Celtrix Reports Phase I Clinical Study Findings On SomatoKine, Its Novel IGF-BP3 Complex; Safe administration of IGF-I observed at high dosage levels.

SAN FRANCISCO--(BUSINESS WIRE)--June 12, 1996--Data emerging from a Phase I human clinical study indicate that SomatoKine(R) allows the safe administration of IGF-I at doses many times higher than have ever been possible before, Celtrix Pharmaceuticals, Inc. (Nasdaq: CTRX) announced today. SomatoKine is the recombinant equivalent of the natural complex formed by insulin-like growth factor-I (IGF-I) and its major binding protein (BP3).

In this first study in humans, SomatoKine (IGF-BP3) was administered as single intravenous doses to 12 healthy men and women. Four escalating dosage levels were tested. The lowest dosage level provided a substantially higher amount of IGF-I than others have been able to safely administer using free (unbound) IGF-I in clinical testing, and subsequent dosage levels were many times higher. The first three dosage levels were safe and well tolerated, and minor, reversible side effects were observed at the highest dosage. Specific details, including pharmacokinetic data, await final analysis and presentation to the scientific community.

"These positive safety findings could have a significant impact on the therapeutic potential of IGF-I," said Andreas Sommer, Ph.D., Celtrix's president and chief executive officer. "Researchers throughout the world have long sought to use IGF-I for the treatment of a wide range of medical conditions because it is a key anabolic hormone that plays a major role in diverse biological processes, including tissue repair, organ function, and muscle and bone formation. However, the use of IGF-I without its major binding protein, BP3, is hampered by dose-limiting acute side effects and limited and transient efficacy. Furthermore, preclinical studies conducted by Celtrix and others have shown that the best IGF-I efficacies are obtained at doses that are substantially higher than what can be safely administered without the BP3 binding protein."

"Most naturally occurring IGF-I circulates in the body complexed with BP3, and this association appears to be vital," Dr. Sommer said. "The SomatoKine complex of IGF-I and BP3 is designed to be consistent with what is observed in nature. In preclinical studies, this approach was shown to overcome known dose-limiting, acute side effects observed upon administration of free IGF-I. We are highly encouraged that this observation has been repeated in initial human studies. The ability to safely deliver high doses of IGF-I by means of SomatoKine should allow significantly expanded dosing regimens for enhanced therapeutic efficacy."

A multiple-dose Phase I human clinical study of SomatoKine is expected to begin in July with up to 24 healthy men and women. This second study's objectives are to evaluate the safety and metabolic effects of a range of dosage levels, administered daily for six days. Information from this study will guide Phase II efficacy studies planned for later this fiscal year. The company's near-term treatment target is hormone replacement therapy for critically ill patients, such as those undergoing major surgery, organ damage/failure and traumatic injury.

Celtrix is a biopharmaceutical company developing novel therapeutics for seriously debilitating, degenerative conditions primarily associated with severe trauma, chronic diseases or aging. Company programs are focused on the use of SomatoKine, a novel IGF-BP3 complex, to treat destructive metabolic processes (catabolism) in acute indications such as major surgery, organ damage/failure and traumatic injury. Potential chronic indications could include osteoporosis, chronic renal (kidney) failure, and wasting conditions associated with cancer and AIDS. Through strategic alliances with Celtrix, The Green Cross Corporation is developing SomatoKine for the treatment of osteoporosis in Japan, and Genzyme Corporation is developing TGF-beta-2 as part of a comprehensive approach to tissue repair and the treatment of systemic disease.

This press release contains certain forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended. Actual results may differ materially from the statements made, as a result of various factors, including risks associated with future company research, the regulatory approval process, competitive products and other factors which are listed from time to time in Celtrix's Securities and Exchange Commission (SEC) filings. These forward-looking statements represent Celtrix's judgment as of the date of this release.

CONTACT: Celtrix Pharmaceuticals, Inc.

Mary Anne Ribi, 408/988-2500