M-17: Therapeutic Cancer Vaccines: Overview of Phase 3 Clinical Trials
Touro College of Pharmacy United States
Hundreds of clinical trials have resulted in the approval of just one therapeutic cancer vaccine. Researchers continue to search for therapeutic cancer vaccines, a number of which are in Phase 3 trials due to recent research progress. Our objective was to evaluate the vaccines in phase III trials.
A systematic literature search was conducted in PubMed, Ovid, EBSCO and clinicaltrials.gov for clinical trials published between 2000-2016 on therapeutic cancer vaccines. Phase 3 trials completed prior to 2016 were included. The vaccines were categorized by type of cancer and type of vaccine.
The literature review retrieved over 100 articles. The clinical trial review retrieved 230 trials. As of January 2017, there were 52 Phase 3 clinical trials utilizing therapeutic cancer vaccines. The most targeted cancer was lung cancer with 11 studies. Melanoma and prostate cancer were also highly targeted with over five studies each. The least targeted cancers were esophageal, gastric, hepatocellular, renal, myeloma, head, neck, and colon cancer, each having less than three clinical trials. Autologous and peptide vaccines comprise nearly half of the Phase 3 trials. Viral and DNA vaccines are the least studied among the trials. Many of the trials include vaccine combined with immunomodulators and/or adjuvants. Other studies employed the vaccines in combination with other treatment modalities such as surgery, radiotherapy, chemotherapy. Fifty-two percent of the clinical trials investigated the vaccines in combination with other techniques or pharmacological agents. In view of the use of adjuvants, other immunotherapies and modalities, vaccines would not be expected to act as a monotherapy; however, 37% of trials were comprised of a treatment arm where the experimental vaccine was studied as a monotherapy. Most clinical trials had at least two treatment arms consisting of varied treatment regimens. However, some trials lacked an alternative intervention or an alternative treatment arm altogether. Of the trials that did not use alternative treatment arms, over 20% of clinical trials either did not have another treatment arm or did not have an alternative intervention.
Therapeutic vaccines for cancer are in their infancy but under intensive clinical study. From the trials, it is apparent that the optimal combination of vaccine component, adjuvants, delivery vehicles, regimen, and routes of administration are not yet identified. Could one of the vaccines currently in Phase 3 research be a cure for cancer? Could 2017 be the year that this occurs? This research provides an update on therapeutic cancer vaccines in Phase 3 trials and identifies, characterizes and discusses their implications for treatment of cancer.