Liu, Rachael

Introduction Historically, nearly all relapses in classical Hodgkin lymphoma (cHL) occur within the first 5 years (Radford et al, BMJ 1997). In the phase 3 ECHELON-1 study (NCT01712490), treatment with brentuximab vedotin, doxorubicin, vinblastine, and dacarbazine (A+AVD) significantly improved modified progression-free survival (PFS) in patients (pts) with newly-diagnosed Stage III/IV cHL compared with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) (Connors et al, NEJM 2018). 3- and 4-year follow-up (Straus et al, Blood 2020; Bartlett et al, Blood 2019) reported durable PFS benefit with A+AVD vs ABVD in the intent-to-treat (ITT) population that was consistent across most key pt subgroups, irrespective of interim positron emission tomography (PET) scan status, disease stage, and baseline disease risk factor score. We report updated efficacy and safety results for pts in the ECHELON-1 study after a median follow-up of 55.6 months. Methods In this evaluation of longer follow-up, an exploratory analysis of PFS (time from randomization to relapse, progression, or death from any cause) per investigator (INV) was conducted, with a cutoff date of May 18, 2020. Pts with previously untreated Stage III or IV cHL were randomized 1:1 to receive up to six cycles of A+AVD (n=664) or ABVD (n=670) intravenously on days 1 and 15 of a 28-day cycle. An interim PET scan after cycle 2 (PET2) was required. Resolution and improvement (defined as improvement by ≥1 grade from worst grade as of the latest assessment) of peripheral neuropathy (PN) in pts with ongoing symptoms at the end of treatment (EoT) were monitored during the extended follow-up period. The rate of secondary malignancies, and the incidence and outcomes of pregnancies among pts and their partners were also assessed. Results With extended follow-up (median 55.6 months; 95% CI 55.2-56.7) estimated 5-year PFS rates were 82.0% (95% CI 78.7-84.8) for A+AVD and 75.2% (95% CI 71.5-78.4) for ABVD. Overall, PFS per INV favored A+AVD over ABVD (HR 0.691; 95% CI 0.543-0.880; p=0.003) (Table). Exploratory subgroup analyses by PET2 status and age demonstrated PFS benefits regardless of PET2 status (Table); estimated 5-year PFS per INV with A+AVD vs ABVD in the ITT population was 84.7% vs 78.8% in PET2-negative pts (HR 0.676; 95% CI 0.512-0.892; p=0.005), and 60.6% vs 45.9% in PET2-positive pts (HR 0.703; 95% CI 0.393-1.256; p=0.230). PFS benefit with A+AVD over ABVD was also independent of the number of International Prognostic Factors Project (IPFP) risk factors (Figure). After a median follow-up of almost 5-years, 84% (370/442) and 86% (245/286) of pts with treatment-emergent PN reported complete resolution or improvement of symptoms in the A+AVD and ABVD arms, respectively. Median time to complete resolution of PN events that were ongoing at EoT was 30 weeks (range 0-262) in the A+AVD arm and 16 weeks (range 0-267) in the ABVD arm; median time to improvement was 49 weeks (range 8-270) and 12 weeks (range 2-70) , respectively. Of the 132 (30%) pts with ongoing PN in the A+AVD arm, 77 (17%), 39 (9%), 15 (3%) and 1 (<1%) experienced a maximum severity of grade 1, 2, 3 or 4, respectively. In the ABVD arm, PN was ongoing in 61 pts (21%); maximum severity was grade 1, 2, 3 or 4 in 40 (14%), 17 (6%), 4 (1%) and 0 pts, respectively. A total of 124 pregnancies were reported among pts and their partners (40 female and 30 male pts in the A+AVD arm; 26 female and 28 male pts in the ABVD arm). The proportion of live births was similar between arms for female pts (26/40 in the A+AVD arm and 17/26 in the ABVD arm, 65% in each arm) and for male pts' partners (19/30 [63%] in the A+AVD arm and 20/28 [71%] in the ABVD arm). No stillbirths were recorded. Additional follow-up at an estimated median of ~5 years and secondary malignancy data will be presented. Conclusions After a median follow-up of 55.6 months, A+AVD continues to demonstrate a robust and durable treatment benefit independent of disease stage, risk factor score, and PET2 status. In addition, compared with ABVD, treatment adaptation by interim PET2 status is not required and bleomycin exposure is avoided. The sustained PFS benefit with A+AVD is coupled with a manageable safety profile with symptoms of PN improving or resolving over time and similar pregnancy rates in both treatment arms. The benefits observed with A+AVD at this important milestone suggest that A+AVD is an attractive treatment option for all pts with previously untreated Stage III or IV cHL. Disclosures Straus: Karyopharm Therapeutics: Membership on an entity's Board of Directors or advisory committees; Imedex, Inc.: Speakers Bureau; Targeted Oncology: Consultancy, Speakers Bureau; NY Lymphoma Rounds: Consultancy; Takeda Pharmaceuticals: Research Funding, Speakers Bureau; OncLive: Speakers Bureau; Elsevier: Membership on an entity's Board of Directors or advisory committees, Other: CME writer; ASH: Other: Conference in December 2019 on HL to other physicians during ASH; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees. Connors:Seattle Genetics: Other: Sponsorship to educational presentations; Takeda: Other: Sponsorship to educational presentations. Illés:Takeda, Seattle Genetics: Research Funding; Novartis, Janssen, Pfizer, Roche;: Other: Travel, Accommodations, Expenses; Janssen, Celgene, Takeda, Novartis Pharma SAS, Pfizer Pharmaceuticals Israel, Roche;: Consultancy, Honoraria; Celgene, Janssen, Novartis,Roche, Takeda: Consultancy. Lech-Marańda:Roche, Novartis, Takeda, Janssen-Cilag, Amgen, Gilead, AbbVie, Sanofi: Consultancy; Roche, Amgen, Gilead: Speakers Bureau. Feldman:KITE: Honoraria, Speakers Bureau; Abbvie: Honoraria, Speakers Bureau; Morphosis: Other: Ad board; AstraZeneca: Other: Ad board; BMS/Celgene: Consultancy, Honoraria, Speakers Bureau; Seattle Genetics: Consultancy, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Pharmacyclics: Honoraria, Speakers Bureau; Takeda: Honoraria, Speakers Bureau. Smolewski:Roche Poland: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Sandoz: Honoraria; Morphosis: Honoraria. Savage:Roche (institutional): Research Funding; Merck, BMS, Seattle Genetics, Gilead, AstraZeneca, AbbVie, Servier: Consultancy; BeiGene: Other: Steering Committee; Merck, BMS, Seattle Genetics, Gilead, AstraZeneca, AbbVie: Honoraria. Bartlett:Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Consultancy, Research Funding; Roche/Genentech: Consultancy, Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; BTG: Consultancy; Acerta: Consultancy; Affimed Therapeutics: Research Funding; ADC Therapeutics: Consultancy; Autolus: Research Funding; BMS/Celgene: Research Funding; Forty Seven: Research Funding; Immune Design: Research Funding; Janssen: Research Funding; Kite, a Gilead Company: Research Funding; Merck: Research Funding; Millennium: Research Funding. Walewski:Gilead: Consultancy, Honoraria; Servier: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Other: Travel Support, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; GSK: Research Funding. Ramchandren:Janssen: Research Funding; Pharmacyclics LLC, an AbbVie Company: Consultancy, Research Funding. Zinzani:Eusapharma: Consultancy, Speakers Bureau; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Portola: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Immune Design: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Consultancy, Speakers Bureau; MSD: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; AbbVie: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics, Inc.: Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; EUSA Pharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kirin Kyowa: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sandoz: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hutchings:Celgene, Genmab, Janssen, Novartis, F. Hoffmann-La Roche, Takeda: Research Funding; Genmab, F. Hoffmann-La Roche, Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Munoz:Juno/Celgene/BMS: Consultancy, Research Funding, Speakers Bureau; Alexion: Consultancy; Beigene: Consultancy, Speakers Bureau; Fosunkite: Consultancy; Innovent: Consultancy; Acrotech/Aurobindo: Speakers Bureau; Verastem: Speakers Bureau; AstraZeneca: Speakers Bureau; Kyowa: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Research Funding, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Research Funding, Speakers Bureau; Genentech/Roche: Research Funding, Speakers Bureau; AbbVie: Consultancy, Speakers Bureau; Merck: Research Funding; Portola: Research Funding; Incyte: Research Funding; Millenium: Research Funding; Pfizer: Consultancy; Kite, a Gilead Company: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics: Consultancy, Research Funding, Speakers Bureau; Bayer: Consultancy, Research Funding, Speakers Bureau. Kim:JJ: Research Funding; Celltrion: Research Funding; Kyowa Kirn: Research Funding; Donga: Research Funding; Mundipharma: Research Funding; Pfizer: Research Funding; F. Hoffmann-La Roche: Research Funding. Advani:Astra Zeneca, Bayer Healthcare Pharmaceuticals, Cell Medica, Celgene, Genentech/Roche, Gilead, KitePharma, Kyowa, Portola Pharmaceuticals, Sanofi, Seattle Genetics, Takeda: Consultancy; Celgene, Forty Seven, Inc., Genentech/Roche, Janssen Pharmaceutical, Kura, Merck, Millenium, Pharmacyclics, Regeneron, Seattle Genetics: Research Funding. Ansell:Bristol Myers Squibb: Research Funding; Takeda: Research Funding; ADC Therapeutics: Research Funding; AI Therapeutics: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding. Younes:HCM: Consultancy; Daiichi Sankyo: Consultancy; Curis: Consultancy; BMS: Consultancy; Novartis: Consultancy; Epizyme: Consultancy; BioPath: Consultancy; AstraZeneca: Current Employment; Janssen: Consultancy; Takeda: Consultancy. Gallamini:Takeda: Other: Speaker. Liu:Takeda Pharmaceuticals: Current Employment. Little:Takeda: Current Employment, Current equity holder in publicly-traded company. Fenton:Seattle Genetics: Current Employment, Current equity holder in publicly-traded company. Fanale:Seattle Genetics: Current Employment, Current equity holder in publicly-traded company. Radford:GlaxoSmithKline: Current equity holder in publicly-traded company, Other: Spouse; AstraZeneca: Current equity holder in publicly-traded company, Other: Spouse; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau; Pfizer: Research Funding; ADCT: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria; Seattle Genetics: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Abstract Approximately one‐third of patients diagnosed with Hodgkin lymphoma presenting with Stage IV disease do not survive past 5 years. We present updated efficacy and safety analyses in high‐risk patient subgroups, defined by Stage IV disease or International Prognostic Score (IPS) of 4–7, enrolled in the ECHELON‐1 study that compared brentuximab vedotin plus doxorubicin, vinblastine, and dacarbazine (A + AVD) versus doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) as first‐line therapy after a median follow‐up of 37.1 months. Among patients treated with A + AVD ( n = 664) or ABVD ( n = 670), 64% had Stage IV disease and 26% had an IPS of 4–7. Patients with Stage IV disease treated with A + AVD showed consistent improvements in PFS at 3 years as assessed by investigator (hazard ratio [HR], 0.723; 95% confidence interval [CI], 0.537–0.973; p = 0.032). Similar improvements were seen in the subgroup of patients with IPS of 4–7 (HR, 0.588; 95% CI, 0.386–0.894; p = 0.012). The most common adverse events (AEs) in A + AVD‐treated versus ABVD‐treated patients with Stage IV disease were peripheral neuropathy (67% vs. 40%) and neutropenia (71% vs. 55%); in patients with IPS of 4–7, the most common AEs were peripheral neuropathy (69% vs. 45%), neutropenia (66% vs. 55%), and febrile neutropenia (23% vs. 9%), respectively. Patients in high‐risk subgroups did not experience greater AE incidence or severity than patients in the total population. This updated analysis of ECHELON‐1 shows a favorable benefit‐risk balance in high‐risk patients.

Abstract The phase 3 ECHELON-1 study demonstrated that brentuximab vedotin (A) with doxorubicin, vinblastine, and dacarbazine (AVD; A+AVD) exhibited superior modified progression-free survival (PFS) vs doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) for frontline treatment of patients with stage III/IV classical Hodgkin lymphoma (cHL). Maturing positron emission tomography (PET)-adapted trial data highlight potential limitations of PET-adapted approaches, including toxicities with dose intensification and higher-than-expected relapse rates in PET scan after cycle 2 (PET2)-negative (PET2−) patients. We present an update of the ECHELON-1 study, including an exploratory analysis of 3-year PFS per investigator. A total of 1334 patients with stage III or IV cHL were randomized 1:1 to receive 6 cycles of A+AVD (n = 664) or ABVD (n = 670). Interim PET2 was required. At median follow-up of 37 months, 3-year PFS rates were 83.1% with A+AVD and 76.0% with ABVD; 3-year PFS rates in PET2− patients aged <60 years were 87.2% vs 81.0%, respectively. A beneficial trend in PET2+ patients aged <60 years on A+AVD was also observed, with a 3-year PFS rate of 69.2% vs 54.7% with ABVD. The benefit of A+AVD in the intent-to-treat population appeared independent of disease stage and prognostic risk factors. Upon continued follow-up, 78% of patients with peripheral neuropathy on A+AVD had either complete resolution or improvement compared with 83% on ABVD. These data highlight that A+AVD provides a durable efficacy benefit compared with ABVD for frontline stage III/IV cHL, consistent across key subgroups regardless of patient status at PET2, without need for treatment intensification or bleomycin exposure. This trial was registered at www.clinicaltrials.gov as #NCT01712490 (EudraCT no. 2011-005450-60).

Introduction: As previously reported, the combination of brentuximab vedotin with doxorubicin, vinblastine and dacarbazine (A+AVD) demonstrated a statistically significant improvement in modified progression free survival (modified PFS) compared with doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) in patients with newly diagnosed Stage III or IV classical HL in the phase 3 ECHELON-1 trial (NCT01712490). The benefit of A+AVD in the ITT population observed in the primary analysis was maintained at 3-years median follow-up [3-year PFS: A+AVD: 83.1% (79.9-85.9), ABVD: 76% (72.4-79.2)] and appears independent of interim PET status, disease stage, and prognostic risk factors. Here we present the efficacy and safety results of longer follow-up at a median 43.3 months. Methods: Newly diagnosed patients with Stage III or IV cHL were randomized 1:1 to receive A+AVD (n=664) or ABVD (n=670) intravenously on days 1 and 15 of each 28-day cycle for up to 6 cycles. The primary endpoint of the study was modified PFS per independent central review. The present follow-up PFS analysis is exploratory and per investigator assessment, with a cutoff date of June 17th, 2019. Patients with ongoing peripheral neuropathy (PN) at end of treatment were followed for resolution or improvement (defined as improved by ≥1 grade from worst grade as of the latest assessment) during the post-treatment follow-up period. Results: With a median follow-up of 43.3 months, the 42-month PFS per investigator for all patients was 82.4% (95% CI, 79.1-85.2) on the A+AVD arm and 76.2% (95% CI, 72.6-79.4) on the ABVD arm [overall HR 0.697 (95% CI, 0.547-0.890)]. Exploratory subgroup analyses of PET2(+) and PET2(-) patients showed a treatment effect in favor of A+AVD. The 42-month PFS in PET2(-) patients was 85.0% (95% CI, 81.6-87.7) for A+AVD and 79.6% (95% CI, 75.9-82.8) for ABVD [overall HR 0.695 (95% CI, 0.526-0.919)]; in PET2(+) patients 42-month PFS was 68.3% (95% CI, 54.5-78.7) for A+AVD and 51.5% (95% CI, 38.2-63.4) for ABVD [overall HR 0.552 (95% CI, 0.308-0.989)]. Upon continued follow-up, 81% (356/442) of patients with PN in the A+AVD arm had either complete resolution (64%, 283/442) or improvement (17%, 73/442) of their PN events compared with 83% (236/286) with either complete resolution (74%, 212/286) or improvement (8%, 24/286) in the ABVD arm. Among patients with ongoing PN after continued follow-up, the majority were Grade 1/2 events, with 89% (141/159; 59% Grade 1) and 95% (70/74; 65% Grade 1) on the A+AVD and ABVD arms, respectively. Overall survival data are not yet mature; per protocol, the final analysis will be performed after 112 deaths have occurred. Additional follow-up at an estimated median of ~4 years, including data from prespecified subgroups, will be presented. Conclusions: With a median follow-up of 43.3 months, A+AVD continues to provide a robust, durable benefit for patients with previously untreated Stage III or IV cHL compared with ABVD; the benefit is evident regardless of patient status at interim PET [PET2(+) or PET2(-)] and without the need for treatment intensification. PN continued to completely resolve or improve in patients on the A+AVD and ABVD arms. Together, these data further support the clinical advantages of A+AVD versus ABVD as treatment for patients with previously untreated Stage III or IV cHL. Disclosures Bartlett: Affimed Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; Celgene: Research Funding; Dynavax: Research Funding; Forty-Seven: Research Funding; Genentech: Research Funding; Gilead: Research Funding; Immune Design: Research Funding; Janssen: Research Funding; Kite Pharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Medimmune: Research Funding; Merck: Research Funding; Millennium: Research Funding; Novartis: Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmacyclics: Research Funding; Seattle Genetics, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Straus:Elsevier (PracticeUpdate): Consultancy, Honoraria; Hope Funds for Cancer Research: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Honoraria. Dlugosz-Danecka:Servier: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Macrogenomics: Research Funding; Roche: Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau. Illes:Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Feldman:Takeda: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Cell Medica: Research Funding; Amgen: Research Funding; Viracta: Research Funding; Bayer: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Kite Pharma: Honoraria, Other: Travel expenses, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Pharmacyclics: Honoraria, Other: Travel expenses, Speakers Bureau; Pfizer: Research Funding; Portola Pharma: Research Funding; Roche: Research Funding; Eisai: Research Funding; Corvus: Research Funding; Roche: Research Funding; AbbVie: Honoraria, Other: Travel expenses, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Other: Travel expenses, Speakers Bureau; Kyowa Hakko Kirin: Research Funding; Trillium: Research Funding. Smolewski:Roche: Other: Travel Expenses. Savage:Seattle Genetics, Inc.: Consultancy, Honoraria, Research Funding; BMS, Merck, Novartis, Verastem, Abbvie, Servier, and Seattle Genetics: Consultancy, Honoraria. Walewski:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Expenses, Research Funding; Takeda: Honoraria, Research Funding; Incyte: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Servier: Honoraria; Gilead: Other: Travel Expenses; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Zinzani:Portola: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Immune Design: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sandoz: Membership on an entity's Board of Directors or advisory committees; Servier: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen-Cilag: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Sanofi: Consultancy; Eusapharma: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; MSD: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Verastem: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Kyowa Kirin: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; TG Therapeutics: Honoraria, Speakers Bureau. Hutchings:Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Expenses, Research Funding; Genmab: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Travel Expenses, Research Funding; Novartis: Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Other: Travel Expenses, Research Funding. Radford:AstraZeneca: Equity Ownership, Research Funding; Novartis: Consultancy, Honoraria; Seattle Genetics: Consultancy, Honoraria; ADC Therapeutics: Consultancy, Research Funding; Takeda: Consultancy, Honoraria, Research Funding; BMS: Consultancy, Honoraria; GSK: Equity Ownership. Munoz:AstraZeneca: Speakers Bureau; Kite Pharma: Consultancy, Research Funding, Speakers Bureau; Pharmacyclics LLC an AbbVie Company: Consultancy, Research Funding, Speakers Bureau; Gilead: Consultancy, Speakers Bureau; Fosunkite: Speakers Bureau; Kyowa: Consultancy, Honoraria, Speakers Bureau; Bayer: Consultancy, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Research Funding; Celgene: Research Funding; Portola: Research Funding; Incyte: Research Funding. Kim:Roche: Research Funding; Kyowa-Kirin: Research Funding; Novartis: Research Funding; J&J: Research Funding; Mundipharma: Research Funding; Celltrion: Research Funding; Donga: Research Funding. Advani:Cell Medica, Ltd: Consultancy; Pharmacyclics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Merck: Research Funding; Kura: Research Funding; Infinity Pharma: Research Funding; Bristol-Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Consultancy, Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Celmed: Consultancy, Membership on an entity's Board of Directors or advisory committees; Autolus: Consultancy, Membership on an entity's Board of Directors or advisory committees; Agensys: Research Funding; Stanford University: Employment, Equity Ownership; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Consultancy, Research Funding; Kyowa Kirin Pharmaceutical Developments, Inc.: Consultancy; Regeneron: Research Funding; Millennium: Research Funding; Janssen: Research Funding; Roche/Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead Sciences, Inc./Kite Pharma, Inc.: Consultancy, Membership on an entity's Board of Directors or advisory committees; Forty-Seven: Research Funding; AstraZeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees. Ansell:Mayo Clinic Rochester: Employment; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Trillium: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; LAM Therapeutics: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Mayo Clinic Rochester: Employment; Mayo Clinic Rochester: Employment; Trillium: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Bristol-Myers Squibb: Research Funding; Seattle Genetics: Research Funding; LAM Therapeutics: Research Funding; Bristol-Myers Squibb: Research Funding; LAM Therapeutics: Research Funding; Regeneron: Research Funding; Regeneron: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; Bristol-Myers Squibb: Research Funding; Bristol-Myers Squibb: Research Funding; Mayo Clinic Rochester: Employment; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Seattle Genetics: Research Funding; Seattle Genetics: Research Funding; Bristol-Myers Squibb: Research Funding; Trillium: Research Funding; Mayo Clinic Rochester: Employment. Younes:Roche: Consultancy, Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Curis: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Abbvie: Honoraria; Takeda: Honoraria; Pharmacyclics: Research Funding; AstraZeneca: Research Funding; Genentech: Research Funding; Biopath: Consultancy; Xynomics: Consultancy; Epizyme: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; HCM: Consultancy; BMS: Research Funding; Syndax: Research Funding. Gallamini:Takeda: Consultancy; Roche: Consultancy. Miao:Millennium Pharmaceuticals, Inc., Cambridge, MA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment, Equity Ownership. Liu:Takeda: Employment. Fenton:Seattle Genetics, Inc.: Employment, Equity Ownership. Forero-Torres:Seattle Genetics: Employment, Equity Ownership, Honoraria, Research Funding.

Abstract Background Survival rates for older pts with advanced HL (aged ≥60 yrs) were historically poor with doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD). Reasons may include decreased tolerance of therapy, increased toxicity (particularly with bleomycin), comorbidities, and disease biology. The pivotal phase 3 ECHELON-1 study demonstrated superior 2-yr modified progression-free survival (mPFS) with frontline brentuximab vedotin + doxorubicin, vinblastine and dacarbazine (A+AVD) vs ABVD in pts with stage III/IV cHL (Connors JM et al, NEJM 2018). The study allowed entry of older pts, with no upper age limit. Alternative dosing schedules of the A+AVD regimen have been studied (e.g., sequential brentuximab vedotin before and after AVD; NCT01476410, Evens AM et al, J Clin Oncol 2018). We report efficacy and safety results from ECHELON-1 for older pts with cHL and compare these with those for pts aged <60 yrs. Methods mPFS per independent review facility (IRF) for pts ≥60 years was a prespecified subgroup analysis of ECHELON-1. Additional exploratory safety and efficacy analyses were also assessed and compared with younger pts (<60 yrs). The study was not powered for age-based subgroup analyses; p-values are descriptive without multiplicity adjustment. Results 14% (186/1334) of pts in the intent-to-treat (ITT) population were aged ≥60 yrs (A+AVD, n=84; ABVD, n=102) and included in the sub analyses. Median age (range) of older pts was: A+AVD, 68.0 yrs (60-82); ABVD, 66.0 yrs (60-83). Baseline pt and disease characteristics in older pts were similar in both arms. ECOG PS scores were 0 (36% vs 36%), 1 (52% vs 54%), and 2 (12% vs 10%) in A+AVD and ABVD arms, respectively. Pts received a median of 6 cycles with mean relative dose intensities for each drug (%) in older pts of: A+AVD, 92.3, 96.6, 93.3, and 97.9; ABVD, 97.3, 88.7, 93.3, and 95.9. With median follow-up of ~25 months, 2-yr mPFS per IRF was similar in both arms for older ITT pts (A+AVD 70.3% [95% CI: 58.4, 79.4] vs ABVD 71.4% [95% CI: 60.5, 79.8]; HR=1.00 [95% CI: 0.58, 1.72]; p=0.993). An exploratory analysis of standard PFS per investigator (INV) showed HR=0.85 ([95% CI: 0.49, 1.48]; p=0.576) (Table 1). For older pts with stage IV cHL (A+AVD n=51; ABVD n=67), there was an increase in 2-yr PFS per INV with A+AVD vs ABVD (74.0% [95% CI: 59.5, 84.0] vs 59.9% [95% CI: 45.6, 71.5]; HR, 0.66 [95% CI: 0.34, 1.26]; p=0.20); mPFS per IRF improvement with A+AVD in older stage IV pts was lower (HR=0.80; [95% CI: 0.42, 1.53]). In younger stage III/IV pts (<60 yrs) 2-yr mPFS per IRF and PFS per INV were also higher compared with older pts in both arms (Table 1). 66 of 83 older A+AVD pts required ≥1 dose modification of brentuximab vedotin, reasons were: dose reduction (n=27), dose held (n=4), dose delayed (n=51), brentuximab vedotin discontinued (n=17). In older pts, grade (G) 3/4 AEs occurred in 88% of A+AVD pts vs 80% ABVD pts; for younger pts, rates were 82% (A+AVD) vs 63% (ABVD) (Table 2). In older pts there were 3 (4%) on-study deaths in the A+AVD arm (1 each: hemophagocytosis, neutropenic sepsis, and myocardial infarction) and 5 (5%) with ABVD (all pulmonary-related). In pts <60 yrs, there were 6 on-study deaths (1%) with A+AVD vs 8 (1%) with ABVD. G3 neutropenia in older pts was (70%) A+AVD pts vs (59%) ABVD pts, and febrile neutropenia (FN) in 31 (37%) vs 17 (17%) pts. In older pts who had G-CSF primary prophylaxis (PP) neutropenia was seen in 4/10 (40%) A+AVD pts vs 1/9 (11%) ABVD pts (on-study FN in 3 [30%] vs 2 [22%] pts). In older pts, treatment-emergent peripheral neuropathy (PN) was reported in 54 (65%) of A+AVD pts vs 42 (43%) of ABVD pts (G≥3 in 15 [18%] vs 3 [3%] pts), respectively. In pts <60 yrs PN was reported in 388 (67%) A+AVD pts vs 244 (43%) ABVD pts (G≥3 in 55 [9%] vs 8 [1%] pts), respectively. In older pts at last follow-up, 65% (35/54) of A+AVD pts and 60% (25/42) of ABVD pts had complete resolution (A+AVD, 39%; ABVD, 38%) or improvement (A+AVD, 26%; ABVD, 21%) of PN events. 2% older A+AVD pts had pulmonary AEs (both G1/2 pulmonary infiltration) vs 13% older ABVD pts. Conclusions For older ECHELON-1 pts, mPFS and PFS were similar in both arms. In the larger subgroup of younger pts, mPFS and PFS were improved vs older pts. As expected, incidence of treatment-emergent AEs was higher in older pts, with regimen-specific AEs seen, including fatal pulmonary events in ABVD pts. The high incidence of FN in older A+AVD pts points to the need for G-CSF PP. Disclosures Evens: Acerta: Consultancy; Pharmacyclics International DMC: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics, Inc.: Membership on an entity's Board of Directors or advisory committees, Research Funding; Affimed: Consultancy; Janssen: Consultancy; Abbvie: Consultancy; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy; Tesaro: Research Funding; Novartis: Consultancy. Connors:Merck: Research Funding; Amgen: Research Funding; Takeda: Research Funding; Roche Canada: Research Funding; NanoString Technologies: Patents & Royalties: Named Inventor on a patent licensed to NanoString Technologies, Research Funding; Seattle Genetics: Honoraria, Research Funding; Janssen: Research Funding; F Hoffmann-La Roche: Research Funding; Bayer Healthcare: Research Funding; Cephalon: Research Funding; Bristol Myers-Squibb: Research Funding; Lilly: Research Funding; Genentech: Research Funding. Younes:Sanofi: Honoraria; Merck: Honoraria; Astra Zeneca: Research Funding; Celgene: Honoraria; Incyte: Honoraria; Seattle Genetics: Honoraria; Bayer: Honoraria; Novartis: Research Funding; Curis: Research Funding; J&J: Research Funding; Genentech: Research Funding; Takeda: Honoraria; Roche: Honoraria, Research Funding; Abbvie: Honoraria; Janssen: Honoraria, Research Funding; Pharmacyclics: Research Funding; BMS: Honoraria, Research Funding. Ansell:Merck & Co: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Affimed: Research Funding; Seattle Genetics: Research Funding; Regeneron: Research Funding; Takeda: Research Funding; Pfizer: Research Funding; Celldex: Research Funding; Bristol-Myers Squibb: Research Funding. Radford:Takeda: Consultancy, Research Funding, Speakers Bureau; GlaxoSmithKline: Equity Ownership; AstraZeneca: Equity Ownership; Seattle Genetics: Consultancy, Speakers Bureau; ADC Therapeutics: Consultancy, Research Funding; Novartis: Consultancy, Speakers Bureau; Pfizer: Research Funding; Celgene: Research Funding; BMS: Consultancy, Speakers Bureau. Feldman:Seattle Genetics: Research Funding, Speakers Bureau; Janssen: Speakers Bureau; Pharmacyclics: Speakers Bureau; Johnson and Johnson: Speakers Bureau; Celgene: Speakers Bureau; Portola: Research Funding; KITE: Speakers Bureau. Tuscano:Takeda: Research Funding; Genentech: Consultancy, Research Funding; Amgen: Honoraria, Speakers Bureau; Seattle Genetics: Honoraria, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Pharmacyclics: Research Funding. Oki:Seattle Genetics: Research Funding; Takeda Millenium: Honoraria, Research Funding; Jazz Pharmaceuticals: Employment. Grigg:Roche: Membership on an entity's Board of Directors or advisory committees; Gilead: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Pocock:Kent & Canterbury Hospital: Employment. Dlugosz-Danecka:Roche: Consultancy; Servier: Consultancy. Fenton:Seattle Genetics, Inc.: Employment, Equity Ownership. Engley:Seattle Genetics: Employment. Liu:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Miao:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Jolin:Takeda Pharmaceuticals International Co.: Employment. Gautam:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Gallamini:Takeda: Consultancy, Speakers Bureau.

Abstract Background: The pivotal phase 3 ECHELON-1 study demonstrated superior efficacy of brentuximab vedotin plus doxorubicin, vinblastine and dacarbazine (A+AVD) versus doxorubicin, bleomycin, vinblastine and dacarbazine (ABVD) in patients with previously untreated advanced stage classical Hodgkin lymphoma (cHL) with a 2-year modified progression-free survival (mPFS) of 82.1% in the A+AVD group versus 77.2% in the ABVD group (Hazard Ratio=0.77; 95% confidence interval [CI] 0.60, 0.98; p=0.04). PN is a known toxicity associated with anti-mitotic agents, including vinblastine and the MMAE component of brentuximab vedotin. In the ECHELON-1 study, the incidence of any-grade PN events was 67% (442 of 662 patients) and 43% (286 of 659 patients) in the A+AVD and ABVD arms, respectively; the incidence of grade ≥3 PN was 11% and 2%, respectively. At the time of the initial analysis, 67% of A+AVD-treated patients had either resolution (43%) or improvement (24%) of PN events. A total of the 92% of ongoing PN events were grade 1 (64%) or grade 2 (29%). Here, we report rates of PN resolution and improvement in patients participating in the ECHELON-1 study after long-term follow-up. Methods: Patients with Stage III or IV cHL were randomized 1:1 to receive up to six cycles of A+AVD (n=664) or ABVD (n=670). Pre-existing PN was an exclusion factor at study entry. Peripheral neuropathy was determined on the basis of a standardized MedDRA query; patients who developed PN were monitored throughout the study and those with ongoing PN at end of treatment were followed for resolution or improvement during the post-treatment follow-up period; follow-up visits were scheduled for every 12 weeks ±1 week until 36 months, then every 6 months until study closure. PN resolution was defined as completely resolved and improvement was defined as improved by ≥1 grade from worst grade as of the latest assessment. Results: At the time of the primary analysis, 51% (226/442) and 61% (174/286) of patients in the A+AVD and ABVD arms, respectively, had resolution or improvement of PN events at EOT. Upon continued follow-up (~10 additional months) for approximately 30 months (range 0-78.5) after end of treatment, 76% (335/442) of patients with PN in the A+AVD arm had either complete resolution (59%, 260/442) or improvement (17%, 75/442) of their PN events compared with 82% (234/286) with either resolution (72%) or improvement (10%) in the ABVD arm. In the A+AVD arm, 90% of ongoing PN cases (n=182) were grade 1/2; grade 1=58% (n=106), grade 2=32% (n=58). Residual grade 3 PN was reported in 9% (n=17) of patients (1 patient with grade 4 PN died before resolution). In the ABVD arm, residual PN (n=81) was grade 1 (65%; n=53), grade 2 (30%; n=24), and grade 3 (5%; n=4). For the subset of patients with PN that had not resolved by end of treatment, the median time to resolution of all PN events from AE start date was 28 weeks for A+AVD and 14 weeks for ABVD, the median time to improvement of PN was 39 weeks for A+AVD and 18.5 weeks for ABVD. Conclusions: After approximately 2.5 years of continued follow-up, PN continues to resolve and improve for patients who were treated with A+AVD or ABVD in the ECHELON-1 study. In both study arms, the majority of ongoing PN cases are grade 1 or grade 2. Further follow-up is ongoing. Disclosures Radford: Celgene: Research Funding; ADC Therapeutics: Consultancy, Research Funding; Seattle Genetics: Consultancy, Speakers Bureau; GlaxoSmithKline: Equity Ownership; Takeda: Consultancy, Research Funding, Speakers Bureau; Pfizer: Research Funding; BMS: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; AstraZeneca: Equity Ownership. Connors:Takeda: Research Funding; Seattle Genetics: Honoraria, Research Funding; Roche Canada: Research Funding; Genentech: Research Funding; Cephalon: Research Funding; Bristol Myers-Squibb: Research Funding; Janssen: Research Funding; Bayer Healthcare: Research Funding; NanoString Technologies: Patents & Royalties: Named Inventor on a patent licensed to NanoString Technologies, Research Funding; Merck: Research Funding; F Hoffmann-La Roche: Research Funding; Amgen: Research Funding; Lilly: Research Funding. Younes:Astra Zeneca: Research Funding; J&J: Research Funding; Curis: Research Funding; BMS: Honoraria, Research Funding; Bayer: Honoraria; Takeda: Honoraria; Sanofi: Honoraria; Roche: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Merck: Honoraria; Seattle Genetics: Honoraria; Celgene: Honoraria; Incyte: Honoraria; Abbvie: Honoraria; Novartis: Research Funding; Pharmacyclics: Research Funding; Genentech: Research Funding. Gallamini:Takeda: Consultancy, Speakers Bureau. Ansell:Affimed: Research Funding; Merck & Co: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Trillium: Research Funding; Pfizer: Research Funding; Takeda: Research Funding; Bristol-Myers Squibb: Research Funding; Celldex: Research Funding; Seattle Genetics: Research Funding. Gopal:Aptevo: Consultancy; Janssen: Consultancy, Research Funding; Merck: Research Funding; Gilead: Consultancy, Research Funding; Brim: Consultancy; Spectrum: Research Funding; Takeda: Research Funding; BMS: Research Funding; Pfizer: Research Funding; Seattle Genetics: Consultancy, Research Funding; Incyte: Consultancy; Teva: Research Funding; Asana: Consultancy. Flinn:Trillium: Research Funding; Calithera: Research Funding; Forma: Research Funding; Portola: Research Funding; Verastem: Research Funding; Janssen: Research Funding; Infinity: Research Funding; Genentech: Research Funding; Forty Seven: Research Funding; Constellation: Research Funding; Merck: Research Funding; Curis: Research Funding; Takeda: Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Research Funding; Incyte: Research Funding; ArQule: Research Funding; Verastem: Consultancy, Research Funding; Celgene: Research Funding; Agios: Research Funding; Novartis: Research Funding; Gilead: Research Funding; Pfizer: Research Funding; TG Therapeutics: Research Funding; Kite: Research Funding; BeiGene: Research Funding. Pettengell:CTI: Honoraria; Pfizer: Honoraria; Roche: Honoraria; Servier: Honoraria; Takeda: Honoraria. Dlugosz-Danecka:Servier: Consultancy; Roche: Consultancy. Engley:Seattle Genetics: Employment. Fenton:Seattle Genetics, Inc.: Employment, Equity Ownership. Liu:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Purevjal:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Miao:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Gautam:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Kuruvilla:Janssen: Consultancy, Honoraria, Research Funding; Princess Margaret Cancer Foundation: Research Funding; BMS: Consultancy, Honoraria; Abbvie: Consultancy; Karyopharm: Honoraria; Celgene: Honoraria; Seattle Genetics: Consultancy, Honoraria; Lundbeck: Honoraria; Merck: Consultancy, Honoraria; Amgen: Honoraria; Roche: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria; Leukemia and Lymphoma Society Canada: Research Funding.

Abstract Background: The phase 3 ECHELON-1 study assessed frontline brentuximab vedotin administered with doxorubicin, vinblastine, and dacarbazine (A+AVD) vs doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) in patients (pts) with advanced cHL (NCT01712490). The primary endpoint of ECHELON-1, modified PFS (mPFS) per independent review facility (IRF), is defined as (1) progressive disease, (2) death, or (3) subsequent anticancer therapy (chemotherapy [chemo] and/or radiotherapy [RT]) following detection of a non-complete response (non-CR = Deauville score 3-5) at end of frontline therapy. A+AVD was superior to ABVD (hazard ratio [HR]=0.77; p=0.035) with 2-year mPFS rates of 82.1% and 77.2%; as previously reported. In pts with newly diagnosed cHL, the aim of frontline therapy is curative. Pts who do not achieve a satisfactory response to frontline therapy may initiate subsequent anticancer therapy prior to response criteria-defined progression. The measurement of traditional PFS becomes confounded, as pts may effectively be rescued from criteria-defined progression by subsequent treatment, resulting in an overestimation of PFS with frontline therapy (Connors et al. Haematologica 2016;101[s5]:22-3[P007]). To further evaluate modified and traditional PFS in the ECHELON-1 study, two sensitivity analyses were conducted. Methods: 1334 pts with Stage III (36%) or IV (64%) cHL were randomized 1:1 to receive A+AVD (n=664) or ABVD (n=670) on days 1 and 15, for up to six 28-day cycles. In addition to mPFS per IRF, mPFS per investigator (INV) was collected. A sensitivity analysis (mPFS-chemo) was performed in which RT following a non-CR at the completion of frontline therapy was not counted as an event: in this case, mPFS-chemo was defined as (1) progression, (2) death, or (3) receipt of additional anticancer chemo excluding RT for pts who are not in CR after completion of frontline therapy. A second sensitivity analysis of traditional PFS (PFS-traditional), defined as (1) progression or (2) death, was also performed. All analyses were performed per INV as, per protocol, IRF follow up of pts was not conducted after the initiation of subsequent therapy. Results: At 2 years, the rates of mPFS per INV (95% CI) for A+AVD vs ABVD were 81.0% (77.6-83.9%) vs 74.4% (70.7-77.7%), respectively; HR=0.72 (95% CI: 0.573, 0.914; p=0.006). Concordance between IRF and INV mPFS assessments was high among all pts in both arms, at 91%. A total of 123 mPFS events per INV were observed among pts treated with A+AVD, including 73 pts with PD, 15 deaths, and 35 who received additional anticancer therapy following evidence of non-CR at the end of frontline therapy, vs 164 per INV mPFS events among pts treated with ABVD, of which 103 were PD, 22 were deaths, and 39 were additional anticancer therapy following evidence of non-CR at the end of frontline therapy. Of the 35 (A+AVD) and 39 (ABVD) additional anticancer therapy events, chemo/RT following evidence of non-CR at the end of frontline therapy accounted for 11/24 and 17/22 of these events, respectively. For mPFS-chemo, a larger benefit in favor of A+AVD vs ABVD, with a HR=0.687 (95% CI: 0.534, 0.885; p=0.003), was observed. The 2-year mPFS-chemo (95% CI) was estimated as 84.0% (80.9-86.7%) for pts treated with A+AVD vs 77.3% (73.7-80.4%) for pts treated with ABVD. A total of 103 events were observed among pts in the A+AVD arm, including 78 pts with PD, 15 deaths, and 10 who received additional chemo following evidence of a non-CR at the end of frontline therapy, vs 145 events among pts treated with ABVD, of which 106 were PD, 22 were deaths, and 17 were additional chemo following evidence of non-CR at the end of frontline therapy. For PFS-traditional, an advantage in favor of A+AVD vs ABVD was also observed: HR=0.70 (95% CI: 0.54-0.91; p=0.006). The 2-year PFS estimate (95% CI) was 84.2% (81.1-86.9%) for A+AVD vs 78.0% (74.4-81.1%) for ABVD. In total, there were 101 PFS events in the A+AVD arm, including 86 pts with PD and 15 deaths; vs 140 PFS events in the ABVD arm, including 118 pts with PD and 22 deaths. Conclusions: Consistent with the primary outcome of ECHELON-1, a benefit in favor of A+AVD vs ABVD was observed independent of the inclusion of additional anticancer RT or chemo as survival events, in addition to progression or death. A traditional PFS assessment including only progression or death events demonstrated that A+AVD resulted in a 30% reduction in the risk of progression or death compared to ABVD. Figure. Figure. Disclosures Connors: Lilly: Research Funding; Bayer Healthcare: Research Funding; Janssen: Research Funding; Bristol Myers-Squibb: Research Funding; Merck: Research Funding; NanoString Technologies: Patents & Royalties: Named Inventor on a patent licensed to NanoString Technologies, Research Funding; Seattle Genetics: Honoraria, Research Funding; Roche Canada: Research Funding; Amgen: Research Funding; Genentech: Research Funding; F Hoffmann-La Roche: Research Funding; Cephalon: Research Funding; Takeda: Research Funding. Younes:J&J: Research Funding; Celgene: Honoraria; BMS: Honoraria, Research Funding; Sanofi: Honoraria; Abbvie: Honoraria; Curis: Research Funding; Genentech: Research Funding; Merck: Honoraria; Bayer: Honoraria; Pharmacyclics: Research Funding; Janssen: Honoraria, Research Funding; Novartis: Research Funding; Incyte: Honoraria; Seattle Genetics: Honoraria; Roche: Honoraria, Research Funding; Astra Zeneca: Research Funding; Takeda: Honoraria. Gallamini:Takeda: Consultancy, Speakers Bureau. Ansell:Pfizer: Research Funding; Trillium: Research Funding; Bristol-Myers Squibb: Research Funding; Affimed: Research Funding; Regeneron: Research Funding; LAM Therapeutics: Research Funding; Takeda: Research Funding; Merck & Co: Research Funding; Celldex: Research Funding; Seattle Genetics: Research Funding. Kim:J&J: Research Funding; Kyowa-Kirin: Research Funding; Mundipharma: Research Funding; Celltrion: Honoraria, Research Funding; Novartis: Research Funding; Takeda: Research Funding; Roche: Honoraria, Research Funding; Eisai: Honoraria, Research Funding; Celgene: Research Funding; Merck: Research Funding. Advani:Janssen: Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Cell Medica: Consultancy, 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; Forty Seven Inc.: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Kura: Research Funding; Kyowa: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Merck: Research Funding; Astra Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Celgene: Research Funding; Autolus: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Millenium: Research Funding; Agensys: Research Funding; Infinity: Research Funding; Regeneron: Research Funding; Celgene: Research Funding; Gilead/Kite: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board, Research Funding; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer: Membership on an entity's Board of Directors or advisory committees, Other: Participated in an advisory board. Bartlett:KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; ImaginAB: Research Funding; Celgene: Research Funding; Pharmacyclics: Research Funding; Pharmacyclics: Research Funding; Pfizer: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Acerta: Membership on an entity's Board of Directors or advisory committees; Millennium: Research Funding; Seattle Genetics: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Meyers Squibb: Research Funding; Immune Design: Research Funding; Astra Zeneca: Research Funding; Forty Seven: Research Funding; Affimed: Research Funding; Genentech: Research Funding; Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Research Funding; Merck & Co: Research Funding; Janssen: Research Funding. Straus:Onco Tracker: Consultancy; Roch China: Speakers Bureau; Memorial Sloan Kettering Cancer Center: Employment; JUNO: Consultancy; Medical Crossfire: Speakers Bureau; DAVA Oncology: Consultancy, Honoraria; Bayer: Consultancy; InPractice Elselvier: Consultancy; Millenium (Takeda): Consultancy, Research Funding; Seattle Genetics: Consultancy. Sureda:BMS: Consultancy, Honoraria; Sanofi: Honoraria; Roche: Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy, Honoraria. Hutchings:Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche/Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Dlugosz-Danecka:Servier: Consultancy; Roche: Consultancy. Engley:Seattle Genetics: Employment. Fenton:Seattle Genetics, Inc.: Employment, Equity Ownership. Liu:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Miao:Millennium Pharmaceuticals Inc., a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Jolin:Takeda Pharmaceuticals International Co.: Employment. Gautam:Millennium Pharmaceuticals, Inc., Cambridge, MA, USA, a wholly owned subsidiary of Takeda Pharmaceutical Company Limited: Employment. Radford:Novartis: Consultancy, Speakers Bureau; Celgene: Research Funding; Pfizer: Research Funding; GlaxoSmithKline: Equity Ownership; Takeda: Consultancy, Research Funding, Speakers Bureau; AstraZeneca: Equity Ownership; Seattle Genetics: Consultancy, Speakers Bureau; BMS: Consultancy, Speakers Bureau; ADC Therapeutics: Consultancy, Research Funding.