In Tyco Healthcare Group LP v. Mutual Pharmaceutical Co., Inc., the Federal Circuit affirmed the district court's finding that product claims reciting a specific dose of temazepam were obvious in view of an entry in a medical reference book. Although Tyco tried to overcome the disclosure with evidence of unexpected results and commercial success, its arguments were unavailing.
The Patent At Issue
The patent at issue, U.S. 5,211,954, is directed to "Low Dose Temazepam." The patent has a 1986 priority date (through a series of continuation and divisional applications) and was issued in 1993 with two claims:
- A hard gelatin capsule containing a temazepam formulation consisting essentially of 6 to 8 milligrams of crystalline temazepam having a surface area of from 0.65 to 1.1 m2 /g and 95% of the temazepam having a particle size of less than 65 microns in admixture with a pharmaceutically acceptable carrier therefor.
- A hard gelatin capsule containing a temazepam formulation consisting essentially of 7.5 milligrams of crystalline temazepam having a surface area of from 0.65 to 1.1 m2 /g and 95% of the temazepam having a particle size of less than 65 microns in admixture with a pharmaceutically acceptable carrier therefor.
The Prior Art
Temazepam has been used to treat insomnia since the 1970's, and has been marketed in the U.S. as Restoril® since 1981. Restoril® was available in 15 mg and 30 mg dosage forms long before the '954 patent was filed.
The 1983 edition of the British National Formulary (BNF) contained the following entry for temazepam:
Indications: insomnia (useful in the elderly)
Cautions; Side-effects: see under Nitrazepam, but except at high dosage hangover is uncommon and doses less cumulative. Less appropriate in patients with early wakening
Dose: 10-30 mg (elderly patients 5-15 mg), increasing in severe insomnia to 60 mg, 30 minutes before bedtime
The ANDA Litigation
Mutual filed an Abbreviated New Drug Application (ANDA) for a 7.5 mg temazepam product in November 2006, and Tyco responded with an infringement action. After Mutual's ANDA received tentative FDA approval in 2009, Tyco sought a preliminary injunction to keep Mutual's product off the market. That motion was denied on non-infringement grounds, because the Mutual product did not satisfy the surface area requirements of the patent claims. Mutual then moved for summary judgment of non-infringement and invalidity.
The district court found clear and convincing evidence that the patent was invalid as obvious, based on the previous marketing of 15 mg and 30 mg dosage forms, the BNF entry, and the general principle that "physicians always seeks to prescribe the lowest effective dose of any medication."
The Federal Circuit Decision
The Federal Circuit noted that "[t]he only physical feature distinguishing the '954 claims from the Restoril® 15 mg capsules is the amount of temazepam contained in the capsule." The court noted that, on its face, the BNF entry discloses a range (5 to 15 mg) that encompassed the claimed amount of 7.5 mg. The Federal Circuit cited the general rule that, "where there is a range disclosed in the prior art, and the claimed invention falls within that range, there is a presumption of obviousness," but noted that this presumption is rebuttable by
- a showing that the prior art taught away from the invention or
- a showing of new and unexpected results relative to the prior art
Tyco presented arguments on these points, but they were not successful.
The Federal Circuit rejected Tyco's arguments that the BNF entry did not give rise to a prima facie case of obviousness of the 7.5 mg dosage form. The court considered Tyco's argument that "5-15 mg" did not disclose all dosages between 5 and 15 mg, but characterized that argument as "silly."
(Ouch! At least they said it in footnote #3)
The Federal Circuit considered Tyco's argument that the efficacy of temazepam at 7.5 mg saved the claims from being obvious, because the BNF entry did not provide any data supporting efficacy at that dose. The court rejected that argument based on the BNF entry itself:
The recommendation in the BNF of a range of temazepam dosages that include the dosages claimed in the ’954 patent renders obvious the claims to those dosages even in the absence of documentation in the BNF of the effectiveness of such dosages.
The Federal Circuit emphasized the fact that product claims, not method claims, were at issue:
[A]s already discussed, the ’954 claims are not tied to product efficacy, so the absence of any particularized discussion of efficacy in the BNF reference is immaterial to obviousness . . . .
The Federal Circuit also considered and rejected Tyco's arguments based on unexpected results. The court stated that the "[u]nsupported statements" in the patent specification that the reported results were "unexpected" did not support a finding of non-obviousness, and agreed with the district court that Tyco's other evidence on point was not persuasive.
The Federal Circuit noted that the district court had accepted the commercial success of the 7.5 mg dosage form, which has had average annual sales of more than $30 million, but agreed with the district court that the product's commercial success "did not overcome Mutual's strong prima facie case of obviousness."
The Challenge of Product Claims
This case highlights the difficulties that can be encountered with product claims relating to a known drug. In particular, when the point of novelty relates to the dosage amount only (and not, for example, a new formulation), it may be more difficult to sustain arguments relating to the enabling quality of the prior art. As shown here, a minimal disclosure of a range encompassing the claimed dosage can be sufficient to render product claims obvious. (Tyco does have a parallel method patent, U.S. 5,030,632, which was not at issue in this case.)
Practitioners may want to read the Federal Circuit opinion for the portions that I did not discuss. In addition to footnote #3, the opinion includes several remarks that, taken as a whole, imply that, because of several apparent inaccuracies and inconsistencies in Tyco's arguments, the court did not trust Tyco's representation of the facts and evidence.