(P-276) Clinical Outcomes Among Relapsed/refractory (R/R) Adult and Pediatric Classical Hodgkin’s Lymphoma (cHL) Patients: A Global Systematic Literature Review (SLR)

Background: The introduction of risk-adapted combined modality treatment has made cHL curable for a majority of patients; however, around 20% may progress after front line therapy. Roughly half of these have the potential to still be cured through salvage chemotherapy followed by autologous stem cell transplantation (ASCT), but prognosis is less favorable for those who are ASCT ineligible, or who fail such treatment.

Objectives: To summarize clinical outcomes among adult and pediatric R/R cHL patients by line of therapy and ASCT eligibility.

Methods: A global SLR was conducted to identify R/R cHL clinical trials. Eligible studies were captured by searching MEDLINE, Embase, and Cochrane Central Register of Controlled Trials using pre-defined search strategies (up to May 2020), as well as manual searches of major conference proceedings (last two years) and clinicaltrials.gov. Relevant outcomes were overall survival (OS), progression-free survival (PFS), and objective response. Reported outcomes were stratified for the following populations where possible: patients who were primary refractory/relapsed after front line therapy, patients who had received two or more prior lines of therapy, or patients who failed/were ineligible for transplant.

Results: The SLR identified 76 unique trials. There was significant heterogeneity among inclusion/exclusion criteria, most notably in lines of prior treatment (1, ≥1, ≥2) and ASCT status (naïve/ineligible, failed, mixed). The majority of trials were conducted in adult patients (n=70) and evaluated chemotherapy ± ASCT (n=43). Improved survival was observed among patients in earlier lines who were able to receive ASCT. Trials investigating newer immunotherapies pembrolizumab (n=5) and nivolumab (n=4) in adults tended to be in more heavily pretreated populations, although median OS was not reached in any of these studies. Trials featuring brentuximab vedotin (n=9) were more diverse regarding prior treatments, with associated variability in outcomes. Six studies were identified in pediatric patients, only one of which reported median PFS (12.2 months), and limited evidence was found for patients confirmed to be ineligible for ASCT.

Conclusions: Evidence supports the continuing role of salvage chemotherapy followed by ASCT in patients who are eligible for transplant. For patients who fail ASCT or are ineligible for ASCT, the introduction of new therapies such as pembrolizumab may have helped improve prognosis. Key gaps in evidence remain for pediatric patients and those who are ineligible for ASCT.