Phase II study of the oral HIF-2α inhibitor MK-6482 for Von Hippel-Lindau disease–associated renal cell carcinoma.
Eric Jonasch, Frede Donskov, Othon Iliopoulos, W. Kimryn Rathmell, Vivek Narayan, Benjamin L. Maughan, Stéphane Oudard, Tobias Else, Jodi K. Maranchie, Sarah J. Welsh, Sanjay Thamake, Eric Kristopher Park, Naseem J. Zojwalla, Rodolfo F. Perini, W. Marston Linehan, Ramaprasad Srinivasan
Abstract
5003 Background: Patients (pts) with Von Hippel-Lindau disease (VHL) are at risk for several cancers, including clear cell renal cell carcinoma (ccRCC). Inactivation of VHL results in constitutive activation of the HIF-2α transcription factor, which drives tumor growth. MK-6482, a potent, selective, small molecule HIF-2α inhibitor, has shown favorable safety and antitumor activity in a phase 1/2 study. We present initial results of the open-label phase 2 study of MK-6482 for treatment of VHL-associated ccRCC (NCT03401788). Methods: Adult pts with a pathogenic germline VHL variation, measurable localized/nonmetastatic ccRCC, no prior systemic anticancer therapy, and ECOG PS of 0/1 received MK-6482 120 mg orally once daily until progression, intolerable toxicity, or investigator/pt decision to withdraw. Primary end point was ORR of VHL-associated ccRCC tumors per RECIST v1.1 by independent radiology review. Secondary end points were DOR, time to response (TTR), PFS, and safety and tolerability. Results: As of December 6, 2019, 61 pts were enrolled; median (range) age was 41 years (19-66) and most pts were male (52.5%) and had ECOG PS of 0 (82.0%). The most common lesions outside the kidney (non-RCC tumors) were CNS hemangioblastomas (80.3%) and pancreatic lesions (50.8%). Median (range) duration of treatment was 9.9 mo (1.9-18.2) and 95.1% of pts remain on therapy. Three pts discontinued (AE, n = 1; death [fentanyl toxicity], n = 1; pt decision, n = 1). There were 17 confirmed responses (ORR, 27.9% [95% CI, 17.1-40.8%]) and 8 (13.1%) unconfirmed (documented at 1 timepoint and to be confirmed at subsequent timepoint) responses; all responses were PRs. Of 61 pts, 53 (86.9%) had decrease in size of target lesions. In 17 pts with confirmed response, median (range) DOR was not reached (2.1-9.0 mo) and median (range) TTR was 5.5 mo (2.7-14.0). Responses were also observed in CNS, retinal, and pancreatic lesions. Median PFS was not reached; 12-mo PFS rate was 98.3%. Treatment-related AEs (TRAEs) occurred in 96.7% of pts, mostly grade 1 (44.3%) or grade 2 (42.6%) and primarily (≥20%) anemia (83.6%; considered an on-target-toxicity), fatigue (49.2%), and dizziness (21.3%). Grade 3 TRAEs occurred in 9.8% of pts, primarily fatigue (4.9%) and anemia (3.3%). There were no grade 4 or 5 TRAEs. One pt discontinued because of a TRAE (dizziness). Conclusions: MK-6482 showed promising efficacy and tolerability in pts with VHL-associated ccRCC and responses in other VHL-related lesions. These data support further investigation of MK-6482 in VHL disease. Clinical trial information: NCT03401788 .