WASHINGTON _ Immunex Corp. on Monday said theFDA has approved one of two new indications it hadsought to expand the use of Leukine (sargramostim) tomore leukemia patients. Also, an FDA advisory panelrecommended approval of the first treatment foramyotrophic lateral sclerosis (ALS).

Immunex, of Seattle, said the FDA's approval, whichcame late Friday, of the additional indication for Leukinewill make the drug available to 6,400 patients diagnosedannually with acute myelogenous leukemia (AML).

Immunex's stock (NASDAQ:IMNX) was up 75 centsMonday, closing at $14.75 per share.

Still pending before the FDA is the company's request toexpand the labeling to include allogeneic bone marrowtransplants and the more controversial request to broadenthe labeling for most chemotherapy regimens.

Leukine, a yeast-derived growth factor has been on themarket since 1991 for use following autologous bonemarrow transplantation and engraftment delay.

"This is the first growth factor approved for AML," saidValoree Dowell, vice president for corporatecommunications at Immunex. "While there was someconcern that a growth factor would cause leukemicregrowth our data show that Leukine is safe andeffective," said Dowell.

One analyst expects that FDA's decision to permitImmunex to expand the labeling will enhance sales andperhaps sharply increase off-label use. "Immunex cannow claim that Leukine reduces deaths and seriousinfections. That is a powerful claim which may convincephysicians to view Leukine in a more favorable light andperhaps increase off-label use," said Andrew Heyward, ananalyst with Ragen MacKenzie, of Seattle.

Leukine Phase III clinical trials showed that the drugdecreased mortality in AML patients and delayed theonset of life-threatening infections. The study involved 99AML patients between the ages of 55 and 70 who had notreceived either radiation or chemotherapy. While patientsreceiving Leukine experienced a 52 percent infection rate,patients receiving a placebo had a 74 percent incidence ofinfection, according to Immunex.

FDA's action puts Immunex on a more solid footing tocompete with Amgen Inc.'s Neupogen, which dominatesthe growth factor market. Amgen, based in ThousandOaks, Calif., earned more than $600 million in 1994 fromsales of Neupogen.

FDA's Biological Response Modifiers AdvisoryCommittee in April recommended approval of thecompany's petition to expand Leukine's labeling forinduction chemotherapy in AML, the most common formof acute leukemia. (See BioWorld Today, April 12, 1995,p. 1.)

However, the panel withheld its recommendation in favorof the broader indications when FDA officials presenteddata showing significantly higher adverse eventsassociated with Leukine.

Immunex's cash position has improved recently. Cashpayments from New York-based American HomeProducts Corp., which holds a majority interest inImmunex, will total nearly $150 million over the nextthree years and have put the company in a positiveposition, said Heyward.

Immunex's next possibility for a profitable drug isPixykine, a fused protein for myelosuppression inducedby chemotherapy or radiation treatment now in Phase IIIclinical trials.

Committee Gives Rilutek A Thumbs Up

In other FDA news Monday, the agency's Peripheral andCentral Nervous System Drugs Advisory Committeerecommended approval of Rilutek (riluzole), a syntheticdrug for treatment of ALS, or Lou Gehrig's disease.

Currently there is no treatment for ALS, a fatalneurodegenerative disease affecting approximately30,000 people in the U.S. The disease attacks the nervecells in the brain and spinal cord, resulting in paralysisand respiratory failure.

Frank Baldino, president and CEO of Cephalon Inc.,which is in the final stages of testing a biotech ALStherapeutic, said the panel's action bodes well for hiscompany. Baldino, who attended the Monday advisorycommittee meeting, said the panel "voted approval in theface of a weak package. Several times the panel chairnoted that Rilutek has no definitive effect and thatperhaps the placebo group did better. From ourperspective it seems that the panel was ready to approvethe drug even though its efficacy is in question."

Baldino said West Chester, Pa.-based Cephalon is now"racing" to file its new drug application for Myotrophin, aneuronal growth factor, "because the data are compellingthat the drug alters the progression of the disease andoffers a better quality of life. It is clearly superior toRilutek," Baldino told BioWorld Today. n

-- Michele L. Robinson Washington Editor

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