critically reviewed the manuscript; and all authors contributed to the concept and design of the study and approved the final version of the manuscript. Conflict-of-interest disclosure: Seattle Genetics, Inc provided research funding to the institutions of R.C., A.K.G., S.E.S., S.M.A., J.D.R., K.J.S., J.M.C., A.E., and A.Y. complete response (CR) to brentuximab vedotin (N = 34) had estimated OS and PFS rates of 64% (95% CI: 48-80%) and 52% (95% CI: 34-69%), respectively. The median OS and PFS were not reached in CR patients, with 13 patients (38% of all CR patients) remaining in follow-up and in remission at study closure. Of the 13 patients, 4 received consolidative hematopoietic allogeneic stem cell transplant, and 9 (9% of all enrolled patients) remain in sustained CR without receiving any further anticancer therapy after treatment with brentuximab vedotin. Of the patients who experienced treatment-emergent peripheral neuropathy, 88% experienced Vatiquinone either resolution (73%) or improvement (14%) in symptoms. These 5-year follow-up data demonstrate that a subset of patients with R/R HL who obtained CR with single-agent brentuximab vedotin achieved long-term disease control and may potentially be cured. The trial was registered at www.clinicaltrials.gov as #”type”:”clinical-trial”,”attrs”:”text”:”NCT00848926″,”term_id”:”NCT00848926″NCT00848926. Introduction Brentuximab vedotin (ADCETRIS; Aptuit [Glasgow] Ltd., Glasgow, United Kingdom) is an anti-CD30 antibody conjugated by a protease-cleavable linker to the microtubule-disrupting agent monomethyl auristatin E (MMAE). Targeted delivery of MMAE to CD30-expressing tumor cells is the primary mechanism of action.1 Additional mechanisms of tumor cell killing that may contribute to the clinical activity of brentuximab vedotin include antibody-dependent cellular phagocytosis, immunogenic cell death, and the bystander effect.2-6 We previously reported the primary results for the pivotal trial of brentuximab vedotin in 102 patients with relapsed/refractory (R/R) Hodgkin lymphoma (HL) after failed autologous stem cell transplantation (auto-SCT),7 with a complete response (CR) rate of 34% (95% confidence interval [CI]: 25.2-44.4) and objective response rate of 75% (95% CI: 64.9-82.6) per independent review. Brentuximab vedotin received accelerated US Food and Drug Administration (FDA) approval for C10rf4 patients with R/R HL after auto-SCT or failure of 2 prior therapies. In the preCbrentuximab vedotin era, options were limited and outcomes were poor for HL patients who relapsed or Vatiquinone progressed after auto-SCT, with median overall survival (OS) ranging from 10.5 to 27.6 months.8,9 Reduced intensity conditioning (RIC) allogeneic SCT (allo-SCT) strategies have been studied, but toxicity is high and relapses are common, with 2- to 3-year nonrelapse mortality and median progression-free survival (PFS) ranging from 13% to 23% and 20% to 30%, respectively,10-13 and a 5-year OS of 28%.13 Previous reports from the pivotal phase 2 trial of brentuximab vedotin demonstrated both significant efficacy and 3-year disease control in heavily pretreated R/R HL patients.7,14 Herein, we present the final end-of study results per investigator assessment. Study design Complete descriptions of the study design and statistical analyses have been reported.7 Patients received 1.8 mg/kg brentuximab vedotin via outpatient intravenous infusion over 30 minutes, once every 3 weeks, for up to 16 cycles. Clinical response was determined by independent central review and by investigators using the Revised Response Criteria for Malignant Lymphoma.15 Response Vatiquinone duration was calculated from the first objective tumor response (CR or partial response [PR]) to tumor progression or death due to any cause, and PFS was calculated from the start of treatment to tumor progression or death. Patients were censored at their last radiologic or clinical assessment Vatiquinone that documented the absence of progressive disease. OS was calculated from the start of study treatment to date of death due to any cause and Vatiquinone was censored at the last date the patient was known to be alive. To capture all peripheral neuropathy (PN) events, an analysis was performed using the standard Medical Dictionary for Regulatory Activities. Grade of severity was determined per the National Cancer Institute Common Terminology Criteria for Adverse Events, version 3. Prior to study initiation, the protocol, informed consent form, and any advertisements for patient recruitment were approved by each sites institutional review board or independent ethics committee. Results and discussion At the time of study closure, which occurred 5 years from the last patients end of treatment visit, 15 patients remained on study and in remission without the start of new therapy other than consolidative allo-SCT. These 15 patients had a median observation time of 69.5 months (range, 66.5-72.9 months). The median observation time for all enrolled patients (N = 102) from first dose was.