March 23, 2004

News Release: CytRx Corporation, Advanced BioScience Laboratories and University of Massachusetts Announce FDA Acceptance of IND For Unique HIV Vaccine

CytRx Corporation (Nasdaq: CYTR), Advanced BioScience Laboratories (ABL) and the University of Massachusetts Medical School (UMMS) announced today that the HIV vaccine formulation developed by the University of Massachusetts Medical School and ABL and funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, has been designated an investigational new drug by the U.S. Food and Drug Administration. By allowing the IND to go into effect, the FDA has cleared the way for UMMS to begin a clinical trial to test the safety and immunogenicity of the vaccine. 'This vaccine represents a novel approach to HIV vaccine development, and we are excited to contribute to the effort to fight the worldwide HIV epidemic,'said Steven A. Kriegsman, President and Chief Executive Officer of CytRx.

UMMS will conduct the Phase I clinical trial and begin recruiting patients shortly. The Phase I trial will involve 36 people and is expected to last 12-18 months. The study is to be initiated in Worcester, Massachusetts.

'This is a landmark development and a major step forward in HIV vaccine research,'said Shan Lu, M.D., Ph.D., associate professor of medicine and head of the HIV vaccine effort at UMMS. 'Our vaccine is based on elements from primary virus isolates drawn from all over the world, and that, I think, will make a difference in the efficacy of the vaccine.'

Dr. Phillip Markham, Director of Cell Biology and principal investigator of the ABL/UMMS HIV Vaccine Development and Design contract team agrees that this is a very promising vaccine approach which should address certain shortcomings observed in previous trials.

HIV, the virus that leads to acquired immune deficiency syndrome (AIDS), remains a global epidemic. World health officials estimate 42 million people are now infected with HIV. Some 3 million people died of AIDS last year, worldwide, and millions more are expected to die from AIDS this year. With the rate of infection accelerating in many parts of the world, the search for an effective HIV vaccine is one of the highest public health priorities. Yet, development of an HIV vaccine has been challenging because of the virus' extraordinary degree of genetic diversity. HIV mutates rapidly in the environment making it an elusive target for traditional vaccine strategies. That's where UMMS and ABL have made significant progress. They have created a novel 'polyvalent'HIV vaccine based on multiple strains of HIV collected directly from infected people living in five locations around the globe, representing five different strains of the virus. 'Instead of hitting HIV with one target, we are using five in this vaccine,'Dr. Lu said. 'The goal with this vaccine is to trigger the immune system to target multiple strains of the virus.'

The approach uses elements of HIV's DNA to induce an immune response to the virus. The DNA is then boosted by an injection of recombinant viral proteins that have been shown to enhance the host's immune response to the DNA elements of the vaccine in animal models.

So far, the DNA and protein combination has been tested in two animal models with very promising results. Antibodies produced by the immunized animals effectively neutralized live HIV isolates collected from several parts of the world. That success facilitated taking the novel vaccine to the next step, a clinical trial in humans. 'There is no live HIV in the vaccine, only elements from the DNA that code for the envelope and gag proteins of the virus, so there is no chance of getting HIV from this vaccine,'Dr. Lu said.

The new HIV vaccine incorporates DNA and protein-proprietary technology exclusively licensed to CytRx by UMMS and ABL. The HIV Vaccine project has been funded, to date, under a 5-year HIV Vaccine Design &Development Teams contract from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. The funds under this program, totaling approximately $16 million, are expected to provide all of the needed funding for the Phase I trial.

Under the terms of CytRx's collaboration agreement with ABL, CytRx will assume ownership of and responsibility for the HIV vaccine FDA registration following completion of the Phase I trial. ABL will have an option to acquire the commercial manufacturing rights for the vaccine if the FDA approves it for use.

About CytRx Corporation

CytRx Corporation is a biopharmaceutical research and development company, based in Los Angeles with a subsidiary in Worcester, Massachusetts. The company is engaged in the development of products, primarily in the area of ribonucleic acid interference (RNAi), for the human health care market, in a variety of therapeutic categories. The company has a broad-based strategic alliance with the University of Massachusetts Medical School to develop novel compounds in the areas of obesity, type 2 diabetes, CMV and ALS using RNAi technology. CytRx also licensed from UMMS the rights to a DNA-based HIV vaccine technology. The company also has a research program with Massachusetts General Hospital, Harvard University's teaching hospital, to use RNAi technology to develop a drug for the treatment of ALS. For more information, visit CytRx's website at www.cytrx.com.

ABOUT ADVANCED BIOSCIENCE LABORATORIES

Advanced BioScience Laboratories, Inc. (ABL) located in Kensington Maryland, is a biomedical research, development and manufacturing company focusing on human retroviral diseases. ABL has been a leader in HIV-1 research for more than two decades and has been involved in the development of methods to both prevent and treat HIV-1 infection.

ABOUT THE UNIVERSITY OF MASSACHUSETTS

The University of Massachusetts Medical School, one of the fastest growing academic health centers in the country, has built a reputation as a world- class research institution, consistently producing noteworthy advances in clinical and basic research. The Medical School attracts more than $153 million in research funding annually, 80% of which comes from federal funding sources. Research funding enables UMMS scientists to explore human disease from the molecular level to large-scale clinical trials. Basic and clinical research leads to new approaches for diagnosis, treatment and prevention of disease. Visit www.umassmed.edu for additional information.

This press release contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended, that involve risks and uncertainties that could cause actual events or results to differ materially from the events or results described in the forward-looking statements, including risks or uncertainties related to the risk that ABL may encounter delays in starting the Phase I vaccine trial due to delays in obtaining clinical supplies of the vaccine or for other reasons, the risk of delays in completing and the uncertainty of the results of the Phase I trial or future trials, the risk of the NIH contract being cancelled or providing insufficient funds to complete the Phase I trial, the risk of obtaining adequate or any patent coverage for the HIV vaccine, and the need to obtain substantial funding to carry out subsequent clinical trials for the HIV vaccine. Additional uncertainties and risks are described in CytRx's most recently filed SEC documents, such as its most recent annual report on Form 10-K, all quarterly reports on Form 10-Q and any current reports on Form 8-K filed since the date of the last Form 10-K. All forward-looking statements are based upon information available to CytRx on the date the statements are first published. CytRx undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

SOURCE CytRx Corporation

Carolyn French of CytRx Corporation, +1-310-826-5648, This email address is being protected from spambots. You need JavaScript enabled to view it.; or Michael Cohen of University of Massachusetts, +1-508-856-2000, This email address is being protected from spambots. You need JavaScript enabled to view it.

http://www.umassmed.edu

WEBSITE This email address is being protected from spambots. You need JavaScript enabled to view it.