100 Inhibition of PDGFRalpha in tumor stroma with MEDI-575 enhances activity of carboplatin/paclitaxel and delays tumor regrowth in a NSCLC xenograft model

Phase 1b/2 Randomized Study of MEDI-575 in Combination With Carboplatin Plus Paclitaxel Versus Carboplatin Plus Paclitaxel Alone in Adult Patients With Previously Untreated Advanced Non-Small-Cell Lung Cancer

INTRODUCTION

Platinum doublet chemotherapy has represented the standard of care in advanced non-small-cell lung cancer for decades. Targeting platelet-derived growth factor receptors (PDGFR) is a potential mechanism to improve the efficacy of first-line therapy. This randomized phase 1b/2 trial investigated the addition of the anti-PDGFRα monoclonal antibody MEDI-575 to first-line carboplatin/paclitaxel (CP) chemotherapy.

PATIENTS AND METHODS

The phase 1b component was a dose-escalation study combining MEDI-575 with carboplatin area under the plasma concentration versus time curve 6 and paclitaxel 200 mg/m² (CPM), with the end point of identifying a recommended phase 2 dose. The phase 2 component randomized patients to CPM or CP, with primary end point of progression-free survival. Secondary end points included overall survival, overall response rate, and adverse event rates.

RESULTS

Overall, 99 patients were enrolled and received either CPM (n = 53; 4 phase 1b, 49 phase 2) or CP (n = 46). Demographics were as follows: 63/36 male/female, 78/21 aged ≤ 70/> 70 years; 37/62 squamous/nonsquamous, 42/53 Eastern Cooperative Oncology Group performance status 0/1. The phase 2 portion of the trial did not meet its primary end point: progression-free survival was shorter with CPM (4.6 vs. 5.5 months) than CP. No significant difference was seen in overall response rate (31.7% vs. 22.5%) or median overall survival (10.0 vs. 11.8 months). More serious adverse events were observed in patients receiving CPM (47% vs. 40%); in particular, 9 patients in the CPM group had significant gastrointestinal or respiratory adverse events (including abscess, perforation, and pneumothorax).

CONCLUSION

The addition of MEDI-575 to CP chemotherapy as first-line treatment of advanced non-small-cell lung cancer did not improve efficacy and resulted in increased toxicity.