GEMA/ZENITH’s CEFADROXIL DC DOES NOT INFRINGE DURICEF

GEMA/ZENITH's CEFADROXIL DC DOES NOT INFRINGE DURICEF from Bristol-Myers Squibb, Newark, N.J. Federal Court Judge Alfred Wolin ruled Feb. 21 in a case brought by Zenith Labs (Northvale, N.J.). Wolin's ruling could pave the way for a future return into the U.S. market of generic versions of the antibiotic, which have not been available since March 1990. Zenith is negotiating with Gema, a Spanish subsidiary of Sandoz, to supply the bulk product. Gema withdrew from its supply agreement with Zenith in September; the generic marketer hopes that the favorable patent ruling will provide a basis for Gema to reconsider. Bristol-Myers Squibb filed suit against Gema parent Sandoz in Baltimore federal court in June 1991, charging that Gema's cefadroxil DC infringed Bristol-Myers Squibb's patent 4,504,657 for Duricef. Zenith countersued in Newark federal court on Aug. 6. After Gema backed out of the supply agreement with Zenith, the initial BMS suit was settled with a stipulated order of dismissal on Oct. 25. Bristol then filed a motion to have Zenith's suit thrown out as irrelevant on the grounds that the generic firm had no supplier. That motion was denied on Dec. 12 by Judge Wolin. The patent decision leaves Zenith at least two steps from marketing a generic cefadroxil. The company must complete a deal with Gema for supply of the product, and it must obtain approval of a pending ANDA supplement citing Gema as the raw material supplier. In addition, BMS may appeal the ruling once an order is entered with the court. Bristol said it is considering its legal options. Duricef has not been available as a generic for nearly two years after Zenith and Biocraft settled a patent infringement suit for a different cefadroxil formulation with BMS by agreeing to pay over $17 mil. combined ("The Pink Sheet" April 2, 1990, T&G-13). A third generic cefadroxil marketer, Purepac, went to court against BMS and lost. Zenith's approved ANDA cited the Italian firm Dobfar Industria Chimica Farmaceutica as its supplier. Gema was a supplier for the other generic versions. BMS also had pursued the infringement case before the International Trade Commission. Zenith has been anticipating approval of its ANDA supplement for the new cefadroxil formulation since last summer. The firm said FDA is completing a preapproval inspection of its St. Croix, Virgin Islands facility. The Feb. 21 ruling states that "FDA has found that" Zenith's cefadroxil and Bristol-Myers Squibb's brandname product "are bioavailable and bioequivalent." Separately, Zenith said an April hearing date has been scheduled to discuss the preliminary injunction request filed in November by FDA's Newark district office seeking to shut down the company's Northvale facility for good manufacturing practices violations ("The Pink Sheet" Nov. 25, p. 7). Zenith said it is in discussions with the district office to resolve outstanding issues. Wolin ruled that Bristol had failed to raise a "triable issue" in the case, hence providing grounds for a summary judgment in Zenith's favor. Bristol claimed that Zenith/Gema's new cefadroxil, cefadroxil DC, converts into the Bristol product, known as the Bouzard monohydrate, in the stomach. Bristol submitted expert declarations and experimental evidence that cefadroxil DC converts to the Bouzard monohydrate when mixed with water. While Zenith did not contest the studies, the firm did offer "evidence, unrebutted by Bristol, that the conditions in the human stomach are so unlike the conditions present in the...studies, that those studies shed insufficient light on the conversion question to raise a genuine issue," Wolin's decision notes. In a Jan. 27 brief, Bristol argued that the Bouzard monohydrate "is the only form of cefadroxil stable enough to be absorbed slowly enough so that the person ingesting it does not develop colitis." Bristol-Myers Squibb "reasons that because of cefadroxil DC's higher dissolution rate, if it did not convert into the Bouzard monohydrate in the capsule, it could not be absorbed slowly enough to be bioavailable or bioequivalent," the ruling states. "Although this theory may have some appeal were it supported by anything more than argument of counsel," Wolin said, "because of its late provenance and lack of support by way of declaration or evidence other than the generalized medical literature offered by Bristol at oral argument without prior notice to Zenith, the Court finds that it is not entitled to any serious consideration."