US pharmaceutical company Merck & Co Inc (MSD) has discontinued a Phase III trial investigating a co-formulation of vibostolimab and pembrolizumab (Keytruda) for patients with resected high-risk melanoma (Stage IIB-IV).
The decision to cancel the KeyVibe-010 trial follows a pre-planned analysis indicating that the study's primary endpoint of recurrence-free survival (RFS) was unlikely to be met.
The randomised, active comparator-controlled study was designed to compare vibostolimab with pembrolizumab against Keytruda alone.
It enrolled 1,594 subjects who were randomised at a 1:1 ratio to receive either the vibostolimab/pembrolizumab coformulation or pembrolizumab monotherapy.
Interim analysis showed that the coformulation arm met the pre-defined futility criteria for RFS.
In addition, more patients in the coformulation arm discontinued the all-adjuvant therapy than those in the Keytruda-only arm.
MSD attributed the discontinuation mainly to immune-mediated adverse events, which made it 'highly unlikely' for the trial to achieve a statistically significant improvement in RFS.
Following the recommendation of an independent Data Monitoring Committee (DMC), Merck is unblinding the trial.
The company said it would continue to analyse data from the study and share the results with regulatory agencies in due course.
Merck Research Laboratories global clinical development oncology head and senior vice-president Dr Marjorie Green said: “Through our clinical development programme, 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 Keytruda, with a goal to improve upon current standards of care and help even more patients with cancer.
“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 co-formulation in lung cancer.”
MSD recently reported that its Phase III KEYNOTE-B21 trial of Keytruda plus chemotherapy in patients with newly diagnosed high-risk endometrial cancer did not meet its primary endpoint.
