Dostarlimab Cures All Patients in Rectal Cancer Clinical Trial

By Emily Menendez - Last Updated: June 10, 2022

A recent study published in the New England Journal of Medicine revealed that the new drug dostarlimab has led to the complete remission of cancer tumors in all 14 patients of a small trial.

Conducted at Memorial Sloan Kettering Cancer Center in New York in 2019, the six-month trial involved 14 patients who were each diagnosed with early-stage rectal cancer. All patients shared a similar genetic instability in their cancer and had not undergone treatment. Nine doses of dostarlimab were given to each patient intravenously over the course of the six-month period.

What Is Dostarlimab?

Dostarlimab is a type of immunotherapy drug known as an immune checkpoint inhibitor. Specifically, it is a programmed death receptor-1 (PD-1)-blocking monoclonal antibody medication. The FDA approved the drug in April 2021.

As of 2020, the drug has been undergoing Phase I, II, and III clinical trials, and it has shown prior potential in treating recurrent or advanced endometrial cancer in women.

None of the patients involved in the dostarlimab trial experienced any significant complications from the drug. In contrast, traditional rectal cancer treatments such as chemotherapy, radiation, and surgery tend to cause long-lasting effects, including:

  • Difficulty sleeping
  • Fatigue
  • Gastrointestinal issues
  • Bowel or bladder dysfunction
  • Infertility
  • Urinary incontinence
  • Anxiety
  • Depression

Rectal Cancer Trial Results

After the full six months of the trial, scans of each patient revealed that clear tissue had replaced what was once discolored tumors. No traces of cancer were found in any other scans, biopsies, or physical exams.

Due to the success of the dostarlimab treatment, none of the patients involved in the trial had to receive their initially planned follow-up treatment of chemo-radiation or surgery. Four patients involved in the trial are currently still undergoing treatment, but their results so far have been similarly positive.

“I don’t think anyone has seen this before, where every single patient has had the tumor disappear,” said Andrea Cercek, lead author of the study and oncologist at Memorial Sloan Kettering Cancer Center. “All 14 patients? The odds are exceedingly low and really unheard of in oncology.”

Some caveats of study included its small sample size, and several years of observation will still be needed to ensure that each patient’s tumors do not reappear or metastasize. The participants will need to be routinely monitored in the future by specialists to ensure that tumors do not resurface.

Dostarlimab was also only tested on patients who shared a similar genetic instability in their rectal cancer, known as mismatch repair-deficiency. This instability only occurs in 5-10% of all rectal cancer patients and is often resistant to chemotherapy. It causes errors in the body’s ability to repair abnormalities when cells divide, which can result in mutations.

Nevertheless, David Ryan, director of clinical oncology at Massachusetts General Hospital, says that “the results are a game changer for cancer patients with mismatch-repair deficiency.”

For more on this type of treatment, read about the most common immune-related adverse events with immune checkpoint inhibitors.

Post Tags:Colorectal Cancer