A Phase 3 trial evaluating a coformulation of pembrolizumab/vibostolimab (MK-7684A) against pembrolizumab (Keytruda) monotherapy for PD-L1 positive metastatic non-small cell lung cancer reached primary completion on 2024-09-05. The study, KEYVIBE-003, did not demonstrate improved overall survival with the coformulation compared to monotherapy. For participants with PD-L1 TPS ≥50%, median OS was 15.7 months for the coformulation versus 20.3 months for pembrolizumab alone.

Background

The study investigated a coformulation of pembrolizumab and vibostolimab as a potential new treatment for PD-L1 positive metastatic non-small cell lung cancer (NSCLC). The trial aimed to assess if the combination could lead to longer overall survival and progression-free survival compared to pembrolizumab monotherapy.

Trial design

This was a Phase 3 trial (NCT04738487) titled "Coformulation of Pembrolizumab/Vibostolimab (MK-7684A) Versus Pembrolizumab (MK-3475) Monotherapy for Programmed Cell Death 1 Ligand 1 (PD-L1) Positive Metastatic Non-Small Cell Lung Cancer (MK-7684A-003, KEYVIBE-003)". The study enrolled 1264 participants with lung neoplasms and non-small cell lung carcinoma. Participants received either the coformulation of pembrolizumab/vibostolimab or pembrolizumab monotherapy. The primary objective was to evaluate if the coformulation could improve overall survival and progression-free survival.

Key results

The trial reported median overall survival (OS) and hazard ratios across different PD-L1 expression levels:

  • For participants with PD-L1 TPS ≥50%:
    • Median OS for pembrolizumab/vibostolimab was 15.7 months.
    • Median OS for pembrolizumab monotherapy was 20.3 months.
    • The hazard ratio (HR) was 1.06 (95% CI: 0.83, 1.35) with a p-value of 0.6712.
  • For participants with PD-L1 TPS ≥1%:
    • Median OS for pembrolizumab/vibostolimab was 15.0 months.
    • Median OS for pembrolizumab monotherapy was 16.4 months.
    • The hazard ratio (HR) was 0.96 (95% CI: 0.82, 1.13) with a p-value of 0.332.
  • For participants with PD-L1 TPS 1% to 49%:
    • Median OS for pembrolizumab/vibostolimab was 14.3 months.
    • Median OS for pembrolizumab monotherapy was 14.3 months.
    • The hazard ratio (HR) was 0.90 (95% CI: 0.72, 1.11) with a p-value of 0.1646.

What this means

The results indicate that the coformulation of pembrolizumab/vibostolimab did not demonstrate a statistically significant improvement in overall survival compared to pembrolizumab monotherapy in patients with PD-L1 positive metastatic non-small cell lung cancer. In the key subgroup of patients with PD-L1 TPS ≥50%, median OS was numerically lower for the coformulation (15.7 months) compared to monotherapy (20.3 months), with a hazard ratio of 1.06. Similar trends of no significant benefit were observed across other PD-L1 expression subgroups, with hazard ratios close to 1 and p-values above the conventional threshold for statistical significance.

Source

The primary completion results for this trial were posted on 2024-09-05 on ClinicalTrials.gov, an official database of clinical studies. The full details are available on clinicaltrials.gov under the identifier NCT04738487.