FDA Approval Summary: Belzutifan for von Hippel-Lindau Disease-Associated Tumors.

On August 13, 2021, the FDA approved belzutifan (WELIREG, Merck), a first-in-class hypoxia-inducible factor (HIF) inhibitor for adult patients with von Hippel-Lindau (VHL) disease who require therapy for associated renal cell carcinoma (RCC), central nervous system (CNS) hemangioblastomas, or pancreatic neuroendocrine tumors (pNET), not requiring immediate surgery. The FDA granted approval based on the clinically meaningful effects on overall response rate (ORR) observed in patients enrolled in Study MK-6482-004. All 61 patients had VHL-associated RCC; some also had CNS hemangioblastomas and/or pNET. For VHL disease-associated RCC, ORR was 49% [95% confidence interval (CI), 36-62], median duration of response (DoR) was not reached, 56% of responders had DoR ≥12 months, and median time to response was 8 months. Twenty-four patients had measurable CNS hemangioblastomas with an ORR of 63% (95% CI, 41-81), and 12 patients had measurable pNET with an ORR of 83% (95% CI, 52-98). For these tumors, median DoR was not reached, with 73% and 50% of patients having response durations ≥12 months for CNS hemangioblastomas and pNET, respectively. The most common adverse reactions, including laboratory abnormalities, reported in ≥20% were anemia, fatigue, increased creatinine, headache, dizziness, increased glucose, and nausea. Belzutifan can render some hormonal contraceptives ineffective and can cause embryo-fetal harm during pregnancy. This article summarizes the data and the FDA thought process supporting traditional approval of belzutifan for this indication.

FDA Approval Summary: Accelerated Approval of Sacituzumab Govitecan-hziy for Third-line Treatment of Metastatic Triple-negative Breast Cancer.

On April 22, 2020, the FDA granted accelerated approval to sacituzumab govitecan-hziy (TRODELVY; Immunomedics, Inc.) for the treatment of patients with metastatic triple-negative breast cancer (mTNBC) who have received at least two prior therapies for metastatic disease. Approval was based on data from the IMMU-132-01 trial, a single-arm, multicohort, multicenter, phase I/II trial of sacituzumab govitecan. The assessment of efficacy was based on 108 patients with mTNBC who had previously received at least two prior lines of therapy in the metastatic setting and who received sacituzumab govitecan 10 mg/kg i.v. The assessment of safety was based on 408 patients with advanced solid tumors who had received sacituzumab govitecan at doses up to 10 mg/kg i.v. The primary efficacy endpoint was investigator-assessed objective response rate (ORR) and duration of response (DoR) was a key secondary endpoint. The ORR was 33.3% [36/108; 95% confidence interval (CI), 24.6-43.1], and median DoR among responders was 7.7 months (95% CI, 4.9-10.8). The most common adverse reactions occurring in ≥25% of patients were nausea, neutropenia, diarrhea, fatigue, anemia, vomiting, alopecia, constipation, rash, decreased appetite, and abdominal pain. This article summarizes the FDA review process and data supporting the approval of sacituzumab govitecan.

FDA Approval Summary: Niraparib for the Maintenance Treatment of Patients with Recurrent Ovarian Cancer in Response to Platinum-Based Chemotherapy.

The FDA approved niraparib, a poly(ADP-ribose) polymerase (PARP) inhibitor, on March 27, 2017, for maintenance treatment of patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in response to platinum-based chemotherapy. Approval was based on data from the NOVA trial comparing niraparib with placebo in two independent cohorts, based on germline BRCA mutation status (gBRCAm vs. non-gBRCAm). Progression-free survival (PFS) in each cohort was the primary endpoint. In the gBRCAm cohort, estimated median PFS on niraparib was 21 months versus 5.5 months on placebo [HR, 0.26; 95% confidence interval (CI), 0.17-0.41; P < 0.0001]. In the non-gBRCAm cohort, estimated median PFS for niraparib and placebo was 9.3 and 3.9 months, respectively (HR, 0.45; 95% CI, 0.34-0.61; P < 0.0001). Common adverse reactions (>20% and higher incidence in the niraparib arm) with niraparib included thrombocytopenia, anemia, neutropenia, nausea, constipation, vomiting, mucositis, fatigue, decreased appetite, headache, insomnia, nasopharyngitis, dyspnea, rash, and hypertension. There were five cases of myelodysplastic syndrome and acute myeloid leukemia (1.4%) in patients treated with niraparib compared with two cases (1.1%) on placebo. Niraparib is the first PARP inhibitor approved as maintenance therapy for patients with ovarian, fallopian tube, or primary peritoneal cancer, with improvement in PFS, regardless of gBRCAm status. Clin Cancer Res; 24(17); 4066-71. ©2018 AACRSee related commentary by Konstantinopoulos and Matulonis, p. 4062.

FDA Approval: Uridine Triacetate for the Treatment of Patients Following Fluorouracil or Capecitabine Overdose or Exhibiting Early-Onset Severe Toxicities Following Administration of These Drugs.

On December 11, 2015, the FDA approved uridine triacetate (VISTOGARD; Wellstat Therapeutics Corporation) for the emergency treatment of adult and pediatric patients following a fluorouracil or capecitabine overdose regardless of the presence of symptoms, and of those who exhibit early-onset, severe, or life-threatening toxicity affecting the cardiac or central nervous system, and/or early onset, unusually severe adverse reactions (e.g., gastrointestinal toxicity and/or neutropenia) within 96 hours following the end of fluorouracil or capecitabine administration. Uridine triacetate is not recommended for the nonemergent treatment of adverse reactions associated with fluorouracil or capecitabine because it may diminish the efficacy of these drugs, and the safety and efficacy of uridine triacetate initiated more than 96 hours following the end of administration of these drugs has not been established. The approval is based on data from two single-arm, open-label, expanded-access trials in 135 patients receiving uridine triacetate (10 g or 6.2 g/m(2) orally every 6 hours for 20 doses) for fluorouracil or capecitabine overdose, or who exhibited severe or life-threatening toxicities within 96 hours following the end of fluorouracil or capecitabine administration. Ninety-six percent of patients met the major efficacy outcome measure, which was survival at 30 days or survival until the resumption of chemotherapy, if prior to 30 days. The most common adverse reactions were vomiting, nausea, and diarrhea. This article summarizes the FDA review of this New Drug Application, the data supporting approval of uridine triacetate, and the unique regulatory situations encountered by this approval. Clin Cancer Res; 22(18); 4545-49. ©2016 AACR.