Krystal Biotech has discontinued a clinical trial for its melanoma drug candidate KB707 following the U.S. Food and Drug Administration's (FDA) rejection of a similar therapy, RP1, developed by Replimune Group. The FDA's decision, announced last month, has created heightened uncertainty around the potential for an accelerated approval pathway for these treatments. Krystal cited this regulatory uncertainty as a primary factor in halting its trial. Replimune's RP1 was intended for melanoma treatment but faced regulatory setbacks. Meanwhile, other developments in oncology include a phase 2 study of BB-1701 showing a 28.6% overall response rate and 78.6% disease control rate in breast cancer patients, with higher efficacy in the HER2-low/HR+ subgroup. Additionally, the FDA recently removed Risk Evaluation and Mitigation Strategies (REMS) for CD19- and BCMA-directed CAR T-cell therapies, potentially improving patient access and addressing long-term toxicity concerns. The FDA also issued a complete response letter (CRL) on August 1 for the biologics license application (BLA) of odronextamab, targeting relapsed or refractory follicular lymphoma after at least two prior therapies.