Dostarlimab: Developments in Cancer Therapy

In News

• Recently in a medical trial, 12 patients in the United States (US) were completely cured of rectal cancer without requiring any surgery or chemotherapy.

About the Study

• Monoclonal Antibody: The trial used a monoclonal antibody called dostarlimab every three weeks for six months for the treatment of a particular kind of stage two or three rectal cancer.
  • Dostarlimab is an experimental drug. It contains laboratory-produced molecules.
  • It acts as substitute antibodies. It is sold under the brand name Jemperli.
• Findings: 
  • It could completely cure the patients with a particular kind of rectal cancer called ‘mismatch repair deficient’ cancer”.
  • All 12 patients had completed the treatment and were followed for six to 25 months after.
  • No cases of progression or recurrence had been reported during the follow-up.
  • The response too was rapid, with symptoms resolving in 81% of the patients within nine weeks of starting the therapy.

How does this drug cure?

• PD1 Protein used: It is a protein that regulates immune function and can sometimes keep T cells from killing cancer cells. 
  • The therapy in the trial used PD1 blockades, allowing T cells to kill cancer cells. 
  • The immunotherapy belongs to this category called PD1 blockades that are now recommended for the treatment of such cancers rather than chemotherapy or radiotherapy. 

Image Courtesy: IE 

• Mismatch Repair Deficient Cancer: It is most common among colorectal, gastrointestinal, and endometrial cancers. 
  • Patients suffering from this condition lack the genes to correct typos in the DNA that occur naturally while cells make copies.
• The anomalies in the DNA: It results in cancerous growths in patients with mismatch repair deficient cancers. 
• India has a couple of PD1 blockades available, although not the one used for this study.

Significance

• Eliminating other treatments can improve a patient’s quality of life by preserving fertility, sexual health, and bladder and bowel functions.
• Earlier, this therapy was used post-surgery, but the study has shown that a surgery may not be required.
• Although the therapy is usually used for cancers that have metastasis (spread to locations other than where the cancer formed), it is now recommended for all mismatch repair deficient cancers as they result in quicker improvement and lesser toxicity as compared to traditional chemo and radiotherapy. 

Issues

• Cost is believed to be a major hurdle: The problem with immunotherapies is that they are expensive and unaffordable for most people in India, and certainly for those coming to AIIMS. A genetic test can also cost up to Rs 30,000, the patients here cannot afford all this.
• Surgeries anyway not needed: The patients can be well managed with chemotherapy and radiotherapy as well. Around 10 to 15% of cancer patients actually do not need surgeries.
• Precision medicine, such as using particular immunotherapy drugs for particular types of cancers, is still at a nascent stage in India. 

Way Ahead

• More research needs to be conducted for cancer treatment with the help of immunotherapy alone.
• Also, for cancer treatment, the field of radiation oncology is showing satisfactory results.
• People need to be guided properly to address myths and misinformation associated with radiation therapy.

Source: IE