PS1242 RETREATMENT WITH NIVOLUMAB IN PATIENTS WITH R/R CLASSICAL HODGKIN LYMPHOMA AFTER DISCONTINUATION OF THE THERAPY WITH IMMUNE CHECKPOINT INHIBITORS

Background: Immune checkpoint inhibitors (ICI) may allow to achieve a durable remission in patients with resistant or refractory (r/r) classical Hodgkin lymphoma. The population of patients who discontinued therapy due to various causes is increasing. In case of relapse after the ICI treatment the optimal treatment is not yet defined. One of the possible options is the retreatment of the patient with ICI. To date there is lack of information regarding the retreatment of patients with relapse after ICI cessation. Aims: To determine the effectiveness of nivolumab therapy in patients with r/r Hodgkin lymphoma with relapse of disease after achievement of complete remission with ICI and cessation of therapy. Methods: This analysis included 20 patients (5 male/15 female) with median age 32 (20–47) years with r/r classical Hodgkin lymphoma who were treated with nivolumab (3 mg/kg every 14 days) and achieved CR. After nivolumab therapy was stopped the patients received no other treatment before the disease progression. Response was assessed by positron‐emission tomography/computed tomography (PET/CT) using LYRIC criteria every 3 months. After relapse of the disease the patients were retreated with nivolumab monotherapy or in combination with chemotherapy. Median follow‐up after the retreatment initiation was 10 (6–14) months. Results: In 20 patients previously treated with nivolumab the median number of cycles was 25 (18–30). CR was achieved after median of 6 (6–18) cycles. The median duration of therapy after CR achievement was 7 (1–15) months. Median follow‐up after therapy discontinuation was 23 (13–24) months. At the moment of analysis, all patients were alive. Eight (40%) out of 20 patients relapsed after therapy discontinuation. In 4 out of 8 patients relapse was confirmed by biopsy. Median time before the relapse was 11(5–20) month. All patients had undergone the retreatment with nivolumab: 7 were treated with monotherapy and 1‐ in combination with chemotherapy. Doses of nivolumab were 3 mg/kg in 5 patients, 1,5; 1,0 and 0,5 mg/kg in one patient each. Six patients were evaluated for response: CR (n = 3), PR (n = 1), indeterminate response type 2 (n = 2). The best response was achieved after median of 6 (6–12) cycles. It is worth noting that 3 patients had adverse events after retreatment with nivolumab. Two of these patients did not have any complications during initial nivolumab treatment. Adverse events included pyrexia, thrombocytopenia and pneumonitis. In last case therapy was discontinued before resolution of complication, but the patient achieved complete remission before therapy cessation. Summary/Conclusion: This analysis demonstrates that patients with relapse after nivolumab discontinuation sustained sensitivity to nivolumab and achieved a response during retreatment with nivolumab monotherapy or with chemotherapy combination. Further research is required to determine response rate and durability of response.