What Patients With Hairy Cell Leukemia Should Know About Infection Risk and Follow-Up Care

With only about 1,000 to 1,500 people diagnosed each year in the United States, hairy cell leukemia is rare enough that many doctors seldom see it. That makes it all the more important for patients to understand their options and speak up, according to Dr. Jacqueline Barrientos, chief of hematologic malignancies at Mount Sinai Medical Center in Miami Beach.

At the Hairy Cell Leukemia Foundation annual meeting, Barrientos presented the case of a 72-year-old patient with kidney failure who reached remission and received a kidney transplant. She also spoke with CURE about the long-term infection risks of some treatments, how patients are monitored after therapy, why seeking an expert opinion matters and what's ahead in research.

This interview has been edited for length and clarity.

CURE: How common is hairy cell leukemia, and how are outcomes improving?

Barrientos: Hairy cell leukemia is a very rare disease. It affects only about 1,000 to 1,500 patients a year in the United States. But we have made significant advances, to the point that most of our patients can now have a good quality of life and reach remission after therapy.

Because these cases are so rare, working together is essential. We're part of a national consortium that collects data through a registry of patients with hairy cell leukemia to evaluate the natural course of the disease, how patients respond to treatment and their demographics. Miami is a very multicultural city, with many patients of Hispanic ancestry, so it's very important for us to capture their outcomes.

How do you weigh the risk of serious infection?

Cladribine causes a lot of myelosuppression, and with that, you can have severe infections. One of my patients is in her early 40s, and for the last two years after cladribine, she has had recurrent sinusitis.

That's why the choice of therapy matters. For a patient whose kidneys were failing, for example, we avoided cladribine and used vemurafenib, an oral targeted agent that inhibits the signaling pathway of BRAF, the mutated gene that drives the cancer. Rituximab also puts you at higher risk for infection, so we think about timing. In that case, we gave it during the summer, when there's less chance of opportunistic or lung infections.

We consider this with all our patients. That's why we often give prophylactic medications, such as Bactrim (sulfamethoxazole and trimethoprim) to prevent lung infections and antivirals to prevent shingles reactivation, and in some patients, we consider antifungals.

Once treatment ends, how are patients monitored?

I see patients every couple of months. The goal is a neutrophil count above 1,000, hemoglobin above 10 and platelets above 100. My patient who received a kidney transplant, for example, now has a hemoglobin of 12 and normal white blood cell and platelet counts.

We also check serum soluble interleukin-2 receptor, or CD25, which reflects disease activity. And we can look at the peripheral blood smear to see whether any lymphocytes show the characteristic hairy projections.

What advice do you have for patients with a rare cancer like hairy cell leukemia?

You have to be an advocate for yourself. Even within the same center, if you don't like your doctor or your doctor doesn't listen to you, ask for another doctor in the same practice or go to a different center. If a doctor doesn't have experience treating a certain disease, it is harder to figure out.

In oncology, we are always running cases by our colleagues at tumor boards. In one recent case, the patient was originally a colleague's, and he asked me to take over. So don't be afraid to ask or question your doctor.

It is very important to read and listen to podcasts, webinars and educational forums from organizations that are not biased, such as the Hairy Cell Leukemia Foundation. Many times, patients tell me what they heard on social media. Some sites are research-driven, and others are just trying to sell you a medication that we don't have any data to support. I'm not saying it doesn't work. It's just that if we don't have the data, it's hard for me to recommend it.

What should patients who don't fit the typical profile keep in mind?

The disease usually affects older men, but if you are a young woman facing this disease and trying to get pregnant, you should go to a center of excellence where experts can discuss your case. The last thing you want is to receive therapy when you don't need it. Some guidelines say you can be observed, and other times you need to start therapy right away. You can also reach out to any of us in the Hairy Cell Leukemia Consortium. Because Miami is so close to Latin America, many patients come here to discuss their cases.

The young woman I mentioned with sinus infections was treated in another country. Her doctor followed the guidelines but didn't know about the immunosuppression. Two years later, she still can't produce antibodies, so she now receives intravenous immunoglobulin (IVIG) every month, and it's helping prevent more infections.

There is an art to medicine, but patients also have a part to play in educating themselves. An educated patient can ask questions that may not have come to the mind of the doctor or may have been missed.

Is there anything else you think is important for patients to know?

It's important to find a community, because a diagnosis this rare can feel isolating. As much as social media can be isolating, it can also help you find other people going through the same thing. For example, if you have fatigue, is it related to the condition or to something else? A doctor may not have time to explain everything, and somebody who has gone through it may help you identify what is more worrisome or not.

At our meetings and patient advocacy events, patients tell me they've never seen so many people with their same diagnosis. You feel that you're not alone with a condition that is so rare. Learning from other patients can also help with your own decisions about where and how to be treated.

It's OK to not know everything, and that's why education is so important. Participating in webinars can help you learn about novel research. Maybe you don't want chemotherapy and would rather participate in a clinical trial of a novel targeted agent.

We now have many new drugs that can be used even if you relapse, and the traditional drugs can keep patients in remission for over a decade. It is an amazing time. I'm very happy to be living in this era where we can offer things to our patients.

What's next in hairy cell leukemia research?

We're discussing novel agents in the pipeline and in clinical research. One is chimeric antigen receptor (CAR) T-cell therapy for patients with relapsed or refractory disease. It teaches your own immune system to identify and kill leukemia cells, the same way we do in other lymphoproliferative disorders such as lymphoma.

We're also incorporating agents used in other lymphoproliferative disorders, such as BCL2 inhibitors and BTK inhibitors, and discussing combination treatment strategies and novel approaches. The goal is to offer patients better, safer and more tolerable drugs, with fewer complications than chemoimmunotherapy.

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