Ogden, Carol Anne

Abstract Introduction Brentuximab vedotin (BV) is an ADC directed against CD30, a receptor expressed by malignant Reed-Sternberg (RS) cells present in the inflammatory/immune cell microenvironment of classical Hodgkin lymphomas (cHL). Through induction of immunogenic cell death, BV may prime an antitumor immune response via microtubule disruption of CD30-expressing RS cells (Gardai 2015). Tumor cells expressing PD-1 ligands use the PD-1 pathway to evade an immune response. Nivolumab (Nivo) blocks the PD-1 receptor, inhibits binding of PD-1 ligands, and restores an effective antitumor immune response. Targeted killing of CD30-expressing RS cells, concurrent with restoration of the immune response, may lead to higher complete response (CR) rates in patients (pts) with relapsed or refractory cHL (R/R HL), as well as improved durability of responses post autologous stem cell transplant (ASCT). Here we present updated results from the phase 1/2 study of BV + Nivo in pts with R/R HL. Methods BV + Nivo was evaluated in cHL that had relapsed or was refractory to frontline (FL) chemotherapy in adult pts (NCT02572167). Pts were excluded if they had received prior salvage therapy, BV or immuno-oncology therapy, or allogeneic SCT or ASCT. Pts were treated in 21-day cycles for up to 4 cycles. In Parts 1 and 2 of the trial, BV (1.8 mg/kg) was given on Cycle 1 Day 1 and Nivo (3 mg/kg) on Cycle 1 Day 8. For Cycles 2-4, BV and Nivo were given on Day 1. After the Cycle 4 response assessment, pts were eligible to undergo ASCT. The investigators assessed response per the Lugano Classification (Cheson 2014). Results 62 pts with R/R HL were enrolled in Parts 1 and 2; 61 pts received BV + Nivo, of whom 58 completed treatment (tx). 4 pts discontinued the study due to pt decision (2), AE (1), and investigator decision (1). Median age was 36 years, 52% were female, and 90% had received FL ABVD. 45% of pts had primary refractory disease and 31% experienced relapse within 1 year of FL therapy. Infusion-related reactions (IRRs) occurred in 41% of pts. Tx emergent AEs occurred in 98% of pts prior to ASCT (33% G3, 5% G4). Excluding IRRs, potential immune-related AEs (IrAEs) occurred in 84% of pts (10% G3, 3% G4) with 5 pts (8%) treated with systemic steroids for G4 pneumonitis, G4 pneumonitis and colitis, G2 pneumonitis, G3 diarrhea and G2 colitis, and G3 AST elevation. Among the 60 efficacy-evaluable pts, the CR rate was 62%, (48% of CR pts had Deauville ≤ 2) with an objective response rate of 85%; 5 pts (8%) had stable disease and 4 pts (7%) progressed on tx. At the time of this analysis, 39 pts had initiated ASCT with a median 5.1x106 CD34+ cells/kg (range; 3-60) collected. Median times to neutrophil and platelet engraftment were 12 and 15 days, respectively. Pts were followed for a median of 3 months from ASCT (N=39, range; 0-12) and 5.7 months from first dose (N=61, range; 1-17). BV and Nivo effects on the immune system were evaluated by peripheral blood immunophenotyping, serum cytokine/chemokine analyses, T-cell receptor sequencing, and intracellular cytokine staining. The first dose of BV resulted in elevation of pro-inflammatory cytokines and chemokines and concurrent reduction in serum TARC levels, with these results maintained post Nivo. We observed a reduction in Tregs and other T cell subsets after the first dose of BV with an elevation of T cell subsets post BV + Nivo. While TCR clonality in the periphery did not change over the course of the trial, T cell clonal expansion was observed post BV + Nivo, concurrent with T cell elevation measured by flow cytometry. Ex vivo peptide stimulation of PBMCs isolated from blood revealed the enhanced ability of T cell subsets to respond to MHC I and MHC II antigens following BV + Nivo compared to baseline: e.g., effector memory CD8+ T cells from some pts displayed increased intracellular IL-2, and TNFa after stimulation with MHCI and MHCII peptide pools compared to baseline, potentially indicating elevated activation status of the immune system following combination tx. Conclusion R/R HL remains an unmet clinical need despite recent medical advances. These data suggest the combination BV + Nivo is a well tolerated and an active salvage therapy with a high rate of CR (62%) that has no adverse impact on stem cell collection. The safety and activity of this novel combination support further exploration in an ongoing pivotal phase 3 trial in pts with R/R HL who have either already received or are considered ineligible for ASCT (NCT03138499). Disclosures Herrera: Seattle Genetics: Research Funding; Merck: Consultancy; Genentech: Consultancy; BMS: Consultancy; Pharmacyclics: Consultancy. Moskowitz: Seattle Genetics: Honoraria, Research Funding; Takeda: Honoraria; Incyte: Research Funding; ADC Therapeutics: Research Funding; Bristol Myers-Squibb: Consultancy, Research Funding. Bartlett: Novartis: Research Funding; ImaginAB: Research Funding; Astra Zeneca: Research Funding; Millenium: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding; Affimed: Research Funding; Forty Seven: Research Funding; Immune Design: Research Funding; Bristol-Meyers Squibb: Research Funding; Merck & Co: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Research Funding. Vose: Merck: Research Funding; Kite: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Allos Therapeutics: Research Funding; Acerta: Research Funding; Incyte: Research Funding; Onyx: Research Funding; Seattle Genetics: Research Funding; US Biotest: Research Funding; Bristol-Myers Squibb: Research Funding. Ramchandren: Seattle Genetics: Consultancy; MERCK: Research Funding; Pharmacyclics: Research Funding; Janssen: Research Funding. Feldman: AbbVie: Speakers Bureau; Janssen: Speakers Bureau; Kite Pharma: Speakers Bureau; Celgene: Speakers Bureau; Pharmacyclics: Speakers Bureau; Seattle Genetics: Honoraria, Research Funding, Speakers Bureau; Bristol-Myers Squibb: Consultancy. LaCasce: BMS: Consultancy; Forty Seven: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Research Funding. Ansell: Merck: Research Funding; Bristol-Myers Squibb: Research Funding; Celldex: Research Funding; Seattle Genetics: Research Funding; Affimed: Research Funding. Moskowitz: Celgene: Consultancy; Seattle Genetics: Consultancy, Other: Ad Board, Research Funding; Genentech BioOncology: Consultancy; Pharmacyclics: Research Funding; Merck: Consultancy, Research Funding. Fenton: Seattle Genetics: Employment, Equity Ownership. Ogden: Seattle Genetics: Employment, Equity Ownership. Taft: Seattle Genetics: Employment, Research Funding. Zhang: Seattle Genetics: Employment, Research Funding. Kato: Bristol-Myers Squibb: Employment, Equity Ownership; Seattle Genetic: Research Funding. Campbell: Seattle Genetics: Employment, Equity Ownership; CTI BioPharma: Employment, Equity Ownership. Advani: Agensys: Research Funding; Pharmacyclics: Research Funding; Regeneron: Research Funding; FortySeven: Research Funding; Nanostring: Consultancy; Celgene: Research Funding; Pharmacyclics: Consultancy; Merck: Research Funding; Juno Therapeutics: Consultancy; Kura: Research Funding; Janssen: Research Funding; Millennium: Research Funding; Seattle Genetics: Research Funding; Gilead: Consultancy; Bristol-Myers Squibb: Consultancy, Research Funding; Spectrum: Consultancy; Bayer Healthcare Pharmaceuticals: Research Funding; Infinity: Research Funding; Genentech: Research Funding; Cell Medica: Research Funding; Sutro: Consultancy.

Abstract Introduction This phase 1/2 study evaluated the safety and antitumor activity of brentuximab vedotin (BV) administered in combination with nivolumab (Nivo) in adult patients (pts) with relapsed/refractory classic Hodgkin lymphoma (R/R cHL) who have failed frontline therapy (NCT02572167). Results from Parts 1 & 2 have been previously reported, wherein safety, efficacy, and biomarkers consistent with immune activation were observed in pts with R/R cHL (Herrera et al., Blood 2018). In Part 3, patients were treated with BV + Nivo on Day 1 of each cycle. In contrast, pts in Parts 1 & 2 received BV on C1D1 and Nivo on C1D8 with concurrent admin on subsequent cycles. Herein we present safety, efficacy, and biomarker results for Part 3 and updated progression free survival (PFS) from Parts 1 & 2. Methods Pts in Parts 1 & 2 received up to four 21-day cycles of staggered dosing (day 1 BV 1.8 mg/kg, day 8 Nivo 3 mg/kg in Cycle 1) and concurrent thereafter, with steroid and antihistamine premedication. Pts in Part 3 received up to four 21-day cycles of concurrent BV + Nivo on Day 1 with antihistamine premedication. Following Cycle 4 response assessment (Lugano Classification Revised Staging System with the incorporation of the Lymphoma Response to Immunomodulatory Therapy Criteria [LYRIC, 2016]) responding pts were eligible to undergo autologous stem cell transplant (ASCT). Results 30 pts were treated in Part 3 and all were evaluable for efficacy. Pt characteristics included the following: median age 31.5 yrs (range; 20 - 66), 63% female, 93% prior ABVD, 37% primary refractory HL, 30% relapsed within 1year of frontline therapy, 30% with extranodal disease and 17% with bulky disease at enrollment. 28 pts completed all 4 cycles. 1 pt discontinued treatment (tx) due to an adverse event (AE; Grade 3 [G3] elevated Gamma-Glutamyltransferase) and 1 pt due to progressive disease (PD). The latter pt eventually died due to PD. All pts are off tx and have been observed through the safety reporting period. 37% of pts experienced a G3 or higher tx emergent AE prior to ASCT. 30% of the pts experienced infusion related reactions (IRRs), which occurred most frequently during Cycle 2. Potential G3 or higher immune-related AEs (IRAEs), excluding IRRs, occurred in 2 pts, one of whom required steroids for G4 pneumonitis, which subsequently resolved. Among the 30 efficacy evaluable pts, the complete response (CR) rate was 80% (24/30), with an objective response rate (ORR) of 93%. 47% of pts (14) had a Deauville ≤2, and 17% (5) had Deauville 3. 5 pts with CR had a Deauville >3 and met LYRIC criteria for IR-2. 4/5 pts had a negative follow-up biopsy that confirmed CR and in 1 pt the PET finding was considered to be a false positive as contrast enhanced CT did not reveal any abnormality. All 5 pts proceeded directly to ASCT and remain in CR at follow-up. Among all treated patients, 25 went directly to ASCT after completing BV + Nivo tx with a median 6.8 x 106 CD34+ cells/kg (range 1-20) collected. Median times to neutrophil and platelet engraftment were 12 and 14 days, respectively. 4 pts required additional salvage therapy subsequent to study tx. Patients were followed for a median of 6 months from ASCT (N=25, range 0.8-8.8) and 10 months from first dose (N=30, range 1.8-12.7). The estimated 9-month PFS rate in all-treated pts was 88%. This is comparable to all-treated pts in Parts 1 & 2, whose estimated 9 and 15 month PFS were 86% and 82%, respectively (Fig 2). Biomarker testing was performed on peripheral blood samples, included immunophenotyping, serum cytokine analysis, and TCRβ sequencing. Concurrent dosing of BV+ Nivo resulted in increased levels of both activated and dividing CD4+ and CD8+ T cells, as well as increased regulatory T-cells and circulating plasmablasts. Cytokines and chemokines associated with innate and adaptive immune activation, including Type I and Type II interferons, IL-18, and IP-10, were significantly upregulated following BV + Nivo, while TARC levels were significantly diminished following therapy. TCRβ sequencing revealed clonal expansion in the periphery following BV + Nivo. Conclusion A concurrent dosing schedule of BV + Nivo was well tolerated with a high CR rate of 80%. Biomarkers evaluated in Part 3 indicate immune activation in the periphery following BV + Nivo. Cumulatively, the results in Part 3, along with the durable remissions noted in Parts 1 & 2, support BV + Nivo combination as an encouraging first salvage therapy prior to ASCT in pts with R/R cHL. Disclosures Advani: Forty Seven: Research Funding; Infinity: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Gilead/Kite: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Merck: Research Funding; Agensys: Research Funding; Millenium: Research Funding; Janssen: Research Funding; Celgene: Research Funding; Autolus: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Kura: Research Funding; Kyowa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Regeneron: Research Funding; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Cell Medica: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding. Moskowitz:Bristol Myers-Squibb: Consultancy, Research Funding; Incyte: Research Funding; Takeda: Honoraria; Merck: Research Funding; ADC Therapeutics: Research Funding; Seattle Genetics: Consultancy, Honoraria, Research Funding. Bartlett:Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. Vose:Celgene: Research Funding; Legend Pharmaceuticals: Honoraria; Bristol Myers Squibb: Research Funding; Merck Sharp & Dohme Corp.: Research Funding; Incyte Corp.: Research Funding; Roche: Honoraria; Novartis: Honoraria, Research Funding; Seattle Genetics, Inc.: Research Funding; Acerta Pharma: Research Funding; Abbvie: Honoraria; Epizyme: Honoraria; Kite Pharma: Research Funding. Ramchandren:Merck: Research Funding; Bristol-Myers Squibb: Consultancy; Seattle Genetics: Consultancy, Research Funding; Pharmacyclics LLC an AbbVie Company: Consultancy, Research Funding; Janssen: Consultancy, Research Funding. Feldman:Johnson and Johnson: Speakers Bureau; Celgene: Speakers Bureau; Pharmacyclics: Speakers Bureau; Seattle Genetics: Research Funding, Speakers Bureau; Portola: Research Funding; Janssen: Speakers Bureau; KITE: Speakers Bureau. LaCasce:Seattle Genetics: Consultancy, Honoraria; Bristol-Myers Squibb: Other: Data safety and monitoring board; Research to Practice: Speakers Bureau; Humanigen: Consultancy, Honoraria. Christian:Acerta: Research Funding; Merck: Research Funding; Bristol-Myers Squibb: Research Funding; Immunomedics: Research Funding; Celgene: Research Funding; Seattle Genetics: Research Funding; Genentech: Membership on an entity's Board of Directors or advisory committees, Research Funding. Ansell:LAM Therapeutics: Research Funding; Pfizer: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Merck & Co: Research Funding; Bristol-Myers Squibb: Research Funding; Celldex: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Takeda: Research Funding. Moskowitz:Celgene: Consultancy; Merck & Co: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Consultancy, Research Funding. Fenton:Seattle Genetics, Inc.: Employment, Equity Ownership. Ogden:Seattle Genetics, Inc: Employment, Equity Ownership. Taft:Seattle Genetics: Employment, Equity Ownership. Zak:Seattle Genetics: Employment, Equity Ownership. Sacchi:Bristol-Myers Squibb: Employment, Equity Ownership. Galderisi:Seattle Genetics: Employment, Equity Ownership. Herrera:Immune Design: Research Funding; Merck, Inc.: Consultancy, Research Funding; KiTE Pharma: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Seattle Genetics: Research Funding; AstraZeneca: Research Funding; Pharmacyclics: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Gilead Sciences: Research Funding.

Key Points BV and Nivo were well-tolerated in patients with R/R HL, with less than 10% of patients treated with systemic steroids for immune-related AEs. The complete response rate was 61% (82% objective response rate), and patients were able to undergo stem cell transplant without adverse impact.