Gastrointestinal adverse events following brentuximab vedotin and polatuzumab vedotin therapy

Background: Brentuximab vedotin (BV) and polatuzumab vedotin (PV), CD30-specific and CD79b-specific monoclonal antibody conjugates, respectively, are used in the treatment of hematologic cancers. Both have been observed to cause gastrointestinal adverse events (GI AEs). Objectives: We aimed to assess the clinical characteristics, disease course, treatment, and outcomes of patients who developed GI AEs following treatment with BV or PV. Design: We retrospectively identified 879 adult cancer patients who received BV or PV therapy between March 1, 2016, and March 31, 2023, at our tertiary cancer center. Patients with alternate diagnoses were excluded. Methods: Clinical characteristics, management, and outcomes of GI AEs were retrospectively evaluated and statistically analyzed. Results: Sixty-four patients were included, and the median duration from therapy initiation to GI AE onset was 37 days. GI AEs occurred in the lower gastrointestinal tract (78%), upper gastrointestinal tract (45%), hepatobiliary system (11%), and pancreatic system (4.3%). Common symptoms were diarrhea (77%), nausea (61%), and abdominal pain (52%). Some patients had Common Terminology Criteria for Adverse Events grade ⩾3 toxicity (19% with diarrhea and 2.7% with colitis symptoms). Most patients (81%) received supportive care alone, and three received corticosteroids. Most patients (93%) achieved symptom resolution following treatment. Symptoms recurred in 37% of patients, and 41% of patients stopped BV/PV therapy due to GI AE. Conclusion: GI AEs following the use of targeted antibody-drug conjugates can involve various gastrointestinal systems. In our patient cohort who received BV or PV, GI AEs were typically low grade and managed with supportive care or corticosteroids. Nonetheless, some patients experienced high-grade AEs or symptom recurrence and stopped BV/PV therapy. Future studies may provide clarification and guide clinical practice.