Summit's Bispecific Antibody Outperforms Cancer Treatments, Challenging Keytruda's Dominance

Summit Therapeutics and Akeso's investigational bispecific antibody, ivonescimab, has demonstrated superior efficacy in non-small cell lung cancer (NSCLC) treatment, potentially reshaping the competitive landscape in oncology. Recent clinical trial results have shown ivonescimab's ability to outperform established therapies, including Merck's blockbuster drug Keytruda and BeiGene's Tevimbra.

HARMONi-6 Trial Results Bolster Ivonescimab's Potential

The Phase III HARMONi-6 trial, conducted in China, revealed that ivonescimab in combination with chemotherapy led to a "statistically significant and clinically meaningful improvement" in progression-free survival (PFS) compared to the standard of care, Tevimbra plus chemotherapy. Notably, ivonescimab maintained its PFS advantage across patients with both PD-L1 positive and negative tumors.

While specific data points were not disclosed, Summit and Akeso have promised to present detailed findings at an upcoming conference. This positive outcome follows the earlier HARMONi-2 trial results, where ivonescimab demonstrated a median PFS of 11.14 months versus Keytruda's 5.82 months, nearly halving the risk of disease progression or death.

Implications for the Cancer Treatment Landscape

Ivonescimab's dual targeting of PD-1 and VEGF pathways represents a novel approach in cancer therapy. This mechanism not only prevents cancer cells from evading the immune system but also limits tumor-sustaining blood vessel formation. BMO Capital Markets analysts suggest that these findings will "further heat up competition" in the lung cancer arena and "reflect positively" on the emerging approach of targeting both PD-1 and VEGF in cancer treatment.

The success of ivonescimab is expected to have positive implications for other companies exploring similar approaches, including BioNTech. Moreover, analysts anticipate that Merck's stock may come under pressure as Summit and Akeso strengthen their case to "challenge Keytruda's supremacy."

Global Expansion and Future Prospects

While the HARMONi-6 and HARMONi-2 trials were conducted exclusively in China, raising questions about the generalizability of results, Summit is currently enrolling patients in the global HARMONi-3 trial. This study is being conducted with "registrational intent" in the United States, potentially paving the way for FDA approval.

Truist Securities analysts expressed optimism about the HARMONi-6 results, suggesting "several positive read-throughs" to the ongoing HARMONi-3 trial. An interim analysis from this global study is expected in the fourth quarter of 2026, with final results anticipated in early 2028.

As the bispecific antibody continues to demonstrate promising results, the pharmaceutical industry watches closely to see if ivonescimab will indeed become the "Keytruda slayer" that some analysts have speculated it could be.