Sun to launch copy of Novartis' best-selling drug Gleevec Feb. 1

The day of reckoning is on the books for Novartis' ($NVS) top-selling drug, cancer pill Gleevec. Sun Pharma said today that the FDA has approved its generic of the blockbuster and that it will launch its version in two months, beginning Feb. 1.

Because the Indian drugmaker was the first to file with the FDA for a copycat of the drug, it will have the market in the U.S. to itself for 6 months. And a big market it is. Gleevec had $2.2 billion in sales in the U.S. last year. An Express Scripts ($ESRX) report this year showed that Gleevec held the largest piece of the U.S. cancer drug market with a 12.5% share.

First approved in 2001 to treat chronic myeloid leukemia, Gleevec was considered a wonder drug that turned some blood cancers into chronic diseases. Worldwide the drug rang up $4.7 billion in sales last year, slightly more than in 2013.

It is not as if the Sun copy is a surprise. The two companies hammered out a patent lawsuit settlement last year that assured Sun's right to bring out its copy in exchange for delaying that launch by 7 months, a delay that should allow the Swiss drugmaker to reap another $1 billion in sales for its longtime standard bearer.

When Novartis and Sun first started wrangling over the patent, Novartis claimed it had patent protection through 2019. That drew a separate lawsuit this year from two union funds that accused Novartis of using "sham" patent-infringement claims to get Sun to agree to the delay beyond the patent loss last July. Novartis has denied the claims.

While Gleevec has continued to be its best seller, in recent years Novartis has been touting the superior results from follow-up drug Tasigna, trying to get doctors to move patients to it ahead of losing patent protection. While it is also a blockbuster, it has not nearly reached the sales levels that Gleevec enjoys. Tasigna had U.S. sales of $540 million last year and worldwide sales of $1.5 billion.

While generic competition is a big deal for Novartis, having Gleevec to itself for 6 months is a big deal for Sun Pharmaceutical, which has seen its sales hammered by regulatory issues brought up by the FDA for one of its key plants. In its last first quarter, Sun said its U.S. sales of $488 million were down 4%, primarily because of plant issues, and sales were down 28% in the second quarter to $510 million, although that was impacted by its launch of Diovan in the same quarter the year before. One analyst in India told the Business Standard that Sun could conservatively expect to pull in between $250 million and $300 million during the 6-months exclusivity period from its Gleevec copy.

- here's the announcement 
- read the Business Today story

Special Reports: Top 10 best-selling cancer drugs of 2013 - Gleevec