Updated Hairy Cell Leukemia Guidelines Bring Hope, Progress, and New Treatment Options
Webinar Recap: Updated Guidelines for Hairy Cell Leukemia (HCL) and Hairy Cell Leukemia Variant (HCLv)
June 1, 2026
More than 40 leading Hairy Cell Leukemia (HCL) experts from around the world came together to update the international consensus guidelines for the diagnosis and management of Hairy Cell Leukemia (HCL) and Hairy Cell Leukemia Variant (HCLv). These updated guidelines, published in April 2026, reflect nearly a decade of new research, clinical trials, and advances in patient care since the original guidelines were published in 2017.
To help patients understand what has changed and why it matters, the Hairy Cell Leukemia Foundation hosted a webinar featuring two of the guideline co-authors, Dr. Michael Grever of The Ohio State University and Dr. Clive Zent of the University of Rochester. Together, they discussed the most important updates and answered questions from the community.
A Message of Hope for Patients
One of the most encouraging messages from the webinar was that Hairy Cell Leukemia remains one of the most treatable blood cancers.
As Dr. Michael Grever shared:
"Hairy Cell Leukemia is one of the more treatable lymphoid malignancies. With treatment, most patients expect to live almost a normal lifespan."
He also emphasized the remarkable progress that has been made over the last several decades:
"We've made tremendous advances in progress, and we need to continue to work toward improving outcomes and, hopefully, eventually curing this group of diseases."
For people who have recently been diagnosed, this is an important reminder that there are highly effective treatments available today and even more promising therapies under development.
Strong Evidence Supporting Cladribine Plus Rituximab
Purine analog therapies such as cladribine and pentostatin remain the standard first treatment for most patients with classic HCL. However, one of the most important updates in the 2026 guidelines is the growing evidence supporting the addition of rituximab.
Dr. Grever explained:
"The 2026 guidelines show strong evidence that combining cladribine with rituximab, either together or in sequence, could lead to better results."
In one study highlighted during the webinar:
"In one study with one hundred and eight patients, ninety-eight percent reached a complete remission. Only three percent had a relapse after almost eight years."
These findings demonstrate how treatment strategies continue to improve long-term outcomes for patients.
BRAF Testing Is Now a Standard Part of Diagnosis
Another major update is the recommendation that all patients undergo testing for the BRAF V600E mutation during their initial diagnostic evaluation.
According to the guidelines, more than 95% of patients with classic HCL have this mutation. Identifying it helps doctors confirm the diagnosis and select the most appropriate treatment.
Dr. Grever emphasized:
"The 2026 guidelines have emphasized that testing for the BRAF V600E mutation is now standard, and it's an expected part of the diagnosis. It's not just something done in a research setting."
He added:
"People who do not have this mutation may have other genetic changes, and they need to be explored because they may result in a different treatment plan."
Expanding Treatment Options Beyond Chemotherapy
The updated guidelines also reflect the growing role of targeted therapies, particularly BRAF inhibitors such as vemurafenib.
These treatments may be considered for patients whose disease has relapsed, does not respond to standard therapies, or who have active infections that make chemotherapy more difficult.
As Dr. Grever noted:
"BRAF inhibitors are an important treatment option."
One advantage of these therapies is that they generally do not suppress blood counts in the same way that chemotherapy can.
"Chemotherapy with purine analogs is very effective in getting a remission, but it does lower the counts before they get better. So, if you have an ongoing serious infection, one option would be to consider treating a patient initially with a BRAF inhibitor, because it does not lower the white blood cell count."
The guidelines also discuss additional emerging therapies including dabrafenib plus trametinib, ibrutinib, zanubrutinib, venetoclax, and CAR T-cell therapy for selected patients.
New Attention to Hairy Cell Leukemia Variant (HCLv)
Patients with Hairy Cell Leukemia Variant (HCLv) will find significant new information in the 2026 guidelines.
As HCL Foundation Executive Director Anna Lambertson explained:
"If you have Hairy Cell Leukemia Variant, the 2026 guidelines go over that disease, whereas the 2017 guidelines did not."
Dr. Zent highlighted one of the biggest advances for HCLv:
"We now know that HCLv responds very well to a combination of cladribine and rituximab, which has improved response rates from really very small numbers to about ninety-five percent of people."
The updated guidelines also recommend additional genetic testing for patients with HCLv, including TP53, MAP2K1, and IGHV mutation testing, which may help guide treatment decisions.
Supportive Care Takes Center Stage
For the first time, the guidelines include a dedicated section on supportive care.
Anna Lambertson noted:
"Supportive care is a really important addition that these authors included in the 2026 guidelines that was not included in the 2017 guidelines."
The updated recommendations address:
Preventing infections
Antiviral and antimicrobial prophylaxis during treatment
Vaccinations
Blood transfusion safety
Managing treatment-related side effects
Dr. Zent emphasized the importance of infection prevention:
"Anybody who gets cladribine or pentostatin should receive prophylaxis using antimicrobial therapy to prevent herpes viruses, shingles from varicella-zoster, and a fungus called Pneumocystis that can cause pneumonia."
The guidelines also provide recommendations about vaccinations, including seasonal influenza and COVID-19 vaccines, and explain when vaccination may be most effective depending on the treatment a patient receives.
Relapse Is Manageable
Many patients worry about relapse, but the webinar reinforced an encouraging message: more treatment options are available today than ever before.
Dr. Grever explained:
"The key message is that relapse is manageable, and there are now more options at each stage than ever before."
The guidelines provide treatment recommendations based on how long a patient's previous remission lasted and outline several effective approaches for patients who require additional therapy.
The Importance of Clinical Trials
The updated guidelines also highlight the role of clinical trials in advancing care and expanding treatment options for patients.
Dr. Grever encouraged patients to discuss clinical trial opportunities with their healthcare team:
"The importance of clinical trials can't be underestimated, so we strongly encourage patients to consider enrolling in a clinical trial, which is the way that promising new therapies become available to everyone."
Looking Ahead
The 2026 International Consensus Guidelines provide an updated roadmap for the diagnosis, treatment, and supportive care of people living with Hairy Cell Leukemia and Hairy Cell Leukemia Variant. They reflect years of collaboration among experts worldwide and the progress made through research, clinical trials, and patient participation.
For patients and families, the message is clear: there is more reason for hope than ever before. Treatment outcomes continue to improve, new therapies are emerging, and researchers remain committed to advancing toward even better treatments—and ultimately, a cure.
The Hairy Cell Leukemia Foundation thanks Dr. Michael Grever and Dr. Clive Zent for sharing their expertise and helping patients better understand these important updates.
Watch the Webinar and Access the Materials
If you were unable to attend the webinar or would like to review the information again, we invite you to watch the recording and explore the presentation slides, transcript, and additional resources.
The updated 2026 International Consensus Guidelines provide valuable information about diagnosis, treatment options, supportive care, relapse management, and emerging therapies for both Hairy Cell Leukemia (HCL) and Hairy Cell Leukemia Variant (HCLv).
Access the webinar recording and materials: CLICK HERE>>