Nectin-4 Antibody-Drug Conjugate Targets Second-Line Oropharyngeal Cancer as CRB-701 Cleared to Begin Registrational Trial

Patients with oropharyngeal cancer have limited options after first-line treatment fails, and responses are often not durable. The U.S. Food and Drug Administration (FDA) has cleared Corbus Pharmaceuticals to initiate the registrational TEMPO-1 trial evaluating CRB-701, a Nectin-4-targeting antibody-drug conjugate, as second-line treatment for oropharyngeal squamous cell carcinoma. The company expects enrollment to begin in September 2026.

TEMPO-1 plans to enroll 250 patients, who will be randomized to receive either CRB-701 or the investigator’s choice of capecitabine, cetuximab, or docetaxel. The primary endpoint is objective response rate. If the result meets the target, the company hopes to use it to seek accelerated approval; overall survival will be used to support a future conversion to full approval. This design evaluates the more rapidly obtainable tumor-shrinkage signal separately from the more clinically meaningful survival outcome, which requires longer follow-up.

CRB-701 is also known as SYS6002 within the CSPC Pharmaceutical Group system. It uses an antibody to recognize Nectin-4 on the tumor surface and then delivers the microtubule inhibitor MMAE through a cleavable linker. It has a drug-to-antibody ratio of 2 and uses site-specific conjugation to reduce variation in product composition. Nectin-4 has been clinically validated in urothelial cancer and is also found in some head and neck and cervical tumors, but whether expression of the marker can translate into consistent efficacy must still be confirmed separately in each cancer type.

The early signal supporting the FDA’s clearance came from an ongoing Phase 1/2 study. According to an analysis released by Corbus, patients with second-line or later oropharyngeal squamous cell carcinoma who received a dose of 3.6 mg/kg had a confirmed objective response rate of 42.9%, a median duration of response of 6.3 months, and median progression-free survival of 5.6 months. CSPC Pharmaceutical Group subsequently also announced confirmation that the FDA had agreed to this second-line registrational trial.

These figures provide a rationale for proceeding to a randomized study, but they do not yet prove that CRB-701 is superior to existing treatments. In the same summary, the company’s announcement did not provide the full number of patients in the dose subgroup, all safety results, or outcomes across different biomarker populations. Early single-arm data are also susceptible to the effects of patient selection and sample size. TEMPO-1’s control arm, toxicity data, and overall survival results will be central to assessing the benefit-risk profile.

FDA clearance of a clinical trial means that the study may proceed as planned; it does not mean that the drug has been approved for marketing or that its efficacy has been endorsed. The original market report noted that the relevant shares fell by about 4% at one point, but short-term share-price movements cannot answer clinical questions. For CRB-701, the true dividing line will be whether it can reproduce the responses in a larger, controlled patient population and ultimately deliver a survival benefit.