Hugely promising cancer drug dostarlimab is one step closer to being widely available, after the Food and Drug Administration granted it Breakthrough Therapy Designation status that, if successful, will expedite its path to market.
Dorstarlimab (brand name Jemperli) had some remarkable trial results in June, and the results of that research can be found in The New England Journal of Medicine. Dorstarlimab, a programmed death receptor-1 (PD-1)-blocking antibody, completely eradicated rectal cancer tumors without the need for surgery, radiation treatment or chemotherapy.
An effective immunotherapy would be life-changing for rectal cancer patients, with current treatments often resulting in a suite of negative outcomes in survivors, including loss of fertility and incontinence.
“Today’s designation, which is based on the unprecedented 100% clinical complete response rate of dostarlimab reported to date, supports a path to help change the treatment paradigm for patients with locally advanced dMMR/MSI-H rectal cancer, who face long-term adverse quality-of-life effects," said Hesham Abdullah, Senior Vice President of research and development at GlaxoSmithKline (GSK), in a December 16 press release.
Breakthrough Therapy Designation is designed to fast-track novel drugs that treat serious conditions where no other comparable treatment is available. For some perspective, as of June 2024, the FDA received 1,516 requests for this designation, and only 587 have been granted. This is in line with previous years, during which around 30-40% of requests have been approved.
Dostarlimab has been watched closely by oncologists since its trial on rectal cancer patients at Memorial Sloan Kettering Cancer Center. It eradicated patient tumors, and they've remained cancer-free. After initially reporting on 24 patients, MSK updated the findings to include 42 participants.
"Everyone on the clinical trial is doing great,” MSK gastrointestinal oncologist Andrea Cercek said in June. “So far, 42 people have completed treatment, and all of them have no evidence of disease. Side effects were quite mild and well tolerated.
“This new treatment is also proving very durable," she added. "Most people on the trial have been free of cancer for at least a year, and the original participants have been healthy for up to four years and counting. The success rate remains 100%.”
The "100% clinical complete response rate" is "defined as complete pathologic response or no evidence of tumors as assessed by magnetic resonance imaging, endoscopy and digital rectal exam."
The Breakthrough status is the second FDA designation for dostarlimab, which treats locally advanced dMMR/MSI-H rectal cancer. It received a Fast Track designation in January 2023.
Now, it'll undergo further testing and a more rapid review, with FDA assistance speeding up the process. If successful at this stage, it could be available to the public around three years sooner than non-breakthrough drugs.
In the US, some 46,220 people are diagnosed with rectal cancer each year, and up to 10% are dMMR/MSI-H cancers.
Source: MSK
