Outcomes of Myelofibrosis Patients After Allogeneic HSCT in Retrospective Study

A retrospective study observed a three-year overall survival (OS) rate of 66.7% in primary myelofibrosis (MF) patients and 55.6% in secondary MF patients in the period following allogeneic hematopoietic stem cell transplantation (HSCT).

The results were presented at the 10th Annual Meeting of the Society of Hematologic Oncology (SOHO) by Vincent Louie Mendiola MD, MPH, and colleagues at the University of Southern California (USC).

“Given most of our patients were high/very high risks, achieving [three-year] OS of 66.7% in primary and 55.6% in secondary MF since the time of transplant is appreciable,” the investigators wrote.

Dr. Mendiola and colleagues wrote that no standard-of-care pre- or post-transplant management exists for this patient group.

The retrospective study reviewed charts at the Norris Comprehensive Cancer Center at USC, analyzing 18 patients aged 18 to 99 years (median, 60.7 years) with a MF diagnosis by bone marrow biopsy in the years 2012 to 2020 who had received an allogeneic HSCT at USC. Of these patients, 66.7% were diagnosed with primary MF.

In terms of risk categories, 44.4% of the patients were classified as high risk and 55.6% as intermediate-1/2 risk by the Dynamic International Prognostic Scoring System (DIPSS). Using the Mutation-Enhanced International Prognostic Scoring System for Transplant-Age Patients (MIPSS70)-plus score, 27.8% were high risk and 33.3% very high risk.

One year after allogeneic HSCT, 78% of the patients were alive. The three-year OS was 66.7% in primary MF patients and 55.6% (P=.75) in secondary MF patients with similar event-free survival (EFS) rates. OS and EFS rates were generally lower with higher DIPSS and MIPSS70+ risk scores.

Of the patients, 44.4% had JAK2 V617F mutation; 16.7% had either ASXL1, EZH2, SRSF2, IDHL1/2, or U2AF1 mutations; and 11.1% had high-risk karyotype/cytogenetics. Pre-transplant, 61.1% received a JAK2 inhibitor, and 72% received non-JAK2 inhibitor treatments.

The three-year OS in patients with a JAK2 V617F mutation was 83.3% (P=.13) with similar EFS. The three-year OS of those who received a JAK2 inhibitor pre-transplant was 47.7% (P=.17) with similar EFS (P=.16).

“Interestingly, even with higher OS/EFS for JAK2V+ patients, the OS/EFS is lower for those who received a JAK2 inhibitor,” they concluded. “This could be from the low sample size. Further studies are necessary.”

Reference

Mendiola V L, Chennapan K, Chen D, et al. Outcomes of myelofibrosis patients post allogeneic-HSCT at the University of Southern California, a retrospective study. Abstract #MPN-215. Presented at the 2022 Society of Hematologic Oncology (SOHO) Annual Meeting, September 28-October 1, 2022.