Researchers reported a number of important findings in the treatment of myeloproliferative neoplasms (MPNS) at the 2017 Annual Meeting of the American Society of Clinical Oncology:

Anagrelide formulation compared to placebo in intermediate risk essential thrombocythemia

The randomized, multicenter phase lll trial ARETA compared a novel, extended-release anagrelide (blood thinner) formulation to a placebo (a look-alike containing no active ingredient) for early intervention in essential thrombocythemia (ET) patients with intermediate risk status. The results showed platelet count normalization and delayed progression to high risk status.

What Patients Need to Know

Data from ARETA supported the “treat early” concept for ET patients for whom the reduction of platelet counts and/or symptoms is a goal. Additionally, the extended-release anagrelide formulation was found to be as safe as the immediate-release formulations.

Pegylated interferon-alpha-2a compared with hydroxyurea in the treatment of high-risk essential thrombocythemia and polycythemia vera

A randomized phase lll trial, MPD-RC 112, compared pegylated interferon-alpha-2a (an antiviral medication approved by the FDA to treat hepatitis C and hepatitis B) with the chemotherapy hydroxyurea in the frontline treatment of patients with high-risk essential thrombocythemia (ET) and high-risk polycythemia vera (PV). The comparison of these drugs is important because of their different mechanisms of action and toxicity profiles.

What Patients Need to Know

Interim trial results indicated that both drugs were active in controlling platelet counts and helping to decrease the risk of blood clots and bleeding, but it was not clear if one drug was superior to the other. It is not yet known whether pegylated interferon-alpha-2a will provide better long-term disease control than hydroxyurea; this will be continued to be studied in the MPD-RC 112 trial.

Ruxolitinib studied as second-line therapy for advanced polycythemia vera (PV)

RESPONSE 2, a global, randomized phase lll trial, compared ruxolitinib to the best available therapy in patients with advanced polycythemia vera (PV) whose disease is resistant to the chemotherapy hydroxyurea.

The results showed that ruxolitinib, as a second-line therapy, provided rapid and durable clinical benefits and was superior to the best available therapy at controlling the volume of red blood cells and improving spleen enlargement.

What Patients Need to Know

The RESPONSE 2 trial also included patients who could not continue to take hydroxyurea because of side effects. Results from the trial indicated that ruxolitinib was generally well tolerated.

Phase lll trial compared pacritinib to best available therapy in subset of myelofibrosis patients

The phase lll PERSIST-2 trial compared the investigational drug pacritinib with the best available therapy in the treatment of high-risk myelofibrosis patients who have thrombocytopenia (a low blood platelet count).

Pacritinib met the primary endpoint of the trial, achieving a significant reduction in spleen volume as compared to the best available therapy, including the targeted treatment ruxolitinib.

What Patients Need to Know

Ruxolitinib is approved by the FDA for treatment of intermediate-risk or high-risk myelofibrosis, but it is not indicated for people with thrombocytopenia. Research is continuing to determine if pacritinib might play a role in the treatment of this group of patients.