People with hairy cell leukemia (HCL) benefit from the expertise of a team of specialists. This includes doctors, nurses, and pharmacists. Our HCL team carefully considers each person’s overall health and what makes their HCL unique, including the genetics of the leukemia cells. This allows us to create the most personalized care plan possible. We have expertise in using currently approved therapies and in creating the next generation of treatments.
Some people begin treatment immediately after an HCL diagnosis. Others can be observed closely and may not start therapy until they develop symptoms or a low blood count. Our team evaluates each person individually. We can come up with a plan to monitor the disease and discuss when it’s time to consider HCL treatment.
Current therapies help with the symptoms of HCL. The typical goals of treatment are to restore a normal blood count and reduce the size of the spleen if necessary. The number of HCL cells in the bone marrow generally goes down in those who respond to treatment, but treatment does not get rid of HCL cells entirely.
Approved Therapies for HCL
Our team members have expertise and access to all current treatments approved by the US Food and Drug Administration. The most common approved treatment for HCL is an anticancer medication called cladribine (Leustatin®). Most people who receive initial treatment with a single cycle of cladribine have a good response. A single cycle lasts five to seven days. After that, many people will not require additional treatment for several years or more.
For those who respond to cladribine initially but need further treatment for HCL years later, cladribine may bring about a second response. Another standard anticancer medication sometimes used to treat HCL is called pentostatin (Nipent®).
Cancer-targeted antibody therapy is another approved form of anticancer therapy sometimes used to treat HCL. One example is rituximab (Rituxan®). Rituximab may be used by itself or with other chemotherapy drugs, such as cladribine.
In very rare cases of HCL, removing the spleen (splenectomy) may be considered.
New Therapeutic Drugs for HCL
Researchers conduct clinical trials to find new therapies for HCL. Trials are available for people who have had prior treatment for HCL as well as those who’ve never been treated.
MSK is a leader in HCL research. We are seeking out new drug therapies to improve the outlook for people with the disease. We have a dedicated team of HCL scientists who are studying the comprehensive genetic mutations in HCL in the laboratory. They are seeking to understand why certain drugs work better than others and to identify new drug therapies for HCL.
Clinical Trial for People Who’ve Never Received HCL Treatment Before
MSK is leading a clinical trial investigating a chemotherapy-free drug combination for people with HCL who are receiving treatment for the first time. This trial is studying the combination of two therapies: obinutuzumab (Gazyva®) and a BRAF-targeted therapy called vemurafenib (Zelboraf®). This approach does not include standard chemotherapy. People who receive it may experience fewer side effects than those who receive initial treatment with chemotherapy drugs.
Enrollment in the trial is ongoing.
Clinical Trials for People Who Have Received Prior HCL Treatment
Among the therapies tested at MSK is a targeted therapy called vemurafenib (Zelboraf®). Vemurafenib is an oral drug that can bring about remission (when no trace of cancer is detectable) or slow the growth of HCL in people with a BRAF mutation. MSK led the largest clinical trial of vemurafenib in the United States. For the first time, vemurafenib was shown to be highly effective in people with HCL that has been resistant to or has come back after standard treatments.
We are also studying other therapies for HCL that has been resistant to or has come back after standard treatments. These include moxetumomab pasudotox (Lumoxiti®) and ibrutinib (Imbruvica®). Moxetumomab pasudotox is an anticancer medication that targets HCL cells. It delivers a drug that helps kill the leukemia cells. Ibrutinib is commonly used in the treatment of chronic lymphocytic leukemia and certain lymphomas. It may be considered in some people with HCL.