Pembrolizumab/Vibostolimab Coformulation for Melanoma to be Discontinued

Melanoma cells: © David A Litman - stock.adobe.com

The vibostolimab and pembrolizumab (Keytruda; MK-7684A) coformulation arm of the phase 3 KeyVibe-010 study (NCT05665595) investigating the agents as an adjuvant treatment in resected high-risk melanoma will be discontinued due to futility, according to Merck.¹

A higher discontinuation rate was observed in the coformulation arm vs the pembrolizumab monotherapy arm, making it unlikely that the study could achieve statistical significance for its primary end point of recurrence-free survival (RFS). The study will be unblinded and patients in the coformulation arm will have the option to receive pembrolizumab monotherapy.

Results from the ongoing data analysis will be shared with the scientific community and regulatory agencies in the future.

“Through our clinical development program, we continue to ask the tough questions in an effort to fully explore the potential of novel coformulations and combinations that build on the foundation of [pembrolizumab], with a goal to improve upon current standards of care and help even more patients with cancer,” said Marjorie Green, MD, senior vice president and head of oncology, global clinical development, Merck Research Laboratories, in a press release. “We are grateful to the patients and investigators for their participation and will leverage insights from this trial as we rapidly advance our diverse pipeline of novel mechanisms, including further study of this coformulation in lung cancer.”

Pembrolizumab is presently approved for 2 indications in melanoma, including unresectable or metastatic melanoma or stage IIB, IIC, or III melanoma following resection. KeyVibe-010 is comparing a coformulation of pembrolizumab 200 mg/20 mL and vibostolimab 200 mg administered as an intravenous (IV) infusion for up to 17 administrations vs pembrolizumab 25 mg/mL administered as IV infusion for up to 17 administrations.²

Additional KeyVibe studies are exploring the coformulation of vibostolimab and pembrolizumab in lung cancer. These include KeyVibe-003 (NCT04738487), KeyVibe-006 (NCT05298423), KeyVibe-007 (NCT05226598), and KeyVibe-008 (NCT05224141).¹

Findings from the KeyVibe-002 (NCT04725188) study of the coformulation in patients with previously treated non-small cell lung cancer were presented at the European Society for Medical Oncology (ESMO) Immuno-Oncology Congress in December 2023. Here, the improvement in progression-free survival (PFS) over docetaxel alone did not reach statistical significance.³

Specifically, vibostolimab and pembrolizumab plus docetaxel (n = 87) elicited a median PFS of 5.6 months (95% CI, 3.9-6.8) compared with 3.2 months (95% CI, 2.8-5.7) with docetaxel alone (n = 85; HR, 0.77; 95% CI, 0.53-1.13; P = .0910). The median PFS was not prolonged with vibostolimab and pembrolizumab alone (n = 83) at 2.7 months (95% CI, 1.8-4.0) vs 3.2 months (HR, 1.40; 95% CI, 0.96-2.02; P = .9622).

Additional findings from the 2023 ESMO Immuno-Oncology Annual Congress showed that the PFS rates at 12 months were (95% CI, 13.4%-34.5%), with vibostolimab and pembrolizumab plus docetaxel, 23.2% 8.0% (95% CI, 2.5%-17.5%) for vibostolimab and pembrolizumab alone, and 12.5% (95% CI, 3.3%-28.2%) for docetaxel alone, respectively.

REFERENCES:

1. Merck provides update on phase 3 KeyVibe-010 trial evaluating an investigational coformulation of vibostolimab and pembrolizumab as adjuvant treatment for patients with resected high-risk melanoma. News release. Merck. May 13, 2024. Accessed May 13, 2024. https://tinyurl.com/3vd6k9x6

2. A atudy of adjuvant pembrolizumab/​cibostolimab (MK-7684A) versus pembrolizumab for resected high-risk melanoma in participants with high-risk stage II-IV melanoma (MK-7684A-010/​KEYVIBE-010). ClinicalTrials.gov. Updated May 6, 2024. Accessed May 13, 2024. https://clinicaltrials.gov/study/NCT05665595

3. Merck announces findings from phase 2 KeyVibe-002 trial evaluating an investigational coformulation of vibostolimab and pembrolizumab in previously treated patients with metastatic non-small cell lung cancer (NSCLC). News release. Merck. December 7, 2023. Accessed May 13, 2024. https://tinyurl.com/3z8wdet2