Eckel, Robert H.

Background Different approaches to safety event collection influence the determination of liver toxicity within drug development programs. Herein, a description of how fasiglifam-induced liver injury was detected is provided. Methods This eight-trial drug development program was intended to evaluate fasiglifam (25 mg, 50 mg) against placebo or active comparators (glimepiride, sitagliptin) in approximately 11,000 suboptimally controlled patients with type 2 diabetes (terminated Dec 2013 due to liver toxicity). Liver safety had been pre-identified as a concern, and within the phase 3 trials, was measured through (1) adverse event reporting, (2) central predefined liver monitoring schedule with various thresholds for potential drug-induced liver injury, and (3) blinded adjudication of serious liver toxicity by a panel of experts in drug-induced liver injury. A single data monitoring committee provided safety oversight across all trials within the program. Findings Prior to program termination, 7595 of 7602 (99.9%) randomized participants across the eight trials received at least one dose of the study drug (fasiglifam, placebo, or active control). No concerning trends were noted in adverse or serious adverse event frequency, suspected unexpected serious adverse reaction, alanine or aspartate transaminase elevations, or hepatobiliary or gastrointestinal adverse events as reported by local site investigators. However, the predefined central liver safety measurements revealed a greater frequency of possible Hy’s Law cases (5 vs 2) and a 3- to 7-fold greater relative risk in alanine or aspartate transaminase elevation (with respect to upper limit of normal) within fasiglifam recipients compared with placebo/active control: alanine or aspartate transaminase > 3×: relative risk 3.34 (95% confidence interval 2.29–4.90), alanine or aspartate transaminase > 5×: relative risk 6.60 (95% confidence interval 3.03–14.38), alanine or aspartate transaminase > 8×: relative risk 6.14 (95% confidence interval 2.18–17.27), and alanine or aspartate transaminase > 10×: relative risk 6.74 (95% confidence interval 2.05, 22.14). All elevations resolved on study drug discontinuation. Drug-induced liver injury was adjudicated as highly likely or probably related in 0.64% of fasiglifam-treated versus 0.06% placebo or active control-treated patients. Conclusion In spite of clear liver toxicity detected with a systematic surveillance program, liver safety signals were not identified from investigator adverse event reporting alone. By integrating key safety monitoring processes within the randomized design of adequately sized clinical trials, the rare but serious liver toxicity signal became clear, leading to timely program termination.

An assay for plasma lipoprotein lipase activity was used without prior injection of heparin to study arteriovenous differences of lipases across skeletal muscle and adipose tissue of normal male volunteers. Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activities and triglyceride?concentrations were measured in arterial plasma and in venous effluent plasma from forearm skeletal muscle and subcutaneous abdominal adipose tissue, in the postabsorptive state and after a mixed meal. Triglyceride clearance by the tissues was greater across adipose tissue than across muscle. There were no arteriovenous differences for HTGL activity. In the postabsorptive state skeletal muscle released LPL activity, but adipose tissue did not. Postprandially the arterial LPL and HTGL activities did not change. LPL activity in adipose tissue venous effluent rose, whereas that in muscle venous effluent decreased. These results show that the release of LPL from subcutaneous adipose and forearm tissues is regulated differently, reflecting in vivo differences in LPL regulation at the tissue level.