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                                                                      EXHIBIT 21
                                     [LOGO]
NEWS RELEASE

                 CONTACT: David M. Rosen, Ph.D.
                          Vice President, Research and Development [Letterhead]
                          (408) 988-2500


                  CELTRIX RECEIVES TWO ADDITIONAL U.S. PATENTS

         SANTA CLARA, CA -- May 22, 1997 -- Celtrix Pharmaceuticals, Inc.
(Nasdaq: CTRX) announced today that it has received two additional patents from
the United States Patent and Trademark Office, further protecting its
proprietary technology relating to the production and use of SomatoKine(R), the
company's novel IGF-BP3 complex. SomatoKine is currently undergoing early-stage
Phase II human clinical testing.

         U.S. Patent No. 5,629,172, entitled "Expression of Fusion Polypeptides
Transported Out of the Cytoplasm Without Leader Sequences," relates to
recombinant protein production using fusion protein technology. The new patent,
which is related to U.S. Patent No. 5,563,046 issued to Celtrix last year,
claims compositions and methods involving fusion proteins which use variants of
the bacterial proteins DsbA and DsbC as fusion partners. The claimed
compositions and methods are generally applicable to the production of
recombinant proteins and may also be useful in the manufacture of SomatoKine.

         U.S. Patent No. 5,624,805, entitled "Uses for Antibodies Which Bind to 
Human Somatomedin Carrier Protein Subunits," was issued with claims relating to
the use of antibodies to an insulin-like growth factor (IGF) binding protein in
methods for determining levels of free (unbound) IGF.

         Celtrix is a biopharmaceutical company developing novel therapeutics
for the treatment of seriously debilitating, degenerative conditions primarily
associated with severe trauma, chronic diseases or aging. The company's focus is
on SomatoKine, a novel IGF-BP3 complex, for use in regenerating lost muscle,
bone and other tissues essential for the patient's health and quality of life.
Initial product development programs target acute traumatic injury, such as hip
fracture surgery in the elderly, and severe burns. Other potential indications
include severe osteoporosis and protein wasting diseases associated with cancer,
AIDS and other life-threatening conditions. 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 news 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 unforeseen interference
proceedings related to these new patents, ability of third parties to engineer
or develop processes or products around these patent claims, future company
research, clinical study results, 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 news release.

                                      -end-