IPSS Scores, Line of Therapy Predict Better Response to Ruxolitinib in Myelofibrosis

By Ariel Jones - Last Updated: May 12, 2021

An analysis of data from the large, prospective, multinational, phase IIIb JUMP trial evaluated patient and disease characteristics that could predict response to ruxolitinib in patients with myelofibrosis (MF). The results were published in Leukemia & Lymphoma by Vikas Gupta, MD, from Princess Margaret Cancer Centre in Toronto, and colleagues.

The phase IIIb JUMP trial (JAK Inhibitor RUxolitinib in Myelofibrosis Patients) was launched to collect additional safety and efficacy data and provide access to ruxolitinib for patients in countries where the drug is not available outside of a clinical trial. A total of 2,233 patients were included in the study.

“Consistent with results from previous studies, patients in the JUMP study experienced durable improvements in splenomegaly and MF symptoms,” Dr. Gupta and coauthors wrote. “Although most patients with MF benefit from ruxolitinib treatment, response may vary among individual patients. […] The JUMP study provides data from a large patient population with MF that can be used to analyze and identify clinical factors that might be associated with response to ruxolitinib.”

According to the analysis, three factors were significantly associated with higher spleen response rates:

  • IPSS low/intermediate-1 risk vs. intermediate-2/high risk MF: 43.1% vs. 30.6% (adjusted odds ratio [aOR] = 0.65)
  • ruxolitinib as first- vs. second- or later-line therapy: 40.2% vs. 31.5% (aOR=0.53)
  • ruxolitinib total daily dose at week 12 of >20?mg/day vs. ?20?mg/day: 41.3% vs. 30.4% (aOR=0.47)

The authors found no association between baseline characteristics or total daily dose at week 12 and symptom response.

“Ruxolitinib led to higher spleen response rates in patients with lower IPSS risk, and when used earlier in treatment,” the researchers concluded. “Higher doses of ruxolitinib were associated with higher spleen response rates, but not with symptom improvement.”