GlaxoSmithKline Pharmaceuticals India has launched its special breast cancer drug Tykerb (lapatinib) in India, priced 25 per cent cheaper than overseas market.

In the US, Tykerb costs as much as $2,900 (over Rs 1,20,000) per month since the usual dosage is once a day for 21 days in a row for a cycle.

The drug is indicated for the treatment of patients, who do not respond to trastuzumab (sold under the trade name Herceptin), a blockbuster drug from the stable of Swiss drug major Hoffman-La Roche.

Herceptin is indicated for the treatment of a particularly aggressive form of tumour (HER2-positive), which accounts for 20-30 per cent of all breast cancers.

The drug is expected to post global sales of over $1 billion annually by 2012.