Veliparib may delay progression in extensive-stage small cell lung cancer

Use of the oral PARP inhibitor veliparib in the first-line and maintenance settings appears to confer progression-free survival (PFS) benefit on patients with extensive-stage small cell lung cancer (ED-SCLC), according to the results of a phase II trial.

A total of 181 treatment-naïve patients with ED-SCLC were randomly assigned to the following treatment groups: (1) veliparib 240 mg twice daily for 14 days plus chemotherapy (carboplatin and etoposide) followed by veliparib maintenance (400 mg twice daily; veliparib throughout group), (2) veliparib plus chemotherapy followed by placebo (veliparib combination group), or placebo plus chemotherapy followed by placebo (control).

All patients received four to six cycles of combination therapy, then maintenance until unacceptable toxicity/progression.

The primary endpoint of PFS was significantly longer in the veliparib throughout than in the control group (median, 5.8 vs 5.6 months; hazard ratio [HR], 0.67, 80 percent confidence interval [CI], 0.50–0.88; p=0.059).

Among patients with SLFN11-positive disease, use of veliparib throughout likewise showed a trend toward improved PFS as compared with control treatment (HR, 0.6, 80 percent CI, 0.36–0.97).

However, there was no significant difference in overall survival seen between the veliparib throughout and control groups (median, 10.1 versus 12.4 months, respectively; HR, 1.43, 80 percent CI, 1.09–1.88).

In terms of safety, higher grade (3 and 4) adverse events (AEs) occurred in 82 percent of patients in the veliparib throughout group, 88 percent in the veliparib combination group, and 68 percent in the control group. The most common AEs were haematologic events.

More studies are needed to define the role of biomarkers in this setting.