Co-Development and Co-Marketing Agreement Secured for the Antiresorptive Bisphosphonate R484

September 12, 2006 (Tokyo) - Chugai Pharmaceutical Co., Ltd. ("Chugai") [Head Office: Chuo-ku, Tokyo; President: Osamu Nagayama] announced today that it has entered into an agreement with Taisho Pharmaceutical Co., Ltd. ("Taisho") [Head Office: Toshima-ku, Tokyo; President: Akira Uehara] to co-develop and co-market R484 [generic name: ibandronic acid], a bisphosphonate which Chugai is currently developing in Japan for the treatment of osteoporosis.  Under the agreement, Chugai will co-develop the compound with Taisho and co-market it with Taisho Toyama Pharmaceutical Co., Ltd.[Head Office: Toshima-ku, Tokyo; President: Akira Ohira], a subsidiary of Taisho.  Chugai will receive an upfront fee and milestone payments from Taisho.

R484, a bisphosphonate compound owned by Roche, demonstrates a strong inhibitory effect on bone resorption.  A less frequent dosing and administration has been developed (for oral and injection) to improve convenience and compliance by reducing complicated restrictions when administering the medicine and to reduce  the adverse reactions often seen in oral bisphosphonate preparations, mainly reactions related to the gastrointestinal track.  In Japan, a phase II clinical trial is ongoing for the oral formulation and a phase II clinical trail has been completed for the injectable formulation.

Since there are an estimated 12 million osteoporosis patients in Japan, it is becoming increasingly important to develop a drug which increases bone mass and reduces the risk of bone fractures, while being easy to administer.  R484 is expected to become a next generation osteoporosis treatment that improves compliance by decreasing the problems associated with the conventional bisphosphonates, and offers patients more choice of administration routes.

Chugai and Taisho are determined to provide patients with access to this new osteoporosis treatment as early as possible, and believe the joint effort to develop R484 will accelerate the process.

Notes to editor
Overseas, Roche and their co-development partner, GSK, markets the product under the brand name Bonviva (Boniva in US) as a once-monthly oral formulation and a once-every-three-months injection formulation for the treatment of osteoporosis in post menopausal women.