What's the success rate for patients treated with ruxolitinib in combination with azacitidine?

Ruxolitinib is usually combined with azacitidine for patients whose myelofibrosis has progressed to acute myeloid leukemia or for newly diagnosed acute myeloid leukemia unfit for intensive chemotherapy.

How long do patients survive on this combination?
Patients treated with ruxolitinib plus azacitidine show overall survival ranging from 7 to 15 months in several small studies. Survival figures vary because they include both newly diagnosed and relapsed cases and differ by molecular profile.

What response rates are reported?
Complete response or complete response with incomplete recovery rates range from 25 percent to 55 percent. A larger prospective study enrolling 33 patients showed 42 percent composite complete response.

What happens if patients stop treatment?
Early discontinuation is common. Many patients leave the trial because of toxicity or disease progression. A group of 55 patients who started on the combination had 55 percent of them drop out before completing six cycles.

How does this combination compare with azacitidine alone?
No randomized trial has yet finished comparing ruxolitinib plus azacitidine with azacitidine alone. Current data show that the combined regimen may improve response rates modestly over azacitidine alone in patients who carry JAK2 mutations.

Why are companies challenging this patent?
Ruxolitinib is already approved alone for myelofibrosis and polycythemia vera. New formulations or fixed-dose combinations with azacitidine are now protected by additional patents held by Incyte Corporation. Companies are challenging these secondary patents to accelerate generic entry.