Ruxolitinib as Maintenance Therapy Following Allogeneic SCT Is Safe, Tolerable in Myelofibrosis

Ruxolitinib (Jakafi) is recommended for symptom relief for patients with myelofibrosis who are ineligible for allogeneic stem cell transplantation (SCT), and previous studies have demonstrated improved allogeneic SCT outcomes among patients previously treated with the JAK1/JAK2 inhibitor. Now, a pilot study is suggesting that ruxolitinib is safe and tolerable as maintenance therapy following the procedure.

The retrospective study separated patients into 3 groups: 3 patients in Cohort A never received ruxolitinib, 9 patients in Cohort B received ruxolitinib prior to SCT, and 4 patients in Cohort C received ruxolitinib both before and after SCT. At 11.5 months, all 3 patients in Cohort C achieved a complete response while 2 patients in Cohort A were in stable condition and 1 had disease progression. Four patients in Cohort B achieved a complete response, 2 achieved a partial response, and 5 had stable disease.

“With respect to the measured outcomes, Cohort C achieved a greater spleen size reduction, better fibrosis resolution, and rapid engraftment in comparison to Cohorts A and B,” wrote the researchers. “The significant spleen size reduction might, to some extent, explain the better platelet count recovery observed in Cohort C.”

They noted that it took longer for patients in Cohort C to achieve transfusion independence, which might be caused by ruxolitinib-induced bone marrow suppression.

All 3 patients in Cohort A experienced viral infections before day 100, including disseminated herpes zoster and cytomegalovirus. Two other patients experienced vancomycin-resistant Enterococcus bacteria, and none developed a fungal infection. Three patients in Cohort B experienced viral and fungal infections including aspergillus and cytomegalovirus. There were 4 patients who experienced bacterial infections.

In Cohort C, 2 patients experienced viral infections with herpes voster and cytomegalovirus viremia. There were no observed fungal infections.

All patients had exhibited symptoms and splenomegaly at diagnosis, with the exception of 1 patient who had prior splenectomy. The median duration of pre-SCT was 8 months and the median duration of the treatment following SCT was 20 months. Pre-SCT doses of ruxolitinib were titrated from 10 mg to 20 mg twice daily before being weaned off the therapy 5 days before starting conditioning. In the post-SCT setting, patients received 5 mg of ruxolitinib twice daily, starting once the patient’s absolute neutrophil count hit 0.5 x 10⁹/L for 3 consecutive days.

Reflecting on the findings, the researchers said that a large-scale prospective study is needed to determine whether this approach can be implemented in daily practice.

Reference:

Pu J, Poulose J, Malysz J, et al. Impact of ruxolitinib on myelofibrosis patients post allogeneic stem cell transplant—a pilot study [published online May 22, 2019]. Br J Haematol. doi: 10.1111/bjh.15967.