Ruxolitinib's Impact on OS in the Real World for Elderly Patients Diagnosed With Myelofibrosis

June 17, 2020

In the real-world, ruxolitinib's approval to treat myelofibrosis has improved overall survival (OS) for elderly patients.

Two abstracts presented at the 25th European Hematology Association Annual Congress analyzed the impact of ruxolitinib in the real-world setting on elderly patients.

The first found that elderly patients who were exposed to ruxolitinib after a diagnosis of myelofibrosis (MF) had a longer survival and a lower risk of mortality compared with patients who never received ruxolitinib.1

The only curative treatment for MF is allogeneic hematopoietic cell transplantation, which has toxicities and complications. Ruxolitinib is a Janus kinase 1 and 2 inhibitor approved to treat patients with intermediate- and high-risk MF. While the drug was approved based on the COMFORT clinical trials, which showed significant improvements in overall survival (OS), there have been limited real-world data available.

The researchers analyzed a 1399 Medicare fee-for-service beneficiaries with claims from January 2012 to December 2017. They included patients 65 years and older with 1 or more inpatient or 2 or more outpatient claims with an MF diagnosis. The individuals were stratified into ruxolitinib-exposed (n = 272) and ruxolitinib-unexposed (n = 1127) groups.

They found that the ruxolitinib-exposed group was slightly younger (75.4 years vs 78.0 years), but the ruxolitinib-exposed group was more likely to have a previous diagnosis of polycythemia vera (20.2% vs 6.8%) or essential thrombocytopenia (19.5% vs 15.9%).

Whereas the median OS for the ruxolitinib-unexposed group was 44.4 months (95% CI, 37.3-62.0), the median OS was not reached (95% CI, 51.0-not reached) for ruxolitinib-exposed patients. For ruxolitinib-exposed patients, the 1-year survival rate was 82.3% (76.7-86.7%) and the 2-year survival rate was 76.1% (69.2%-81.7%) compared with a 1-year survival rate of 72.5% (69.5%-75.2%) and a 2-year survival rate of 60.6% (56.9%-64.0%) for ruxolitinib-unexposed patients.

In an accompanying abstract with the same lead author, researchers found that OS for elderly patients who never received ruxolitinib was still longer following the approval of ruxolitinib for MF.2

The authors sought to understand the real-world clinical benefit of ruxolitinib by evaluating patient outcomes, independent of ruxolitinib treatment, before and after the therapy was approved.

There were a total of 1405 Medicare fee-for-service beneficiaries analyzed between January 2010 and December 2017. A total of 278 were diagnosed with MF before ruxolitinib’s approval and 1127 diagnosed post approval. The 1-year survival for the preapproval group was 55.6% (95% CI, 49.4%-61.3%) compared with 72.5% (95% CI, 69.5%-75.2%) for the postapproval group. They also found that patients diagnosed with MF prior to ruxolitinib approval had a higher risk of mortality compared with the patients diagnosed after ruxolitinib’s approval (adjusted hazard ratio, 1.41; 95% CI, 1.11-1.78; P = .0043).

They found that in the real world, among elderly patients who have never received ruxolitinib, OS was higher following the therapy’s approval.

“Many factors may have contributed to the observed improvement in survival following RUX approval, including increased disease awareness and improved patient management,” the authors concluded.

References

1. Verstovsek S, Parasuraman S, Yu J, et al. Real-world survival in elderly patients with myelofibrosis in the United States: ruxolitinib exposed vs unexposed. Presented at: EHA25 2020; June 11-21, 2020; Abstract EP1124.

2. Verstovsek S, Parasuraman S, Yu J, et al. Real-world survival in elderly patients with myelofibrosis in the United States: pre- vs post-ruxolitinib approval. Presented at: EHA25 2020; June 11-21, 2020; Abstract EP1120.