A phase I study of erlotinib and hydroxychloroquine in advanced non-small-cell lung cancer

Abstract

Introduction: This investigator-initiated study explores the safety, maximum tolerated dose, clinical response, and pharmacokinetics of hydroxychloroquine (HCQ) with and without erlotinib in patients with advanced non-small-cell lung cancer.

Methods: Patients with prior clinical benefit from an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor were randomized to HCQ or HCQ plus erlotinib in a 3 + 3 dose-escalation schema.

Results: Twenty-seven patients were treated, eight with HCQ (arm A) and 19 with HCQ plus erlotinib (arm B). EGFR mutations were detected in 74% of the patients and 85% had received two or more prior therapies. Arm A had no dose-limiting toxicities, but the maximum tolerated dose was not reached as this arm closed early to increase overall study accrual. In arm B, one patient each experienced grade 3 rash, nail changes, skin changes, nausea, dehydration, and neutropenia; one had grade 4 anemia; and one developed fatal pneumonitis, all considered unrelated to HCQ. There were no dose-limiting toxicities, therefore the highest tested dose for HCQ with erlotinib 150 mg was 1000 mg daily. One patient had a partial response to erlotinib/HCQ, for an overall response rate of 5% (95% confidence interval, 1-25). This patient had an EGFR mutation and remained on therapy for 20 months. Administration of HCQ did not alter the pharmacokinetics of erlotinib.

Conclusions: HCQ with or without erlotinib was safe and well tolerated. The recommended phase 2 dose of HCQ was 1000 mg when given in combination with erlotinib 150 mg.

Figure 1. Disruption of drug resistance by chloroquine or hydroxychloroquine

(A) Photomicrographs illustrating the morphology of untreated PC9 NSCLC cells and three representative clones that had been selected for resistance either to gefitinib (GR3) or erlotinib (ER3 and ER4) by continuous culture in 1 micromolar (μM) drug for several weeks. (B). Viability of parental PC9 cells and several gefitinib-resistant (GR) or erlotinib-resistant (ER) PC9-derived clones following 72 hr treatment with 10 μM chloroquine (CQ), as measured using SYTO60 nuclear staining. (C) Comparison of the effects of CQ and hydroxychloroquine (HCQ) on the viability of representative tested resistant clones using the assay described in B. (D). Upper panels: Representative plates of cells stained with SYTO60 following drug treatment in the presence or absence of HCQ for the indicated number of days. Included are PC9 cells treated with erlotinib (ERL) or cisplatin (CISPLAT), the HER2-amplified breast cancer cell line SKBR3, treated with the HER2 kinase inhibitor lapatinib (LAPAT), and the BRAF mutant melanoma cell line M14 treated with the RAF kinase inhibitor AZ628. Lower panels: Graphs depicting the quantitative analysis of drug-resistant colonies detected, as averaged from three independent plates, with error bars representing the standard deviation.

Figure 2. Individual response to therapy

Bars indicate the individual patient best response to treatment expressed as a percent change of tumor burden compared to baseline for HCQ alone (white) and HCQ plus erlotinib (black).

Figure 3. Pharmacokinetic Assays

Cmin^ss is measured in whole blood (A) and plasma (B). Data points represent Cmin^ss values for individual patients who received HCQ alone (open markers) or in combination with erlotinib (closed markers). The solid bars depict mean values of the Cmin^ss for the group of patients evaluated at each dose level.