Recurrent and de-novo autoimmune hemolytic anemia in patients treated with immunotherapy for advanced cancer.

Abstract

e14170 Background: Immunotherapy (IO) has brought dramatic clinical benefit to cancer patients. Serious immune-related adverse events (irAE) have been reported, however, hematological toxicities such as autoimmune hemolytic anemia (AIHA) remains poorly characterized. Here we performed a single institution retrospective study to determine the incidence and risk factors for AIHA and if prior positive direct anti-globulin test (DAT) or anti-RBC alloantibodies (alloAb) on type and screen predicts subsequent AIHA in patients treated with IO. Methods: This is a retrospective review of patients treated with IO between November 2012 and February 2017 at the Ohio State University. Patients who received IO either on clinical trial or as standard of care were included. The electronic medical records were reviewed for patients who developed AIHA. Overall survival (OS) was calculated from the date of initiation of IO to death from any cause or date or last follow-up. Medians and 95% CIs were estimated using Kaplan-Meier method and differences compared using the Log-Rank test. The association between irAE and DAT or alloAb testing was studied using Fisher’s exact test. Results: In 1,097 patients treated with IO, we identified 179 (16.6%) patients who had a DAT or alloAb testing at any time, 126 (11.5%) had this done prior to receiving IO. Of the 179 tested 10 (5.6%) had positive alloAb and 7 (3.9%) had a positive DAT. During treatment, two patients with prior history of AIHA experienced recurrence of AIHA during treatment. Three patients had positive DAT after IO, one was diagnosed as a delayed hemolytic transfusion reaction, and the patient required transfusion every 2 weeks since DAT positivity. The other two with positive DAT were not diagnosed with AIHA and did not require intervention. Patients with positive baseline alloAb (n = 6) had higher rate of irAE than patients without (n = 120) (13.3% vs 2.1%, p = 0.03), including 2 thyroid dysfunction, 2 skin rash, 2 myalgia, 2 hemolytic anemia. Patients with a positive DAT at baseline did not have a higher rate of irAEs (p = 0.09). Median OS for the entire cohort was 7.6 (5.8-9.9) months. No association was found between baseline positive DAT or alloAb and OS (p = 0.1748 and p = 0.3164 respectively). Conclusions: The incidence of hemolytic anemia in patients treated with IO was low. Presence of alloAb at baseline may predict irAE during IO treatment as patients with positive alloAb at baseline had a higher rate of irAE than those without.