CTEP #8342 autophagy modulation with antiangiogenic therapy: A phase I trial of sunitinib (Su) and hydroxychloroquine (HCQ).

2553 Background: Angiogenesis inhibitors promote autophagy, a response to nutrient deprivation in which autophagosomes (AP) and lysosomes fuse to recycle intracellular constituents, leading to sustained tumor viability. We hypothesized that the VEGF-R2, c-kit, PDGFR inhibitor Su induces autophagy. The autophagy inhibitor HCQ may then interfere with autophagy dependent tumor survival, possibly improving patient (pt) outcomes. Methods: This trial determined the MTD of Su+HCQ in pts with advanced malignancies using a 3+3 design. Su 50 mg qd was given in 4 week on/2 week off cycles (C) with daily HCQ in escalating dose cohorts. A MTD expansion cohort of 12 pts was also enrolled. Modulation of autophagy was measured by changes in the AP marker light chain-3 (LC3)II/I ratio in paired PBMC samples from C1 and C2. Results: 21 pts, median age 59, PS 0 (7), 1 (13) or 2 (1) enrolled, including 5 colon, 2 renal and 5 sarcomatous tumors. 4 DLTs were observed: 3 DLTs (gr 3 confusion, gr 3 colon fistula, gr 3 thrombocytopenia) in DL2 (50 mg Su, 200 mg bid HCQ), and 1 DLT (gr 3 dehydration) in DL1 (50 mg Su, 200 mg HCQ). DL1 was thus declared the MTD. Gr 3/ 4 toxicities included: related to Su, thrombocytopenia (14%), fatigue (19%), neutropenia (14%), hypertension (14%), intestinal perforation (10%); related to HCQ, fatigue (14%). PK data of Su alone, its active metabolite SU012662 and the total were evaluated using noncompartmental analysis. Cmax and AUCs of the active metabolite SU012662 significantly increased (p<0.005) during C2 relative to C1, indicating drug-drug interactions between HCQ and Su. 9 of 21 (43%) had stable disease for > 3 cycles (median 73 days). Inconsistent autophagy modulation was seen in PBMCs. LC3 immunohistochemistry on baseline tumor blocks to assess individual tumor autophagy levels is in progress. Conclusions: pK interaction between Su and HCQ resulting in accumulation of Su metabolites may be responsible for the predominantly Su-associated toxicities observed which prohibited further HCQ dose escalation. Lack of evidence for autophagy modulation is likely due to the inability to escalate HCQ to doses necessary to induce autophagy inhibition. Further study of this combination seems unwarranted. Clinical trial information: NCT00813423.