Reinvigorated Interest in Immunotherapy Heralds New Era for Cancer Vaccines

Two hundred years after Edward Jenner discovered the smallpox vaccine, the world’s first successful vaccine, recent achievements in the field of cancer immunotherapy have reinvigorated interest in cancer vaccines. Consider these:

• The Nobel Prize in Physiology or Medicine 2011 was awarded one half jointly to Bruce A. Beutler and Jules A. Hoffman “for their discoveries concerning the activation of innate immunity” and the other half to Ralph M. Steinman “for his discovery of the dendritic cell and its role in adaptive immunity.”¹

• The US Food and Drug Administration has approved two immunotherapeutics, sipuleucel-T (Provenge, Dendreon), the first therapeutic cancer vaccine, for castration-resistant metastatic prostate cancer, in 2010,² and ipilimumab (Yervoy, Bristol-Myers Squibb), a human cytotoxic T-lymphocyte antigen 4 (CTLA-4)-blocking antibody indicated for the treatment of unresectable or metastatic melanoma, in 2011.³

• The Washington, DC-based Pharmaceutical Research and Manufacturers of America (PhRMA) has identified 102 vaccines in development for cancer, 18 now in phase 3 clinical trials.⁴ (See Table 1)

• Emerging data from agents being evaluated in clinical trials that appear promising, including results of two large phase 1 studies of the anti–programmed death (PD-1) and anti–PD-L1 antibodies,^5,6 which “have broken the ceiling of durable tumor response rates of 10% to 15%, the highest rate of antitumor activity of the many immunotherapy approaches tested in the clinic for the treatment of cancer during the past 30 years.”⁷