BETHESDA, MD 26 October 2012—FDA on October 26 approved the cephalotaxine omacetaxine mepesuccinate for the second-line treatment of chronic myelogenous leukemia (CML) in adults.

The drug is indicated for use in adults with chronic or accelerated phase CML who did not tolerate other therapy or whose illness did not respond to past treatment with two or more tyrosine kinase inhibitors.

Omacetaxine mepesuccinate will be marketed as Synribo by Teva Pharmaceuticals USA. The company has not announced a launch date for the product.

The recommended induction phase dosage of omacetaxine mepesuccinate is 1.25 mg/m² injected subcutaneously twice daily for 14 consecutive days in a 28-day cycle, according to the drug's labeling (PDF). The cycle should be repeated every 28 days until the patient exhibits a hematologic response.

For maintenance therapy, the recommended dosage is 1.25 mg/m² injected subcutaneously twice daily for 7 consecutive days in a 28-day cycle, with cycles continuing as long as the patient responds to the therapy.

Omacetaxine mepesuccinate was approved under FDA's accelerated approval program, which allows the agency to use surrogate markers to evaluate a drug's efficacy.

According to the agency, 18.4% of 76 clinical trial participants with kinase-resistant, chronic phase CML exhibited a major cytogenetic response after 3.5 months of therapy, on average. The median duration of the response was 12.5 months.

Among 35 clinical trial participants with accelerated phase CML, 14.3% had no evidence of leukemia after 2.3 months, on average. The mediation duration of the response was 4.7 months.

The labeling for omacetaxine mepesuccinate states that the drug has not been demonstrated to increase patients' survival time or improve disease-related symptoms.

Serious adverse events reported in clinical trial participants treated with omacetaxine mepesuccinate include myelosuppression, bleeding, and hypoglycemia. Common adverse events associated with the drug in clinical trials included diarrhea, nausea, weakness, fatigue, and injection-site reactions.

Omacetaxine mepesuccinate will be supplied in 8-mL single-use vials containing 3.5 mg of lyophilized powder. Vials should be stored at controlled room temperature.

To prepare omacetaxine mepesuccinate for injection, add 1 mL of 0.9% Sodium Chloride Injection, USP, to the vial. The reconstituted material will contain 3.5 mg of omacetaxine mepesuccinate at a concentration of 1 mg/mL.

After reconstitution, omacetaxine mepesuccinate for injection can be stored for up to 12 hours at room temperature or up to 24 hours at 2–8 °C. The material should be protected from light until use.