Indian Patents Office has revoked a patent for an asthma drug held by US-based Merck & Co following a challenge from domestic pharma firm Cipla.
In an order, Assistant Controller of Patents & Designs T V Madhusudhan revoked the patent on the ground that it lacked invention.
"The sole process claim also in its entirety is not inventive as the said claim does not describe any inventive feature," the order said.
"In view of the above conclusion I hereby order that the patent bearing number 246328 is revoked," Madhusudhan said in his order.
Schering Corporation, which was later acquired by Merck & Co, had applied for patent of the asthma drug in February 2004, and the Indian Patents Office had granted the patent in March 2011. Cipla had challenged the patent.
The development is the latest in a series of patent revocations by India's Patent Office.
Last month, the Intellectual Property Appellate Board (IPAB) had turned down drug firm AstraZeneca's plea for a patent on the lung cancer drug Gefitinib.
Similarly, it had also revoked Pfizer's patent on cancer drug 'Sutent'. The drug was granted a patent in India in 2007 but Cipla had opposed it the following year.
Earlier during the year, India Patents Office had invoked compulsory licensing permitting the Hyderabad-based Natco Pharma to manufacture and sell cancer-treatment drug Nexavar at a price, over 30 times lower than charged by its patent-holder Bayer Corporation.