Cylembio plus pembrolizumab shows improvement in progression-free survival.

Patients treated with Cylembio (imsapepimut and etimupepimut, adjuvanted) plus pembrolizumab achieved improvement in progression-free survival (PFS) compared to pembrolizumab monotherapy, with a median PFS of 19.4 months vs. 11.0 months, respectively. In patients without prior neo-adjuvant/adjuvant anti-PD-1 treatment, PFS improvement was achieved, with a median PFS of 24.8 months vs. 11.0 months for the control arm. The effect was observed across virtually all subgroups, including those with poor prognostic factors.

IO Biotech (Nasdaq: IOBT) has announced topline results from its pivotal Phase 3 trial (IOB-013/KN-D18) of Cylembio® (imsapepimut and etimupepimut, adjuvanted) in combination with Merck’s anti-PD-1 therapy, KEYTRUDA® (pembrolizumab), versus pembrolizumab alone as a first-line treatment for unresectable or metastatic melanoma. The trial, which enrolled 407 patients, demonstrated a significant improvement in progression-free survival (PFS) for patients treated with Cylembio plus pembrolizumab compared to those treated with pembrolizumab monotherapy.

The median PFS for patients in the combination arm was 19.4 months, compared to 11.0 months in the monotherapy arm. This improvement was observed across virtually all subgroups, including those with poor prognostic factors. Notably, patients without prior neo-adjuvant/adjuvant anti-PD-1 treatment showed a median PFS of 24.8 months with Cylembio plus pembrolizumab, compared to 11.0 months in the control arm. The effect was particularly pronounced in patients with PD-L1 negative tumors, where the median PFS was 16.6 months versus 3.0 months in the monotherapy group [1].

While the primary endpoint narrowly missed statistical significance (p=0.056), a trend toward improvement in overall survival (OS) was observed, with a hazard ratio of 0.79 (CI 0.57-1.10). The company expects OS data to mature over the next six to nine months.

The combination therapy was well tolerated, with no new safety signals observed. Injection site reactions were the most commonly reported adverse events, occurring in 56% of patients in the combination arm. The clinical trial was conducted in collaboration with Merck, which is supplying pembrolizumab.

IO Biotech plans to meet with the FDA this fall to discuss the totality of data and determine next steps for submission of a Biologics License Application (BLA) for the treatment of advanced melanoma. The company will also present more detailed results from the IOB-013 study at an upcoming medical meeting.

The results of this trial highlight the potential of a therapeutic cancer vaccine in improving PFS for patients with metastatic melanoma. IO Biotech’s Cylembio, if approved, has the potential to become a new standard of care for patients with advanced melanoma.

References:

[1] https://finance.yahoo.com/news/io-biotech-announces-clinical-improvement-120000640.html