Hyderabad: Natco Pharma Ltd and its partner Alvogen Inc. have settled a patent infringement case with US drug maker Gilead Sciences Inc., and Hoffmann-La Roche Inc., F. Hoffmann-La Roche Ltd and Genentech Inc., paving the way for the Indian drug maker to launch generic (copycat) versions of anti-influenza drug Tamiflu in the world’s largest pharmaceutical market.

Tamiflu developed by Gilead is used in the prevention and treatment of influenza A and B viruses, including swine flu, and has a market size of around $500 million in the US.

The settlement covers 30 mg, 45 mg and 75 mg versions of Tamiflu, generically called oseltamivir phosphate. Analysts expect Natco’s generic version in the form of oral capsules to enjoy low competition and sales of at least $50-60 million in the US in the first year of the launch, depending on the flu season.

Hoffmann-La Roche, F. Hoffmann-La Roche and Genentech are all part of Switzerland-based Roche Holding AG, which is Gilead’s marketing partner for the key flu drug.

Natco teamed up with US-based drug maker Alvogen Inc. to challenge Tamiflu patents held by Gilead and its partner.

The US Food and Drug Administration granted tentative approval to Natco for the generic oseltamivir phosphate capsules on 14 March 2014.

“Under the terms of the settlement, Natco’s partner Alvogen will be able to market the oseltamivir phosphate capsules before the expiration of the pediatric exclusivity period listed in FDA’s Orange Book for US Patent No. 5,763,483, which is 23 February 2017," Natco said in a statement.

Natco declined to give further details on conditions of the settlement and launch date, citing confidentiality.

The settlement with Gilead and its partners ahead of the court’s verdict in the patent infringement litigation makes Natco ineligible for the 180-day marketing exclusivity in the US, said Afzaal Mohammed, pharma expert at Karvy Stock Broking Ltd.

Typically, a generic company will become eligible for 180-day marketing exclusivity if it successfully defends the patent infringement action forced by the branded company.

“The settlement gives surety of launch for Natco, as outcome of litigation at times can go against the generic maker," Mohammed said.

Mohammed said the Natco’s generic Tamiflu launch could be most likely between September and November next year—the beginning of the flu-season in US market.

Even without 180-day exclusivity, generic Tamiflu will still be a windfall gain for Natco, as generic competition can enter only after February 2017, Mohammed of Karvy said.

“Conservatively, it can be $50-60 million revenue opportunity for Natco," said Mumbai-based brokerage house India Infoline Ltd (IIFL) in a research note dated 9 December.

Shares of Natco rose 3.21% to close at 549.25, the benchmark Sensex gained 0.42% closed at 25,150.35 points.

In a separate development, Natco and Hetero Drugs Ltd, said that they have won approvals from Drug Controller General of India (DCGI) to launch 30mg and 60mg versions of generic hepatitis-C drug Daclatasvir Dihydrochloride tablets in India.

Daclatasvir is used in combination with sofosbuvir for the treatment of patients with chronic hepatitis C virus (HCV) of genotype 3 infection.

It is a generic version of Bristol-Myers Squibb’s brand ‘Daklinza’—approved by US FDA in July 2015. Daclatasvir is included the World Health Organization’s list of essential medicines.

Natco said it will market Daclatasvir under its own brand NATDAC, and through its strategic partners in India.

“Natco will launch immediately in India at maximum retail price of 6,000 and 4,000 for the 60mg and 30mg strengths, respectively, for a bottle of 28 tablets," the company said.

Hetero didn’t disclose the pricing and launch plans for Indian market.