An experimental immunotherapy has demonstrated a high response rate and improved survival in patients with advanced colorectal cancer, according to new data from a mid-stage clinical trial. The results offer a promising signal for a patient group with limited treatment options.
The Phase II study, led by investigators at the National Cancer Institute, tested a drug called PDS01ADC in patients whose cancer had spread to the liver and who had previously failed chemotherapy. The drug is a fused antibody conjugate designed to deliver a powerful immune-stimulating agent, Interleukin-12, directly to tumors. When combined with a chemotherapy infusion directly into the liver, the treatment elicited an objective response rate of 77.8% after six months. This was more than double the 35% response rate observed in a parallel trial group that did not receive PDS01ADC.
Survival data were equally striking. The 24-month survival rate was approximately 85% for patients on the PDS01ADC regimen, compared to 40% in the comparator group. The therapy also markedly delayed cancer progression outside the liver; the median progression-free survival had not been reached after a minimum follow-up of 13.1 months, whereas it was 8.1 months in the parallel trial. Researchers highlight that the subcutaneous administration of the drug aims to activate the immune system against cancer while potentially avoiding the severe side effects historically linked to systemic cytokine therapies.
A Competitive Landscape in Colorectal Cancer Treatment
The positive data emerge amid significant activity in developing new treatments for metastatic colorectal cancer. Recently at a major oncology congress, Merck KGaA's antibody-drug conjugate precemtabart tocentecan showed a 31% response rate in heavily pre-treated patients. Earlier this year, a Phase III trial for a combination therapy from Pfizer, which includes Braftovi (encorafenib) and other agents, also reported improved progression-free survival. These advances are critical for a disease that causes nearly 900,000 deaths globally each year.
PDS Biotech, the developer of PDS01ADC, stated the early results support further development of their targeted immune-based approach. The company plans to engage with regulatory agencies to design later-stage trials. For patients facing a diagnosis with liver metastases, a common and challenging complication, these findings represent a hopeful step toward more effective and tolerable treatments.