Regulatory considerations for clinical development of cancer vaccines

Cancer vaccines are aimed at stimulating an immune response to tumor tissue. There is a high level of clinical activity in this rapidly advancing field with over 1,400 trials registered on Clincaltrials.gov. The recent approval of Sipuleucel-T which is the first cancer vaccine approved in the US and EU has encouraged developers in this field. In contrast to more established approaches for treating cancer such as chemotherapy, regulatory guidelines have been developed relatively recently for cancer vaccines. These guidelines advise on general clinical requirements. As there is an increase in innovative strategies with novel products, a 2-way dialog with regulators is recommended on a case-by-case basis to justify the clinical development plan, taking into account specific quality issues related to the product(s) in development. It is important that the rationale, background and justification for the planned development is convincing when interacting with the regulatory authorities, to enable drug developers and regulators to reach agreement.

Pancreatic cancer: role of the immune system in cancer progression and vaccine-based immunotherapy

Pancreatic cancer (PC) is the 5th leading cause of cancer related death in the developed world with more than 260,000 deaths annually worldwide and with a dismal 5-year survival. Surgery is the only potential hope of cure for PC, but, unfortunately, only 20% PC patients is resectable at the time of diagnosis. Therapeutic research efforts have mainly focused on improvements in radio/ chemo treatments and to date, there are only a few chemotherapeutic agents that have shown to be effective against PC, including gemcitabine with or without abraxane as well as a combination of 5-FU, leucovorin, oxaliplatin and irinotecan (the so-called FOLFIRINOX regimen). The survival of patients treated with these regimens is marginal and hence we are in urgent need of novel therapeutic approaches to treat pancreatic cancer. The success of immunotherapeutic strategies in other cancers and various evidences that pancreatic adenocarcinoma elicits antitumor immune responses, suggest that immunotherapies can be a promising alternative treatment modality for this deadly disease. PC immunotherapy treatments include passive immunotherapeutic approaches, such as the use of effector cells generated in vitro, and active immunotherapeutic strategies, which goal is to stimulate an antitumor response in vivo, by means of vaccination. In this review, we describe the immune suppressive mechanisms of pancreatic cancer and discuss recent preclinical and clinical efforts toward PC immunotherapy, including passive approaches, such as the use of antibodies and active strategies (vaccination), with a special mention of most recent treatment with CRS-207 and GVAX.