Patients with advanced renal cell cancer (RCC), expressing a specific type of antigen, respond favorably to IMA901, which is the first therapeutic multipeptide vaccine for the disease, reports a study published in Nature Medicine this week.
Therapeutic vaccines differ from traditional preventative vaccines in that they are not administered prior to the disease, but as a means of delivering medication to those suffering from a disease. The development of therapeutic cancer vaccines has remained a challenge as there are gaps in our knowledge on several crucial issues, such as appropriate tumor antigens to target or biomarkers to predict patient’s response to therapy.
Using tissue samples from RCC patients expressing the human leukocyte antigen HLA-A on their cancer cells, Harpreet Singh-Jasuja and colleagues identified multiple specific peptides from which they developed a vaccine. The vaccine, IMA901, elicits an immune response specifically in RCC patients who express these antigens. In a phase 1 study, IMA901 vaccine induced multiple T cell immune responses that were associated with low numbers of T regulatory cells, which normally suppress immune responses. The authors also found that patients who were given a single-dose of cyclophosphamide-a drug presently used to treat various types of cancer-prior to IMA901 vaccination, had even fewer regulatory T cells, which resulted in prolonged survival of patients. Further clinical testing is needed to assess its benefit in a larger population.