On Aug. 9, Marqibo (vincristine sulfate liposome injection) received an accelerated approval from the FDA. Marqibo is approved to treat adult patients with Philadelphia chromosome negative (Ph-) acute lymphoblastic leukemia (ALL) who have either relapsed two or more times or whose disease has progressed after two or more therapies.ALL is a disease in which the marrow produces too many abnormal white blood cells, and the rapidly growing abnormal cells push out the other healthy blood cells. It is also a fairly aggressive cancer that can worsen quickly if not treated.In their March report on Marqibo, an FDA advisory panel noted that of the 2,000 new cases of adult ALL diagnosed annually, 1,400 of them will be Ph- and fewer than 500 of them will relapse more than once. The panel also noted that patients who relapse more than once or have refractory disease after a first relapse have a median survival time of less than three months and there are no approved treatment options for this population--a need Marqibo meets.Marqibo is made up of vincristine, an older chemotherapy drug, which is enclosed in a nanoparticle lipsome that helps convey the drug to the tumor. Marqibo is given once a week.A single trial with 65 patients who had relapsed at least twice established the effectiveness of the drug. Ten of the 65 patients had a complete response (disease remission) that lasted a median of 28 days. There is no definitive overall survival data as of yet.Two single-arm studies established safety and identified potential side effects, with 76 percent of participants experiencing serious effects, including respiratory issues and cardiac arrest. Common side effects include low blood cell counts, nausea, nerve damage, fatigue and constipation.Read the full announcement from the FDA.