Phase 2 study of belzutifan (MK-6482), an oral hypoxia-inducible factor 2α (HIF-2α) inhibitor, for Von Hippel-Lindau (VHL) disease-associated clear cell renal cell carcinoma (ccRCC).

Authors

Ramaprasad Srinivasan

Ramaprasad Srinivasan

Center for Cancer Research, National Cancer Institute, Bethesda, MD

Ramaprasad Srinivasan , Frede Donskov , Othon Iliopoulos , Wendy Kimryn Rathmell , Vivek Narayan , Benjamin L. Maughan , Stephane Oudard , Tobias Else , Jodi K. Maranchie , Sarah Joanne Welsh , Ananya Roy , Yanfang Liu , Rodolfo F. Perini , W. Marston Linehan , Eric Jonasch

Organizations

Center for Cancer Research, National Cancer Institute, Bethesda, MD, Aarhus University Hospital, Aarhus, Denmark, Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, MA, Vanderbilt-Ingram Cancer Center, Nashville, TN, University of Pennsylvania, Philadelphia, PA, University of Utah, Salt Lake City, UT, Hôpital Européen Georges Pompidou, Paris, France, University of Michigan, Ann Arbor, MI, University of Pittsburgh, Pittsburgh, PA, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom, Merck & Co., Inc., Kenilworth, NJ, The University of Texas MD Anderson Cancer Center, Houston, TX

Research Funding

Pharmaceutical/Biotech Company
Merck Sharp & Dohme Corp., a subsidiary of Merck & Co., Inc., Kenilworth, NJ, USA

Background: Inactivation of VHL leads to aberrant stabilization and accumulation of HIF-2α, which drives tumor growth. Patients (pts) with VHL disease are at risk for ccRCC, pancreatic neuroendocrine tumors (pNETs), and hemangioblastomas. Repeated surgeries are often needed to control ccRCC and other VHL disease manifestations. Prior results of this ongoing open-label phase 2 study (NCT03401788) showed activity with belzutifan in VHL disease. Updated results are presented. Methods: Adults with germline VHL alterations, measurable and localized/nonmetastatic ccRCC, no prior systemic anticancer therapy, and ECOG PS 0 or 1 received belzutifan 120 mg once daily until progression, intolerable toxicity, or decision to withdraw. The primary end point is ORR of VHL-associated ccRCC tumors per RECIST v1.1 by independent review committee (IRC). Secondary end points include DOR, time to response (TTR), PFS, and safety. Results: As of June 1, 2020, 61 pts enrolled. Most pts (82%) had ECOG PS 0, and the median number of prior tumor reduction procedures (eg, partial nephrectomy, craniotomy, radiation therapy) per pt was 5 (range, 0-15). Lesions outside the kidney (non-RCC tumors) evaluable by IRC included pNETs (33%) and CNS hemangioblastomas (82%). Median follow-up was 69 wk (range, 18-105), median duration of treatment was 68 wk (range, 8-105), and 56 pts (92%) remain on therapy. There were 22 confirmed responses (ORR, 36% [95% CI, 24-49]) and 7 (11%) unconfirmed responses (documented at 1 time point, to be confirmed at subsequent time point); all were PRs. In pts with confirmed PR, median DOR was not reached (range, 12+ to 62+ wk), median TTR was 31 wk (range, 12-61), and 56 pts (92%) had some reduction in the sum of all target lesion diameters. PFS rate at 52 wk was 98% (95% CI, 89-100). For non-RCC tumors, ORR was 80% (16/20; 1 CR) in pNETs and 32% (16/50; 1 CR) in CNS hemangioblastomas. Of 16 pts with evaluable retinal hemangioblastomas at baseline, 11 (69%) showed improvement per IRC. In those 16 pts, 29 eyes were monitored for retinal hemangioblastomas: 16 eyes (55%) showed improvement, 12 (41%) were stable, and no evaluation was available for 1 eye (3%). All 61 pts (100%) had at least one AE. The most common all-cause AE was anemia (90%), which is considered an on-target toxicity. Treatment-related AEs (TRAE) were reported by 60 pts (98%), and 8 pts (13%) had a grade 3 TRAE. No pts had grade 4/5 TRAEs. One pt discontinued treatment because of a TRAE (grade 1 dizziness). Conclusions: Belzutifan demonstrates clinical benefit and has a favorable safety profile in patients with VHL disease–associated ccRCC, pNETs, and hemangioblastomas. Clinical trial information: NCT03401788

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Abstract Details

Meeting

2021 ASCO Annual Meeting

Session Type

Poster Session

Session Title

Genitourinary Cancer—Kidney and Bladder

Track

Genitourinary Cancer—Kidney and Bladder

Sub Track

Kidney Cancer

Clinical Trial Registration Number

NCT03401788

Citation

J Clin Oncol 39, 2021 (suppl 15; abstr 4555)

DOI

10.1200/JCO.2021.39.15_suppl.4555

Abstract #

4555

Poster Bd #

Online Only

Abstract Disclosures

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