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In what researchers have described as an “unprecedented” result, a new medicine that treats locally advanced rectal cancer has fully removed tumours in all 42 patients who participated in the Phase II study.

The drug, Jemperli (dostarlimab-gxly), had earlier shown great potential for curing mismatch repair deficient (dMMR) cancers, which make up 5-10% of colorectal cancers. Following the recent trial, the first 24 patients showed a “sustained complete clinical response” – in other words, no cancer remaining – after an average of three years.

“These findings demonstrate the potential of dostarlimab-gxly as a novel approach to treating locally advanced dMMR rectal cancer that leads to durable complete tumour regression without the need for life-altering treatment,” said Dr Andrea Cercek, researcher and oncologist at the Memorial Sloan Kettering Cancer Center.

The drug has huge potential as a first-line treatment option and bypasses the need for chemotherapy and radiation.

While current cancer treatment is effective, it’s incredibly invasive and impacts negatively on the long-term quality of a cancer survivor’s life. Ultimately, a third of patients who undergo standard treatment will see their cancer metastasise and become terminal.

Patients with rectal cancer who undergo surgery often experience life-changing impacts on their health, including bowel, urinary and sexual dysfunction, as well as secondary cancers and infertility. This new treatment might just avoid all of that.

Dr Luis Diaz Jr said that after preliminary trial research showed how effective this drug was at targeting cancer, “We wanted to see if we could make a tumour with the MMR(d) mutation recede and eventually disappear using only immunotherapy to spare patients these life-altering consequences of standard treatment.”

Unlike chemotherapy, dostarlimab-gxly is an antibody that blocks the ‘programmed death receptor-1’ (PD-1) and once inside the body, binds to the PD-1 cells and then encourages them to target cancer cells.