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Patients with advanced Merkel cell carcinoma who have achieved a complete response (CR) with avelumab may be able to safely discontinue treatment after 1 year, according to research published in Cancer.
The researchers noted that their study is limited by its small size and retrospective nature, but the results suggest discontinuation at 1 year may be safe for many patients.
The study included 65 patients with unresectable stage III or stage IV Merkel cell carcinoma who had received at least 1 cycle of avelumab. The patients’ median age at baseline was 74 years, 65% of patients were men, and 77% had stage IV disease.
Patients received avelumab at 800 mg every 2 weeks until disease progression, CR after 26 cycles (1 year), unacceptable toxicity, or the patient wanted to stop treatment. Most patients (89%) received avelumab as first-line treatment, but 11% had received prior chemotherapy.
The median follow-up was 14 months. The median duration of avelumab treatment was 6 months, and the median number of cycles received was 12. Response was evaluated via CT or FDG-PET/CT every 3 months. FDG-PET/CT scans were also performed at baseline and after 26 cycles.
Responses were seen in 29 patients (44%), and 25 patients had a CR (38%). Two patients were not evaluable for response because they died of preexisting comorbidities.
The patients who achieved a CR had a median follow-up of 27 months. They had received a median of 26 cycles of avelumab, and their median duration of treatment was 11 months. The median duration of CR was 23 months.
The reasons for discontinuation among complete responders was completing 1 year of treatment (52%), toxicity (20%), and patient preference (28%).
Among complete responders, the 6-month recurrence-free survival (RFS) rate was 96%, and the 12-month RFS rate was 88%. Two patients (8%) had a recurrence 4 months and 7 months after discontinuation, respectively. Both patients had stage IV disease, had received the full year of avelumab, and had received avelumab as first-line treatment.
“In this real‐world cohort, patients with metastatic MCC [Merkel cell carcinoma] with a confirmed CR on FDG‐PET/CT imaging had a durable response after discontinuation of treatment after 1 year,” the researchers concluded. “This study highlights the importance of addressing optimal duration of treatment of patients with mMCC and identifying those patients who can safely stop early on to prevent overtreatment.”
Disclosures: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Reference
Zijlker LP, Levy S, Wolters W, et al. Avelumab treatment for patients with metastatic Merkel cell carcinoma can be safely stopped after 1 year and a PET/CT–confirmed complete response. Cancer. Published online October 3, 2023. doi:10.1002/cncr.35050
This article originally appeared on Cancer Therapy Advisor
