Doctors are being warned that a lifesaving cancer therapy may cause new tumors to form in rare cases.
In a report in the New England Journal of Medicine, researchers urged physicians to ‘be on the lookout’ for unusual symptoms in patients who receive CAR-T therapy.
Twenty-five people in the US out of around 30,000 have been diagnosed with secondary cancer after receiving the treatment for a separate cancer.
CAR-T – which was approved in 2017 – takes immune cells from the body and engineers them to attack tumors before being infused back into the blood.
CAR-T therapies, or chimeric antigen receptor T-cell therapies, was first approved in November 2017 and is reserved for cancer patients who would otherwise die without it
But the way it is delivered may disrupt cell DNA and lead to other cancers, which is a small risk with all so-called gene therapies.
This, the study authors emphasize, is a very rare scenario. According to their reports, than 1 percent of people who’ve gotten the CAR-T therapy have developed a secondary cancer from it.
But another new study from oncologists at Stanford that was published in the same journal found that as many as 6.5 percent of patients developed a secondary cancer in the three years after getting CAR-T therapy.
Even with these risks, CAR-T therapy saved the lives of far more people than it’s endangered, the authors in both new papers wrote.
It’s been especially crucial in treating people who haven’t been responsive to any other therapies.
But however rare this condition is, they want to raise awareness for it so that oncologists can be on the lookout for new cancer developments in their patients, Dr Metin Ozdemirli, a professor of pathology at Georgetown who co-authored the paper, said.
‘When we know what to look for ahead of time, it becomes easier to catch problems earlier,’ Dr Ozdemirli said.
This is especially prudent if trends persist, and the therapy becomes more widely adopted. The FDA announced a review of the therapy in November 2023 in order to investigate 19 of these cases.
The NEJM report, published by oncologists and pathologists from Georgetown University Hospital, presented the case study of a 71 year old woman who had been fighting cancer for eight years.
She was given the CAR-T therapy to treat myeloma, a type of cancer that affects the white blood cells within your bones.
After the treatment, doctors took tests and found no signs of cancer left in her system.
Four months later, the patient came back to the doctor after suddenly losing 12 pounds and developing persistent diarrhea.
Doctors took a blood test and fed a tube through the patients GI tract to try and find the cause – narrowing in on a series of abnormal cells in the intestine.
An illustration of a T cell, blue, attacking a cancer cell, red
They initially diagnosed her with an auto immune disease, and gave her steroids to treat the condition.
But when she didn’t get better, doctors took a biopsy of a wound in her small intestine and discovered the truth: she had cancer again.
This time, the patient had developed lymphoma- which is a type of cancer that affects the body’s immune system – about nine months after CAR-T treatment.
When the scientists analyzed the DNA of the new cancer cells, they determined they had likely grown from the immune cells that the patient was treated with to initially cure their myeloma.
Scientist don’t yet understand how this happens, but theorize that the cells they collected from the patient to make the therapy in the first place could’ve had cancerous mutations. If that was the case, when the cells were put into the patient, they might’ve grown into cancer.
The cells also could’ve mutated after being removed and before they were engineered to become the therapy, or after being re-introduced to the patient’s body, the case study explained.
Regardless of when the mutations developed, they caution that this rare side effect of the treatment should be something providers consider when using CAR-T therapy.
The patient has yet to beat this new round of cancer, but as of April 2024, her symptoms have been improving slightly, the report detailed.
