Safe Start of Ibrutinib in Patients with Chronic Lymphocytic Leukemia and Uncontrolled Autoimmune Hemolytic Anemia
Authors: Garcia-Horton Alejandro , St. Bernard Rosanne , Lazo-Langner Alejandro , Xenocostas Anargyros , Mangel Joy , Howson-Jan Kang , Lam Selay , Hsia Cyrus C. 
Published: October 2019

Abstract
It is estimated that 4-10% of patients with chronic lymphocytic leukemia (CLL) will develop autoimmune hemolytic anemia (AIHA) over the course of their disease. Ibrutinib has proven to be effective in treatment of relapsed, refractory, 17p deleted, and treatment naïve CLL. The effect of ibrutinib on AIHA in the context of CLL has not been established since patients with active hemolysis were excluded from major trials. In this abstract, we present a case series of patients that were actively hemolyzing at the start of ibrutinib therapy and in which their AIHA achieved prolonged response.
Patient characteristics and laboratory data are shown in Table. Five patients (3 women, 2 men), median age 61 years (range 57 to 78), with CLL and active, uncontrolled AIHA at the time of ibrutinib initiation were identified. Uncontrolled AIHA was defined as anemia with evidence of hemolysis (at least two of the following: increased reticulocyte count, elevated lactate dehydrogenase, elevated indirect bilirubin, and reduced haptoglobin and a positive direct antiglobulin test (DAT)). Patients had a median hemoglobin of 70 g/L (range 69-96) prior to start of ibrutinib and 3 of them required transfusion support for symptomatic anemia. All patients were receiving prednisone for management of AIHA at the time of ibrutinib initiation and had been on it for a median of 10 days (range 9 - 25) without AIHA resolution. 1 patient received intravenous immunoglobulin concurrently. All patients had received at least one line of therapy for CLL in the past and 3 had experienced previous AIHA responsive to steroids. AIHA in 2 patients was related to previous fludarabine exposure but had responded to a prednisone tapering schedule and were off steroids by the time of the new AIHA flare. Median hemoglobin of 130 g/L (range 113-149) was reached at time of AIHA response.
All 5 patients tolerated 420mg oral daily of ibrutinib therapy and AIHA was controlled in a median of 6.5 weeks (range 6-10). Discontinuation of steroids was achieved in all patients at a median of 10 weeks (range 6-17) without evidence of further hemolysis. All patients except one are receiving ongoing follow up and have been followed up for a median of 130 weeks (range 15-150) since ibrutinib start. Patients have not shown evidence of AIHA relapse and continue off AIHA treatment (prednisone). One patient required discontinuation of ibrutinib 6 months after starting due to neutropenia but there was no evidence of AIHA relapse in follow up. The patient has passed away from unrelated GI bleed 2 years after the initial AIHA event.
This is the largest case series to our knowledge on the safe start of ibrutinib in CLL complicated by active AIHA. Hemolysis in all patients responded to a short prednisone taper with ibrutinib concurrently and obtained a sustained response at follow up without any flare ups or further AIHA treatment use. These cases suggest that it is safe to start ibrutinib during uncontrolled, active hemolysis in contrast to 2 previous case reports that suggested causal relationship between ibrutinib and onset of severe CLL-associated AIHA (Rider et al, 2015; Hodskins et al, 2014). As previously reported, AIHA occurrence or relapse once ibrutinib has been started is rare (Rogers et al, 2016).

Disclosures
No relevant conflicts of interest to declare.