Serono Laboratories Inc. could become the newest competitor in theU.S. for a share of the market for recombinant human growthhormone to treat growth insufficiency in children. The Norwell,Mass. company, a U.S. affiliate of Swiss-based Ares-Serono Group,received an approvable letter from the FDA last Friday for itsmammalian cell-derived growth hormone product Saizen.

This drug is identical to Serono's product Serostim, which itdeveloped to treat cachexia in AIDS patients. But while the FDA hasyet to decide whether it will approve the product for AIDS wasting(see BioWorld Today, March 5, 1996, p. 1), it has finally ruled forthe growth insufficiency indication.

Although the FDA has requested some additional information prior togranting full marketing approval for Saizen _ information whichSerono is now in the process of providing _ the agency had most ofits questions answered long ago on this product.

Serono submitted its new drug application (NDA) on Saizen in 1989;it was left hanging until Eli Lilly & Co.'s orphan drug exclusivity onHumatrope, its recombinant human growth hormone for treatinggrowth stature insufficiency, expired in March 1994. (So, too, werethe NDAs submitted by Bio-Technology General Corp. and NovoNordisk A/S on their human growth hormone products.) In theinterim, the FDA has taken all the other steps necessary for productapproval, including an inspection of Serono's facilities, according toGina Cella, director of corporate communications.

Worldwide, however, Serono already has established a strongpresence for its recombinant growth hormone, where it has been onthe market for about 10 years. Serono now sells Saizen for treatinggrowth deficiency in 60 countries and for treating Turner's syndromeas well in about 30 countries.

Novo Nordisk and Bio-Technology General received FDA approvalsof their products in May 1995, but were originally prevented fromselling them in the U.S. by a series of patent-infringement lawsuitsbrought by Genentech Inc. (All three products are made in bacteria,whereas Serono's is produced by mammalian cells and thus notsubject to the ongoing litigation.)

In February 1996, a U.S. Appeals Court for the Federal Circuit inWashington threw out a lower court's injunction preventing NovoNordisk, of Bagsvaerd, Denmark, from selling its productNorditropin in the U.S. pending resolution of the patent battle. ButBio-Technology General was not so lucky: In early April 1996, theAppeals Court upheld the lower court injunction, thus preventingBio-Technology General, of Iselin, N.J., from selling its product Bio-Tropin. (See BioWorld Today, April 10, 1996, p. 1 and Jan. 4, 1996,p. 1.)

Once approved, Saizen will have to force its way into a U.S. marketthat is thus still dominated by Genentech. The South San Franciscofirm controls about 75 percent of the market with two versions ofrecombinant human growth hormone, Protropin and Nutropin, as wellas a new liquid formulation called Nutropin AQ, which the FDAapproved in January 1996. Genentech reported total 1995 sales of$56 million for the products.

"As long as Serono doesn't significantly undercut Genentech [onproduct price]," Saizen won't make a dramatic impact in marketshare, said Mark Simon, a managing director at Robertson, Stephens& Co., in San Francisco. "The product may get a reasonable share ofnew patients [those who are not currently taking any growth hormonefor this indication], but those doctors who have already beenprescribing Genentech's products are very satisfied," Simon toldBioWorld Today. n

-- Jennifer Van Brunt Business Editor

(c) 1997 American Health Consultants. All rights reserved.