The FDA has approved omacetaxine mepesuccinate (Synribo) to treat adults with chronic myelogenous leukemia (CML) whose cancer has progressed after treatment with at least two tyrosine kinase inhibitors.
Omacetaxine is injected subcutaneously twice daily for 14 consecutive days over a 28-day cycle until hematologic response is achieved. The agent is then administered twice daily for 7 consecutive days over a 28-day cycle as long as patients continue to clinically benefit from therapy.
“Today’s approval provides a new treatment option for patients who are resistant to or cannot tolerate other FDA-approved drugs for chronic or accelerated phases of CML,” said Richard Pazdur, MD, Director of the Office of Hematology and Oncology Products in FDA’s Center for Drug Evaluation and Research.
Omacetaxine is approved under the FDA’s accelerated approval program. The drug also received orphan-product designation by the FDA.
The effectiveness of omacetaxine was evaluated using a combined cohort of patients whose cancer progressed after previous treatment with two or more tyrosine kinase inhibitors. All participants were treated with omacetaxine.
The drug’s effectiveness in chronic-phase CML was demonstrated by a reduction in the percentage of cells expressing the Philadelphia chromosome mutation found in most CML patients. Fourteen out of 76 patients (18.4%) achieved a reduction in an average time of 3.5 months. The median length of the reduction was 12.5 months.
In the setting of accelerated-phase CML, omacetaxine’s effectiveness was determined by the number of patients who achieved major hematologic response. Results showed 5 out of 35 patients (14.3%) achieved major hematologic response in an average time of 2.3 months. The median duration of major hematologic response in these patients was 4.7 months.
The most common side effects reported during clinical studies include thrombocytopenia, anemia, neutropenia, diarrhea, nausea, weakness and fatigue, injection site reaction, and lymphopenia.
Omacetaxine is marketed by Teva Pharmaceuticals. ■