Sun Pharmaceutical Industries, India's largest drug maker has lost $3-billion revenue potential from the US market after a rival beat it to gain the US regulator’s approval to sell the world’s best-selling anti-depressant drug, Venlafaxine.
The US Food and Drug Administration (FDA) recently approved the generic of the tablet form of Effexor XR (Venlafaxine) to the US-based Osmotica Pharmaceutical's marketing application. The approval makes Sun Pharma's marketing application (abbreviated new drug application or ANDA) invalid.
Now, Sun Pharma will have to conduct fresh bio-equivalence study comparing with Osmotica's tablets and resubmit their ANDA, which effectively prevents its plans of launching the drug in the US market.
Effexor XR extended release drug in capsule form had annual sales of $3 billion for the month ended September 2008 and is the largest selling drug of Wyeth. Osmotica has already launched its tablet version following the product patent expiry of the basic ingredient in June, this year.
Unlike normal patent challenges by generic companies, Osmotica and Sun Pharma both developed an improvised tablet form of the drug and challenged the patent on basic ingredient venlafaxine, and not the original capsule version of the drug. While the product patents on Effexor are expected to expire by 2017, the patent on key ingredient venlafaxine expired this year.
Osmotica's generic version of Venlafaxine extended release tablets was approved by US FDA in May 2008 before Sun Pharma could get approval. Following this, Osmotica filed a citizen petition with US FDA directing all subsequent ANDA filers to resubmit their ANDA for proving bio-equivalence to Osmotica's tablet version, and not Wyeth's capsule version.
Though Sun Pharma had challenged the patents on three strengths of Effexor in 37.5 mg, 75 mg and 150 mg, based on an innovative technology for extended release tablets, Wyeth Pharmaceuticals did not sue Sun Pharma for infringing its patent and had issued a ‘covenant not to sue’ (a legal term in which an aggrieved party agrees not to sue the party liable to such action).
US generic drug major Mylan Pharmaceuticals is believed to be the first to file ANDA for this drug on capsule form. Wyeth had also entered into an out-of-court settlement with Teva Pharmaceuticals of the US for the same product in capsule form. However, Wyeth chose to sue other challengers such as India's Lupin Pharmaceuticals, Impax Laboratories, Anchen Pharmaceuticals and Alsa Corporation (a subsidiary of Johnson & Johnson) in the case of Effexor XR capsules.
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