Abstract 3513: Hydroxychoroquine (HCQ) modulates autophagy in melanoma: preliminary results of a phase 0 trial in patients with resectable melanoma. (2013)

Abstract Autophagy enables tumors to survive metabolic stress by recycling intracellular components to sustain metabolism. This suggests that inhibiting autophagy with drugs such as HCQ, a lysosomotropic agent that blocks the final step of autophagy when autophagosomes fuse with lysosomes, may promote tumor cell death. In melanoma cell lines and animal models, HCQ administration resulted in inhibition of flux through the autophagy pathway as measured by visualization of increased numbers of autophagic vesicles (AVs) and processing of the autophagosome marker LC3 from LC3-I to LC3-II. We hypothesized that administration of HCQ can modulate autophagy in human melanoma tumors that can be detected by increased autophagic vesicle (AV) formation and by increased LC3-II/I ratio. Methods: To test this hypothesis, we conducted a phase 0 trial in patients with resectable stage III or IV melanoma. Patients who consented underwent pretreatment tumor biopsies, were treated with either 200 or 400 mg bid of HCQ for 14 days, and then underwent surgery. Paired tumor samples were processed for electron microscopy (EM) and scored by counting AVs per high powered field in multiple fields. Changes in the LC3II/I ratio were examined by Western blot. Quantitation of HCQ in blood was performed using HPLC-fluorescence method in whole blood, plasma and ultrafiltrates. Changes in AV formation on EM, LC3 II/I ratio, and pharmacokinetic (PK) data from the paired observations were to be correlated. Otherwise, the statistics utilized were descriptive. Results: 12 of 14 patients enrolled had tumor sufficient for evaluation. 8 patients were enrolled at 200 mg bid and 4 at 400 mg bid. No significant toxicities were observed. Autophagy modulation was observed in 4 of the 12 tumors as evidenced by increased LC3II/I ratio on Western blot. Observed changes in AV formation correlated with pre-post changes in LC3II/I ratio (correlation r = 0.42, p = 0.20) in this small sample size. HCQ concentrations (ssmin) showed dose proportional increases in blood, plasma and ultrafiltrate. No correlations were evident between changes on EM and HCQ concentration in plasma, whole blood, or plasma ultrafiltrates. Analyses for common driver mutations in melanoma are ongoing. Conclusions: Treatment with HCQ for 14 days resulted in increased LC3II/I ratio indicative of autophagy modulation in 1/3 of tumors from patients with resectable stage III or IV melanoma. The correlation between pre-post changes in AV formation and LC3II/I ratio suggests that LC3II/I ratio may be a useful measurement of autophagy in human tumors, as in the laboratory. The degree of modulation after 14 days of therapy did not appear to be dose or exposure dependent, although HCQ levels had likely not reached steady state at 14 days. Enrollment continues at 600 mg bid to assess if higher doses produce saturable PK, increased AV formation, and stronger correlations among them. Citation Format: Janice M. Mehnert, Xiaoqi Xie, Megha Rajpal, Liesel Dudek, Monal Mehta, Vassiliki Karantza, Murugesan Gounder, Joseph Aisner, Weichung Shih, Rajesh Patel, Chunxia Chen, James Goydos, Ravi K. Amaravadi, Eileen P. White. Hydroxychoroquine (HCQ) modulates autophagy in melanoma: preliminary results of a phase 0 trial in patients with resectable melanoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3513. doi:10.1158/1538-7445.AM2013-3513