Clinical Design and Treatment Strategy

The E1305 trial, conducted by the National Cancer Institute (NCI) and ECOG-ACRIN, was a completed Phase 3 trial that randomized 403 patients with recurrent or metastatic squamous cell carcinoma of the head and neck. The experimental group received Avastin (bevacizumab) in addition to investigator-choice, platinum-based doublet chemotherapy, while the control group received the same chemotherapy alone. Avastin, from Roche's Genentech, is a marketed monoclonal antibody that inhibits vascular endothelial growth factor A (VEGF-A) and suppresses tumor angiogenesis. In the trial, it was administered intravenously every three weeks at a dose of 15 mg/kg until disease progression.

Efficacy Results and Clinical Interpretation

The primary endpoint, median overall survival, was 12.6 months in the combination group and 11.0 months in the control group, with a hazard ratio of 0.87, a 95% confidence interval of 0.70 to 1.09, and a p-value of 0.22. This did not achieve statistically significant survival benefits, and therefore does not provide a Phase 3 basis to support the expansion of the indication for head and neck cancer. Progression-free survival was 6.0 months in the combination group and 4.3 months in the control group, with a hazard ratio of 0.70 and a p-value of 0.0014. Objective response rate was also improved, at 35.5% versus 24.5%, with a p-value of 0.016. The key point is that the tumor suppression effect did not translate into improved overall survival, which is interpreted as a result of treatment toxicity and subsequent treatment limiting the net effect.

Regulatory Status and Competitive Landscape

Avastin is a marketed drug that received FDA approval on February 26, 2004, but it is not approved for squamous cell carcinoma of the head and neck, so the E1305 combination was used for clinical trial purposes. Currently, the primary standard of care for recurrent or metastatic disease is Keytruda (pembrolizumab, a PD-1 inhibitor) from Merck (MRK), and the FDA approved platinum and 5-fluorouracil combination therapy for all patients and monotherapy for patients with PD-L1 CPS ≥ 1 on June 10, 2019. Competing treatments include Erbitux (cetuximab, an EGFR inhibitor) and platinum and 5-fluorouracil in the EXTREME regimen, as well as taxane-based chemotherapy. Compared to the survival benefits of immune checkpoint inhibitors in the KEYNOTE-048 trial, the improvement in progression-free survival with Avastin combination alone is not sufficient to replace the standard of care.

Market and Industry Significance

The global market for squamous cell carcinoma of the head and neck was estimated at approximately USD 2.3 billion in 2024 and is expected to reach USD 3.8 billion in 2030. However, since Avastin did not improve overall survival in this indication, it is difficult to view it as an asset that has created additional revenue opportunities or a new exclusive market for Roche. From a research perspective, it has demonstrated that VEGF-A inhibition can increase response rate and disease control, but may fail to provide survival benefits, highlighting the importance of patient selection biomarkers and immune checkpoint inhibitor combination designs in future development. Compared to bevacizumab, which is already facing generic and biosimilar competition, PD-1-based therapies are driving the commercial value and clinical development direction of this market.