SP16 | CASE REPORT OF RELAPSED HODGKIN LYMPHOMA TREATED WITH PEMBROLIZUMAB DURING PREGNANCY

Background Classical Hodgkin lymphoma (cHL) is often curable, but a subset of patients experiences relapse or becomes refractory (R/R) to standard therapy. Immune checkpoint inhibitors (ICIs), particularly anti-PD-1 agents such as pembrolizumab, have demonstrated high efficacy in the treatment of R/R cHL. However, the PD-1/PD-L1 pathway also plays a fundamental role in maintaining maternal-fetal immune tolerance and proper fetal development. Inhibition of this pathway may interfere with pregnancy physiology. Current data on PD-1 inhibitor exposure during pregnancy are extremely limited. Pregnancies occurring during ICI therapy are rarely documented and pose complex clinical and ethical challenges, including uncertainties about fetal safety, restrictions in disease monitoring and the need to balance maternal treatment with potential fetal risks. Case Report A 36-year-old woman with a diagnosis of classical Hodgkin lymphoma (nodular sclerosis subtype) was treated according to the ABVD protocol. Due to disease progression, she was started on DHAP chemotherapy, followed by peripheral blood stem cell (PBSC) collection. However, stem cell mobilization was inadequate, and concomitantly the patient declined autologous stem cell transplantation. She was therefore switched to a Brentuximab vedotin–Bendamustine regimen. After experiencing septic shock during treatment, she continued with Brentuximab monotherapy for four cycles. Disease progression was documented, and she was subsequently started on pembrolizumab as the next line of therapy. The sixth cycle of pembrolizumab was administered during the periconceptional period, a PET scan was performed in the first trimester. The pregnancy was diagnosed retrospectively during the second trimester. After a detailed fetal anatomical assessment to exclude major malformations, the patient received multidisciplinary counselling and chose to continue the pregnancy. Serial ultrasounds were performed to monitor fetal growth and maternal lymphadenopathy. At 37+5 weeks of gestation, she delivered vaginally a healthy male infant following spontaneous rupture of membranes. Both mother and newborn were discharged in good condition. At six-month follow-up, the infant showed no structural, cognitive, or behavioral abnormalities. Conclusion This case highlights the complex challenges of managing relapsed Hodgkin lymphoma during pregnancy, particularly in the context of ongoing antineoplastic therapy. It underscores the need for personalized treatment approaches, multidisciplinary evaluation, and long-term follow-up of children exposed in utero to immune checkpoint inhibitors. While the outcome in this case was favorable, more evidence is needed to safely guide the use of ICIs during pregnancy.