CRB-701 Cleared to Begin Phase 3 Trial: Nectin-4 Drug Challenges Second-Line Treatment for Oropharyngeal Cancer

When oropharyngeal cancer progresses after immunotherapy, patients are often left with single-agent options of limited efficacy. Corbus Pharmaceuticals said the U.S. Food and Drug Administration (FDA) has agreed to the initiation of the pivotal TEMPO-1 trial of CRB-701, formally advancing this Nectin-4-targeted antibody-drug conjugate into a stage of clinical validation that could support a marketing application.

TEMPO-1 is a randomized, controlled Phase 3 trial expected to enroll 250 patients with second-line oropharyngeal squamous cell carcinoma. Participants will receive either CRB-701 or the investigator’s choice of capecitabine, cetuximab, or docetaxel; the company expects enrollment to begin in September 2026. This design directly compares the new drug with current single-agent treatments rather than relying solely on historical data.

The trial establishes two regulatory pathways: objective response rate will serve as the primary endpoint and, if the results are sufficiently clear, could support accelerated approval; overall survival will be used to determine whether the treatment genuinely prolongs life and may support subsequent conversion to full approval. The FDA’s clearance applies to the trial plan and does not mean that CRB-701 has been confirmed as safe and effective, nor does it constitute marketing authorization for the drug.

CRB-701 uses an antibody to recognize Nectin-4 on the surface of tumor cells and then delivers the microtubule inhibitor MMAE through a cleavable linker. Nectin-4 has become a druggable target in urothelial cancer and is also found in some head and neck cancers. CRB-701 uses site-specific conjugation, with an average of two drug molecules attached to each antibody, but whether these engineering features translate into better clinical benefit remains to be answered by a controlled trial.

The rationale for advancing TEMPO-1 comes from an ongoing Phase 1/2 study. According to an analysis presented by the company at the 2026 American Society of Clinical Oncology Annual Meeting, among 21 patients with second-line or later oropharyngeal cancer in the 3.6 mg/kg dose group, nine had confirmed tumor responses, for a response rate of 42.9%; median duration of response was 6.3 months, and median progression-free survival was 5.6 months. These signals warrant further development, but they still come from a small, non-randomized dataset and are insufficient to rule out biases such as patient selection.

The increase in oropharyngeal cancer cases is closely associated with human papillomavirus infection, and the patient profile is also becoming increasingly distinct from that of head and neck cancers traditionally driven by smoking and alcohol consumption. The key for TEMPO-1 is not only to reproduce the early response rate, but also to determine whether these responses can be sustained and improve survival in a larger population with a control group, while managing the potential toxicities of an antibody-drug conjugate. Once enrollment begins, the trial’s progress, treatment discontinuations, and complete safety data will determine whether CRB-701 can translate its early signals into a practical treatment option.