Pegfilgrastim Significantly Reduces the Incidence of Febrile Neutropenia in Patients on Chemotherapy
By Akanksha, Pharmacology Correspondent
Feb 27, 2005, 13:43

Amgen Inc., the world's largest biotechnology company, today announced that data from the largest randomized placebo-controlled study to date for Neulasta(R) (pegfilgrastim) has been published in the February 20 issue of The Journal of Clinical Oncology.

The phase 3 study showed that administering pegfilgrastim beginning in the first and subsequent cycles of chemotherapy reduced the incidence of febrile neutropenia (low white blood cell count with fever), a serious complication of cancer chemotherapy typically associated with infection, by more than 90 percent.

"In this study, pegfilgrastim administered 24 hours after chemotherapy profoundly reduced the rate of febrile neutropenia from 17 percent to one percent," said the study's lead investigator Charles Vogel, M.D., Cancer Research Network, Plantation, Fla. "The high frequency of first-cycle febrile neutropenia in this study emphasizes the need to initiate pegfilgrastim from the first cycle of chemotherapy to significantly reduce the patient's risk of infection."

Febrile (or feverish) neutropenia is the most common presentation of infection in patients receiving chemotherapy. Infection in this setting can be serious and even life threatening because chemotherapy can compromise the patient's ability to fight infection.

Data from the randomized, double-blind, placebo-controlled study of 928 breast cancer patients show that first and subsequent-cycle administration of pegfilgrastim resulted in a 94 percent reduction in the incidence of febrile neutropenia, a 93 percent reduction in the incidence of hospitalization and an 80 percent reduction in the incidence of intravenous anti-infective use in patients receiving myelosuppressive chemotherapy previously considered at moderate risk for neutropenic complications.

Specifically, in all cycles, one percent of patients in the pegfilgrastim arm (6/463) developed febrile neutropenia compared with 17 percent of patients in the placebo arm (78/465). Pegfilgrastim was also associated with a significantly lower incidence of hospitalizations with one percent of patients (6/463) requiring hospitalization versus 14 percent of patients receiving placebo (64/465).

Two percent of patients in the pegfilgrastim arm (7/463) required intravenous anti-infectives versus 10 percent of patients in the placebo arm (48/465). Febrile neutropenia occurred most often in placebo patients during the first cycle of chemotherapy (65 percent). There were two deaths from septic shock on the placebo arm compared to zero in the pegfilgrastim arm.

In addition, first-cycle administration of pegfilgrastim resulted in a 91 percent reduction in the incidence of febrile neutropenia occurring in the first cycle of chemotherapy, an 89 percent reduction in the incidence of hospitalization and an 83 percent reduction in the incidence of intravenous anti-infective use.

Breast cancer patients (Stage 1-4, ECOG performance of 0-2) receiving 100 mg/m(2) docetaxel every three weeks for up to four cycles were randomized to receive either 6 mg pegfilgrastim (n=463) or placebo (n=465) once-per-cycle on the day after docetaxel administration for up to four cycles.

Docetaxel is associated with an average reported febrile neutropenia incidence of approximately 10 to 20 percent in the absence of growth factor support. Febrile neutropenia was defined as fever with a temperature greater than or equal to 38.2 degrees C and an absolute neutrophil count (ANC) less than 0.5 x 10(9)/L measured the same day or the day after fever was documented.

Pegfilgrastim was well-tolerated in this study with an adverse event profile similar to placebo. Bone pain was a frequently observed adverse event in both arms of the study (31 percent with pegfilgrastim versus 27 percent with placebo).

Pegfilgrastim was approved by the U.S. Food and Drug Administration (FDA) in 2002 for decreasing the incidence of infection, as manifested by neutropenia, in patients with nonmyeloid malignancies receiving myelosuppressive anticancer drugs associated with a clinically significant incidence of febrile neutropenia. Similar indications for pegfilgrastim were approved in Europe and Australia the same year.

Rare cases of splenic rupture and sickle cell crises have been reported in postmarketing experience. Allergic reactions, including anaphylaxis, have also been reported. The majority of these reactions occurred upon initial exposure.

However, in rare cases, allergic reactions, including anaphylaxis, recurred within days after discontinuing anti-allergic treatment. In clinical trials, the only serious adverse event not attributed to the underlying disease or chemotherapy was a case of hypoxia.

The most common adverse event attributed to pegfilgrastim was bone pain, reported in 26 percent of patients. While not reported in patients receiving pegfilgrastim, rare events of adult respiratory distress syndrome have been reported in patients receiving the parent compound, Filgrastim.

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