Dr. Oh Discusses the Differences Between Investigational JAK Inhibitors and Ruxolitinib in MPNs

Stephen Oh, MD, PhD, assistant professor of medicine, Division of Hematology, Washington University School of Medicine in St. Louis, Siteman Cancer Center, discusses the differences between investigational JAK inhibitors and ruxolitinib (Jakafi) in the treatment of patients with myeloproliferative neoplasms (MPNs).

Each of these inhibitors are slightly distinct from ruxolitinib, says Oh. As a class, these drugs seem to provide some degree of symptom relief and spleen improvement. For example, some patients who receive momelotinib will experience anemia improvement, a benefit that is almost never observed with ruxolitinib; in fact, patients on ruxolitinib will sometimes experience worse anemia.

Pacritinib has very little effect on platelet count, states Oh, although, it seems to be safely administered in patients with a platelet count below 50—this is not possible with ruxolitinib, which is why current recommendations call for clinicians to avoid the use of ruxolitinib in patients with a platelet count below 50. Fedratinib is more selective for JAK as opposed to both JAK1/2, he adds. It also hits FLT3, which isn’t affected by ruxolitinib. It remains to be seen whether or not that holds any relevance in myelofibrosis, concludes Oh.