With great successes and disappointing failures, the field of cancer research is not for the faint of heart. Many scientists and physicians are typically quite conservative in showing emotion when a treatment seems promising because there are always so many “what if’s?” to consider. Prominent members of the cancer research community, however, had a tough time hiding their excitement following a presentation earlier this week at the annual meeting for the American Association for the Advancement for Science (AAAS).
Dr. Stanley Riddell, an immunotherapy researcher and oncologist at Fred Hutchinson Cancer Research Center in Seattle, shared the results of early immunotherapy trials in which 94 percent of patients suffering from acute lymphoblastic leukemia went into complete remission. Another study saw 80 percent of individuals with non-Hodgkin lymphoma go into remission as well.
Experimental Immunotherapy Produces “Dramatic Responses”
The concept of immunotherapy is not new, but it has been clawing its way to the top of the cancer treatment ladder in recent years. Immunotherapy, which harnesses the body’s immune system to fight cancer, is finally considered one of the main pillars of cancer therapy, along with chemotherapy, radiation, and surgery.
Riddell’s recent trial was to test the safety of an experimental immunotherapy in patients with B-cell malignancies: acute lymphoblastic leukemia, non-Hodgkin lymphoma, and chronic lymphocytic leukemia. The therapy targeted specific white blood cells, called T cells, that are able to detect foreign or abnormal cells — like those that are cancerous — and kick off an attack on those cells.
T cells, however, are not usually strong enough to completely kill tumors. Riddell’s immunotherapy reprograms T cells by genetically engineering them with synthetic molecules called chimeric antigen receptors (CARs). With the addition of CARs, the T cells are given an added boost that allows them to successfully seek and destroy tumors, explains the Fred Hutchison Cancer Research Center.
“The merging of gene therapy, synthetic biology, and cell biology is providing new treatment options for patients with refractory malignancies and represents a novel class of therapeutics with the potential to transform cancer care,” said Riddell. “In the laboratory and in clinical trials, we are seeing dramatic responses in patients with tumors that are resistant to conventional high-dose chemotherapy.”
Another benefit to Riddell’s immunotherapy treatment is that unlike chemotherapy, only one dose of the CAR-infused T cells is required because T cells have the ability to continue to multiply once they are in the body.
“T cells are a living drug, and in particular, they have the potential to persist in our body for our whole lives,” said Dr. Chiara Bonini of the San Raffaele Scientific Institute in Milan, Italy during the AAAS presentation.
Side Effects and Disappointments
Overall, Ridell’s study was a resounding success. However, as the numbers show, not every trial participant saw their cancer melt away. 27 of 29 patients with acute lymphoblastic leukemia had no traces of cancer following their treatment, and 19 of 30 non-Hodgkin lymphoma patients had partial or full responses.
The individuals that participated in the study already had very advanced forms of cancer and were not expected to live much longer. Seven of the patients with the most tumors were placed in the intensive care unit (ICU) following their dose for cytokine release syndrome, which is quite serious.
After this happened, the team refined the process and gave the lowest doses to the patients with the most tumors; none of these patients required the ICU. The researchers are continuing to work on improving targeting and reducing side effects.
What Does This Mean for Mesothelioma Patients?
While this specific treatment is not for mesothelioma, something similar could be an option in the future. Riddell’s team, and other cancer researchers around the world, are working tirelessly to reproduce the success of this trial for other types of cancer like breast cancer, lung cancer, and even mesothelioma.
The Fred Hutchinson Cancer Research Center notes there are “distinct challenges associated with targeting those types of diseases compared to blood cancers” but Riddell is hopeful that more cancer patients will be able to benefit from immunotherapy in coming years.