SAN FRANCISCO, CA USA (UroToday.com) - Dr. James Gulley of the NIH presented a compilation of data summarizing the exciting potential of immunotherapies to treat cancer.
The past decade has seen a large increase in the number and efficacy of agents used to treat advanced prostate cancer. However, the benefits of therapy are often short-lived and treatment resistance is inevitable. Rapidly changing treatment targets limit the use of traditional drug therapies, but the immune system may provide a similar dynamic adaptability ideally suited to respond to evolving disease states. Novel immune-based agents such as sipuleucel-T, ipilimumab, and anti-PD1/PDL1 therapies are showing promising early results in multiple tumor types, and Science named cancer immunotherapy the breakthrough of the year for 2013.
The immune system is rapid, durable, self-propagating, and adaptable, making it an ideal avenue through which to target cancer. Antigen cascade or spreading is an important mechanism used to generate immune system adaptability. Induction of the immune system to one specific target will inevitably lead to selection of additional target antigens. While tumors may evolve over time and lead to primary antigen loss, subsequent clonal populations will likely share secondary antigens with previous populations of cancer cells, thereby making them amenable to immune attack. In addition, removal of immune checkpoint inhibitors, which are non-specific activators of the immune system, may help release a robust initial immune response.
Combination therapy using immune checkpoint inhibitors and tumor vaccines has the potential to generate a systemic immune response, potentiate antigen cascade, and produce robust tumor killing. Coupling a stronger initial immune response with a persistent immune response can suppress tumor growth over time and perhaps delay morbidity and mortality associated with mCRPC. There is further potential for synergy by combining immunotherapy and traditional non-immune based therapies such as anti-androgens and taxanes. As traditional therapies terminate cells through their particular mechanism of action, additional antigens are released to feed the ongoing adaptive immune response. Trials evaluating therapeutic cancer vaccines in patients with localized and newly diagnosed disease are currently underway.
Highlights of a presentation by James L. Gulley, MD, PhD, FACP at the 2014 Genitourinary Cancers Symposium - January 30 - February 1, 2014 - San Francisco Marriott Marquis - San Francisco, California USA
National Institutes of Health (NIH), Bethesda, MD USA
Click HERE to listen to an exclusive interview with one of the authors of this study