New Delhi: In yet another blow to multinational companies operating in India, the Intellectual Property Appellate Board (IPAB) has revoked the patent for UK drug maker GlaxoSmithKline's GSK anti-cancer drug Tykerb in its salt form.

The court quashed the patent for the salt form of the drug that is used in the treatment of breast cancer citing section 3d of the Indian Patents Act 2005, that deems any incremental innovation non-patentable. The court added that the drug has failed to show significant improvement in the efficacy.

The IPAB said, "As regards the section 3d, the respondent's own statements and the expert's affidavit demonstrate that this invention cannot be held to have enhanced therapeutic efficacy."

Speaking on the issue, a spokesperson of the british drug maker expressed his disappointment at the order. "We are disappointed that the IPAB has revoked our expiring patent for the lapatinib ditosylate salt. This latter ruling only relates to the lapatinib ditosylate salt patent in India and does not affect our basic patent for Tykerb or corresponding patents in other countries."

He added, "We are pleased that the IPAB in India has upheld our basic patent for the lapatinib compound, the active ingredient in Tykerb."

The company however believes that the patent for the salt is valid and will consider appealing the case. The patent for Tykerb is valid till 2019, the company added.

This move by the IPAB comes after the Indian wing of the German drug major Fresenius Kabi moved IPAB challenging the patent of lapatinib and lapatinib ditosylate salt, the key ingredient in Tykerb. The IPAB shot down the salt version of the ingredient, while upholding the patent for lapatinib.