Regulators in Europe have given a partial green light to Pfizer 's leukaemia drug Bosulif.

The European Commission has granted conditional marketing authorisation for Bosulif (bosutinib) for the treatment of adults with chronic, accelerated or blast phase Philadelphia chromosome-positive (Ph+) chronic myelogenous leukaemia (CML). The drug can be given to patients previously treated with one or more tyrosine kinase inhibitors ie Novartis' Gleevec (imatinib) and Tasigna (nilotinib) or Bristol-Myers Squibb's Sprycel (dasatinib).

Pfizer notes that the recommendation is based on data from a Phase I/II study of bosutinib in more than 500 patients with Ph+ CML with separate cohorts for chronic, accelerated and blast phase disease previously treated with one or more prior TKIs. The drug was approved in the USA in September last year.

Conditional approvals are granted to products with a positive benefit/risk assessment that address unmet medical needs and are renewable annually. It means that Pfizer is committed to generating additional efficacy and safety data for Bosulif in the aforementioned patients and will submit the findings to the European Medicines Agency. Following review of the data by the agency's Committee for Medicinal Products for Human Use, the EC will consider granting full marketing authorisation.

The drugs major quoted Carlo Gambacorti-Passerini at the University of Milano Bicocca in Italy as saying that "it's critical to have additional treatment options for CML patients, because each patient responds to therapy differently and has unique needs". He added that "based on my experience with Bosulif, I believe this once-daily treatment, with its distinct safety profile, offers an important new alternative".