A Dose-finding Study Followed by a Phase II Randomized, Placebo-controlled Trial of Chemoradiotherapy With or Without...

We conducted a 2-part study to evaluate the incorporation of veliparib, a PARP inhibitor, into chemoradiotherapy (CRT) for stage III non-small-cell lung cancer.

In the phase I part, patients were treated successively at 3 dose levels of veliparib (40, 80, and 120 mg) twice daily during CRT. In the phase II part, patients were randomized to receive veliparib or placebo during thoracic radiotherapy with concurrent weekly carboplatin and paclitaxel, followed by 2 cycles of consolidation carboplatin and paclitaxel with veliparib or placebo. The study was prematurely discontinued owing to the emergence of adjuvant immunotherapy as standard of care.

Of 21 patients enrolled in phase I, 2 patients developed dose-limiting toxicities (DLTs): 1 grade 3 esophagitis with dysphagia (at 40 mg) and 1 grade 3 esophagitis with dehydration (at 80 mg). No DLTs were seen at veliparib dose of 120 mg twice daily, which was selected for the phase II part that enrolled 31 eligible patients. Progression-free survival (PFS) was not different between the 2 arms (P = .20). For the veliparib and placebo arms, response rates were 56% and 69%, PFS at 1 year 47% and 46%, and overall survival at 1 year 89% and 54%, respectively.

Veliparib with CRT was feasible and well tolerated. Efficacy could not accurately be determined because of early study closure. Nonetheless, there is enthusiasm for the evaluation of PARP inhibitors in lung cancer as predictive biomarkers are being developed and combinations with immunotherapy are attractive.