UC San Diego

Introduction

First-line epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor treatment of advanced non-small-cell lung cancer with EGFR-activating mutations improves outcomes compared with chemotherapy, but resistance develops in most patients. Compensatory signaling through type 1 insulin-like growth factor 1 receptor (IGF-1R) may contribute to resistance; dual blockade of IGF-1R and EGFR may improve outcomes.

Patients and methods

We performed a randomized, double-blind, placebo-controlled phase II study of linsitinib, a dual IGF-1R and insulin receptor tyrosine kinase inhibitor, plus erlotinib versus placebo plus erlotinib in chemotherapy-naive patients with EGFR-mutation positive, advanced non-small-cell lung cancer. Patients received linsitinib 150 mg twice daily or placebo plus erlotinib 150 mg once daily on continuous 21-day cycles. The primary end point was progression-free survival.

Results

After randomization of 88 patients (44 each arm), the trial was unblinded early owing to inferiority in the linsitinib arm. The median progression-free survival for the linsitinib versus the placebo group was 8.4 months versus 12.4 months (hazard ratio, 1.37; P = .29). Overall response rate (47.7% vs. 75.0%; P = .02) and disease control rate (77.3% vs. 95.5%; P = .03) were also inferior. Whereas most adverse events were ≤ grade 2, linsitinib plus erlotinib was associated with increased adverse events that led to decreased erlotinib exposure (median days, 228 vs. 305). No drug-drug interaction was suggested by pharmacokinetic and pharmacodynamic results.

Conclusion

Adding linsitinib to erlotinib resulted in inferior outcomes compared with erlotinib alone. Further understanding of the signaling pathways and a biomarker that can predict efficacy is needed prior to further clinical development of IGF-1R inhibitors in lung cancer.