According to results recently presented at the 46th annual meeting of the American Society of Hematology (ASH), Neulasta® (pegfilgrastim) appears at least as effective as Neupogen® (filgrastim) in the treatment of chemotherapy-induced neutropenia in patients with acute myeloid leukemia. One injection of Neulasta® was comparable to 16 injections of Neupogen® in this group of patients.
Acute myeloid leukemia (AML) is a cancer of the bone marrow and blood characterized by the uncontrolled growth of immature white blood cells (immune cells), which never develop into functioning cells. Besides not being able to carry out the functions of mature immune cells, AML cells may also crowd out normal blood cells in the bone marrow and blood. AML is considered to be an aggressive cancer and patients are often at a high risk of developing a cancer recurrence following therapy, particularly if they are not able to undergo high doses of therapy.
Researchers have learned that the best way to cure patients with AML is to administer large doses of chemotherapeutic agents in a short period of time. The concept is to kill leukemia cells within 6 months before resistance to the drugs occurs. Therapy is divided into two phases: remission induction and post-remission consolidation/maintenance. Induction chemotherapy is administered to produce a complete remission in the bone marrow, which is defined as less than 5% “blasts” in the bone marrow sample and a return to normal blood counts. Patients are at a high risk for developing neutropenia during induction therapy. Neutropenia occurs when white blood cells (immune cells) are destroyed by chemotherapy, leaving the immune system unable to fight bacterial, viral and fungal infections. Chemotherapy-induced neutropenia is a serious condition for several reasons. Patients that develop neutropenia are more likely to get infections, may require hospitalization; and even minor infections can become life threatening. Perhaps more important and often overlooked is that patients who develop neutropenia often require a dose reduction or delay in their chemotherapy treatment, which may prevent patients from achieving the best possible outcome from chemotherapy treatment.
Neulasta® and Neupogen® are agents that stimulate the production of immune cells in the body. The action of Neulasta® and Neupogen® reduces or even completely prevents the development of chemotherapy induced neutropenia and its associated complications in patients undergoing chemotherapy. Neulasta® has been designed so that only one injection is given per chemotherapy cycle compared to the daily injections required for Neupogen® administration. Researchers continue to evaluate which patients benefit the most from treatment with Neulasta®. In addition, research is also directed at evaluating the use of Neulasta® to completely prevent the development of neutropenia associated with chemotherapy.
Researchers from Europe and Australia recently conducted a clinical trial to compare Neulasta® to Neupogen® in the treatment of chemotherapy-induced neutropenia in 83 patients with AML. Patients had undergone induction therapy with idarubicin and cytarabine and had developed severe neutropenia. Patients were then treated with either a single dose of Neulasta® or daily injections of Neupogen® for their severe neutropenia. The average time to recovery from severe neutropenia and the average duration of severe neutropenia was approximately 22 days in both groups of patients. Patients treated with Neulasta® only received one injection and patients treated with Neupogen® received an average of 16 injections. Complications associated with infections occurred in only 12% of patients treated with Neulasta®, compared with 22% of patients treated with Neupogen®.
The researchers concluded that Neulasta® appears at least as effective as Neupogen® and requires significantly fewer injections in treating chemotherapy-induced neutropenia in patients undergoing induction therapy for AML. Patients undergoing induction therapy with AML who have neutropenia may wish to discuss the risks and benefits of a treatment strategy utilizing Neulasta®.
Reference: Bosi A, Szer J, Kassis J, et al. A Multicentre, Double-Blind, Randomized, Phase 2 Trial Comparing Pegfilgrastim with Filgrastim as an Adjunct to Chemotherapy for Acute Myeloid Leukaemia (AML). Proceedings from the 46th annual meeting of the American Society of Hematology (ASH). December 2004. Abstract # 866.