A phase II trial of VNP40101M in patients with relapsed or refractory small cell lung cancer (SCLC) with or without brain metastases

Abstract

7724 Background: Relapsed or refractory SCLC patients (pts) have a poor prognosis. Median survival at relapse is 2–3 months; brain metastases (mets) are common. Alkylating agents have demonstrated activity in SCLC. Cloretazine is a new alkylator that is active against selected alkylating agent resistant tumor cell lines. Xenograft models show distribution across the blood-brain barrier. This study investigates VNP40101M safety and activity in SCLC patients who have relapsed or are refractory to standard 1st line chemotherapy. Methods: Pts are entered in 2 groups based on response to prior chemotherapy: sensitive relapse (chemotherapy-free interval >3 months); or resistant/refractory (chemotherapy-free interval ≤3 months). Eligibility criteria include: measurable or evaluable disease; life expectancy of ≥2 months; and ECOG PS of 0–2. Pts with brain mets are eligible. 31 pts received VNP40101M IV at a starting dose of 125 mg/m2/wk × 3, every 6 weeks. Due to a high incidence of grade 3–4 thrombocytopenia (34%), an amended protocol reduced the dose of VNP40101M to 100 mg/m2 at the same schedule. 13 pts received the reduced dose. Pts are evaluated by RECIST criteria after each 6-week cycle. Results: 44 of 87 planned pts have been treated at 7 sites. Of 41 evaluable pts, 21 patients have sensitive relapse disease, and 20 have resistant/refractory disease. Median age is 64 years (44–86). Median number of cycles received is 1 (1–3). Grade 3–4 thrombocytopenia was seen in 11/31 pts at the 125 mg/m2 dose and 3/13 pts at the 100 mg/m2 dose. Gr 3–4 non-hematologic toxicity is rare, except for fatigue (10%) and GI effects (10%). The response rate (PR) is 6/21 (29%) in the sensitive relapse group, and 1/20 (5%) in the resistant/refractory group. 2/6 PRs, in the sensitive relapse group, occurred at the reduced dose level. 16 pts had brain mets at study entry. Of these, there were 3 PRs (2 with measurable regression of brain mets) and 3 stable diseases. Conclusions: The study is ongoing to confirm efficacy and safety. VNP40101M has activity against SCLC in the 2nd line setting including pts with brain metastases; further study is warranted. No significant financial relationships to disclose.