Management of Older Patients With Metastatic Renal Cell Carcinoma Receiving Sunitinib: A Hypothetical, Illustrative Case Scenario.

CASE STUDY Tom, a 75-year-old white male, was recently diagnosed with metastatic renal cell carcinoma (RCC; Tom's case is not an actual clinical case but has been developed by the authors as an exemplar). Two years prior, he had undergone a left partial (laparoscopic) nephrectomy for clear cell RCC. At that time, he had a stage 3 disease (the tumor extended into perinephric tissues but not into the ipsilateral adrenal gland and not beyond Gerota's fascia [Cancer.net, 2016]), and regularly (every 3-6 months) scheduled surveillance imaging did not show metastatic disease. Recent imaging with a computed tomography (CT) of the chest/abdomen/pelvis revealed small bilateral pulmonary nodules that did not have the radiographic appearance of a primary lung tumor, but rather that of metastatic disease. Therefore, a decision was made to repeat CT scans in a shorter interval (in 6 weeks) to assess growth kinetics. Subsequent CT scan showed an increase in size and number of pulmonary nodules, so the decision was made to begin systemic treatment. At the time of Tom's metastatic evaluation, his Eastern Cooperative Oncology Group performance status was 0 as he was asymptomatic and fully active (Table 1). He was classified as favorable risk according to Heng criteria (Table 2). Tom is married and lives with his wife. He is independent in his self-care but also relies on his wife for health-care decision-making. He does not drink alcohol and is a former smoker with a history of 30 pack-years. Tom's medical history includes hypertension that is adequately controlled with lisinopril (20 mg/day), coronary artery disease (on daily aspirin 81 mg) with left ventricular ejection fraction (LVEF) of > 50%, which is within the normal range (50%-75%), benign prostatic hyperplasia for which he is treated with finasteride, and hyperlipidemia that is treated with atorvastatin.

Phase I study of the mTOR inhibitor ridaforolimus and the HDAC inhibitor vorinostat in advanced renal cell carcinoma and other solid tumors.

INTRODUCTION: Drugs inhibiting the mammalian target of rapamycin (mTOR) are approved in the treatment of renal cell carcinoma (RCC), but resistance inevitably emerges. Proposed escape pathways include increased phosphorylation of Akt, which can be down regulated by histone deacetylase (HDAC) inhibitors. We hypothesized that co-treatment with the mTOR inhibitor ridaforolimus and the HDAC inhibitor vorinostat may abrogate resistance in RCC. METHODS: This phase 1 study evaluated the co-administration of ridaforolimus and vorinostat in patients with advanced solid tumors. The primary objective was to determine the maximum tolerated dose (MTD) in RCC patients. Although all solid tumors were allowed, prior cytotoxic chemotherapy was limited to 1 regimen. Using a modified 3 + 3 dose escalation design, various dose combinations were tested concurrently in separate cohorts. Efficacy was a secondary endpoint. RESULTS: Fifteen patients were treated at one of three dose levels, thirteen with RCC (10 clear cell, 3 papillary). Dosing was limited by thrombocytopenia. The MTD was determined to be ridaforolimus 20 mg daily days 1-5 with vorinostat 100 mg BID days 1-3 weekly, however late onset thrombocytopenia led to a lower recommended phase II dose: ridaforolimus 20 mg daily days 1-5 with vorinostat 100 mg daily days 1-3 weekly. Two patients, both with papillary RCC, maintained disease control for 54 and 80 weeks, respectively. CONCLUSIONS: The combination of ridaforolimus and vorinostat was tolerable at the recommended phase II dose. Two patients with papillary RCC experienced prolonged disease stabilization, thus further study of combined HDAC and mTOR inhibition in this population is warranted.

A phase I study of temsirolimus and bryostatin-1 in patients with metastatic renal cell carcinoma and soft tissue sarcoma.

BACKGROUND: Temsirolimus, an inhibitor of mammalian target of rapamycin (mTOR) complex 1, is approved for the treatment of metastatic renal cell carcinoma (RCC). Bryostatin-1 inhibits protein kinase C, a downstream effector of mTOR complex 2. We observed antitumor effects with the combination of temsirolimus and bryostatin-1 in RCC cell lines. METHODS. Four cohorts of patients received weekly bryostatin-1 (20 µg/m²) with temsirolimus (10, 15, 25, or 37.5 mg) in 28-day cycles. RESULTS: Thirty patients received a total of 138 cycles across four dose levels. Twenty-five patients had RCC (17 clear cell, 7 papillary, and 1 unclassified). Two sarcoma patients with prior cytotoxic therapy experienced dose-limiting toxicity at 15 mg of temsirolimus (grade 3 neutropenia and grade 3 hypophosphatemia). Subsequently, patients with prior cytotoxic therapy were excluded. Two additional dose-limiting toxicities were noted with 37.5 mg of temsirolimus (grade 3 neutropenia and grade 3 creatinine elevation). Consequently, the maximum tolerated dose was defined as temsirolimus at 25 mg and bryostatin-1 at 20 µg/m² every 28 days. Of the 25 RCC patients, 3 patients had partial responses that lasted for 14 months, 28 months, and ≥ 80 months, respectively. Partial responses were seen in both clear cell and papillary histology. CONCLUSION: This combination of 37.5 mg of temsirolimus with 20 µg/m² of bryostatin-1 was reasonably safe and well tolerated. Durable responses were observed in 3 of 25 patients with RCC.