Immune checkpoint inhibitors are the superheroes of cancer therapy. Drugs like Bristol Myers Squibb’s Opdivo and Merck’s Keytruda are among the most profitable in the world—Keytruda pulled in $25 billion last year, making it the bestselling drug of 2023. But every good superhero needs a sidekick.
During the 2024 European Society for Medical Oncology congress, Copenhagen-based IO Biotech presented data showing that its IO102-IO103 cancer vaccine, in combination with Keytruda (pembrolizumab), delivered an objective response rate of 44.4%, hitting the primary endpoint of a phase 2 trial in patients with advanced squamous cell carcinoma of the head and neck (SCCHN).
“With the data we’ve presented from studies in head and neck cancer and in melanoma, evidence is accumulating that the combination of IO102-IO103 with the anti-PD-1 therapy pembrolizumab could be a safe and efficacious first-line treatment for patients with a range of cancers, including those with metastatic and difficult-to-treat disease,” IO Biotech’s chief medical officer, Qasim Ahmad, M.D., said in a Sept. 14 release.
IO Biotech’s IO102-IO103 vaccine is actually a combination of two vaccines that each prime patients’ T cells to target tumors. IO102 induces the immune cells to go after indoleamine-2,3-dioxygenase (IDO), an enzyme found inside of cells, while IO103 directs them toward programmed death-ligand 1 (PD-L1), a protein embedded in the cell membrane. Both IDO and PD-L1 are used by cancer cells to avoid being targeted and destroyed by the body’s immune system.
By activating T cells against IDO and PD-L1, the theory is that the body’s immune system will join the fight against cancerous cells.
The IOB-022/KN-D38 phase 2 trial had a total of 63 patients enrolled across cancer types as of Aug. 2, with 21 SCCHN patients enrolled. SCCHN patients who received the vaccine with Keytruda experienced median progression-free survival of 6.6 months and a disease control rate of 66.7%.
Adverse events were common, with 20 of 21 patients experiencing side effects. Most were of low severity, like rash, fatigue and a reaction at the injection site. One patient suffered a severe treatment-related adverse event, immune thrombocytopenia, which was managed with corticosteroid treatment. Two patients discontinued treatment due to side effects of conjunctivitis and colitis, while another died of an unrelated illness during the trial. That left 18 patients for the data analysis.
Data from the cohort of patients with non-small cell lung cancer will be presented at another meeting this fall, IO Biotech said in the release.
Merck is collaborating on the IO102-IO103 trials, but IO Biotech maintains global commercial rights to the vaccines, according to the release.
IO’s assets aren’t the only cancer vaccines Merck is auditioning for a supporting role alongside Keytruda. At the American Society of Clinical Oncology meeting in June, the Big Pharma shared data from a phase 2 trial of an mRNA vaccine being developed with Moderna. At a typical follow-up of 34.9 months, the vaccine and Keytruda combo reduced the risk of recurrence or death by 49% compared to Keytruda alone in patients with resected melanoma.
IO Biotech raised a $155 million series B in 2021 to advance its cancer vaccines. The Danish company is also testing IO102-IO103 in combination with Opdivo (nivolumab) and BMS’ relatlimab in a phase 2 trial in untreated, unresectable melanoma. The vaccine-Opdivo combo received a breakthrough-therapy designation from the FDA in 2020.
Earlier this year at the World Vaccine Congress, Peter Marks, M.D., Ph.D., director of the FDA’s Center for Biologics Evaluation and Research, expressed the agency’s willingness to review new cancer vaccines.