Last year, we talked about a new cancer “vaccine” currently in clinical trials in an article here, and now a second cancer vaccine is capturing media interest due to impressive results in the lab. The new therapy is now in human clinical trials for lymphoma patients.
Researchers at Stanford Medicine have found that injecting two immune system stimulating agents directly into a solid tumor can eradicate the tumor completely. The treatment is also able to destroy distant metastases that have not been directly treated themselves.
The new vaccine works on various types of cancers, including spontaneous cancers, according to the new study. Cancer often hides in plain sight using various tricks to evade detection by the immune system or even actively suppresses the immune system itself.
The new therapy works by reactivating cancer-specific T cells using two agents that are injected in microgram amounts directly into a tumor. The first is a small section of DNA known as a CpG oligonucleotide, which works with nearby immune cells to boost the expression of activating receptor OX40 on the surface of T cells. The second element is an antibody that binds to OX40 and activates the T cells so that they attack the tumor and rally the immune system to respond.
Because the two injected agents are introduced directly to the tumor, only the T cells that have infiltrated the tumor are activated. Essentially, these T cells are pre-screened by the body, as they are the ones that detected the cancer in the first place.
The researchers also observed that tumors all over the body were destroyed after this therapy. The approach bypasses the need to identify tumor-specific immune targets, and it neither needs the activation of the entire immune system nor any modification of the patient’s immune cells.
Of the two agents used in this therapy, one is already approved for human use, and the other has been tested for human use in a number of unrelated trials. In January this year, a clinical trial was launched to test this therapy on patients with low-grade lymphoma. The trial is anticipated to recruit around 15 patients. If successful, the treatment might be useful for many tumor types.
The researchers also suggest that because the therapy is applied locally and in very small amounts, it could be a fast, effective and relatively inexpensive cancer therapy with a much lower chance of causing the unwanted side effects observed with many systemic cancer treatments.
This is yet another example of revolutionary changes happening in the cancer and immunotherapy field. It is not hard to imagine in a few years’ time that damaging chemotherapy could start to be phased out in favor of superior methods of combating cancer. One thing is certain: the more options we have for preventing and destroying cancer, the better, and so we will be eagerly waiting for more news on progress.
 Sagiv-Barfi, I. Debra, k. Levy, S et al. (2018) Eradication of spontaneous malignancy by local immunotherapy. Science Translational Medicine. DOI: 10.1126/scitranslmed.aan4488