McNEIL's HALDOL (HALOPERIDOL DECANOATE) FIVE-YEAR EXCLUSIVITY

McNEIL's HALDOL (HALOPERIDOL DECANOATE) FIVE-YEAR EXCLUSIVITY is not warranted because the product is not a new chemical entity, Quad Pharmaceuticals maintains in Dec. 29, 1987 comments to FDA. "The five year marketing exclusivity provisions were intended to be limited to truly new chemical entities in which the inventor of the entity was essentially starting from scratch in establishing the safety and effectiveness of the new entity. This was clearly not the case with respect to haloperidol decanoate," Quad contended.

The Par subsidiary asserts that Haldol decanoate does not qualify as a new chemical entity because "McNeil knew (1) that haloperidol was a safe and effective antipsychotic; and (2) that haloperidol decanoate would be converted in the body to haloperidol."

In the comments to FDA, Quad said it agreed with the agency's interpretation of the Waxman/Hatch exclusivity provisions, granting McNeil three years of marketing exclusivity for the long-acting haloperidol. The parenteral form of haloperidol for chronic schizophrenia was approved on Jan. 14, 1986, four months prior to the expiration of McNeil's patent for the daily oral dosage form of haloperidol "The Pink Sheet" Jan. 27, 1986, T&G-3). The three-year exclusivity for Haldol decanoate expires Jan. 14, 1989.

Quad's comments were in response to McNeil's Oct. 6, 1987 petition seeking extended exclusivity for Haldol. Quad asserted that McNeil "incorrectly attempts to equate the issues as to whether a new drug is entitled . . . to ANDA suitability with the issue as to whether . . . a new drug is a 'new chemical entity' entitled to five years marketing exclusivity."

Quad noted that changes in the active ingredient of a single entity drug, "whether 'trivial' or significant, may be sufficient grounds to deny an ANDA suitability petition but it is not sufficient grounds for recognizing entitlement to five years marketing exclusivity in the absence of a showing that the modification results in a new chemical entity."

McNeil maintained in its petition to FDA that "the discovery of haloperidol decanoate was an innovative advance [and] the Patent and Trademark Office confirmed this by granting a product patent." Haloperidol decanoate is a "unique chemical entity", McNeil argued. "It is the decanoate ester of haloperidol . . . Haloperidol, however, is not the same active ingredient as haloperidol decanoate, nor is haloperidol a salt or ester of haloperidol decanoate."

McNeil pointed out that haloperidol decanoate "is hydrolyzed in vivo to haloperidol which may account wholly or in part for its efficacy. However, from the standpoint of the Act, the in vivo active agent is irrelevant. Only the active ingredient which is in the final dosage form has relevancy." FDA classified haloperidol decanoate as a 2 C drug, a new salt with little or no therapeutic gain.