Hana Biosciences, Inc. Initiates Phase I/II Clinical Trial of Talotrexin -PT-523- in Patients with Acute Lymphoblastic Leukemia.

SOUTH SAN FRANCISCO, Calif. -- Hana Biosciences, Inc. (OTCBB: HNAB), a South-San Francisco based biopharmaceutical company focused on advancing cancer care, announced the initiation of a Phase I/II clinical study of talotrexin (PT-523) as a single agent in adult patients with relapsed or refractory acute lymphoblastic leukemia (ALL).

The phase I portion of this multi-center study will determine the dose, safety, tolerability and pharmacokinetics of talotrexin in refractory leukemia patients, including both myeloid and lymphoid leukemias (AML, ALL, blast-phase CML, high-risk MDS). The Phase II component will focus on relapsed or refractory ALL patients to determine the efficacy of talotrexin, as measured by complete response rate.

"Currently, there are no drugs specifically approved for adults with relapsed/refractory ALL. As such, ongoing efforts are needed to investigate agents in these patients for whom current therapy is inadequate, as well as to incorporate active agents, , into frontline therapy," states Francis Giles, MD, Professor of Medicine and Chairman, Section of Developmental Therapeutics,at the UT M.D. Anderson Cancer Center, who is Principle Investigator of the study.

Talotrexin is also currently completing a Phase I trial in patients with advanced solid tumors. This trial is being conducted at the Dana-Farber Cancer Institute, Massachusetts General Hospital, and Beth Israel-Deaconess hospital. In addition, Hana has initiated a multi-center phase I/II study in Non-Small Cell Lung Cancer, and is also planning a trial in cervical cancer with the National Cancer Institute's Gynecologic Oncology Group (GOG).

"This trial represents an important milestone for accelerating the clinical development of talotrexin," said Greg Berk, MD, Chief Medical Officer and Vice-President of Hana Biosciences. "Antifolates have recognized activity in lymphoid malignancies but have been limited by emerging drug resistance. We believe talotrexin may be less susceptible to these mechanisms of resistance. There is currently no effective therapy or approved standard of care for ALL. Talotrexin has a strong pre-clinical basis of activity in this indication and has potential to enhance ALL treatment."

About Talotrexin (PT-523)

Talotrexin is a anticancer agent that enters cells more efficiently, works through an established and proven mechanism of action, overcomes resistance typically associated with this class of therapies, and selectively binds to the key target enzyme. Talotrexin is a novel, non-classical antifolate that is a water-soluble, non-polyglutamatable analogue of aminopterin. Potential advantages of Talotrexin include increased targeting to tumor cells, better tolerability and a superior resistance profile over existing therapies. Talotrexin is 10-fold more efficiently transported by the membrane-bound transporter RFC into cells, 10-fold more tightly bound to the target enzyme, dihydrofolate reductase (DHFR), and 10 to 100-fold more efficacious in a wide variety of tumor cell lines and animal models compared to methotrexate (MTX). Talotrexin has also demonstrated efficacy in MTX resistant tumor models.

About Acute Lymphoblastic Leukemia (ALL)

Acute lymphocytic leukemia (ALL) is a type of cancer of the blood and bone marrow -- the spongy tissue inside bones where blood cells are made. It's called acute leukemia because it progresses rapidly and affects immature blood cells, rather than mature ones. It's called lymphocytic leukemia because it affects a group of white blood cells called lymphocytes, which normally fight infection. Normally, bone marrow produces immature cells (stem cells) in a controlled way, and they mature and specialize into the various types of blood cells, as needed. In people with ALL, this production process goes awry. Large numbers of immature, abnormal lymphocytes called lymphoblasts are produced and released into the bloodstream. These abnormal cells aren't able to mature and perform their usual functions. These blasts usually multiply rapidly and can crowd out healthy blood cells, leaving an adult or child with ALL vulnerable to infection or easy bleeding. Leukemic cells can also collect in certain areas of the body, including the central nervous system and spinal cord, which can cause serious problems. Almost 4,000 Americans are diagnosed with acute lymphocytic leukemia each year. This form of cancer worsens quickly if not treated, but it usually responds well to initial treatment. Adults have a 30 percent to 50 percent cure rate.

About Hana Biosciences

Hana Biosciences, Inc. (OTC: HNAB) is a South San Francisco, CA-based biopharmaceutical company that acquires, develops, and commercializes innovative products to advance cancer care. The company is committed to creating value by building a world-class team, accelerating the development of lead product candidates, expanding its pipeline by being the alliance partner of choice, and nurturing a unique company culture. Additional information on Hana Biosciences can be found at www.hanabiosciences.com.

This press release contains forward-looking statements that involve risks and uncertainties that could cause Hana's actual results to differ materially from the anticipated results and expectations expressed in these forward-looking statements. These statements are based on current expectations, forecasts and assumptions that are subject to risks and uncertainties, which could cause actual outcomes and results to differ materially from these statements. Among other things, there can be no assurances that any of Hana's development efforts relating to its product candidates will be successful. Other risks that may affect forward-looking information contained in this press release include the possibility of being unable to obtain regulatory approval of Hana's product candidates, the risk that the results of clinical trials may not support Hana's claims, Hana's reliance on third party researchers to develop its product candidates and its lack of experience in developing pharmaceutical products. Additional risks are described in the company's Form 8-K filed with the Securities and Exchange Commission on August 4, 2004. Hana assumes no obligation to update these forward-looking statements, except as required by law.