UCSF

Objectives

We report the results of this phase I study to evaluate the maximum tolerated dose (MTD) and safety of veliparib, a poly(ADP-ribose) polymerase (PARP) inhibitor, combined with carboplatin and paclitaxel induction chemotherapy (IC) for locoregionally advanced head and neck squamous cell carcinoma (HNSCC).

Materials and methods

In a 3 + 3 cohort design, patients with stage IVA-B human papillomavirus-negative HNSCC received 2 cycles of carboplatin (AUC 6, day 1), paclitaxel (100 mg/m², days 1, 8, 15) and veliparib (days 1-7) every 21 days followed by standard curative-intent chemoradiotherapy. Primary endpoint: MTD and recommended phase II dose (RP2D) as determined by the first IC cycle.

Results

Twenty patients enrolled. Two withdrew before treatment; 18 patients were analyzed. Median age was 63 years. Primary disease sites included hypopharynx (n = 5), larynx (n = 5), oral cavity (n = 4), oropharynx (n = 3), and nasal cavity (n = 1). Through all of IC, the most common grade 3 + adverse events (AEs) were neutropenia (33%), thrombocytopenia (33%), anemia (11%), and white blood cell decrease (11%). One patient experienced a hematologic DLT at 350 mg BID. The RP2D for veliparib combined with carboplatin/paclitaxel is 350 mg BID. With 40.9 month median follow-up across dose levels for all patients, the 24-month overall and progression free survival was 77.8% (95% CI 60.8-99.6%) and 66.7% (95% CI 48.1-92.4%), respectively. Medians have not been reached.

Conclusion

Addition of veliparib to carboplatin and paclitaxel IC was well tolerated in patients with advanced HNSCC. Hematologic toxicities were the most common AEs.