Single-course Alemtuzumab Active in T-cell Large Granular Lymphocytic Leukemia

A single course of alemtuzumab in patients with mainly relapsed and refractory T-cell large granular lymphocytic leukemia (T-LGL) can induce a hematological response without continued use of oral suppression, a new study published online ahead of print in the journal The Lancet Haematology has shown.¹

T-LGL, a lymphoproliferative disease that presents with immune-mediated cytopenias and is characterized by clonal expansion of cytotoxic CD3+ CD8+ lymphocytes, can be treated with methotrexate, cyclosporine, or cyclophosphamide in the first-line setting; however, long-term use of these agents can lead to toxicity. Therefore, researchers sought to evaluate the activity and safety of alemtuzumab, an anti-CD52 monoclonal antibody, in patients with T-LGL.

For the single-arm, phase 2 trial, researchers enrolled 25 patients with T-LGL. Of those, 19 patients had classical T-LGL, meaning they did not have associated myelodysplastic syndrome or had not received hematopoietic stem cell transplantation. All participants were given alemtuzumab 10 mg intravenously daily for 10 days.

Results showed that 56% (95% CI, 35 – 76) of patients achieved a hematologic response at 3 months. Researchers found that 74% of the patients with classical T-LGL responded.

In regard to safety, 24 patients had a grade 1 to 2 infusion reaction and 1 patient had a grade 3 infusion reaction, with both improving with symptomatic therapy. All patients also developed lymphopenia, with 88% having grade 3 or 4 lymphopenia. Grade 3 and 4 leukopenia and neutropenic infections occurred in 32% and 20% of patients, respectively.

Of note, 7 patients died, all of whom were non-responders to immunotherapy.

“This is the largest and only prospective study of alemtuzumab in patients with T-LGL,” the investigators concluded. “The activity reported with a single course of a lymphocytotoxic drug in patients with mainly relapsed and refractory disease suggests that hematological response can be achieved without continued use of oral immunosuppression.”

Alemtuzumab is approved by the U.S. Food and Drug Administration as a single agent for the treatment of patients with B-cell chronic lymphocytic leukemia.

Reference

1. Dumitriu B, Ito S, Feng X, et al. Alemtuzumab in T-cell large granular lymphocytic leukemia: interim results from a single-arm, open-label, phase 2 study [published online ahead of print December 16, 2015]. Lancet Haematol. doi: 10.1016/S2352-3026(15)00227-6.