Alectinib-induced Hemolytic Anemia with Positive Direct Antiglobulin Test in a Patient with Lung Adenocarcinoma: A Possible Drug-drug Interaction Effect

Abstract

Recent studies have reported that direct antiglobulin test (DAT) results were negative in cases of alectinib-induced hemolytic anemia with abnormal red blood cell (RBC) morphology. We herein report the case of a 72-year-old female patient who was diagnosed with alectinib-induced hemolytic anemia who - in contrast to previous reports - showed a positive DAT result. After discontinuing famotidine and alectinib, the DAT results turned negative; however, when alectinib was resumed, hemolysis recurred. Although alectinib-induced hemolytic anemia has been previously thought to be associated with abnormal morphological changes of the RBCs, we suggest that alectinib-induced anemia may manifest as DAT-positive immune hemolytic anemia because of a complementary effect with other drugs.

Keywords: alectinib; direct antiglobulin test; famotidine; hemolytic anemia; lung cancer.

Figure 1.

Chest computed tomography (before treatment) showed thickening of the interlobular septum and bronchovascular bundles in the right upper lobe and a mass in the right middle lobe. Right pleural effusion was also observed.

Figure 2.

Changes in laboratory test results after the initiation of alectinib treatment. Alectinib repeatedly induced reticulocytosis and the elevation of LDH and bilirubin, while the degree of anemia was greatest when the patient was first treated with famotidine. Ale: alectinib, Fam: famotidine, DAT: direct antiglobulin test, Hb: hemoglobin, LDH: lactate dehydrogenase, Ret: reticulocyte, T-Bil: total bilirubin

Figure 3.

Peripheral blood smears approximately one year after the initiation of alectinib showed the change in erythrocyte morphology. Famotidine was discontinued at this time.