Clinical pharmacology considerations for first-in-human clinical trials for enzyme replacement therapy.

Inborn errors of metabolism (IEM) such as lysosomal storage disorders (LSDs) are conditions caused by deficiency of one or more key enzymes, cofactors, or transporters involved in a specific metabolic pathway. Enzyme replacement therapy (ERT) provides an exogenous source of the affected enzyme and is one of the most effective treatment options for IEMs. In this paper, we review the first-in-human (FIH) protocols for ERT drug development programs supporting 20 Biologic License Applications (BLA) approved by the Center for Drug Evaluation and Research (CDER) at the US Food and Drug Administration (FDA) in the period of May 1994 to September 2023. We surveyed study design elements across these FIH protocols including study population, dosage form, dose selection, treatment duration, immunogenicity, biomarkers, and study follow-up. A total of 18 FIH trials from 20 BLAs were identified and of those, 72% (13/18) used single ascending dose (SAD) and/or multiple ascending dose (MAD) study design, 83% (15/18) had a primary objective of assessing the safety and tolerability, 72% (13/18) included clinical endpoint assessments, and 94% (17/18) included biomarker assessments as secondary or exploratory endpoints. Notably, the majority of ERT products tested the approved route of administration and the approved dose was tested in 83% (15/18) of FIH trials. At last, we offer considerations for the design of FIH studies.

Alternatives to Monkey Reproductive Toxicology Testing for Biotherapeutics.

Embryofetal toxicity studies are conducted to support inclusion of women of childbearing potential in clinical trials and to support labeling for the marketed pharmaceutical product. For biopharmaceuticals, which frequently lack activity in the rodent or rabbit, the nonhuman primate is the standard model to evaluate embryofetal toxicity. These studies have become increasingly challenging to conduct due to the small number of facilities capable of performing them and a shortage of sexually mature monkeys. The low number of animals per group and the high rate of spontaneous abortion in cynomolgus monkeys further complicate interpretation of the data. Recent FDA guidance has proposed a weight of evidence (WoE) approach to support product labeling for reproductive toxicity of products intended to be used for the treatment of cancer (Oncology Pharmaceuticals: Reproductive Toxicity Testing and Labeling Recommendations), an approach that has also supported the approval of biotherapeutics for non-cancer indications. Considerations to determine the appropriateness and content of a WoE approach to support product labeling for embryofetal risk include known class effects in humans; findings from genetically modified animals with or without drug administration; information from surrogate compounds; literature-based assessments about the developmental role of the pharmaceutical target; and the anticipated exposure during embryofetal development. This paper summarizes the content of a session presented at the 42nd annual meeting at the American College of Toxicology, which explored the conditions under which alternative approaches may be appropriate to support product labeling for reproductive risk, and how sponsors can best justify the use of this approach.

FDA Approval Summary: Accelerated Approval of Pembrolizumab for Second-Line Treatment of Metastatic Melanoma.

On September 4, 2014, the FDA approved pembrolizumab (KEYTRUDA; Merck Sharp & Dohme Corp.) with a recommended dose of 2 mg/kg every 3 weeks by intravenous infusion for the treatment of patients with unresectable or metastatic melanoma who have progressed following treatment with ipilimumab and, if BRAF V600 mutation positive, a BRAF inhibitor. Approval was based on demonstration of objective tumor responses with prolonged response durations in 89 patients enrolled in a randomized, multicenter, open-label, dose-finding, and activity-estimating phase 1 trial. The overall response rate (ORR) by blinded independent central review per RECIST v1.1 was 24% (95% confidence interval, 15-34); with 6 months of follow-up, 86% of responses were ongoing. The most common (≥20%) adverse reactions were fatigue, cough, nausea, pruritus, rash, decreased appetite, constipation, arthralgia, and diarrhea. Immune-mediated adverse reactions included pneumonitis, colitis, hepatitis, hypophysitis, and thyroid disorders. The benefits of the observed ORR with prolonged duration of responses outweighed the risks of immune-mediated adverse reactions in this life-threatening disease and represented an improvement over available therapy. Important regulatory issues in this application were role of durability of response in the evaluation of ORR for accelerated approval, reliance on data from a first-in-human trial, and strategies for dose selection. Clin Cancer Res; 23(19); 5666-70. ©2017 AACR.

U.S. FDA Approval Summary: Nivolumab for Treatment of Unresectable or Metastatic Melanoma Following Progression on Ipilimumab.

On December 22, 2014, the FDA granted accelerated approval to nivolumab (OPDIVO; Bristol-Myers Squibb) for the treatment of patients with unresectable or metastatic melanoma and disease progression following ipilimumab and, if BRAF V600 mutation positive, a BRAF inhibitor. Approval was based on a clinically meaningful, durable objective response rate (ORR) in a non-comparative analysis of 120 patients who received 3 mg/kg of nivolumab intravenously every 2 weeks with at least 6-month follow-up in an ongoing, randomized, open-label, active-controlled clinical trial. The ORR as assessed by a blinded independent review committee per RECIST v1.1 was 31.7% (95% confidence interval, 23.5-40.8). Ongoing responses were observed in 87% of responding patients, ranging from 2.6+ to 10+ months. In 13 patients, the response duration was 6 months or longer. The risks of nivolumab, including clinically significant immune-mediated adverse reactions (imARs), were assessed in 268 patients who received at least one dose of nivolumab. The FDA review considered whether the ORR and durations of responses were reasonably likely to predict clinical benefit, the adequacy of the safety database, and systematic approaches to the identification, description, and patient management for imARs in product labeling. Clin Cancer Res; 23(14); 3484-8. ©2017 AACR.