Dose-Intensification in Early Unfavorable Hodgkin Lymphoma: Long-Term Follow up of the German Hodgkin Study Group (GHSG) HD14 Trial
Authors: Gillessen Sarah , Plütschow Annette , Fuchs Michael , Markova Jana , Greil Richard , Topp Max S. , Meissner Julia , Zijlstra Josée M , Eichenauer Dennis A. , Diehl Volker , Borchmann Peter , Engert Andreas , von Tresckow Bastian 
Published: February 2020

Background:
In early unfavorable Hodgkin Lymphoma (HL), long-term tumor control with 4xABVD and 30Gy involved field radiotherapy (IFRT) is approximately 80%. To improve these results, the GHSG HD14 trial compared an intensified chemotherapy regimen consisting of 2xBEACOPPescalated plus 2xABVD (2+2) to 4xABVD. All patients received 30Gy IFRT. Due to a progression-free survival (PFS) difference of 6.2% at five years in favor of the intensified treatment, 2+2 plus 30Gy RT is the current GHSG standard and is a treatment option in the NCCN guidelines for early unfavorable HL. However, there was no overall survival (OS) difference between 2+2 and 4xABVD at the final analysis of HD14 and the potential long-term toxicity of 2+2 is debated. We therefore performed a long-term follow up analysis of HD14.
Patients and Methods:
Between January 2003 and July 2008, 1,550 patients with early unfavorable HL ≤60 years were randomized and treated with 4xABVD or 2+2, followed by 30Gy IFRT in all patients. Randomization was discontinued after the third planned interim analysis showed a significant advantage of 2+2 in terms of the primary endpoint freedom from treatment failure (FFTF, difference 7.2% at 5 years). Accrual to the 2+2 arm continued from July 2008 to December 2009 and 339 additional qualified patients were treated with 2+2 plus 30Gy IFRT. These patients were not reported in the initial report and are added to all analyses of this long-term follow-up. Time-to-event end points were compared between groups using the Kaplan-Meier method as well as univariate and multivariate Cox regression models.
Results:
After a median observation time of 97 months, 10.2% (79 of 777) and 3.4% (38 of 1112) of patients treated with 4xABVD and 2+2, respectively, had progression or relapse. The 10-year PFS was 85.6% for 4xABVD (95%-CI 82.9% to 88.4%) and 91.2% for 2+2 (95%-CI 89.0% to 93.4%) accounting for a significant PFS difference of 5.6% (95%-CI 2.1% to 9.1%) in favor of 2+2 (Figure 1). Two or more relapses were experienced by 21 of 777 (2.7%) and 10 of 1112 (0.9%) patients who had received 4xABVD or 2+2 as first-line treatment, respectively. However, there was still no OS difference between the two groups (OS 94.1% [95%-CI 92.3% to 96%] and 94% [95%-CI 92.3% to 95.8%] for 4xABVD and 2+2, respectively; difference at 10 years -0.1% [95%-CI -2.6% to 2.4%], median observation time for OS 104 months). In a multivariate regression analysis adjusting for age, B-symptoms, infra-diaphragmatic disease, and the 4 GHSG risk factors (elevated ESR, involvement of ≥3 lymph node areas, extranodal disease, and large mediastinal tumor) as predictive factors for PFS, age ≥50 (HR 2.260, 95%-CI 1.543 to 3.309), presence of infra-diaphragmatic disease (HR 1.766, 95%-CI 1.055 to 2.955), or of a large mediastinal tumor (HR 1.811, 95%-CI 1.226 to 2.675) and treatment with 4xABVD (HR 1.929, 95%-CI 1.423 to 2.614) were significant predictors of PFS. Slightly more patients in the 4xABVD group died from toxicity of salvage therapy as compared to 2+2 patients (1% [8 of 777] versus 0.6% [7 of 1112]) whereas there were relatively more deaths due to study therapy in the 2+2 group as compared to 4xABVD patients (0.6% [7 of 1112] versus 0.1% [1 of 777]), leading to a similar OS in both groups. There were no apparent differences in other causes of death including HL (5 of 777 [0.6%] versus 9 of 1112 [0.8%]) and second neoplasms (12 of 777 [1.5%] versus 16 of 1112 [1.4%]) between 4xABVD and 2+2, respectively. A total of 95 second malignancies corresponding to 10-year cumulative second malignancy incidences of 4.7% and 6.4% were reported for 4xABVD and 2+2, respectively, without a difference between the two groups (p=0.86). Standardized incidence ratios (SIR) showed elevation compared to the general German population and no significant difference between 4xABVD (2.3 [95%-CI 1.6 to 3.2]) and 2+2 (2.6 [95%-CI 2.0 to 3.4]).
Conclusions:
This long-term analysis confirms the superior tumor control of 2+2 as compared to 4xABVD in patients ≤60 with early unfavorable HL. However, this does not translate into an OS difference. At longer follow-up, there is no difference regarding second primary malignancies between the groups. In comparison to 4xABVD, the 2+2 regimen spares a significant number of patients from the burden of cancer recurrence and additional treatment without increased long-term toxicity. Therefore, 2+2 remains the GHSG standard for patients with early unfavorable HL ≤60.

Disclosures
Greil: Novartis: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; GSK: Research Funding; Takeda: Consultancy, Honoraria, Research Funding; Ratiopharm: Research Funding; Roche: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; Eisai: Honoraria; Boehringer Ingelheim: Honoraria; Pfizer: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; MSD: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; Amgen: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; Daiichi Sankyo: Consultancy, Honoraria; Sandoz: Honoraria; Janssen-Cilag: Honoraria; Genentech: Honoraria, Research Funding; Sanofi Aventis: Honoraria; Celgene: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding; Merck: Consultancy, Honoraria, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: Travel/accomodation expenses, Research Funding. Topp:Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Regeneron Pharmaceuticals, Inc.: Consultancy, 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; Novartis: Membership on an entity's Board of Directors or advisory committees. Zijlstra:Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria. Borchmann:Novartis: Honoraria, Research Funding. von Tresckow:Takeda: Consultancy, Honoraria, Other: Travel and congress funding, Research Funding; Novartis: Consultancy, Honoraria, Other: Travel and congress funding, Research Funding; Pfizer: Honoraria; Amgen: Honoraria; Roche: Honoraria; MSD: Consultancy, Honoraria, Other: Travel and congress funding, Research Funding.