Inside the Clinic: How One Hematologist Approaches a Rare Leukemia

Treatment for hairy cell leukemia, a rare and chronic blood cancer, should be chosen case by case, according to Dr. Kerry A. Rogers, a hematologist-oncologist and associate professor of internal medicine at The Ohio State University Comprehensive Cancer Center – James.

The disease currently has no cure. Rogers said her aim is to help patients have it “interfere with their life as little as possible.”

Standard treatment includes the chemotherapy drugs cladribine and pentostatin, sometimes combined with an antibody such as rituximab. Rogers said cladribine with rituximab has produced the longest known remissions. Targeted drugs such as vemurafenib, which blocks a mutated form of the BRAF protein, are also used. Vemurafenib is approved for melanoma and prescribed off-label for hairy cell leukemia under national treatment guidelines.

In chronic lymphocytic leukemia (CLL), which Rogers also treats, randomized trials have found targeted drugs more effective than chemotherapy. She said similar evidence does not yet exist for hairy cell leukemia. Trials in the U.S. and Europe are comparing vemurafenib-based and cladribine-based treatment as a first therapy.

Until then, Rogers said, the choice depends on factors such as a patient’s prior treatment, overall health and interest in clinical trials. Because vemurafenib suppresses the immune system less, it may be preferred for patients with active infections. She described a case in Washington state in which a man critically ill with COVID-19 was found to have hairy cell leukemia, was treated with vemurafenib and later recovered.

Each option has side effects. Rogers said cladribine and pentostatin rarely cause hair loss but can lower blood counts and raise infection risk. Vemurafenib can cause joint inflammation and widespread rashes.

She recommended that patients look for information specific to hairy cell leukemia, because general leukemia guidance, such as avoiding fresh fruit, often applies only to intensive treatment for acute leukemia.

Rogers and researchers at Mayo Clinic reviewed 53 patients treated with vemurafenib outside clinical trials. They plan to present the findings at the American Society of Hematology annual meeting in December. Rogers said the analysis is ongoing.

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