TEMHEAD: a single-arm multicentre phase II study of temsirolimus in platin- and cetuximab refractory recurrent and/or metastatic squamous cell carcinoma of the head and neck (SCCHN) of the German SCCHN Group (AIO)

Background: Squamous cell carcinoma of the head and neck (SCCHN) is a common disease, which has a poor prognosis after failure of therapy. Activation of the PI3K-AKT-mTOR axis is commonly detected in recurrent or metastatic SCCHN, and provided the rationale for the clinical phase II trial in pretreated SCCHN. Patients and methods: The primary end point was the progression-free survival rate (PFR) at 12 weeks. Forty eligible patients have been recruited after failure of platinum chemotherapy and cetuximab. A preplanned futility analysis was successfully passed after >= 1 success was detected in 20 patients. Secondary objectives consisted of progression-free survival (PFS), disease control rate (DCR), overall survival (OS), safety and tolerability, and predictive biomarkers for KRAS, BRAF, PIK3CA mutations, and HPV status. Archived tumor tissue was analyzed for DNA sequence. Results: A total of 40 patients were eligible. The PFR at 12 weeks was 40% (95% CI 25.0-54.6). The median PFS and OS were 56 days (95% CI 36-113 days) and 152 days (76-256 days), respectively. In 33 assessable patients, disease stabilization occurred in 57.6%, with tumor shrinkage in 13 patients (39.4%). Overall, the treatment was well tolerated. Fatigue (47.5%), anemia (25.0%), nausea (20.0%), and pneumonia (20.0%) were the most common adverse events. Neither PIK3CA mutations, nor HPV status were predictive for success with temsirolimus treatment. No mutations were found for KRAS or BRAF. Conclusion: Tumor shrinkage and efficacy parameter indicate that inhibition of the PI3K-AKT-mTOR axis was a putative novel treatment paradigm for SCCHN. We could not identify parameters predictive for treatment success of temsirolimus, which underscores the need for refinement of the molecular analysis in future studies.