Checkpoint inhibitors can cause rare, but serious, hematological immune-related adverse events (hem-irAEs), which require early detection and intervention, according to a recent French study.
Immune thrombocytopenia, hemolytic anemia, and neutropenia were the most common hem-irAEs in the population, reported lead author, Nicolas Delanoy, MD, of Gustave Roussy, Université Paris-Saclay, Villejuif, France, and his colleagues.
“About 71% of patients treated have any-grade irAEs and 10% have grade 3-4 irAEs after anti-PD-1 immunotherapy,” the investigators wrote. The report is in The Lancet Haematology. “In most cases, they involve the skin, gastrointestinal tract, thyroid or endocrine glands, liver, lungs, or joints. However, all organs can potentially be affected, including the hemopoietic system.”
Despite this possibility, few reports detail the frequency or character of hematological toxicities from immunotherapy.
The present study involved 948 patients who entered into three French registries between 2014 and 2018. The first registry, consisting of 745 patients, was observed prospectively during checkpoint inhibitor therapy. The other two registries provided retrospective data on confirmed irAEs or hem-irAEs.
Among 745 patients followed during checkpoint inhibitor therapy, four developed hem-irAEs, providing an incidence rate of 0.5%. The other two databases added 31 patients with confirmed hem-irAEs, allowing for characterization of 35 total cases.
The group of 35 patients had a median age of 65 years, with more men (n = 21) than women (n = 14). Melanoma was the most common type of malignancy (43%), followed by non–small-cell lung cancer (34%), lymphoma (11%), and others. The majority of patients received nivolumab (57%), slightly fewer received pembrolizumab (40%), and a small minority received atezolizumab (3%).
Immune thrombocytopenia, hemolytic anemia, and neutropenia were the most common hem-irAEs, each occurring in nine patients (26%). Five patients (14%) had aplastic anemia or pancytopenia, two patients had bicytopenia (6%; neutropenia and anemia or thrombocytopenia and anemia), and one patient had pure red cell aplasia (3%).
Hem-irAEs resolved in 60% of patients, but two patients (6%) died due to febrile neutropenia. Overall, 71% of hem-irAEs were grade 4.
These findings suggest that hem-irAEs are rare, but they are often serious, and potentially life-threatening, the researchers noted.
In 7 of 35 patients (20%) who were rechallenged with checkpoint inhibitor therapy, 3 (43%) had recurrence of hem-irAEs. This finding should elicit caution and close monitoring if rechallenge is elected.
“This observational study encourages further, in-depth investigations of hematological immune toxicities, to search for biomarkers that can be helpful for earlier detection,” the investigators concluded.
This study was funded by Gustave Roussy and the Gustave Roussy Immunotherapy Program. Dr. Delanoy reported nonfinancial support from Sanofi and other authors reported financial relationships with pharmaceutical companies.
SOURCE: Delanoy N et al. Lancet Haematol. 2018 Dec 4. doi: 10.1016/S2352-3026(18)30175-3.