Monday, November 28, 2005

Pfizer gets favorable re-exam result on Lipitor patent, US 5,969,156

Claim 1 of US 5,969,156 (appl. no. 945812) states: A crystalline Form I atorvastatin hydrate having an X-ray powder diffraction containing at least one of the following 2.theta. values measured using CuK.sub..alpha. radiation: 11.9 or 22.0.

The summary of the invention for the '156 patent states:

Accordingly, the present invention is directed to crystalline Form I atorvastatin and hydrates thereof characterized by the following X-ray powder diffraction pattern expressed in terms of the 2.theta., d-spacings, and relative intensities with a relative intensity of >20% measured after 2 minutes of grinding and measured on a Siemens D-500 diffractometer with CuK.sub..alpha. radiation:

(>20%) Ground
2.theta. d 2 Minutes
9.150 9.6565 42.60
9.470 9.3311 41.94
10.266 8.6098 55.67
10.560 8.3705 29.33
11.853 7.4601 41.74
12.195 7.2518 24.62
17.075 5.1887 60.12
19.485 4.5520 73.59
21.626 4.1059 100.00
21.960 4.0442 49.44
22.748 3.9059 45.85
23.335 3.8088 44.72
23.734 3.7457 63.04
24.438 3.6394 21.10
28.915 3.0853 23.42
29.234 3.0524 23.36

Thus, it is interesting to note that claim 1 is directed to x-ray diffraction lines that are not the most intense in the observed pattern. Further, the patent does not appear to index the observed lines to a Bravais lattice. Nevertheless, the USPTO has issued a notice of intent to issue a re-examination certificate.

The blog PatentBaristas reports on the re-examination.

Of Ranbaxy's patent litigation involving Lipitor (which involves different patents):

Ranbaxy is expected to argue that one of Pfizer's patents covers only a combination of two chemical components, but not the separate component that became Lipitor, or atorvastatin calcium.

A second patent covers the specific Lipitor molecule. Ranbaxy is expected to argue that it is too similar to the first patent and should not have been issued. But analysts said that seems like a circular argument in which one appears to cancel out the other.

Also expected to come up in the suit is a claim by Ranbaxy that Pfizer got an unfair patent extension from U.S. regulators to make up for time the drug was under review for approval.

Should Ranbaxy convince the judge to void the second patent and declare the extension on the first patent invalid, Lipitor's patent would then expire in mid-2006, about the same time that Merck & Co's Zocor goes off patent.

Ranbaxy is challenging the legitimacy of two U.S. patents Pfizer holds on Lipitor that protect the drug from cheap generic copycats through 2009 and 2011.

[from yahoofinance via Reuters]

***Update from Forbes-->

Pfizer said the [re-examined] patent is separate from two other patents challenged in court by Indian drug maker Ranbaxy Laboratories Ltd. The challenged patents expire in March 2010 and June 2011, respectively.

A.G. Edwards analyst Al Rauch confirmed in an interview that the crystalline patent, which has been unchallenged in court, is of little relevance to the challenged patents.

"I think Pfizer's just trying to make a statement that they have good intellectual property," Rauch said of the drug maker's announcement. "The other two patents are much stronger." A decision on the challenged U.S. patent is expected by the end of the year. Rauch speculated that at least one of the two U.S. Lipitor patents challenged by Ranbaxy will hold up.


In September 2004, the non-profit organization Public Patent Foundation requested that the PTO open up a review and revoke Pfizer's 1999-issued crystalline patent, claiming that the intellectual property covered had been anticipated by other inventors. Representatives of the Public Patent Foundation were not available for immediate comment.


Post a Comment

<< Home