Cost-Effectiveness and Survival of HRPC Treatments

New Orleans—To determine survival benefits for patients with hormone-refractory prostate cancer (HRPC), researchers conducted a cost-effectiveness analysis that looked at the comparative economics of treating HRPC with sipuleucel-T and docetaxel with prednisone. The findings suggested that sipuleucel-T is not a cost-effective option; however, it is an appropriate treatment strategy when healthcare providers are willing to pay the $34,912 per additional life-month gained over docetaxel plus prednisone. The results were presented at the ASHP meeting during a poster presentation titled Life Extension in Hormone Refractory Prostate Cancer: A Cost-Effectiveness Analysis of Docetaxel and Sipuleucel-T. Before the US Food and Drug Administration approved sipuleucel-T in April 2010, docetaxel was the only HRPC treatment regimen. The median survival time for patients with HRPC who receive docetaxel-based therapy is approximately 19 months. However, docetaxel is associated with myriad adverse effects.

To help guide appropriate therapy decisions, the study’s objective was to compare sipuleucel-T and associated side effects to determine the cost-effectiveness of these available options. The study analyzed the cost-effectiveness of the 2 therapies, as well as compared the cost-effectiveness ratio of sipuleucel-T with docetaxel plus prednisone. Patients in the docetaxel plus prednisone group were selected from the TAX 327 trial, a randomized, multicenter, nonblinded phase 3 study. They were treated with 10 cycles of docetaxel 75 mg/m2 as a 1-hour outpatient infusion every 3 weeks along with prednisone 5 mg by mouth twice a day and dexamethasone 8 mg by mouth at 12, 3, and 1 hour before infusion. For the sipuleucel-T arm, patients were selected from the IMPACT (Immunotherapy Prostate Adenocarcinoma Treatment) trial and were treated with three 1-hour infusions of sipuleucel-T. The researchers determined treatment costs from a third-party payer perspective, and included costs of drugs, administration, and management of associated side effects. They created a decision tree to evaluate the cost-effectiveness of both treatments.

The results from the TAX 327 trial showed an increase in median survival of 2.4 months for the docetaxel plus prednisone group compared with non–life-extending therapy. Data from the IMPACT trial showed an increase in median survival of 4.1 months for the sipuleucel-T group compared with placebo. Sipuleucel-T increased patient life expectancy by an average of 1.7 months with an increased cost of $59,350, resulting in an incremental cost-effectiveness ratio (ICER) of $34,912 per life-month gained, compared with docetaxel plus prednisone. The decision tree also incorporated probabilities of acquiring various associated adverse events independently. The adverse events associated with docetaxel plus prednisone included anemia, thrombocytopenia, neutropenia/leukopenia, febrile neutropenia, diarrhea, sensory neuropathy, stomatitis, and peripheral edema. The adverse effect associated with sipuleucel-T included cerebrovascular accident. The investigators noted study limitations. The baseline characteristics of patients contributed to variations in disease progression and susceptibility to adverse events and life expectancy.

The study only included adverse events deemed relevant to overall costs and the use of International Classification of Diseases, Ninth Edition codes for relevant costs. The primary end point was a measure of treatment costs and life extension, but did not evaluate quality of life. Healthcare providers and payers aiming to treat HRPC in the most cost-effective manner should consider not only the drug cost, but also the costs and clinical need to treat adverse effects of docetaxel plus prednisone, explained the authors. Furthermore, the absence of adverse effects and associated costs improved the ICER of sipuleucel-T compared with docetaxel plus prednisone, but should not be overlooked by the high cost of sipuleucel-T.