Cytopenia in Myelofibrosis Linked to Higher AML Risk, Lower Survival

Cytopenia at myelofibrosis diagnosis raises risk of acute myeloid leukemia and lowers survival: © stock.adobe.com.

The presence of cytopenia showed a higher risk of progression to acute myeloid leukemia (AML) and a lower overall survival probability for patients with myelofibrosis, according to real-world study data published in HemaSphere.

This suggests that cytopenia is a key consideration when selecting treatment for myelofibrosis, though more research is needed to understand how targeting anemia or low platelets may affect the risk of progression to acute myeloid leukemia, overall survival, and chances of receiving a stem cell transplant, as per the study.

According to the National Cancer Institute’s website, cancer.gov, cytopenia is a condition in which there is a lower-than-normal number of blood cells in the body.

“Understanding risk factors for poor prognoses and how to appropriately tailor Janus kinase inhibitor treatment selection for patients with myelofibrosis who are ineligible for transplant is clinically important,” wrote lead study author, Dr. Lindey Rein, and colleagues in the abstract of the study.

Rein is an associate professor of medicine at Duke University, a member of the Duke Cancer Institute, and a researcher in hematologic malignancies and cellular therapy.

Among 1,532 patients with myelofibrosis, 70% were cytopenic at diagnosis. Median follow-up was shorter for patients with cytopenia (21.5 months) than those without (32.5 months). Cytopenic patients were more often 65 or older (85% versus 71%) and had more comorbidities. The five-year overall survival rate was 42.4% overall, 32.8% with cytopenia, and 64.6% without. Median overall survival was 48 months overall, 38 months in cytopenic patients, and not reached in the non-cytopenic group. The five-year probability of progression to acute myeloid leukemia was 16.3% overall, 22% with cytopenia, and 6.9% without.

Researchers conducted a retrospective cohort study using the Optum Research Database to better understand outcomes in adults with myelofibrosis. The study included patients diagnosed between July 2016 and April 2023 who had continuous insurance coverage for at least six months before diagnosis and at least 12 months after, unless they died within the first year. Follow-up began at diagnosis and ended at the earliest of death, loss of insurance, or April 30, 2024.

Cytopenia at diagnosis was identified based on medical claims for anemia or low platelet counts within 30 days before or after diagnosis, or before treatment if it started within that same 30-day period. Researchers used median and interquartile range or mean and standard deviation to describe continuous variables, and counts and percentages for categorical ones.

Myelofibrosis is a rare blood cancer classified as a myeloproliferative neoplasm. While stem cell transplant remains the only curative option, many patients are ineligible. In these cases, progressive disease and worsening cytopenias—such as anemia or low platelets—can lead to infections and early death, as per the study.

Past FDA Approval for Cytopenic Myelofibrosis

In March 2022, the FDA approved Vonjo (pacritinib) for adults with intermediate- or high-risk primary or secondary myelofibrosis, particularly those with very low platelet counts, or cytopenic myelofibrosis.

In a clinical trial, 29% of patients who received Vonjo twice daily experienced a significant reduction in spleen size, compared with 3% of those who received other available therapies. Common side effects included diarrhea, nausea, anemia, swelling in the limbs, and low platelet counts. Serious side effects included pneumonia, heart problems, and skin cancer. A follow-up study, called PACIFICA, is ongoing and expected to report results in 2025.