Long-Term Follow-up Confirms Durability of Single-Agent Brentuximab Vedotin As Pre-Transplant Salvage for Classical Hodgkin Lymphoma

Background/methods: Identifying relapsed or refractory (RR) classical Hodgkin lymphoma (cHL) patients (pts) eligible for lower-intensity second-line therapy (SLT) will aid in improving short-term and long-term treatment-related toxicity. We conducted a phase II study evaluating PET-adapted SLT with single-agent brentuximab vedotin (BV) followed by augICE (augmented ifosfamide, carboplatin, etoposide) for BV-naïve patients with RR cHL (Lancet Oncology 2015). In this study, patients who failed 1 line of therapy for cHL were treated with 2 or 3 cycles of BV, 1.2mg/Kg, administered weekly, 3 weeks on and 1 week off. Those who achieved PET-normalization proceeded directly to consolidation with autologous stem cell transplantation (ASCT). Those with persistent abnormalities on PET received 2 cycles of augICE prior to consideration for ASCT. At 3-year follow-up, outcomes for patients who achieved PET-normalization following BV alone or BV followed by augICE were identical. Furthermore, baseline metabolic tumor volume (bMTV) predicted outcome and improved the prognostic significance of pre-ASCT PET (Blood 2017). We now report 6-year follow-up from this study evaluating PET-adapted SLT with BV and augICE. Results: 65 pts enrolled onto this protocol, of whom 18 achieved PET-normalization (Deauville ≤ 2) after single-agent BV. These 18 pts included 8 (44%) with primary refractory disease, 7 (39%) with advanced stage disease, and 8 (44%) with extranodal disease. 17 of the 18 pts proceeded directly to ASCT and 1 pt experienced delay resulting in disease progression. That individual achieved PET-normalization following additional salvage chemotherapy (gemcitabine/vinorelbine/liposomal doxorubicin) and proceeded to ASCT. Of the other 47 pts who remained PET-positive after single-agent BV, 35 achieved PET-normalization after augICE, 9 remained PET-positive after augICE, 2 received no additional treatment before proceeding to ASCT (1 pt with Deauville 3 response to BV, 1 with Deauville 4 response), and 1 pt withdrew consent and was lost to follow-up. 64 of 65 pts proceeded to transplant and median post-ASCT follow-up is 5.98 yrs (range 4.4-7.2 yrs). 6-yr overall survival is 86%, 6-yr progression free survival (PFS) is 73%, and 6-yr time to tumor progression (TTP) is 78%. Overall, there have been 8 deaths, which were due to disease progression (n=5), progressive multifocal leukencephalopathy (PML) (n=1), treatment-related respiratory failure (n=1), and myelodysplastic syndrome (MDS) (n=1). Pts who proceeded to ASCT following single-agent BV achieved durable remission with 6-year TTP of 80%. Outcomes for the BV-only group were similar to those who required BV and augICE to become PET-negative (6-yr TTP 82%) and were more favorable than for those who remained PET-positive after BV and augICE (6-yr TTP 56%, p=0.058) (Figure 1). With 6-yr follow-up, bMTV > 109.5 cm3remained prognostic for the entire group and aided in predicting which pts ultimately developed disease progression. In particular, among the pts who achieved PET-normalization with BV alone prior to ASCT, 6-yr TTP was 92% vs 40% for low and high bMTV respectively, p=0.017 (Figure 2). Similarly, for pts who achieved PET-normalization following BV and augICE, 6-yr TTP was 85% vs 33% for low and high bMTV respectively, p=0.002. Conclusions: For pts with RR cHL, long-term remission can be achieved following lower-intensity SLT with single-agent BV followed by ASCT, provided PET-normalization is achieved after single-agent BV. bMTV identifies which pts within this favorable group are likely to develop disease progression and therefore treatment strategies using bMTV to direct intensity of therapy should be explored. Disclosures Moskowitz: Erytech Pharma: Consultancy; Incyte: Research Funding; Cell Medica: Consultancy; Incyte: Research Funding; ADC Therapeutics: Consultancy; Cell Medica: Consultancy; Takeda Pharmaceuticals: Consultancy; miRagen Therapeutics Inc: Consultancy, Research Funding; ADC Therapeutics: Consultancy; Merck: Research Funding; Takeda Pharmaceuticals: Consultancy; Takeda Pharmaceuticals: Consultancy; Erytech Pharma: Consultancy; Merck: Research Funding; Cell Medica: Consultancy; Cell Medica: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Takeda Pharmaceuticals: Consultancy; Merck: Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Incyte: Research Funding; Takeda Pharmaceuticals: Consultancy; Takeda Pharmaceuticals: Consultancy; Merck: Research Funding; Takeda Pharmaceuticals: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Cell Medica: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Cell Medica: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Incyte: Research Funding; Cell Medica: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Takeda Pharmaceuticals: Consultancy; Merck: Research Funding; Erytech Pharma: Consultancy; Incyte: Research Funding; Incyte: Research Funding; Incyte: Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Erytech Pharma: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Takeda Pharmaceuticals: Consultancy; miRagen Therapeutics Inc: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Incyte: Research Funding; Merck: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Erytech Pharma: Consultancy; Erytech Pharma: Consultancy; Incyte: Research Funding; Takeda Pharmaceuticals: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Incyte: Research Funding; Erytech Pharma: Consultancy; Merck: Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Merck: Research Funding; ADC Therapeutics: Consultancy; Erytech Pharma: Consultancy; Cell Medica: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; ADC Therapeutics: Consultancy; Merck: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Merck: Research Funding; Cell Medica: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Cell Medica: Consultancy; Takeda Pharmaceuticals: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Takeda Pharmaceuticals: Consultancy; Merck: Research Funding; Merck: Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Takeda Pharmaceuticals: Consultancy; Erytech Pharma: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Cell Medica: Consultancy; ADC Therapeutics: Consultancy; Erytech Pharma: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Erytech Pharma: Consultancy; Takeda Pharmaceuticals: Consultancy; Seattle Genetics: Consultancy, Honoraria, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; ADC Therapeutics: Consultancy; ADC Therapeutics: Consultancy; ADC Therapeutics: Consultancy; miRagen Therapeutics Inc: Consultancy, Research Funding; ADC Therapeutics: Consultancy; Erytech Pharma: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; ADC Therapeutics: Consultancy; Cell Medica: Consultancy; Erytech Pharma: Consultancy; miRagen Therapeutics Inc: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Erytech Pharma: Consultancy; Incyte: Research Funding; Cell Medica: Consultancy; Incyte: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; Incyte: Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; ADC Therapeutics: Consultancy; ADC Therapeutics: Consultancy; ADC Therapeutics: Consultancy; Incyte: Research Funding; ADC Therapeutics: Consultancy; Takeda Pharmaceuticals: Consultancy; Erytech Pharma: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Incyte: Research Funding; Cell Medica: Consultancy; Merck: Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Cell Medica: Consultancy; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding; Merck: Research Funding; Kyowa Hakko Kirin Pharma: Consultancy, Research Funding; miRagen Therapeutics Inc: Consultancy, Research Funding; ADC Therapeutics: Consultancy. Horwitz:Seattle Genetics: Consult