Brentuximab Vedotin Plus Chemotherapy in Patients with Advanced-Stage Classical Hodgkin Lymphoma (cHL): Evaluation of Modified Progression-Free Survival (mPFS) and Traditional PFS in the Phase 3 ECHELON-1 Study
Authors: Connors Joseph M. , Younes Anas , Gallamini Andrea , Ansell Stephen M. , Kim Won-Seog , Advani Ranjana H , Bartlett Nancy L. , Straus David J. , Sureda Anna , Hutchings Martin , Dlugosz-Danecka Monika , Engley Gerald , Fenton Keenan , Liu Rachael , Miao Harry , Jolin Hina , Gautam Ashish , Radford John 
Published: October 2019

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.

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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.