It’s been a busy couple of weeks away — between travels to Europe, a stop in Switzerland, and a wedding in New York, I’ve been grateful for some time to recharge. Now back in clinic, I’m excited to share new updates in the melanoma space. Among the recent developments, one in particular stood out: promising phase 3 data for a therapeutic cancer vaccine in combination with PD-1 blockade. For those of us caring for patients with advanced melanoma, this is an encouraging signal and a reminder of why ongoing innovation matters. I’m eager to see colleagues and friends at Best of ASCO, hosted by Advent Health Cancer Institute at the Ritz-Carlton in Orlando, Florida, on August 23–24.
As someone who treats patients with metastatic melanoma and has participated in this very study, I can say this new data is more than just another press release — it’s a genuinely exciting moment in the melanoma space.
The IOB-013/KN-D18 pivotal phase 3 trial evaluated Cylembio® (a combination of imsapepimut and etimupepimut, adjuvanted), an off-the-shelf therapeutic cancer vaccine, plus pembrolizumab (Keytruda) vs pembrolizumab alone in the first-line setting.
Here’s what caught my eye:
- Progression-Free Survival (PFS) — Median PFS was 19.4 months with the combination vs 11.0 months with pembrolizumab alone (HR 0.77). While the primary endpoint narrowly missed statistical significance (P=0.056 vs threshold 0.045), the clinical improvement is hard to ignore.
- PD-L1–Negative Patients — This is where things get really exciting. Median PFS jumped from just 3.0 monthson pembrolizumab alone to 16.6 months with the combination (HR 0.54). For this population, treatment options are particularly limited, so this is an important signal.
- Prior PD-1–Naïve Patients — In patients without prior anti–PD-1 therapy, median PFS stretched to 24.8 monthson the combination — more than double pembrolizumab alone.
- Safety — Well tolerated overall. Injection site reactions were the most common side effect and were transient. No new safety signals were identified.
While overall survival data are still immature, there’s already a favorable trend emerging. And importantly, these benefits were consistent across nearly all subgroups, even those with poor prognostic factors.
From my perspective, this trial highlights why I always recommend that patients consider clinical trials when possible — especially PD-1–based combinations. They give us the opportunity to push beyond the current standard of care and sometimes, as with Cylembio, the chance to see genuinely meaningful gains.
IO Biotech plans to meet with the FDA this fall to discuss a potential Biologics License Application. We’ll also see more detailed results presented at an upcoming medical meeting. If approved, this could offer a new standard for certain patients — especially those who historically haven’t had strong responses to PD-1 monotherapy.
This is exactly the kind of progress that keeps me optimistic for the future of melanoma treatment.
About the author
Dr. Sajeve Thomas is a distinguished medical professional and a compassionate guide in the field of oncology. With over a decade of dedicated experience as a board-certified medical oncologist/internal medicine specialist, Dr. Thomas has become a trusted expert in the treatment of melanoma, sarcoma, and gastrointestinal conditions. He brings a wealth of expertise to the complex and challenging world of oncology.
Disclosures:
Dr. Thomas serves as a speaker for Bristol Myers Squibb (BMS), Merck, Ipsen, Natera, Immunocore, Pfizer, and SpringWorks. He also receives industry grants in support of numerous clinical trials.