Evaluation of the Regimen Brentuximab Vedotin Plus ESHAP (BRESHAP) in Refractory or Relapsed Hodgkin Lymphoma Patients: Preliminary Results of a Phase I-II Trial from the Spanish Group of Lymphoma and Bone Marrow Transplantation (GELTAMO)

Introduction: Around 30% of Hodgkin Lymphoma (HL) patients are refractory or relapse (RR) after first line therapy. Salvage chemotherapy followed by high-dose chemotherapy and with Autologous Peripheral Blood Stem Cell Transplantation (APBSCT) can cure many patients, but those who are transplanted with active disease detectable by PET-CT have a very poor prognosis. Therefore, the current challenge in HL is to improve the results of the pre-transplant chemotherapy. Phase 2 single agent trials with Brentuximab Vedotin (BV) in highly RRHL patients have demonstrated overall and complete response rates of 75% and 34%, respectively (Younes, JCO 2012; 30:2183); as 2^nd line, BV has provided very promising results in combination with chemotherapy (LaCasce, Blood 2014; 124(21):3099)

Objectives: We conducted a phase I/II trial to determine the dose limiting toxicity (DLT), maximum tolerated dose (MTD), and response rate with combined Brentuximab vedotin with ESHAP chemotherapy [BRESHAP] as 2^nd line therapy for RRHL prior to APBSCT (ClinicalTrials.gov #NCT02243436).

Methods: The primary efficacy endpoint was the proportion of complete responses (CR) pre-APBSCT. It is a phase I-II trial with dose escalation followed by expansion. Treatment consisted of Etoposide (40 mg/m²/ day IV, D1-4), Solumedrol (250 mg/day IV, D1-4), High dose AraC (2 g/m² IV, D5) and cisPlatin (25 mg/m²/day IV, D1-4). BV was administered at three dose levels: 0.9, 1.2 or 1.8 mg/kg IV on day 1 to each cohort of patients, following the scheme of cohorts of 3 patients each, to assess the maximum tolerable dose (MTD). The dose limiting toxicity (DLT) was defined as Grade 4 hematologic toxicity extended over 3 weeks or non-hematologic toxicity grade ≥3 during the first treatment cycle. Patients were evaluated weekly.

Results: Patients with relapsed or refractory classical HL (cHL) after one prior line of therapy were eligible. To date, 27 patients have been included in the trial. The first 9 have completed the three courses as scheduled, without TLD doses. Fifteen patients have received the first full cycle, presenting 4 episodes of severe adverse reactions: non-neutropenic fever due to IV AraC and to complicated catheter insertion; one pneumothorax after catheter insertion; and one febrile neutropenia recovered with antibiotic treatment. Grade 4 hematologic toxicity presented in three of these nine patients: 2 neutropenia and thrombocytopenia 1. All nine patients underwent stem cell mobilization after the 1^st or the 2^nd treatment cycle with subcutaneous G-CSF 5 mcg/Kg days +7 to +14, collecting >2·10e6/Kg peripheral blood CD34+ cells in all cases, with no grade 3-4 toxicity. The number of harvesting procedures was one & two in seven & two patients, respectively. The transplant has been done in 6 patients, with a median of 9 days and 10 days for neutrophil and platelet recovery, respectively. All nine patients had no evidence of disease before the transplant by PET-CT, although one patient had residual FGD uptaking areas without underlying anatomical lesions on CT (metabolic complete response: 89%). Six patients have been evaluated after the APBSCT and they are all in metabolic CR. The phase II of the trial was open on April the 12^th 2015, with BV at the recommended dose of 1.8 mg/kg per course. At the submission of this report, there were 28 patients recruited, and 17 evaluated pre-transplant, achieving 16 CR. The complete results will be presented during the meeting; the projected recruitment by the meeting is 45 (65% of the total planned recruitment).

Conclusions: BRESHAP is a tolerable treatment scheme as remission induction prior to transplant in patients with refractory or relapsed Hodgkin lymphoma, and it offers very promising results.