Long-term survival of patients after ipilimumab and hypofractionated brain radiotherapy for brain metastases of malignant melanoma: sequence matters

PURPOSE: Since the introduction of ipilimumab (IPI) for the treatment of patients with metastatic malignant melanoma, we have observed remarkable responses after hypofractionated whole brain irradiation (WBRT) or stereotactic radiotherapy (STX) for brain metastases of malignant melanoma. We sought to investigate the impact of the sequence of these treatment modalities. METHODS: We retrospectively evaluated the survival of melanoma patients with brain metastases who were treated with WBRT or STX and received IPI in close temporal relation between October 2010 and March 2015. Follow-up was obtained until November 2016. A total of 27 patients with advanced melanoma and brain metastases who were treated with WBRT before 2010, and who had not received IPI, served as historical controls. RESULTS: We identified a total of 41 patients of whom 15 were treated with STX, 7 with a combination of STX and WBRT and 19 with WBRT alone. All patients received at least 2 doses of IPI. The median time interval between radiotherapy and IPI was 2 months. Patients treated with IPI after radiotherapy had a censored median survival of 11 months, compared with 3 months for the patients who received IPI prior to radiotherapy. Patients who received IPI before radiotherapy showed a similar survival as historical controls, who had not received IPI. We observed long-term survivors after radiotherapy of brain metastases followed by IPI. CONCLUSIONS: These data suggest that the sequence of RT and immune checkpoint inhibition with IPI may be crucial for the success of combined modality treatment of melanoma brain metastases.