Checkpoint inhibitor therapy for metastatic melanoma has dramatically improved outcomes. Currently, 20 to 40% of treated patients achieve lengthy remissions. It is not clear whether patients in remission require ongoing therapy or if treatment can be safely discontinued. A retrospective chart review was performed of patients who underwent elective treatment discontinuation after two negative scans three months apart. Of 132 checkpoint inhibitor-treated patients, 46 achieved a complete response (34.8%) and electively discontinued therapy. The progression-free survival was 97.5% at 1 year and 94.7% at 3 years following treatment discontinuation. The median duration of follow-up was 26 months. In total, 4 of 46 individuals (8.7%) eventually relapsed (median time to relapse: 27 months). The median disease-specific survival of the entire cohort was not reached and was 100% at 4 years from the start of therapy. Two patients eventually died, one from melanoma and the other from an unrelated illness. We have identified an elective treatment discontinuation strategy that is generalizable to a variety of checkpoint inhibitor ± targeted therapy regimens. We found that most complete remissions remained durable after elective treatment discontinuation. We hypothesize that this approach could decrease potential drug toxicities, reduce the treatment-related financial burden, and improve patients’ quality of life.

Introduction Eculizumab is a complement inhibitor used in treating atypical hemolytic uremic syndrome (aHUS). This study showcases patient demographics, clinical and laboratory results of these patients, and overall outcomes of patients with aHUS treated with eculizumab. Methods The authors conducted a retrospective case study including 9 patients who received at least 1 dose of eculizumab for treating aHUS. A linear mixed effects model was used with random effects for each patient and fixed effects for eculizumab and time since admission. A p value < 0.05 was significant. Results Nine patients were treated with eculizumab for aHUS. Most patients were Black (n = 5) with either Medicare or Medicaid (n = 5). Genetic mutations were tested for in 5 patients. There were significant decreases in lactate dehydrogenase (LD, p = 0.029) and creatinine (Cr, p = 0.012) when on treatment. No significance was found in hemoglobin (p = 0.258) or platelets (p = 0.569). Treatment was stopped in 7 patients, of which 3 had no evidence of disease relapse. The only adverse event was severe thrombocytopenia (n = 1). Discussion This multicase study is the first of its kind in which most patients are Black, showing that there is a lack of research of this kind, especially on genetic mutations. Most of our patients did not have private insurance or had Medicaid/Medicare. There was a 246.5-day median duration of treatment. There was low risk of adverse events. Conclusion This case series elucidates the effective use of eculizumab for atypical hemolytic uremic syndromein a diverse patient population and emphasizes the need for more research in this area.

Introduction: Checkpoint inhibitor (CKI) therapy has markedly altered the survival of patients with many solid tumors. It appears clear that 10-40% of patients with a number of metastatic cancers can achieve lengthy remissions following CKI therapy. The optimal duration of treatment or whether treatment can ever be safely stopped is still controversial. Based on melanoma-derived data, we tested whether CKI treatment could safely be discontinued in patients with other solid tumors. Methods:A retrospective analysis was performed in adults with metastatic solid tumors treated with CKI-based therapy. Patients with solid tumors who achieved complete remission on 2 sequential scans at least 3 months apart during ongoing treatment were identified from our computerized patient database. Patient data was analyzed for patient characteristics, as well as progression-free and overall survival.Results: A total of 69 non-melanoma solid tumor patients were treated with CKI-based regimens in our clinic and 14 achieved complete remission (20.3%). Five patients were female (35.7%) and the remaining nine were male (64.3%). A 100% progressionfree survival was observed for these patients. The median duration of complete remission was over 20 months from the time of elective treatment discontinuation. Median overall survival was not reached in this cohort. One patient died of non cancerrelated causes.Conclusions: Based on this retrospective case series, elective treatment discontinuation in patients who achieved complete remission appears feasible. All patients remained in a durable complete remission after treatment discontinuation. We hypothesize that appropriate selection of patients for early treatment discontinuation may decrease their economic burden related to ongoing treatment, limit potential toxicity, and improve quality of life.

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