Phase II study of dichloroacetate, an inhibitor of pyruvate dehydrogenase, in combination with chemoradiotherapy for unresected, locally advanced head and neck squamous cell carcinoma.

Chemoradiotherapy (CRT) for locally-advanced head and neck squamous cell carcinoma (LA-HSNCC) yields 5-year survival rates near 50% despite causing significant toxicity. Dichloroacetate (DCA), a pyruvate dehydrogenase kinase metabolic inhibitor, reduces tumor lactate production and has been used in cancer therapy previously. The safety of adding this agent to CRT is unknown. Our randomized, placebo-controlled, double-blind phase II study added DCA to cisplatin-based CRT in patients with LA-HNSCC. The primary endpoint was safety by adverse events (AEs). Secondary endpoints compared efficacy via 3-month end-of-treatment response, 5-year progression-free and overall survival. Translational research evaluated pharmacodynamics of serum metabolite response. 45 participants (21 DCA, 24 Placebo) were enrolled from May 2011-April 2014. Higher rates of all-grade drug related fevers (43% vs 8%, p = 0.01) and decreased platelet count (67% vs 33%, p = 0.02) were seen in DCA versus placebo. However, there were no significant differences in grade 3/4 AE rates. Treatment compliance to DCA/placebo, radiation therapy, and cisplatin showed no significant difference between groups. While end-of-treatment complete response rates were significantly higher in the DCA group compared to placebo (71.4% vs 37.5%, p = 0.0362), survival outcomes were not significantly different between groups. Treatment to baseline metabolites demonstrated a significant drop in pyruvate (0.47, p < 0.005) and lactate (0.61, p < 0.005) in the DCA group. Adding DCA to cisplatin-based CRT appears safe with no detrimental effect on survival and expected metabolite changes compared to placebo. This supports further investigation into combining metabolic agents to CRT. Trial registration number: NCT01386632, Date of Registration: July 1, 2011.

Safety and Efficacy of Pembrolizumab With Chemoradiotherapy in Locally Advanced Head and Neck Squamous Cell Carcinoma: A Phase IB Study.

PURPOSE: Pembrolizumab is a humanized monoclonal antibody that blocks interaction between programmed death receptor-1 (PD-1) and its ligands (PD-L1, PD-L2). Although pembrolizumab is approved for recurrent/metastatic head and neck squamous cell carcinoma (HNSCC), its role in the management of locally advanced (LA) disease is not defined. We report a phase IB study evaluating the safety and efficacy of adding pembrolizumab to cisplatin-based chemoradiotherapy in patients with LA HNSCC. PATIENTS AND METHODS: Eligible patients included those with oral cavity (excluding lip), oropharyngeal, hypopharyngeal, or laryngeal stage III to IVB HNSCC (according to American Joint Committee on Cancer, 7th edition, staging system) eligible for cisplatin-based, standard-dose (70 Gy) chemoradiotherapy. Pembrolizumab was administered concurrently with and after chemoradiotherapy with weekly cisplatin. Safety was the primary end point and was determined by incidence of chemoradiotherapy adverse events (AEs) and immune-related AEs (irAEs). Efficacy was defined as complete response (CR) rate on end-of-treatment (EOT) imaging or with pathologic confirmation at 100 days postradiotherapy completion. Key secondary end points included overall (OS) and progression-free survival (PFS). RESULTS: The study accrued 59 patients (human papillomavirus [HPV] positive, n = 34; HPV negative, n = 25) from November 2015 to October 2018. Five patients (8.8%) required discontinuation of pembrolizumab because of irAEs, all of which occurred during concurrent chemoradiotherapy; 98.3% of patients completed the full planned treatment dose (70 Gy) of radiotherapy without any delays ≥ 5 days; 88.1% of patients completed the goal cisplatin dose of ≥ 200 mg/m2. EOT CR rates were 85.3% and 78.3% for those with HPV-positive and -negative HNSCC, respectively. CONCLUSION: Pembrolizumab in combination with weekly cisplatin-based chemoradiotherapy is safe and does not impair delivery of curative radiotherapy or chemotherapy in HNSCC. Early efficacy data support further investigation of this approach.