Phase 2 Study of Hydroxychloroquine to Increase Tumor Suppressor PAR-4 Levels in Oligometastatic Prostate Cancer

This investigator-initiated clinical trial (IIT) builds on and extends research on autophagy in prostate cancer with PAR-4 and HCQ conducted by a transdisciplinary investigative team, and is sponsored by funding from Markey Cancer Center.

Prostate cancer is the most common cancer in men and the 2nd most common cause of cancer death in men. Secondary to the greying of the U.S. population and increasing life expectancy, metastatic prostate cancer (mPCa) rates are increasing. Androgen deprivation therapy (ADT) has been the primary treatment for metastatic prostate cancer. The survival benefit of ADT is juxtaposed against significant adverse effects including cardiovascular morbidity, skeletal fractures, diabetes, sexual dysfunction, and a decrease in cognitive function. Recent studies have indicated a potential benefit to treatment of metastatic lesions in men with limited metastatic disease and have identified a potential delay in initiation of ADT in men whose limited metastatic lesions were treated with stereotactic radiotherapy. Prostate apoptosis response-4 (PAR-4) is a tumor suppressor protein that facilitates apoptosis in numerous types of cancer cells. Hydroxychloroquine (HCQ) has been found to induce PAR-4 expression and subsequently promote apoptosis of cancer cells and inhibit metastatic progression. HCQ has also been reported to both inhibit and enhance immune responses via changes in Th1, Th2, Th17 and Treg subsets and reduce inflammatory markers. It also acidifies lysosomes which potentially inhibits antigen presentation by antigen-presenting cells, and can be measured with LysoSensor Yellow/Blue DND-160 by flow cytometry and induces autophagy which can be detected by measuring up-regulation of the microtubule associated protein LC3B. Treatment of oligometastatic prostate cancer may be enhanced by the addition of Hydroxychloroquine to either surgical resection or radiation treatment of metastatic lesions. Potential benefits of Hydroxychloroquine include delayed disease progression and delayed initiation of ADT, lessening morbidity and increasing quality of life in men with oligometastatic prostate cancer.

A single-arm, open-label phase II trial will be conducted in a population of men with recurrent oligometastatic prostate cancer following primary treatment of localized disease. The oligometastatic sites will be treated with either surgical resection or stereotactic radiation per standard of care, in addition to 400 mg of Hydroxychloroquine per day for a period of 3 months.

Sample Size:

Based on an ongoing Phase I trial of HCQ, the proportion of patients who will exhibit a 50% induction in PAR-4 from baseline levels is equal to 0.50, compared to a null hypothesis of 0.20. A sample of 18 patients will provide 84% power to detect this hypothesized difference in proportion based on a two-sided test with 5% significance level. Prior studies at Markey Cancer Center in this population have demonstrated an attrition rate of less than a 10%. Thus, a total of 20 patients will be enrolled into the study.