Abstract T001

CHOP/miniCHOP And Tislelizumab in EldeRly patients with classical Hodgkin Lymphoma (cHL). A report of the phase II CATER-HL trial (HD12) from the Australasian Lymphoma and Leukaemia Group (ALLG)

Anti-PD-1 therapy with Adriamycin, vinblastine, dacarbazine (AVD) is effective in older patients (pts) with cHL with limited data in those ≥70 years. CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) is active in older cHL pts but has not been combined with anti-PD-1.

Methods: CATER-HL (ALLG-HD12) is a single arm phase II study of anti-PD-1 agent, tislelizumab (T), with CHOP or miniCHOP in older (≥61 years) pts with untreated cHL. Eligible pts were stage 2 unfavourable to stage 4, with no anthracycline/immunotherapy contraindications. T monotherapy (200mg q3W) was given for 3 cycles, followed by T in combination with CHOP (or miniCHOP if aged >80 or frail) q3W for 4-6 cycles (T-CHOP[mini]). Radiotherapy (RT) or 4 extra doses of T was allowed for those with residual PET-CT avidity or if stage 2 (RT). Primary end points were complete remission (CR) and deliverability of T monotherapy (no grade 3/4 toxicity and no symptomatic progressive disease [PD]). Secondary end points were post-therapy overall response (ORR)/CR, PFS, OS and quality of life (QOL).

Results: 35 pts from 11 Australian sites were enrolled from May 2023-2025. Baseline characteristics: median age 74 years (range 63-90), ≥70 years 69%, male 66%, ECOG 0-1 86%, European ethnicity 77%, advanced stage 89%, EBER-ish positive 46%, median Charlson’s comorbidity score 4 (range 3–12). After T monotherapy the CR rate was 17% (ORR 69%); deliverability was 86%. 5 pts ceased T monotherapy prematurely: 2 from immune related adverse event (IRAE) of grade 4 hepatitis and 3 for other reasons. 30 pts commenced T-CHOP[mini] (CHOP:70%, miniCHOP:30%). After 2 cycles of T-CHOP[mini] the ORR was 87% (CR 50%). At the end of T-CHOP[mini], ORR was 87% (CR 67%). Median follow up is 562 days (range 24–902). Estimated 2- year PFS/OS is 77%/94% (figure 1) and 81%/100% for the 30 pts who commenced T-CHOP(mini). Grade 3/4 treatment emergent AEs affected 51% of pts: infection 17%, hepatitis 11%, fever 9% peripheral neuropathy 6%, confusion 6%. IRAEs affected 37% pts: thyroid dysfunction 14%, hepatitis 14%, raised creatinine kinase 3%, pancreatitis 3%, pruritis 3%. 2 pts died from PD, there was no treatment related mortality. QOL scores improved by 10% after T monotherapy, and 7% post therapy.

Conclusion: T monotherapy is deliverable and demonstrated early metabolic response. Sequential treatment with T-CHOP[mini] is well tolerated with promising PFS and OS in this predominantly over 70 year old cohort.