Current Status of JAK Inhibition for the Primary Myelofibrosis Population

Raajit Rampal, MD, PhD, hematologic oncologist at Memorial Sloan Kettering Cancer Center, discusses the current treatment landscape for patients with myelofibrosis.

According to Rampal, there are 3 approved JAK (Janus kinase) inhibitors—ruxolitinib (Jakafi), fedratinib (Inrebic), and pacritinib (Vonjo)—that can be used to treat myelofibrosis, but they are mainly effective in improving patient quality of life by reducing symptoms and treating an enlarged spleen. However, ad hoc analyses of patients in the COMFORT-I (NCT00952289) and COMFORT-II (NCT00934544) trials have shown potential survival benefit to patients receiving ruxolitinib.

Treatment may vary based on the needs of the patient, Rampal says. While JAK inhibitors are effective for constitutional symptoms and reducing spleen size, anemia may be treated with immunomodulatory agents such as danazol, erythropoiesis-stimulating agents, or steroids. Another JAK inhibitor, momelotinib, is being compared with danazol in the phase 3 MOMENTUM trial (NCT04173494), and showed superiority in symptom response, transfusion requirements, and spleen responses.

For patients whose disease has progressed to leukemic transformation, hypomethylating agents are used. However, Rampal says the only curative treatment for myelofibrosis is allogeneic hematopoietic cell transplant.

TRANSCRIPTION:

0:08 |The drugs that we have currently FDA approved, ruxolitinib, fedratinib, and now pacritinib, which was just approved at the end of March of this year, all do a good job of reducing symptoms in patients with myelofibrosis and reducing the size of the spleen. I think all of them do make a difference in how patients feel. That being said, there also [are] potentially data to indicate that ruxolitinib in particular may confer a survival advantage based on some ad hoc analyses.

0:48 | The treatment of the disease depends on what the situation is or what problems are facing the patient. In other words, JAK inhibitors are not necessarily the only tool that we should employ; it depends on what the patient's dealing with. If a patient has anemia, for example, there are a variety of other medications that can be used, things like immunomodulatory agents like danazol or steroids, like erythropoiesis-stimulating agents. For patients who have constitutional symptoms, or an enlarged spleen, JAK inhibitors are really the mainstay of therapy.

1:27 | Again, we have now 3 FDA-approved JAK inhibitors with another that is in phase 3 trials currently. For our patients who have progressive disease and are progressing toward leukemic-phase disease, we do use hypomethylating agents. At the end of the day, the only treatments that we have that can change the course of the disease and cure the disease is a stem cell transplant.