Biomodulatory Treatment of Patients with Castration-Resistant Prostate Cancer: A Phase II Study of Imatinib with Pioglitazone, Etoricoxib, Dexamethasone and Low-Dose Treosulfan

Therapeutic options for patients with castration-resistant prostate cancer (CRPC) remain limited. In a multicenter, Phase II study, 65 patients with histologically confirmed CRPC received a biomodulatory regimen during the six-month core study. Treatment comprised daily doses of imatinib mesylate, pioglitazone, etoricoxib, treosulfan and dexamethasone. The primary endpoint was prostate-specific antigen (PSA) response. Responders could enter an extension phase until disease progression or intolerable toxicity occurred. Mean PSA was 45.3 ng/mL at baseline, and 77 % of patients had a PSA doubling time <3 months. Of the 61 evaluable patients, 37 patients (60.6 %) responded or had stable disease and 23 of them (37.7 % of 61 patients) were PSA responders. Among the 23 responders mean PSA decreased from 278.9 ± 784.1 ng/mL at baseline to 8.8 ± 11.6 ng/mL at the final visit (week 24). The progression-free survival (PFS) was 467 days in the ITT population. Of the 947 adverse events, 57.6 % were suspected to be drug-related, 13.8 % led to dose adjustment or permanent discontinuation and 40.2 % required concomitant medication. This novel combination approach led to an impressive PSA response rate of 37.7 % in CRPC patients. The good PSA response and PFS rate combined with the manageable toxicity profile suggest an alternative treatment option.

The effect of zoledronic acid on bone metastasis in patients suffering from renal cell cancer (RCC): A German prospective single-arm clinical trial

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Background: The incidence of RCC increased over the last decades and about 30% of patients will develop bone metastasis. These pts. face considerable skeletal morbidity e.g. bone pain, pathologic fractures, spinal cord compression or tumor induced hypercalcemia (TIH). A prospective trial was initiated in RCC metastatic to bone evaluating the SRE (skeletal related event) rate under therapy with zoledronic acid (ZA). Primary objective was the proportion of pts. with at least one SRE after 12 months. Methods: Patients with RCC must have had ≥1 bone metastasis and ≤2 prior applications of a bisphosphonate. Bone lesions were diagnosed by bone scan and ≥1 lesion was confirmed using X-ray, CT or MRI. Pts. passed a 12 months treatment period receiving 4 mg ZA every 3 weeks. Pts. were followed every 3 weeks for 54 weeks for development of SREs (radiation or surgery to bone, spinal cord compression, pathologic bone fractures) and TIH. A bone scan was done, if AP or LDH were >2xULN or symptoms occurred. Suspected SRE was confirmed by X-ray, CT or MRI. After end of treatment patients entered a survival follow-up. Results: 51 pts. participated in the study. Median age was 63 years and 2/3 were male. Proportions of MSKCC risk groups good/intermediate/poor for pretreated pts. were 8%, 56%, and 18%, respectively. 78% of pts. suffered from ≤6 bone metastases. 18% had already experienced at least one SRE before study entry. 26% obtained prior medications, mainly interferons (20%), interleukins (16%) and chemotherapy (16%). 25 pts. completed the 12 months treatment period. Based on a preliminary analysis 13 pts. (26%) experienced at least one SRE with an absolute number of 23 events. No TIH was observed. Bone lesions response was observed in 3 pts. (2 CR, 1 PR) out of 33 pts. currently available. Final efficacy and safety results of the 12 months treatment phase will be shown at presentation. Conclusions: Pts. with mRCC and bone metastases are at high risk for experiencing an SRE with a reported incidence of up to 74%. This is the first study prospectively evaluating SRE rate in patients with mRCC and bone lesions receiving ZA. A preliminary analysis indicates an SRE-rate of 26% and no TIH was observed. Final results of this trial could further support the use of ZA in mRCC.

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