An experimental cancer drug appears to have cured every single patient in a small clinical trial conducted in the US.
The 12 patients, all of whom had been diagnosed with rectal cancer, entered remission after taking dostarlimab over a six-month period, according to a study published in The New England Journal of Medicine.
The drug, called dostarlimab, was given to 12 people with a specific type of rectal cancer every three weeks for six months in a small study at the Memorial Sloan Kettering Cancer Center in New York.
After the course of treatment, cancer was undetectable on physical exam, endoscopy, PET, and MRI scans for every person, the researchers from MSKCC said in a presentation at the annual meeting of the American Society of Clinical Oncology on Sunday.
The participants didn't need any other treatment for up to a year, on average, and there were no side effects bad enough to impact day-to-day activities, the researchers said.
Dr. Alan P. Venook, a colorectal cancer specialist at the University of California, San Francisco, who was not involved with the study, told the New York Times that complete remission in every single patient was "unheard-of".
Dr. Andrea Cercek, an oncologist at MSKCC and a study co-author, said there were "a lot of happy tears" from the trial participants when they found out no further treatment was necessary.
Dostarlimab works by helping the immune system identify and destroy cancer cells. The drug, which is branded as Jemperli, is already used for patients with endometrial cancer, but it wasn't clear if it would work for rectal malignancies.
The participants in the trial had a type of rectal cancer called "mismatch repair deficiency". About 5 to 10% of people with rectal cancer have this type of cancer, where the genes responsible for correcting any mistakes during cell replication are faulty. The study can't tell us if dostarlimab will work in patients with other types of rectal cancer.
Hanna K. Sanoff, an oncologist at the Lineberger Comprehensive Cancer Center at the University of North Carolina, wrote in a New England Journal editorial that it was a "compelling" study.
"These results are cause for great optimism, but such an approach cannot yet supplant our current curative treatment approach," Sanoff said.
The study was also too small to show rarer side effects, Sanoff said.