Immune checkpoint inhibitor-induced pure red cell aplasia: a nationwide retrospective case series and literature review.

Immune checkpoint inhibitors (ICIs) may lead to rare but severe hematological adverse events, including pure red cell aplasia (ICI-PRCA). We conducted a nationwide retrospective national case-series and compiled our data with patients from the VigiBase international pharmacovigilance database. We gathered 16 cases of ICI-PRCA Among all the grade ≥ 3 adverse event reported in VigiBase, PRCA was more than two times more reported with ICI compared to all other drugs ROR [IC95%] 2.43 [1.89;3.13]. We identified 15 additional patients in our literature review. Half of the patients were women (52%), median age 63 years (range: 29-90). ICIs were mostly used in melanoma (48%) and lung adenocarcinoma (16%) in metastatic stage (29%). Monoclonal antibody targeting programmed death-1 (PD-1) alone was involved in 61% of cases. The median time from ICI initiation to symptoms onset was 63 days (range: 28-465). Grade ≥3 anemia in found in all cases (100%). Thirteen patients (42%) were treated with corticosteroids as monotherapy with an ORR of 69%. Thirteen patients (42%) required additional therapy. ICI therapy was discontinued in all patients and rechallenge was attempted in 4 patients (13%), with recurrence in one case. ICI-PRCA is a severe and early-onset immune adverse event. Both systemic steroids and cicloporine A seems effective in these immune-related forms.