Brentuximab vedotin for paediatric relapsed or refractory Hodgkin's lymphoma and anaplastic large-cell lymphoma: a multicentre, open-label, phase 1/2 study.

Background: Despite remarkable progress in the treatment of newly-diagnosed classical Hodgkin's lymphoma and systemic anaplastic large-cell lymphoma, treatment of relapsed or refractory disease remains challenging. The aims of this study were to assess the safety, tolerability, recommended phase 2 dose, and efficacy of brentuximab vedotin in paediatric patients with relapsed or refractory Hodgkin's lymphoma or systemic anaplastic large-cell lymphoma.

Methods: This open-label, dose-escalation phase 1/2 study was done at 12 centres across eight countries (France, Germany, Italy, Mexico, The Netherlands, Spain, UK, and USA). We recruited paediatric patients aged 7-18 years with relapsed or refractory classical Hodgkin's lymphoma or systemic anaplastic large-cell lymphoma, for whom standard treatment was unavailable or no longer effective. Participants were allocated to receive brentuximab vedotin at 1·4 mg/kg (phase 1) or 1·8 mg/kg (phases 1 and 2) via intravenous infusion once every 3 weeks for up to 16 cycles. Dose escalation was done via a 3+3 design. Key exclusion criteria were stem-cell transplantation less than 3 months before administration of the first dose of study drug, presence of cytomegalovirus infection after allogeneic stem-cell transplantation, previous treatment with an anti-CD30 antibody, and concurrent immunosuppressive or systemic therapy for chronic graft-versus-host disease. Primary outcomes were safety profile in the safety-evaluable population and maximum tolerated dose, recommended phase 2 dose, pharmacokinetics (phase 1), and proportion of patients who achieved best overall response (phase 2; evaluated by an independent review facility) in the response-evaluable population. This trial is registered with ClinicalTrials.gov, number NCT01492088.

Findings: Between April 16, 2012, and April 4, 2016, we screened 41 paediatric patients and enrolled 36 (aged 7-18 years), of whom 19 had relapsed or refractory classical Hodgkin's lymphoma and 17 had relapsed or refractory systemic anaplastic large-cell lymphoma. At the data cutoff (Oct 12, 2016), all 36 patients had discontinued study drug treatment; the most common reason was progressive disease (15 patients). The maximum tolerated dose was not reached. The recommended phase 2 dose was 1·8 mg/kg. The proportion of patients who achieved overall response was 47% (95% CI 21-73) for classical Hodgkin's lymphoma and 53% (28-77) for systemic anaplastic large-cell lymphoma. All 36 patients had a treatment-emergent adverse event and 16 patients (44%) had at least one grade 3 or worse treatment-emergent adverse event. The most common treatment-emergent adverse events were pyrexia (16 [44%] of 36) and nausea (13 [36%]). The most common grade 3 or worse treatment-emergent adverse events were neutropenia (four [11%]), increased γ-glutamyl transpeptidase (two [6%]), and pyrexia (two [6%]). 12 (33%) patients had transient, limited-severity peripheral neuropathy. Eight patients (22%) had a serious adverse event; three (8%) had a drug-related serious adverse event. One patient died of cardiac arrest (disease progression of a large huge mediastinal mass, unrelated to the study drug). Paediatric pharmacokinetic profiles were consistent with those from studies of adult patients.

Interpretation: Brentuximab vedotin has manageable toxicity and is associated with clinically meaningful responses in paediatric patients with relapsed or refractory Hodgkin's lymphoma or systemic anaplastic large-cell lymphoma, and could allow subsequent stem-cell transplantation in some patients who were initially ineligible for stem-cell transplantation.

Funding: Millennium Pharmaceuticals Inc.