mumolo MG, Ceccarelli L, et al. Calprotectin is a stronger predictive marker of relapse in ulcerative colitis than in Crohn's disease. Gut 2005; 54: 364-368.

7 Garcia-Sanchez V, Iglesias-Flores E, Gonzalez R, et al. Does fecal calprotectin predict relapse in patients with Crohn's disease and ulcerative colitis? J Crohns Colitis 2010; 4: 144-152. 8 Calder PC. Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance. Biochim Biophys Acta 2015; 1851 : 469-484.

9 Yaqoob P. Mechanisms underlying the immunomodulatory effects of n-3 PUFA. Proc Nutr Soc 2010; 69: 311-315.

10 Lev-Tzion R, Griffiths AM, Leder O, et al. Omega 3 fatty acids (fish oil) for maintenance of remission in Crohn's disease. Cochrane Database Syst Rev 2014; (2):

CD006320.

11 Turner D, Shah PS, Steinhart AH, et al. Maintenance of remission in inflammatory bowel disease using omega-3 fatty acids (fish oil): a systematic review and meta-analyses. Inflamm Bowel Dis 2011; 17: 336-345.

12 MacLean CH, Mojica WA, Newberry SJ, et al. Systematic review of the effects of n-3 fatty acids in inflammatory bowel disease. Am J Clin Nutr 2005; 82: 611-619.

13 Lee D, Albenberg L, Compher C, et al. Diet in the pathogenesis and treatment of inflammatory bowel diseases. Gastroenterology 2015; 148: 1087-1106.

14 Ananthakrishnan AN, Khalili H, Konijeti GG, et al. Long-term intake of dietary fat and risk of ulcerative colitis and Crohn's disease. Gut 2014; 63 : 776-784.

15 Lewis JD, Abreu MT. Diet as a Trigger or Therapy for Inflammatory Bowel Diseases. Gastroenterology 201"/ '; 152: 398-414. e6. 16 Schroeder KW, Tremaine WJ, Ilstrup DM. Coated Oral 5-Aminosalicylic Acid Therapy for Mildly to Moderately Active Ulcerative Colitis. N Engl J Med 1987; 317: 1625-1629.

17 Daperno M, Castiglione F, de Ridder L, et al. Results of the 2nd part Scientific Workshop of the ECCO (II): Measures and markers of prediction to achieve, detect, and monitor intestinal healing in Inflammatory Bowel Disease. J Crohns Colitis 2011; 5: 484-498.

18 Geboes K, Riddell R, Ost A, Jensfelt B, et al. A reproducible grading scale for histological assessment of inflammation in ulcerative colitis. Gut 2000; 47: 404-409.

19 de Silva PSA, Olsen A, Christensen J, et al. An Association Between Dietary Arachidonic Acid, Measured in Adipose Tissue, and Ulcerative Colitis.

Gastroenterology 2010; 139: 1912-1917.

20 De Ley M, de Vos R, Hommes DW, et al. Fish oil for induction of remission in ulcerative colitis. Cochrane Database Syst Rev 2007; (4):CD005986.

21 Cheifetz AS, Gianotti R, Luber R, et al. Complementary and alternative medicines used by patients with inflammatory bowel diseases. Gastroenterology 2017;

152: 415-29.el5.

22 Marion-Letellier R, Savoye G, Beck PL, et al. Polyunsaturated fatty acids in inflammatory bowel diseases: a reappraisal of effects and therapeutic approaches. Inflamm Bowel Dis 2013; 19: 650-661.

23 Belluzzi A, Brignola C, Campieri M, et al. Effects of new fish oil derivative on fatty acid phospholipid-membrane pattern in a group of Crohn's disease patients. Dig Dis Sci 1994; 39: 2589-2594.

24 el Boustani S, Colette C, Monnier L, et al. Enteral absorption in man of eicosapentaenoic acid in different chemical forms. Lipids 1987; 22: 711-714.

25 Davidson MH, Johnson J, Rooney MW, et al. A novel omega-3 free fatty acid formulation has dramatically improved bioavailability during a low-fat diet compared with omega-3 -acid ethyl esters: the ECLIPSE (Epanova ^® compared to Lovaza ^® in a pharmacokinetic single-dose evaluation) study. J Clin Lipidol 2012; 6: 573-584.

26 Scaioli E, Cardamone C, Liverani E, et al. The pharmacokinetic profile of a new gastroresistant capsule preparation of eicosapentaenoic acid as the free fatty acid. BioMed Res Int 2015; 2015: 360825. 27 Sandborn WJ, Panes J, Zhang H, et al. Correlation between concentrations of fecal calprotectin and outcomes of patients with ulcerative colitis in a phase 2 trial. Gastroenterology 2016; 150: 96-102.

28 Feagan BG, Sandborn WJ, Mittmann U, et al. Omega-3 free fatty acids for the maintenance of remission in Crohn disease: the EPIC Randomized Controlled Trials. JAMA 2008; 299: 1690-1697.

29 Sahmoud T, Hoctin-Boes G, Modigliani R, et al. Identifying patients with a high risk of relapse in quiescent Crohn's disease. The GET AID Group. The Groupe d'Etudes Therapeutiques des Affections Inflammatoires Digestives. Gut 1995; 37: 811- 818. 30 Zenlea T, Yee EU, Rosenberg L, et al. Histology Grade Is Independently Associated With Relapse Risk in Patients With Ulcerative Colitis in Clinical Remission: A Prospective Study . Am J Gastroenterol 2016; 111 : 685-690.

31 Mooiweer E, Severs M, Schipper MEI, et al. Low fecal calprotectin predicts sustained clinical remission in inflammatory bowel disease patients: a plea for deep remission. J Crohns Colitis 2015; 9: 50-55.

32 Prossomariti A, Scaioli E, Piazzi G, et al. Short-term treatment with eicosapentaenoic acid improves inflammation and affects colonic differentiation markers and microbiota in patients with ulcerative colitis. Sci Rep 2017; 7: 7458.

33 Vermeire S, Van Assche G, Rutgeerts P. Laboratory markers in IBD: useful, magic, or unnecessary toys? Gut 2006; 55: 426-431.

34 Molander P, Farkkila M, Ristimaki A, et al. Does fecal calprotectin predict short-term relapse after stopping T Fa-blocking agents in inflammatory bowel disease patients in deep remission? J Crohns Colitis 2015; 9: 33-40.

Table 1. Patient demographics and baseline characteristics

¹ Chi-square test

² T-test

³ Mann- Whitney U-test

4 Fisher's exact test

EPA-FFA: eicosapentaenoic free fatty acid; BMI: body mass index; EFMs: extraintestinal manifestations; 5 AS A: mesalazine; AZA: azathioprine; FC: fecal calprotectin; BMI: body mass index; CRP: C-reactive protein; IQR: interquartile range; SD: standard deviation; TNF: tumor necrosis factor.

Table 2. Characteristics of patients at clinical relapse (n=18)

EPA-FFA: eicosapentaenoic free fatty acid; FC: fecal calprotectin; IQR: interquartile range.