683 ESTIMATING THE OVERALL SURVIVAL BENEFIT OF SIPULEUCEL-T IN THE IMPACT TRIAL ACCOUNTING FOR CROSSOVER TREATMENT IN CONTROL SUBJECTS WITH AUTOLOGOUS IMMUNOTHERAPY GENERATED FROM CYROPRESERVED CELLS

Standard of care in immunotherapy trials: Challenges and considerations

The success of immunotherapeutics over the past decade has fundamentally altered the therapeutic landscape in melanoma and non-small cell lung (NSCLC) cancer care. Multiple clinical trials have confirmed significant improvements in survival with a variety of immunotherapeutic strategies. The careful and appropriate selection of standard of care (SOC) therapies is key to the successful design and interpretation of these trials. To date immunotherapeutic trials have used best supportive care, matched placebo, chemotherapy, targeted therapy or, more recently, established immunotherapeutics in melanoma clinical trials as SOCs. Each of these SOC choices has a fundamental impact on the selection and validity of response assessment criteria and clinical endpoints. As yet there is no established approach, thus new data must be interpreted with an understanding of the limitations of the current paradigm. Additionally, the pace of development has mandated the use of novel clinical trial designs, answering multiple therapeutic questions simultaneously and designed to expedite regulatory approval. This review addresses the most important challenges in the selection of SOC in immunotherapeutic trials and the current and future challenges in trial design.

Cancer vaccines: what do we need to measure in clinical trials?

Cancer immunotherapy has seen a tremendous number of failures and only few recent regulatory successes. This review is dedicated to evaluate remaining challenges in capturing clinical response with cancer vaccines. Definition of disease progression in context of clinical rather image-specific criteria and interpretation of efficacy in relation to delayed effect of cancer vaccines should be taken into account in the design of future of immunotherapy trials.

Economic evaluation of sipuleucel-T immunotherapy in castration-resistant prostate cancer

The objective is to examine the cost-utility of sipuleucel-T immunotherapy in asymptomatic or minimally symptomatic castration-resistant prostate cancer patients. The addition of sipuleucel-T immunotherapy to standard treatment led to a gain of 0.37 quality-adjusted life-year (QALY) at an additional cost of US$104,536. The incremental cost-utility ratio was US$283,000 per QALY saved. Threshold sensitivity analyses indicated that a price reduction of at least 53%, or application in a group of patients resulting in the relative reduction in the mortality rate of at least 39%, ought to augment the economic value of this regimen. Sipuleucel-T immunotherapy treatment at the current price with 96.5% certainty is not cost-effective. The specific group of patients who will benefit more from the treatment should be revealed and treated, or the cost of the vaccine should be lowered significantly to increase its economic value. Accounting for crossover treatment in control patients improves sipuleucel-T's value (US$132,000 per QALY saved) although further investigation is necessary.

Management of castrate resistant prostate cancer-recent advances and optimal sequence of treatments

Until 2010, chemotherapy with docetaxel was the only approved agent for treatment of metastatic castrate resistant prostate cancer (mCRPC). Since then, the therapeutic landscape of mCRPC has changed rapidly. Multiple novel agents have received regulatory approval after demonstrating improved overall survival in separate randomized Phase 3 studies. These include immunotherapeutic agent sipuleucel-T, androgen axis inhibitors abiraterone and enzalutamide, and a novel microtubule inhibitor cabazitaxel. More recently, radium-223, a bone-targeting alpha emitting radiopharmaceutical, was reported to improve skeletal related events, as well as overall survival in a Phase 3 randomized study. Additionally, there are several promising agents in the advanced stages of clinical development. Here, we describe the agents recently shown to improve overall survival, and those that have reached the advanced stages of development in Phase 3 clinical trials. We will also propose a strategy for optimal sequencing of these agents in the treatment of mCRPC.

Overview of cancer vaccines: considerations for development

Cancer immunotherapy has seen a tremendous number of failures and only few recent regulatory successes. This is a review dedicated to determine major regulatory and developmental issues around cancer immunotherapeutics. A three pillar approach should be used in setting a development path: discovery platforms and sufficient pool of validated tumor antigens, product development strategy enabling to bring the product closer to the patient and clinical development strategy accounting for competitive landscape, treatment paradigm, technical and commercial risks. Regulatory framework existing around cancer vaccines in the EU, US, Japan and some developing countries is outlined. In addition, the review covers some specific issues on the design and conduct of clinical trials with cancer vaccines.