Washington Editor

Genentech Inc. got the green light to expand its growth hormone market, as the FDA approved Nutropin (somatropin [rDNA origin] for injection) and Nutropin AQ (somatropin [rDNA origin] injection) for the long-term treatment of idiopathic short stature (ISS).

The South San Francisco-based company received new clearances on the approved products following review of two supplemental new drug applications containing data from a long-term, open-label U.S. study of 122 children with ISS, as well as supporting safety data from the National Cooperative Growth Study. The condition, also called non-growth hormone-deficient short stature, is defined as height at least 2.25 standard deviations below the mean for age in childhood, and associated with growth rates unlikely to permit attainment of adult height in the normal range.

Officials at Genentech were not available for comment.

Both products have been on the market for quite some time: Nutropin, which has an amino acid sequence identical to naturally occurring growth hormone, was released in 1993, followed two years later by Nutropin AQ, a ready-to-use liquid growth hormone formulation. And before the latest FDA action, both already were indicated for a range of pediatric conditions, including growth failure due to growth hormone deficiency, growth failure associated with chronic renal insufficiency up to time of renal transplantation and short stature associated with Turner syndrome.

The newest indication is based on data showing that 70 percent of children reached near-adult height after receiving between two and 10 years of Nutropin treatment. The mean duration of therapy was 6.2 years for boys and 5.5 years for girls, and the mean difference between adult height and pre-treatment predicted height was two inches in boys and 2.4 inches in girls. Also among patients treated in the study, mean fasting and post-prandial insulin levels increased, while mean fasting and post-prandial glucose levels were unchanged. Mean hemoglobin A1c levels rose slightly from baseline as expected during adolescence, the company said, adding that sporadic values outside normal limits occurred transiently.

In a post-marketing surveillance evaluation called the National Cooperative Growth Study, the pattern of adverse events in more than 8,000 ISS patients was consistent with the known safety profile of growth hormone, and no new safety signals attributable to growth hormone were identified.

Soon after filing the supplemental NDAs in late 2003, Genentech estimated there to be about 1 million children in the U.S. with ISS. In the last fiscal year, the growth hormone products were among several the company labels "legacy products" that generated $731.3 million in sales, part of its more than $3.7 billion in total sales for the period ended Dec. 31. Genentech does not publicly break down individual sales totals for the growth hormone products.

The company s growth hormone franchise also includes Nutropin AQ Pen for use with the Nutropin AQ Pen Cartridge. Previously, a long-acting version also was on the market, Nutropin Depot, though a year ago Genentech and partner Alkermes Inc., of Cambridge, Mass., discontinued its commercialization because the drug's production was no longer cost-effective. (See BioWorld Today, June 3, 2004.)

On Thursday, Genentech shares (NYSE:DNA) gained $2.08 to close at $82.99.

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