LILLY's HUMATROPE DIFFERS FROM PITUITARY hGH FOR PURPOSES OF ORPHAN DRUG ACT: D.C. COURT DENIES GENENTECH MOTION AGAINST HUMATROPE EXCLUSIVITY

Lilly's Humatrope and pituitary-derived human growth hormone are different products, District of Columbia Federal Court Judge Stanley Harris concluded in a Sept. 18 order. The ruling denies Genentech's motion for partial summary judgment against FDA's orphan drug designation for Humatrope. Genentech and intervenor-plaintiff Nordisk argued against orphan status for Humatrope on grounds that Humatrope is identical to the pituitary-derived human growth hormone (hGH) products approved in the 1970s. However, the court ruled: "Assuming, without deciding, that movants' construction of [the Orphan Drug Act] is correct, the court rejects their argument in this case because it is plain that Humatrope and pituitary-derived hGH are not the same drug for the purposes of [the Act]." Genentech and Nordisk had contended that under the Orphan Drug Act and FDA regulations, orphan drug designation must be granted prior to NDA approval. The firms maintained that Humatrope was not entitled to orphan drug status (and the seven years of marketing exclusivity accompanying that status) because NDAs for pituitary-derived hGH were held by KabiVitrum and Serono prior to the approval of Humatrope in October 1986. Pituitary-derived hGH is chemically identical to Humatrope. KabiVitrum and Serono still hold valid NDAs, for hGH; however, the firms voluntarily withdrew their products from the market in 1985 when three patients treated with government-produced hGH developed Creutzfeldt-Jakob Disease. Judge Harris emphasized that his ruling that genetically engineered hGH is a different drug than naturally occurring hGH "is narrow and confined to the particular facts of this case." Harris indirectly urged FDA to expedite its effort to set a definition that allows for distinctions between "different" orphan drug candidates. The court, Harris said, "sets down no universal rule for determining whether two drugs are 'different' for the purposes of the Orphan Drug Act. That responsibility is statutorily imposed on the FDA [and] until the FDA endeavors to meet that obligation, the courts will be forced to make case-by-case determinations based on the broad policies embodied in the Act." Harris noted that because neither FDA regulations nor the Orphan Drug Act specifically address the definition of 'drug,' the court, in ruling on Humatrope's orphan drug status, was "left to apply the Act's broad policy objectives to the unique situation at hand." The ruling finds two reasons, based on Congressional intent, for considering Humatrope and pituitary-derived hGH different drugs for purposes of the Orphan Drug Act: (1) Humatrope, a recombinant-produced product, is safer because it does not present the danger of Creutzfeldt-Jakob Disease associated with pituitary-derived hGH; and (2) pituitary-derived hGH is no longer marketed. In enacting the Orphan Drug Act, the ruling states, "Congress clearly focused on the availability of treatments, not the existence of prior NDAs." The court's ruling does not address whether or not the approval of Humatrope violated Genentech's exclusivity for Protropin. Genentech had originally argued that Humatrope should not have been approved because of Protropin exclusivity. Subsequent court filings, however, acknowledged that the company was most concerned with getting its methionyl-free hGH (Protropin II) on the market and argued against exclusivity for Humatrope. Protropin contains an extra methionyl group not present in Humatrope or in pituitary-derived hGH. Genentech, Nordisk, and Serono, an intervenor-defendant in Genentech's suit against HHS, all have NDAs pending for recombinant-produced hGH products identical in chemical structure to pituitary-derived hGH. Protropin II, Nordisk's Norditropin, and Humatrope are produced in E. coli, while Serono's Saizen is produced in a mammalian cell line. Serono, which became involved in the suit as an intervenor-defendant because of Genentech's original argument that Protropin exclusivity should prevent approval of other hGH products, has argued that its product is different from Humatrope because of the manufacturing process used to produce the drug and, therefore, should not be affected by Humatrope exclusivity ("The Pink Sheet" March 30, p. 5).