From the Journals

Checkpoint inhibitor rechallenge is possible for select patients



An immune-related adverse event during initial treatment with an immune checkpoint inhibitor does not necessarily preclude a rechallenge, based on a review of outcomes in 93 patients with a variety of cancers who were part of a cohort study.

Rechallenge resulted in the recurrence of a grade 2 or higher immune-related adverse event (irAE) in 55% of rechallenged patients, but no deaths occurred, according to Audrey Simonaggio, MD, of the department of drug development at Gustave Roussy, Villejuif, France, and colleagues.

In those rechallenged patients who had a second irAE, the second event was not more severe than the first. “The rechallenge should first be assessed in a multidisciplinary team meeting with regard to each patient’s individual risk-reward ratio. ... We recommend close monitoring,” the researchers wrote in a study published in JAMA Oncology.

As there are no specific recommendations to guide the decision to rechallenge, the usefulness of the rechallenge was considered. The readministration could be delayed if the patient was in complete or excellent partial response. The existence of other therapeutic alternatives was also important as was the patient’s clinical state. Rechallenge was considered possible only after the grade of the initial irAE returned to 0 or 1.

“Because of life-threatening risk, we did not support rechallenge for cardiac (myocarditis) and neurologic irAEs [such] as Guillain-Barré syndrome, encephalitis, and severe myositis,” they said. CT scans were used to guide the decision to rechallenge in those with initial lung adverse events.

The cohort study included 93 consecutive adult patients who were referred over an 18-month period to the ImmunoTOX assessment board at the Gustave Roussy cancer center and followed for at least 1 year. The cohort was balanced for gender and ranged in age from 33 to 85 years, with a median age of 62.5 years. Melanoma was the predominant tumor (33%), followed by lung (16%), colorectal (9%), and lymphoma (9%).

The initial immune-related adverse event was a grade 2 event in 46% of patients, grade 3 in 39%, and grade 4 in 15%. Events included hepatitis (18%), skin toxicity (15%), pneumonitis (14%), colitis (12%), and arthralgia (7.5%). A rechallenge with the same anti–PD-1 or anti–PD-L1 was conducted in 43% of patients.

When compared with patients who were not rechallenged, there was no difference in median patient age, time to initial immune-related adverse event (five vs. three treatment cycles), event severity, or steroid use. With a median follow-up period of 14 months, the same or a different immune-related adverse event occurred in 22 patients (55%). A shorter time to the initial event was linked to the occurrence of a second event (9 vs. 15 weeks; P = .04).

“However, we did observe a trend toward a higher recurrence rate after a more severe initial irAE and a trend toward more frequent recurrence in patients treated with corticosteroids after the initial irAE,” the researchers wrote. “An anti–PD-1or anti–PD-L1 rechallenge after a grade 4 irAE should always be considered with caution.” Three of the five patients with these events were being treated for lymphoma, they said.

“As long as patients are closely monitored, anti–PD-1 or anti–PD-L1 rechallenge appears to have an acceptable toxic effect profile. Myocarditis and neurologic toxic effect should remain a contraindication. Rechallenge conditions require further investigation in a prospective clinical trial. ... Well-powered, prospective studies with a larger number of patients would be required to generate information on putative risk factors for the recurrence of irAEs. Our results highlighted the value of a review board, like ImmunoTOX, with intention to build a large irAE database and then establish evidence-based guidelines on the safety of a rechallenge,” the researchers concluded.

The study was supported by the Gustave Roussy cancer center and the Gustave Roussy immunotherapy program. Dr. Simonaggio had no relevant disclosures; several coauthors reported consultancy fees and research support from multiple drug companies.

SOURCE: Simonaggio A et al. JAMA Oncol. 2019 Jun 6. doi:10.1001/jamaoncol.2019.1022.

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