Phase I/II trial of custirsen (OGX-011), an inhibitor of clusterin, in combination with a gemcitabine and platinum regimen in patients with previously untreated advanced non-small cell lung cancer

Purpose: Clusterin (CLU), an antiapoptotic, stress-associated protein, confers resistance to therapy when overexpressed. This trial tested custirsen (OGX-011), an inhibitor of CLU protein production, combined with gemcitabine/platinum in patients with advanced non-small cell lung cancer (NSCLC). Patients and Methods: This was a single-arm, multicenter, phase I/II study in chemotherapy-naive stage IIIB/IV NSCLC. Custirsen was infused during a loading dose period and weekly in combination with gemcitabine (1250 mg/m ²) on days 1 and 8 and with cisplatin (75 mg/m²) or carboplatin (area under the curve 5) on day 1 of each 21-day cycle. Ten patients were treated in a phase I lead-in and 71 in the phase II component. The primary efficacy endpoint was response rate, with exploratory analyses of other efficacy outcomes and biomarker relationships. Results: Eighty-one patients received custirsen and were included in the primary analysis. The median age was 61 years; 82% had stage IV disease. Overall response was 25 of 81 (31%; 95% confidence interval 21-42). The 1- and 2-year survivals were 54 and 30%, respectively. Toxicity of the combination was not appreciably different from what is reported for gemcitabine/platinum combinations. Custirsen treatment decreased serum CLU levels in 95% of patients evaluated. Patients who achieved a minimum median CLU level for the population of ≤38 μg/ml during treatment had a median survival of 27.1 compared with 16.1 months for patients who did not (p = 0.02). Conclusion: Based on the above results, a randomized phase 3 trial to evaluate the survival benefit of custirsen in patients with NSCLC is warranted.