Amgen’s white blood cell-boosting drug Neulasta (pegfilgrastim) has had its labelling updated in the USA to reflect new data showing it can protect cancer patients from a serious complication of chemotherapy.

The new label raises the proportion of cancer patients eligible to receive Neulasta in their first chemotherapy cycle in order to prevent febrile neutropenia, which can lead to life-threatening infections. Previously, the drug was indicated for use in patients with at high risk of developing neutropenia (30%-40%), but now it can be used with chemotherapy regimens that carry a modest risk (17% or more), said Amgen.

“The Phase III study demonstrated that administering Neulasta beginning in the first chemotherapy cycle reduced the incidence of febrile neutropenia by 94%,” said Willard Dere, Amgen’s chief medical officer.

Neulasta, a long-acting follow-up to Amgen’s Neupogen (filgrastim) white blood cell stimulator, is seeing rapid sales growth, helped by its favourable dosing of just one dose per chemotherapy cycle. Sales of the drug topped $1 billion in the first half of the year, up by a third over the first half of 2004, with $906 million coming from the US and $182 million from overseas [[20/07/05d]].

Total sales of Neupogen and Neulasta were around $1.7 billion in the same period, with Neupogen’s share declining just as the drug faces the first threat of generic competition from the likes of Pliva and Barr Laboratories [[06/05/05e]]. The new data should help drive prescribing of Neulasta and help defend Amgen’s franchise from sales erosion once generic competition kicks in.