Immune system infusions creating hope for cancer therapies
The list of cancers effectively treated by immunotherapy is getting longer, such that the methodology was recently named 2016 Advance of the Year by the American Society of Clinical Oncology (ASCO).
Known alternately as biologic therapy, the field uses substances made by the body (or in a lab) to boost natural defenses, improving or restoring immune system function in cancer patients. It causes fewer side effects than chemotherapy, and researchers believe it helps control tumor growth. To date three related checkpoint inhibitor drugs have been approved by the government for treatment against melanoma and lung and kidney cancers.
“No recent advance has been more transformative than the rise of immunotherapy, particularly over this past year,” confirms ASCO President Dr. Julie M. Vose. “These new therapies are not only transforming patient lives, they are also opening intriguing avenues for further research.”
Scientists caution further research is necessary to make the infusion drugs effective to a wider population, with the current stage of technology compared to that of chemotherapy when first appeared in the 1960s. The medical world is still uncertain why many patients haven’t responded to immunotherapy at all, theorizing some may need combinations of the drugs with varying measures of chemotherapy, radiation and/or surgery.
Some recent developments in immunotherapy research:
- In April, studies were released pointing to the immunotherapy drug Opdivo as the first to extend life for those with recurrent, difficult-to-treat head and neck cancers (specifically, recurrent or metastatic squamous cell carcinoma). A drug called Keytruda had similar effects against lethal skin cancer Merkel cell carcinoma. Both kinds of cancer can be caused by viruses or DNA mutations, explains the Washington Post, and the aforementioned drugs can recognize and attack cancer cells of either origin. The findings have wider implications since viruses and similar pathogens cause 20 percent of all cancers. In one well-publicized case, former President Jimmy Carter’s advanced melanoma was successfully treated with Keytruda last year.
- Research results earlier this year suggests chemotherapy resistance in ovarian cancer may be overcome when chemotherapy is combined with immunotherapy. Traditionally, ovarian cancer has been treated with the drug Cisplatin, which makes platinum damage the insides of cancer cells, preventing division. The problem has been that the body often responds by producing compounds countering that effect. Now, scientists are adding immune T-cells containing interferon to the chemotherapy cocktail, which makes tumor cells die off as planned. “Thus it should be possible to return to the same chemotherapy drug the patient has become resistant to,” explain study authors.
- Scientists are hopeful about recently successful clinical trials involving the engineering of immune system T-cells to target the blood cancer acute lymphoblastic leukemia. The therapy has extended patients’ lives after doctors removed such immune cells from their bodies, tagged them with “receptor” molecules structured to target the leukemia, then infused them back into the patients. In one study, 94 percent of participating patients saw symptoms vanish completely, while those with other blood cancers had response rates exceeding 80 percent and more than half experienced complete remission. Lower doses of the T-cells are expected to reduce dangerous side effects, but researchers still need to measure remission intervals, learn whether tumors can be reduced and determine how long the T-cells “remember” to fight the cancer. “(But) T-cells are a living drug … and they have the potential to persist in our body our whole lives,” explains researcher Chiara Bonini.
Similar trials involved 40 patients with lymphoma, who displayed remission rates higher than 50 percent when treated with the T-cells. Likewise, 80 percent of non-Hodgkin’s lymphoma patients in a test group realized diminished cancer symptoms with the therapy.
The government’s $1 billion National Cancer Moonshot Initiative to fast-track better cancer therapies in the next five years points to immunotherapy as a source of great promise.
“This approach has shown success with melanoma, leukemia and lymphoma, and is ripe for further exploration in a wider range of cancers,” summarizes a February White House press release. “Moonshot will work to accelerate these research efforts and break down barriers to progress by enhancing data access and facilitating collaborations with researchers, doctors, philanthropies, patients, patient advocates and biotechnology and pharmaceutical companies.”