Nick Mulcahy

April 21, 2015

PHILADELPHIA — "In a New York minute" is an American catchphrase that means a very short or supercompressed period of time. And it just might be an apt description of the treatment response of a recent melanoma patient at the Memorial Sloan Kettering (MSK) Cancer Center in New York City.

The patient, a 49-year-old woman with metastatic melanoma, had a large pedunculated, necrotic tumor under her left breast disappear only 3 weeks after a single dose of an experimental immunotherapy combination.

The extent and speed of the response was "remarkable," write a trio of clinicians from MSK in a letter published online April 20 in the New England Journal of Medicine.

"This is one of the most astonishing responses I have seen," said one of the letter authors, medical oncologist Paul Chapman, MD, in a press statement. "It reminds us of the potential power of the immune system if we can remove the 'brakes' that keep it from attacking cancer cells."

Dr Chapman is referring to the patient's treatment with a combination of two immune checkpoint blockers. The woman is one of 13 patients at MSK to be treated with the combination of nivolumab (Opdivo, Bristol-Myers Squibb), a programmed cell death-1 (PD-1) inhibitor, and ipilimumab, a cytotoxic T-lymphocyte antigen 4 (CTLA-4) inhibitor.

 

The combination was the subject of a much-discussed study here at the American Association for Cancer Research (AACR) 2015 Annual Meeting. The combination produced an "eye-opening" complete response rate of 22% (16 of 74 patients had undetectable tumors after treatment), an investigator reported at the meeting.

Nevertheless, cancer immunotherapies have a reputation for slowly evoking responses from patients, said Michael Atkins, MD, from the Georgetown Comprehensive Cancer Center in Washington, DC, who was not involved with the MSK patient.

"People tend to think that immunotherapy takes longer to work than other types of treatment," he told Medscape Medical News.

 
The normal tissue did not have a chance to repair itself.
 

But the immune system "can work pretty quickly" if you release its brakes or blocks, he said. In the case of the MSK patient, the "response was so fast that the normal tissue did not have a chance to repair itself," Dr Atkins explained.

The letter from the MSK clinicians describes the patient's case in detail.

But the "rapid eradication" of the large tumor mass is not their only subject.

They are worried about safety. "Grave consequences" could result if such a "rapid and dramatic" antitumor effect had occurred in other common sites of metastatic melanoma, such as the small bowel or myocardium, they write.

 

"It is ironic that we are now concerned about the possibility of overly vigorous antimelanoma responses," they conclude.

Dr Chapman and Dr Atkins report financial ties to Bristol-Myers Squibb and other pharmaceutical companies.

New Engl J Med. Published April 20, 2015. Abstract

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