Dabrafenib Versus Dabrafenib + Trametinib in BRAF-Mutated Radioactive Iodine Refractory Differentiated Thyroid Cancer: Results of a Randomized, Phase 2, Open-Label Multicenter Trial

Background: Oncogenic BRAF mutations are commonly found in advanced differentiated thyroid cancer (DTC), and reports have shown efficacy of BRAF inhibitors in these tumors. We investigated the difference in response between dabrafenib monotherapy and dabrafenib + trametinib therapy in patients with BRAF-mutated radioactive iodine refractory DTC. Methods: In this open-label randomized phase 2 multicenter trial, patients aged ≥18 years with BRAF-mutated radioactive iodine refractory DTC with progressive disease by Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 within 13 months before enrollment were eligible. Patients were randomly assigned to receive dabrafenib alone or dabrafenib + trametinib. The primary endpoint was objective response rate by modified RECIST (minor response of -20% to -29%, partial and complete response) within the first 24 weeks of therapy. Trial Registration Number: NCT01723202. Results: A total of 53 patients were enrolled. The objective response rate (modified RECIST) was 42% (11/26 [95% confidence interval {CI} 23-63%]) with dabrafenib versus 48% (13/27 [CI 29-68%]) with dabrafenib + trametinib (p = 0.67). Objective response rate (RECIST 1.1) was 35% (9/26 [CI 17-56%]) with dabrafenib and 30% (8/27 [CI 14-51%]) with dabrafenib + trametinib. Most common treatment-related adverse events included skin and subcutaneous tissue disorders (17/26, 65%), fever (13/26, 50%), hyperglycemia (12/26, 46%) with dabrafenib alone and fever (16/27, 59%), nausea, chills, fatigue (14/27, 52% each) with dabrafenib + trametinib. There were no treatment-related deaths. Conclusions: Combination dabrafenib + trametinib was not superior in efficacy compared to dabrafenib monotherapy in patients with BRAF-mutated radioiodine refractory progressive DTC.

A pilot study of the pan-class I PI3K inhibitor buparlisib in combination with cetuximab in patients with recurrent or metastatic head and neck cancer

BACKGROUND

This study assessed the maximum tolerated dose (MTD) of the PI3K inhibitor buparlisib given concurrently with cetuximab in recurrent and metastatic (R/M) head and neck squamous cell carcinoma (HNSCC).

METHODS

Twelve patients with R/M HNSCC were enrolled. Patients were given oral buparlisib starting day 7 and daily thereafter. The dose of buparlisib was escalated in a 3 + 3 design followed by a dose expansion cohort of 6 patients. The MTD of buparlisib per protocol was 100 mg daily with cetuximab given intravenously every 14 days starting day 0.

RESULTS

Ten patients had ≥2 previous treatment regimens (11 with prior cetuximab). There were no dose limiting toxicities observed during dose escalation. One patient achieved a partial response and 4 achieved stable disease.

CONCLUSION

Based on this pilot study, buparlisib at 100 mg daily plus cetuximab proved to be well-tolerated. Patients previously treated with cetuximab monotherapy showed benefit from this combination.