Press Releases

June 27, 2006

Takeda Pharmaceutical Company Limited

PALO ALTO, Calif., and OSAKA, Japan (June 27 2006), - Affymax, Inc. (Affymax) and Takeda Pharmaceutical Company Limited (Takeda) today announced that the companies have entered into an exclusive global agreement to develop and commercialize Affymax's lead product candidate, Hematide™, for the treatment of anemia. The companies will collaborate on the development of the product and co-commercialize Hematidetrade; in the United States while Takeda will hold an exclusive license to develop and commercialize outside the United States, including the right for Japan under the previous agreement announced in February 2006.

Under the terms of the agreement, Affymax will receive US$105 million in an upfront cash payment. In addition, Affymax is eligible to receive development and regulatory milestone payments of up to US$280 million, and commercial milestone payments upon successful commercialization of Hematide of up to US$150 million, for total potential milestone payments of US$430 million. Takeda and Affymax will be jointly responsible for Hematide U.S. development costs with the vast majority of these costs to be the responsibility of Takeda. Outside of the U.S., Takeda also will be responsible for all of the development costs for regulatory approvals and will pay Affymax royalties on sales. Affymax is responsible for the manufacture and supply of drug substance to Takeda, and Takeda is responsible for the final packaging and distribution of Hematide globally.

Hematide, a synthetic, peptide-based erythropoiesis-stimulating agent (ESA), is designed to stimulate the production of red blood cells and is in Phase 2b clinical trials for anemia in dialysis, pre-dialysis and cancer chemotherapy patients. ESAs currently address a US$12 billion market worldwide and have been used successfully to manage anemia in patients with chronic kidney disease (CKD) and cancer-related anemia. They reduce the need for blood transfusions and the frequency and severity of anemia_associated morbidity, resulting in an improved quality of life for patients.

"Takeda is an ideal global partner because they have the development experience, global commercial capabilities, and financial resources to assist us in our efforts to bring Hematide to market worldwide. Moreover, they have significantly grown their business in the U.S.," said Arlene M. Morris, Affymax's president and chief executive officer. "Takeda has already shown their commitment to Hematide with the rapid filing of an investigational new drug application in Japan and we believe will bring a similar dedication to the development of Hematide globally. We are extremely pleased with this collaboration which we believe will facilitate our efforts to build a fully integrated biopharmaceutical business."

"The opportunity to fully-commercialize Hematide is highly compatible with Takeda's strategy to grow our core therapeutic franchises in cardiovascular disease and diabetes, and oncology," said Yasuchika Hasegawa, Takeda's president. "Many patients with cardiovascular diseases and diabetes suffer from CKD as their underlying disease progresses. Also, Hematide helps address an important need in patients with cancer where anemia is commonly seen in association with chemotherapy or cancer itself. We are very pleased to be able to expand our collaboration with Affymax on such a strategically important product to the worldwide market. We believe that this single-partner collaboration will increase the efficiency of development and accelerate Hematide's commercialization globally."

About Affymax

Affymax, Inc. is a privately-held, clinical-stage pharmaceutical company that is developing a pipeline of synthetic peptide-based drugs against clinically validated targets for the treatment of kidney diseases and cancer. Hematide™, the company's first product candidate to enter the clinic, is a novel peptide-based drug designed to stimulate the production of red blood cells. It is in Phase 2 trials for the treatment of anemia associated with chronic kidney disease and cancer. For more information go to www.affymax.com.