Tadalafil - USA (CAFC)
Basic Information:
Appellant:
Icos Corporation
Appelle:
Actelion
Pharmaceuticals Ltd
Court:
The United States Court of Appeals for the Federal Circuit
Earlier
Court: The United States Patent and Trademark Office, Patent
Trial and Appeal Board. (The PTAB of USPTO)
Petition
Number: IPR2015-00561 and IPR2015-00562
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Determination
of the United States Patent and Trademark Office, Patent Trial and Appeal Board
(The PTAB): Claims 1 to 32 of US7182958 and claims 1
to 11 of US6821975 would have been obvious over PCT Application WO1997003675
(“Daugan”), PCT Application WO1996038131 (“Butler”), US4721709 (“Seth”), and
Wadke, et al., Preformulation Testing, in Pharmaceutical Dosage Forms (Herbert
A. Lieberman, et al., eds., 1989) (“Wadke”).
Prior
Arts:
Daugan
discloses a compound having the structural formula depicted in the claims,
i.e., tadalafil, and the excipients included in claim 1 of the ’958 patent.
Butler
discloses that tadalafil is poorly water soluble and teaches a process of
preparing a solid dispersion of tadalafil and a pharmaceutically acceptable
carrier or excipient.
Seth
discloses that when poorly soluble hydrophobic drugs are used in solid dosage
forms, their rate of dissolution is often slow, and a “frequently used method
to overcome such problems is to finely grind or ‘micronize’ drug substances to
reduce their particle-size.”
Wadke
discloses that “it is now generally recognized that poorly soluble drugs
showing a dissolution-rate-limiting step in the absorption process will be more
readily bioavailable when administered in a finely subdivided state than as
coarse material,” and “grinding should reduce coarse material to, preferably,
the 10- to 40 micron range.”
US’958:
- Independent Claim 1 of US’958: A pharmaceutical formulation comprising an active compound having the structural formula: (Structure of Tadalafil) wherein said compound is provided as free drug comprising particles wherein at least 90% of the particles of the said compound have a particle size of less than about 40 microns; about 50% to about 85%, by weight, of a water-soluble diluent; a lubricant; a hydrophilic binder selected from the group consisting of a cellulose derivative, povidone, and a mixture thereof; and a disintegrant selected from the group consisting of croscarmellose sodium, crospovidone, and a mixture thereof.
- Actelion filed IPR2015-00561, alleged claims 1 to 32 of the US’958 patent would have been obvious over the combination of Daugan, Butler, Seth, and the common pharmaceutical knowledge reflected in Wadke and two other references.
- The PTAB instituted IPR of all claims.
- The PTAB’s consideration: The Board found a motivation to combine Butler’s teaching that Tadalafil has poor solubility with Seth’s teaching that compounds with low solubility generally also have a slow dissolution rate, and with Seth and Wadke’s teachings that reducing particle size through micronization can increase dissolution rate. It found ICOS had not shown that a preformulation analysis would have deterred an ordinarily skilled artisan from pursuing micronization. It found that, while Seth recognizes disadvantages to micronization, those disadvantages would not have stopped ordinarily skilled artisans from using the technique. It found there was a reasonable expectation of success in combining the teachings of these references, and rejected ICOS’ claim of unexpected results. It found Daugan teaches the specific required excipients in claim 1 in a limited number of examples.
US’975:
- Independent Claim 1 of US’975: A free drug particulate form of a compound having a formula: (Structure of Tadalafil) or pharmaceutically acceptable salts and solvates thereof, comprising particles of the compound wherein at least 90% of the particles have a particle size of less than about 40 microns.
- Actelion filed IPR2015-00562, alleged claims 1 to 11 of the US’975 patent would have been obvious over Daugan, Butler, Seth, and Wadke, and additionally in view of US4344934.
- The PTAB instituted IPR of all claims.
- The PTAB’s consideration: The Board found Daugan, Butler, Seth, and Wadke disclose every limitation of the challenged claims. It found the general knowledge that Tadalafil is poorly water soluble would have motivated an ordinarily skilled artisan to micronize it to improve its absorption and an ordinarily skilled artisan would have had a reasonable expectation of success in doing so. It found Daugan, Butler, Seth, and Wadke do not teach away from micronization.
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ICOS’s
Appeals to the Court of Appeal for the Federal Circuit: Icos’s
appealed the decision given by the Patent Trial and Appeal Board of USPTO based
on following arguments:
- The Board improperly substituted its own obviousness arguments for those in the petition and improperly shifted the burden to ICOS to show non-obviousness.
- References do not provide a motivation to combine or a reasonable likelihood of success.
The
Court of Appeal of Federal Circuit’s Determination:
- The Court of Appeal of Federal Circuit determined that the Patent Trial and Appeal Board of USPTO (The PTAB) properly found obviousness and also affirmed that references provide reasonable likelihood of success.
- The Court of Appeal for the Federal Circuit (CAFC) affirmed the decision of the Patent Trial and Appeal Board of USPTO.
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