A medical breakthrough has stunned doctors worldwide; a clinical trial by Memorial Sloan Kettering Cancer Center (MSK) found that every participant’s cancer had completely gone away after treatment with an experimental immunotherapy drug. The trial, which was initially compiled of only 12 patients with a specific rectal cancer, has since grown to 42 participants, and all have received the same outcome. A 100% success rate is revolutionary, and offers new hope to patients that may now get to forego life-altering treatments and severe side effects.
Complete Remission
The groundbreaking study focused on patients with advanced rectal cancer that also suffered from a rare genetic mutation called “mismatch repair deficiency” (MMRd). This deficiency happens in about 5-10% of rectal cancer cases. Each of the participants took the drug dostarlimab (aka Jemperli) intravenously once every three weeks for a total of six months. The expectation was that most would still need chemotherapy, radiation, and surgery, and instead instead all patients were 100% cancer free treatment. “The immunotherapy shrank the tumors much faster than I expected,” said Dr. Andrea Cercek, the study’s lead investigator. The patients had been preparing for grueling rounds of radiation and then surgeries – surgeries that could leave them with permanent bowel damage, sexual dysfunction, and infertility. One participant, Sascha Roth, was packing her bags for New York to undergo her radiation when she received the life-changing news.
The drug, which is a little pricey ($11,000 a pop) identifies cancer cells that can usually hide from the immune system by deploying a biological camouflage that stops immune cells from attacking them. Dostarlimab is a checkpoint inhibitor, which disables this camouflage and exposes these cells to the immune system. This approach has proven to be extremely effective against tumors with the MMRd mutation since those cancer cells have more mutations than typical cancer cells do, marking them as more “foreign” to the immune system. Traditional treatments often cause serious collateral damage to any surrounding healthy tissues, and this new, targeted approach allows the body’s natural defenses to shine while leaving healthy cells mostly unaffected. The mild side effects – mainly rashes, itching, fatigue, and nausea – are a far cry from what these patients have had to deal with in the past.
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Long-term Results and Applications
The best part about all of this? Dr. Cercek reported that the patients have remained cancer-free for up to four years following treatment, with no signs of recurrence. This goes against conventional wisdom that cancer comes back returns in some capacity when it is not handled via surgery. The FDA has recognized the importance of these findings and has labled dostarlimab as a “Breakthrough Therapy Designation” for patients with MMRd rectal cancer. This designation will expedite the drug’s development and regulatory review, making its path to commercial use more streamlined. The results have already caused the National Comprehensive Cancer Network to update their directives based on this trial alone. Oncologists have begun adopting the use of dostarlimab, with Dr. Cercek reporting letters of gratitude from doctors in America, Australia, Ireland, and other countries with patients already benefiting from the treatment.
Implications extend far beyond rectal cancer. Dr. Luis Diaz Jr., the study’s senior author and a member of the White House’s National Cancer Advisory Board, has coined the term “immunoablative therapy” to describe the use of immunotherapy to eliminate cancer without surgery, chemotherapy, or radiation. MSK
researchers are already investigating to see if this same approach can be applied to other cancers with the MMRd mutation. This application holds even greater weight for younger patients, as there have been a troubling number of colorectal cancer diagnoses among people under 50. “We are seeing more and more young people with rectal cancer, including people in their 20s in our trial. Immunotherapy might be an important new option for them,” noted Dr. Cercek.
The trial is also responsible for new life. Three of the female participants were able to have healthy babies after the treatment, which would have been nearly impossible as the usual treatments styles cause infertility.
These results will need to be repeated in larger studies since a perfect response rate is a little too good to be true. But, as Dr. Hanna K. Sanoff of the University of North Carolina (was not involved in the study) wrote, “these results are cause for great optimism” and might represent “an early glimpse of a revolutionary treatment shift.” As the trial enrolls more patients and expands into other cancer types, the medical community watches closely and with hope to see if this remarkable approach and remarkable drug really can transform treatment for generations to come.
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