The drug eliminates 100% rare cancers and patients do not need chemotherapy

The drug has already been approved in Brazil and is expected to arrive in the country in August. (Photo: Reproduction)

An immunotherapy-based drug was able to eliminate a rare type of tumor in the rectum in 100% of patients in a clinical study. The findings are from New York researchers and were published this week in The New England Journal of Medicine. The drug is expected to be marketed in Brazil in August.

The drug, called dostarlimab, was given every 3 weeks for 6 months. After treatment, no patient needed chemo or radiation therapy or surgery. They were followed for at least 6 months after the end of treatment (the longest time was 25 months, just over two years). The tumor did not reappear in any of them.

The research was conducted with 12 people who had a local but advanced tumor in the rectum – the last part of the colon. All patients had a specific, rare molecular change that made the cancer susceptible to the drug.

Dr. Rachel Riechelmann, a clinical oncologist at the ACCamargo Cancer Center in São Paulo, explains that this type of approach, with immunotherapy, was already used in cases of metastases – when the cancer has already spread to several organs.

“It was the first time it was tested on a non-metastatic tumor,” says the doctor. She explains that for rectal cancer, the standard treatment is chemotherapy, radiation and surgery. However, once the tumor has the change seen in the study patients – about 1% to 3% of cases – it becomes susceptible to this immunotherapy.

“The medicine alone has already eliminated the disease, without the need for radio, chemo and surgery. It’s amazing though [o tratamento] it will be for a small group of patients where the tumor has developed through this molecular change, ”explains Riechelmann.

The oncologist adds that although the number of patients is small, the fact that the change is rare makes the number sufficient to consider the drug effective. Yet more research is still needed. “The more you collect, and then publish, present, the better,” he says.

Difficulty with access

Dostarlimabe has already been approved for use in Brazil, by the National Health Surveillance Agency (Anvisa), in March this year, and is expected to be marketed in August, according to the manufacturer, GSK.

So far, however, the approval is only for the treatment of one type – also rare – endometrial cancer (the innermost layer of the uterus); there is still no approval for rectal cancer.

But Rachel Riechelmann explains that the same change seen in colorectal cancer in American patients, for example, can occur in the endometrium – and thus the results would be similar.

“All the immunotherapies that we have in Brazil work for this rare molecular change, which is present in rectal cancer, but which can be present in about 1% to 3% of all solid tumors,” he explains.

In the United States, the drug was approved in August 2021. There, it can be used against any type of advanced solid tumor that, even after initial treatment, continues to develop and has no other treatment options. The general approval came four months after an initial authorization – which also only approved use against one type of endometrial cancer.

Here, even though the drug is approved for use in colorectal cancer, access is difficult, explains Rachel Riechelmann, from ACCamargo. This is because the vast majority of immunotherapies against cancer, even those already used in Brazil, are not available in SUS – the first was first approved in 2020 and against melanoma, a type of skin cancer. For rectal cancer, treatment is still traditional in the public system (with chemo, radio and surgery).