Delay to EU approval of GSK

European approval of UK drug major GlaxoSmithKline's oral breast cancer drug Tyverb (lapatinib) will be delayed while regulators consider new data on liver side effects. Final authorization for the dual ErbB1 and ErbB2 inhibitor had been expected by March 8, after the European Commission gave the drug conditional clearance late last year (Marketletter December 24, 2007).

The marketing application has been returned to the European Commission for further discussion after routine blood tests showed that the agent can raise the level of liver enzymes, a possible sign of liver damage. Raised concentrations were observed in four patients out of every 1,000 assessed, and returned to normal after use was discontinued.

GSK, which is the world's second-largest R&D-based drugmaker by sales, has recommended that investigators in ongoing trials, as well as physicians who have prescribed the drug, should increase the frequency of blood testing to keep a close eye on patient liver function.