A recent clinical study of a new drug - dostarlimab, developed by GlaxoSmithKline PLC (GSK) and sold under the brand name Jemperli has left doctors stunned following a 100% success rate in its clinical trials. It appears to be a very promising breakthrough in the treatment of rectal cancer. This immunotherapy drug is used to treat endometrial cancer; however, this was the first time dostarlimab was clinically investigated for rectal cancer tumors. The early study results obtained so far suggest that the drug is surprisingly effective against rectal cancer tumors. All the patients who enrolled for this trial have successfully got their cancer into remission.
“I believe this is the first time this has happened in the history of cancer,” Medical oncologist Luis Diaz Jr. from Memorial Sloan Kettering Cancer Center (MSK) stated.
In a small study of 14 patients with rectal cancer conducted at Memorial Sloan Kettering Cancer Center (MSKCC), positive results have only been seen in 12 patients so far (the trial is ongoing). All of these patients had tumors with mismatch repair deficiency (MMRd) – a genetic mutation seen in a subset of around 5-10% of rectal cancer patients. Patients having such tumors tend to be less responsive to chemotherapy and radiation treatments, which surges the need for surgical removal of their tumors. However, cancer cells can become more vulnerable to immune response following MMRd mutations, mainly bolstered by immune checkpoint inhibitors that unleash restrictions on immune cells so that they can more effectively kill cancer cells.
“When those mutations accumulate in the tumor, they stimulate the immune system, which attacks the mutation-ridden cancer cells,” Luis Diaz further said. “We thought, 'Let's try it before cancer metastasizes as the first line of treatment.”
Generally, before surgical removal of cancer, doctors may suggest patients with these kinds of rectal tumors might undergo chemotherapy and radiation therapy. This range of treatments, however, for many patients, comes with long-lasting consequences that can last the rest of their life. According to Andrea Cercek, MSK Medical Oncologist - “The standard treatment for rectal cancer with surgery, radiation, and chemotherapy can be particularly hard on people because of the location of the tumor.” Cercek also added that "They can suffer life-altering bowel and bladder dysfunction, incontinence, infertility, sexual dysfunction, and more."
Unprecedentedly, all the patients who enrolled in this trial have completely avoided both the procedures and their associated side effects. Doctors further conducted physical exams, endoscopies, PET scans, and MRI scans and were unable to find any trace of cancer in their bodies. It is being considered a massive breakthrough in the field of cancer treatment.
About the drug and its trial
Jemperli is an anti-PD-1 checkpoint inhibitor. The course of Jemperli medication, during its trial, was six months, with its administration done every three weeks in patients with MMRd stage II or III rectal adenocarcinoma. Standard chemoradiotherapy and surgery were followed after the medication during the trial. However, any patient who had obtained a complete clinical response post drug regimen would not require chemoradiotherapy and surgery.
Potential Market for Dostarlimab
Dostarlimab injection is used to treat a certain type of advanced endometrial cancer. Approximately half a million cases are observed across the world, predominantly in North America and the Asia Pacific. The treatment looks promising, but a larger-scale clinical trial on patients is needed to see the efficacy of the drug. The average cost of the injection is estimated at US$ 11,000. Upon commercialization, RationalStat estimates that the market for Dostarlimab drugs to range between US$ 190 million and US$ 210 million in the coming years.