Several months ago, we published the results of a study showing that patients with tumors that have the mismatch repair gene benefit from checkpoint inhibition. Click here for that link. However, only patients with tumors that have the mismatch repair gene benefit from this approach. Now comes a paper from the New England Journal of Medicine showing that when applied to newly diagnosed patients with rectal cancer, immune checkpoint therapy can eliminate the need for surgery, radiation and chemotherapy. Click here for the link. If you wish to read the entire article and are kept from doing this by lack of a subscription, Dr. Stark can email you a PDF. Just submit a request to the right of this page. Click here for the link. If you wish to read the entire article and are kept from doing this by lack of a subscription, Dr. Stark can email you a PDF. Just submit a request to the right of this page.
In this paper twelve patients with locally advanced rectal cancer and the mismatch repair gene were treated with dostarlimab, a new checkpoint inhibitor. All had their tumors completely disappear. Median follow-up, however, was short — only a year. Whether these patients will have a long-term cure is unknown.
Dr. Stark comments: this is huge, proof of principle that immune checkpoint inhibitors work spectacularly well in these patients. The next step is to try them in patients whose tumors contain a high mutation burden, even if this particular mutation is not present. Stay tuned!