Bioequivalence and Pharmacokinetic Profiles of Generic and Branded Obeticholic Acid in Healthy Chinese Subjects Under Fasting and Fed Conditions.

OBJECTIVES: This study was conducted to evaluate the bioequivalence (BE) of a generic form of obeticholic acid (OCA) and OcalivaTM under fasting and fed conditions and to determine the effects of food on the pharmacokinetic (PK) profiles of OCA in healthy Chinese subjects. METHODS: A randomized, single-dose, three-sequence, three-period, partial replicated crossover study was conducted with a 21-day washout interval between periods under fasting (n=48) and fed (n=48) conditions. Blood samples for OCA and its metabolites Glyco-OCA and Tauro-OCA were collected up to 168 hours after administration in each period. PK parameters were calculated using the non-compartmental method. Geometric mean ratios for PK parameters of the test to reference drug under fasting and fed conditions and their 90% confidence intervals were estimated. Safety evaluations were carried out all through the study. RESULTS: A total of 91 subjects completed the study with 45 in a fasted state and 46 receiving a high-fat diet. There were no serious or unexpected drug-related adverse events occurring during the study. There was no significant difference in the main PK parameters of the two preparations, irrespective of the fasting or fed conditions. Under fasting and fed conditions, the SWR of lnCmax, lnAUC0-t and lnAUC0-∞ were 0.445, 0.370, 0.448, 0.340, 0.168, and 0.180, respectively. Thus, the average BE or the reference-scaled average BE was used to verify that the two preparations were bioequivalent under fasting and fed conditions. Compared with the fasting state, the AUC0-t of the test drug, the AUC0-t, and AUC0-∞ of the reference drug were higher in the fed state. CONCLUSION: The test drug and the reference drug were BE and well tolerated in Chinese healthy subjects under both fasting and fed conditions. Food-intake may cause a significant difference in the main PK parameters of the two preparations.

Assessment of Statin Interactions With the Human NTCP Transporter Using a Novel Fluorescence Assay.

Sodium taurocholate cotransporting polypeptide (NTCP), which is highly expressed in the sinusoidal membrane of hepatocytes, maintains bile acid homeostasis and participates in the hepatic disposition of a variety of endogenous substances as well as xenobiotics. Manifested by the involvement of organic anion-transporting polypeptides 1B1 and 1B3 (OATP1B1 and OATP1B3) in the hepatic uptake of statin drugs, sinusoidal membrane transporters play an important role in the pharmacokinetics and pharmacodynamics of these agents. It has been speculated that NTCP may function as an alternative pathway for statin hepatic uptake, complementary to OATP1B1 and OATP1B3. In the current study, we produced stable NTCP-expressing human embryonic kidney 293 (HEK293) cells and developed a fluorescence-based assay using flow cytometry for measuring NTCP transport with chenodeoxycholyl-(Nε-7-nitrobenz-2-oxa-1,3-diazole)-lysine (CDCA-NBD) as the substrate. NTCP-mediated CDCA-NBD transport was time-dependent and exhibited typical Michaelis-Menten kinetics, with a Km of 6.12 µM. Compounds known to interact with NTCP, including chenodeoxycholic acid and taurocholic acid, displayed concentration-dependent inhibition of NTCP-mediated CDCA-NBD transport. We report here a systematic evaluation of the interaction between statins and the NTCP transporter. Utilizing this system, several statins were either found to inhibit NTCP-dependent transport or act as substrates. We find a good correlation between the reported lipophilicity of statins and their ability to inhibit NTCP. The objective was to develop a higher-throughput system to evaluate potential inhibitors such as the statins. The in vitro assays using CDCA-NBD as fluorescent substrate are convenient, rapid, and have utility in screening drug candidates for potential drug-NTCP interactions.

A facile synthesis of ursodeoxycholic acid and obeticholic acid from cholic acid.

A novel synthetic route of producing ursodeoxycholic acid (UDCA) and obeticholic acid (OCA) was developed through multiple reactions from cheap and readily-available cholic acid. The reaction conditions of the key elimination reaction of mesylate ester group were also investigated and optimized, including solvent, base and reaction temperature. In the straightforward synthetic route for preparation of UDCA and OCA, most of the reaction steps have high conversions with average yields of 94% and 92%, and overall yield up to 65% (7 steps) and 36% (11 steps) from cholic acid, respectively. This promising route offers economical and efficient strategies for potential large-scale production of UDCA and OCA.

Assessment of Pharmacokinetic Interactions Between Obeticholic Acid and Caffeine, Midazolam, Warfarin, Dextromethorphan, Omeprazole, Rosuvastatin, and Digoxin in Phase 1 Studies in Healthy Subjects.

INTRODUCTION: Obeticholic acid (OCA), a potent and selective farnesoid X receptor agonist, is indicated for the treatment of primary biliary cholangitis (PBC). We investigated the potential drug-drug interaction effect of OCA on metabolic CYP450 enzymes and drug transporters. METHODS: Five phase 1 single-center, open-label, fixed-sequence, inpatient studies were conducted in healthy adult subjects to evaluate the effect of oral daily doses of 10 or 25 mg OCA on single-dose plasma pharmacokinetics of specific probe substrates for enzymes CYP1A2 (caffeine, R-warfarin), CYP3A (midazolam, R-warfarin), CYP2C9 (S-warfarin), CYP2D6 (dextromethorphan), CYP2C19 (omeprazole), and drug transporters, BCRP/OATP1B1/OATP1B3 (rosuvastatin), and P-gp (digoxin). RESULTS: OCA showed no substantial suppression/inhibition of S-warfarin, digoxin, and dextromethorphan and weak interactions with caffeine, omeprazole, rosuvastatin, and midazolam. The maximal pharmacodynamic responses (E max) to warfarin-based INR, PT, and aPTT were reduced by 11%, 11%, and 1%, respectively, for the 10-mg dose group and by 7%, 7% and 0%, respectively, for the 25-mg dose group. Overall, drugs dosed in combination with OCA were well tolerated, and most adverse events were mild in severity. No clinically important trends were noted in laboratory evaluations, vital signs, or 12-lead ECGs. CONCLUSION: In these studies, OCA showed weak to no suppression/inhibition of metabolic enzymes and drug transporters at the highest recommended therapeutic dose in patients with PBC. On the basis on these analyses, monitoring and maintenance of target INR range are required during coadministration of OCA with drugs that are metabolized by CYP1A2 (R-warfarin). FUNDING: Intercept Pharmaceuticals, Inc.

Long-term clinical impact and cost-effectiveness of obeticholic acid for the treatment of primary biliary cholangitis.

Primary biliary cholangitis (PBC) is a chronic, progressive autoimmune liver disease that mainly affects middle-aged women. Obeticholic acid (OCA), which was recently approved by the Food and Drug Administration for PBC treatment, has demonstrated positive effects on biochemical markers of liver function. Our objective was to evaluate the long-term clinical impact and cost-effectiveness of OCA as a second-line treatment for PBC in combination with ursodeoxycholic acid (UDCA) in adults with an inadequate response to UDCA. We developed a mathematical model to simulate the lifetime course of PBC patients treated with OCA+UDCA versus UDCA alone. Efficacy data were derived from the phase 3 PBC OCA International Study of Efficacy trial, and the natural history of PBC was informed by published clinical studies. Model outcomes were validated using the PBC Global Study. We found that in comparison with UDCA, OCA+UDCA could decrease the 15-year cumulative incidences of decompensated cirrhosis from 12.2% to 4.5%, hepatocellular carcinoma from 9.1% to 4.0%, liver transplants from 4.5% to 1.2%, and liver-related deaths from 16.2% to 5.7% and increase 15-year transplant-free survival from 61.1% to 72.9%. The lifetime cost of PBC treatment would increase from $63,000 to $902,000 (1,330% increment). The discounted quality-adjusted life years with UDCA and OCA+UDCA were 10.74 and 11.78, respectively, and the corresponding costs were $142,300 and $633,900, resulting in an incremental cost-effectiveness ratio of $473,400/quality-adjusted life year gained. The results were most sensitive to the cost of OCA. CONCLUSION: OCA is a promising new therapy to substantially improve the long-term outcomes of PBC patients, but at its current annual price of $69,350, it is not cost-effective using a willingness-to-pay threshold of $100,000/quality-adjusted life year; pricing below $18,450/year is needed to make OCA cost-effective. (Hepatology 2017;65:920-928).

Primary Biliary Cholangitis: Medical and Specialty Pharmacy Management Update.

BACKGROUND: Chronic liver disease and cirrhosis are a leading cause of morbidity and mortality in the United States. Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis and which has been designated an orphan condition, is a chronic autoimmune disease resulting in the destruction of the small bile ducts in the liver. Without effective treatment, disease progression frequently leads to liver failure and death. Until May 2016, the only FDA-approved treatment for PBC was ursodiol (UDCA), an oral hydrophilic bile acid, which can slow progression of liver damage due to PBC. However, 1 out of 3 patients taking UDCA has an inadequate biochemical response, leading to increased risk of disease progression, liver transplantation, and mortality. Given this unmet clinical need, new therapies are in development for the treatment of PBC. To provide pharmacists with an overview of the latest research on the pathophysiology of PBC and potential new treatment options and to highlight medical and specialty pharmacy approaches to managing access to drugs to treat orphan diseases such as PBC, a 2-hour satellite symposium was presented in conjunction with the 2015 Academy of Managed Care Pharmacy (AMCP) Nexus meeting. Although obeticholic acid was approved by the FDA for the treatment of PBC in May 2016, this development occurred after the symposium presentation. The symposium was supported by an independent educational grant from Intercept Pharmaceuticals and was managed by Analysis Group. Robert Navarro, PharmD, moderated the CPE-accredited symposium titled "Medical and Specialty Pharmacy Management Update on Primary Biliary Cirrhosis." Expert panelists included Christopher L. Bowlus, MD; James T. Kenney, RPh, MBA; and Gary Rice, RPh, MS, MBA, CSP. OBJECTIVE: To summarize the educational satellite symposium presentations and discussions. SUMMARY: Autoimmune liver diseases, including PBC, are responsible for 15% of all liver transplants performed and an equal percentage of deaths related to liver disease. UDCA is the only FDA-approved therapy for treatment of PBC and is considered the standard of care. Nevertheless, many patients do not respond to UDCA, creating the need for new therapeutic options to improve clinical outcomes for PBC patients with inadequate response to treatment. While several agents are being studied in combination with UDCA, monotherapy with the novel agent obeticholic acid, a farnesoid X receptor agonist, has also shown promising results. Health plans are anticipated to assign any newly introduced therapy for the treatment of PBC to specialty pharmacy given its orphan disease status. This assignment enables the health plan to receive disease education, which is particularly important when new drugs are indicated for orphan diseases, and assistance with designing appropriate prior authorization criteria. The clinical value of any new therapeutic options that will inform formulary decisions and prior authorization criteria will be assessed based on evidence of efficacy, safety, and tolerability, among other factors, such as the potential to reduce or delay medical resource utilization (e.g., liver transplant). Key considerations for prior authorization of a new therapy will be determining which PBC patients are appropriate candidates for the new therapy and developing criteria for that determination. These are likely to include clinical diagnostic criteria and degree of response to prior treatment with UDCA. Initially, any new therapy would likely be positioned as noncovered until appropriate prior authorization criteria are established. CONCLUSIONS: PBC is a chronic liver disease with significant morbidity and mortality, as well as a significant burden on the health care system if the disease progresses to the point at which a liver transplant is needed. Although UDCA, the current standard of care, has improved outcomes for many patients, others have an inadequate response to this treatment. This symposium discussed these issues and also addressed the overall treatment paradigm for orphan drug therapies, key implications for patient management, and the role of specialty pharmacy management and any associated needs both in general and specifically for new therapeutic options for PBC.