Clinical utility of circulating tumor DNA qualification and quantification in classical Hodgkin lymphoma

Abstract

Background: Classical Hodgkin lymphoma (cHL), the most common lymphoma in young adults, is a disease of poorly understood heterogeneity. The need for enriching tumor cells before assaying has limited the granularity of its molecular sub-classification. Although the cure rates of patients with cHL have increased over time, new biomarkers are still needed for more precise treatment decision-making in this complex patient population. Patients with cHL frequently have significant amounts of circulating tumor DNA (ctDNA), suggesting an alternative approach for studying this enigmatic tumor. Methods: IOSI-EMA003 (NCT03280394) is a prospective, observational, multi-center study of adult patients with newly diagnosed cHL aiming at: (i) identifying subgroups of patients with phenotype- and outcome-associated molecular signatures; (ii) testing and validating baseline ctDNA load as a prognostic biomarker; (iii) testing if ctDNA can be used as biomarker for the early identification of chemoresistance. Blood samples were collected at staging and disease response assessment. PET scans were centrally and blindly reviewed. ctDNA was analyzed by using deep targeted and low pass whole genome sequencing to measure ctDNA load, capture mutations and profile ctDNA fragmentation patterns. Single-cell RNA sequencing has been used to deconvolute the composition of the tumor microenvironment. Results: A total of 215 patients were enrolled. Based on ctDNA fragmentation patterns reflecting chromatin accessibility in the regulatory region of germinal center (GC) B-cell genes, we segregated cHL into two previously unknown subgroups that we named SNCD (for sub-nucleosomal cfDNA) and NCD (for nucleosomal cfDNA). We hypothesized that SNCD cHL stems from a cell that is closer to the GC B-cell differentiation stage than NCD cHL. SNCD cHL and NCD cHL differed in many aspects, including activation induced cytidine deaminase (AID)-hypermutation profile, neoantigen load, immune editing mechanism and response to chemotherapy and checkpoint inhibitors. Clinically, SNCD cHL displayed less sensitivity to both chemotherapy and anti-PD1 antibodies. Immune editing of SNCD cHL points loss of MHC-I, recruitment of Treg and upregulation of LAG3 as prominent immune checkpoint. High load of pre-treatment ctDNA nominated high-risk patients more accurately than clinico-radiological features. In addition, persistence of residual 18FDG avid lesions along with measurable ctDNA after two chemotherapy courses was a better proof of chemoresistance than the sole persistence of residual 18FDG avid lesions. Also, persistence of measurable ctDNA after the end of therapy invariably predicted progression. Conclusions: Collectively, our results provide a roadmap for cHL subtyping and for the clinical use of ctDNA as a biomarker to aid risk stratification and guide treatment decisions in a more personalized approach. Encore Abstract - previously submitted to ASCO 2023 The research was funded by: Research Advisory Board of the Ente Ospedaliero Cantonale, ABREOC 2019-22514, Bellinzona, Switzerland; European Research Council (ERC) Consolidator Grant CLLCLONE, ID: 772051; Swiss Cancer Research Foundation, ID 3746, 4395, 4660, 5257, Bern, Switzerland; Swiss National Science Foundation, ID 320030_169670/1, 310030_192439, 320036_179318, Berne, Switzerland; The Leukemia & Lymphoma Society, Translational Research Program, ID 6594-20, New York; AFRI, Ente Ospedaliero Cantonale, Bellinzona, Switzerland; ASH Global Research Award, Washington DC, USA; Worldwide Cancer Research (ID: 10583); ISREC Foundation; Helmut Horten Foundation, Switzerland; Fondazione Fidinam, Lugano, Switzerland; Nelia & Amadeo Barletta Foundation, Lausanne, Switzerland; Fond’Action, Lausanne, Switzerland; Fondazione Jacob, Lugano, Switzerland; Fondazione Dr. Ettore Balli, Lugano, Switzerland; Fondazione Ticinese per la Ricerca sul Cancro, Bellinzona, Switzerland; Jacques & Gloria Gossweiler Foundation, Berne, Switzerland. Keywords: Diagnostic and Prognostic Biomarkers, Hodgkin lymphoma, Liquid biopsy Conflicts of interests pertinent to the abstract. M. C. Pirosa Educational grants: BeiGene A. Condoluci Honoraria: AbbVie, AstraZeneca and Janssen Research funding: Gilead and Pfizer A. Moccia Honoraria: Janssen and Takeda A. Stathis Honoraria: Eli Lilly, Bayer, Roche, Novartis, Janssen Oncology, AstraZeneca Research funding: ADC Therapeutics, Pfizer, Roche, Novartis, Bayer, Eli Lilly, MEI Pharma, Cellestia, Debiopharm Group, Merck/MSD, Abbvie, Amgen, AstraZeneca, Incyte, Loxo, and Philogen C. Carlo-Stella Consultant or advisory role: Celgene/Bristol-Myers Squibb, ADC Therapeutics, Karyopharm 767 Therapeutics, Roche, and Sanofi Honoraria: Bristol-Myers Squibb, Merck Sharp & Dohme, Janssen Oncology, AstraZeneca, Incyte, Novartis, Takeda, ADC Therapeutics Research funding: ADC Therapeutics, Sanofi, Roche G. Gaidano Honoraria: Abbvie, Astra Zeneca, BeiGene, Incyte, Janssen E. Zucca Honoraria: BeiGene, BMS, Celltion Healthcare, Curis, Eli/Lilly, Incyte, Ipsen, Janssen, Kyte, Merck, Miltenyi, Roche Research funding: AstraZeneca, BMS, Incyte, Janssen, Merck, Roche Educational grants: Abbvie, BeiGene, Janssen and Roche D. Rossi Honoraria: AbbVie, AstraZeneca, BeiGene, BMS, Janssen Research funding: AbbVie, AstraZeneca, Janssen Educational grants: AstraZeneca and Janssen.