Discontinuing anti-PD-1 therapy at 1 year might be feasible for some patients with metastatic melanoma, according to the results of a single-center, real-world observational cohort study published in the Journal for ImmunoTherapy of Cancer.

After 1 year of immunotherapy treatment, most study participants showed no sign of progression in long-term follow-up analyses, and the risk for disease progression was found to be low even in patients with residual disease on imaging. Though halting therapy at this time point might not be appropriate for some patients, elective treatment discontinuation at 1 year could reduce financial and immunotherapy-related toxicity without negatively affecting outcomes, the study authors observed.

At present, the optimal treatment duration for anti–PD-1 therapy in melanoma is unknown, and “continuing immunotherapies indefinitely predisposes patients to immune and financial toxicities and interferes with their quality of life,” the investigators said.

To determine whether treatment duration could be shortened to 1 year, the study authors evaluated the outcomes of 52 patients with metastatic melanoma who received anti–PD-1 monotherapy at Huntsman Cancer Institute between January 1, 2015 and December 31, 2018. Most patients (92.3%) received pembrolizumab; the rest were treated with nivolumab (7.7%).


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All patients electively chose to stop therapy at 1 year (defined as >6 months and <18 months in the setting of ongoing treatment response or disease stability). The median treatment duration from first to last dose was 11.1 months. No patients stopped therapy due to toxicity, and all patients except 1 were alive at the data cutoff.

In all, 25.0% of patients achieved a complete response; 53.8%, a partial response; and 21.2%, stable disease. After a median follow-up of 20.5 months from treatment discontinuation, 75.0% of patients had no disease progression and 25.0% did.

Among patients with disease progression, the median progression-free survival was 3.9 months (range, 0.7–30.9 months). A multivariate analysis revealed 3 factors significantly associated with early disease progression: younger age (P =0.037), history of brain metastasis (P =0.009), and higher lactate dehydrogenase (LDH) after anti-PD-1 therapy (P =0.032).

“Our study presents preliminary evidence for the feasibility of early stopping of anti–PD-1 therapies at 1 year in patients with metastatic melanoma,” the study authors wrote. Patients with younger age, brain metastasis, and greater post-PD-1 LDH may be at higher risk for relapse following early anti-PD-1 therapy discontinuation, and thus may not be ideal candidates for this practice,” they concluded.

Disclosures: Some of the study authors disclosed financial relationships with the pharmaceutical industry and/or the medical device industry. For a full list of disclosures, please refer to the original study.

Reference

Pokorny R, McPherson JP, Haaland B, et al. Real-world experience with elective discontinuation of PD-1 inhibitors at 1 year in patients with metastatic melanoma. J Immunother Cancer. 2021;9(1):e001781. doi:10.1136/jitc-2020-001781