FDA approves Pfizer’s Bosulif pill for patients with rare leukemia
The Food and Drug Administration on Tuesday approved a new Pfizer drug to treat a rare form of blood and bone marrow cancer that causes a buildup of unhealthy white blood cells.
Pfizer’s Bosulif is a daily pill to treat chronic myeloid leukemia patients who carry a specific genetic variation. The disease is one of four types of the blood cancer, and accounts for about 15 percent of leukemia cases.
The disease, which usually affects seniors, causes the bone marrow to produce unhealthy white blood cells that do not grow and die like normal cells. Instead, the cells buildup in the bone marrow and crowd out healthy cells that are needed to fight off infections.
Bosulif works by blocking an enzyme called tyrosine kinase that triggers the production of unhealthy cells. The FDA approved the pill for patients with a genetic mutation, known as the Philadelphia chromosome, who do not respond to other cancer therapies, including Novartis’ Gleevec.
An estimated 5,430 patients will be diagnosed with chronic myelogenous leukemia this year, according to the FDA. The agency cleared the drug under its orphan drug program, which provides financial incentives for the development of drugs for rare diseases.
The FDA approved Bosulif based on a Pfizer study showing 34 percent of patients treated with the drug responded within the first six months of treatment. In patients previously treated with Gleevec, 33 percent had blood counts that returned to a normal range within 48 weeks. Fifty five percent of patients achieved normal blood counts with no evidence of leukemia within that same timeframe.
BOSULIF (bosutinib) Indication and Important Safety Information
BOSULIF is indicated for the treatment of adult patients with chronic, accelerated, or blast phase Ph+ CML with resistance, or intolerance to prior therapy.
Contraindication: Hypersensitivity to BOSULIF. Anaphylactic shock occurred in less than 0.2 percent of treated patients.
Gastrointestinal Toxicity: Diarrhea, nausea, vomiting and abdominal pain have been observed. Median time to onset for diarrhea was two days, median duration was one day and median number of episodes per patient was three. Monitor and manage patients using standards of care, including antidiarrheals, antiemetics, and/or fluid replacement. Withhold, dose reduce, or discontinue BOSULIF as necessary.
Myelosuppression: Thrombocytopenia, anemia and neutropenia have been observed. A complete blood count should be performed weekly for the first month and then monthly or as clinically indicated. Withhold, dose reduce, or discontinue BOSULIF as necessary.
Hepatic Toxicity: Twenty percent of patients experienced an increase in either ALT or AST. Liver enzyme elevation usually occurs early in treatment. Perform monthly hepatic enzyme tests for the first three months and as clinically indicated. In patients with transaminase elevations, monitor liver enzymes more frequently. Drug induced liver injury has occurred. Withhold, dose reduce, or discontinue BOSULIF as necessary.
Fluid Retention: Fluid retention has been reported and may cause pericardial effusion, pleural effusion, pulmonary edema, and/or peripheral edema. Monitor and manage patients using standards of care. Interrupt, dose reduce or discontinue BOSULIF as necessary.
Embryofetal Toxicity: BOSULIF may cause fetal harm when administered to a pregnant woman. Women of childbearing potential should be advised of potential hazard to the fetus and to avoid becoming pregnant while receiving BOSULIF.
The most common adverse reactions observed in greater than 20 percent of the patients in the Phase 1/2 safety population (n=546) were diarrhea, nausea, thrombocytopenia, vomiting, abdominal pain, rash, anemia, pyrexia and fatigue.
The most common Grade 3-4 adverse reactions and laboratory abnormalities observed in greater than 10 percent of patients were thrombocytopenia, anemia and neutropenia.
Drug Interactions: Avoid concurrent use with strong or moderate CYP3A4 inhibitors or inducers.
Proton Pump Inhibitors: Consider using short-acting antacids or H2 blockers instead of PPIs. Separate antacid or H2 blocker dosing and BOSULIF dosing by more than two hours.
Substrates of P-glycoprotein: BOSULIF may increase the plasma concentrations of drugs that are P-gp substrates, such as digoxin.
Nursing mothers: Given the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or BOSULIF.
Hepatic Impairment: Treat with a dose of 200 mg daily in patients with any baseline hepatic impairment.
The most common side effects seen in patients included diarrhea, nausea, abdominal pain, rash and fever.
###
By Associated Press