July 31, 2006

CytRx announced completion of a Phase I clinical trial of the HIV DNA + protein vaccine that it has exclusively licensed. Analysis of the unblinded data confirmed previous preliminary conclusions that the vaccine formulation DP6-001 was generally well-tolerated in volunteers receiving lower vaccine doses and was effective at eliciting HIV-specific T-cell and antibody immune responses. A summary of the Phase I trial results will be filed with the FDA in August.

The DP6-001 vaccine initially primes the subject's immune system through the injection of DNA that causes the subject's own cells to produce the HIV envelope and gag proteins, followed by protein boosts from an injection that contains the corresponding HIV envelope proteins.

The trial of 34 healthy volunteers was divided into three arms: Group A received the DNA vaccine three times under the skin, and Groups B and C received the DNA vaccine three times in muscle, with Group C receiving a six-fold higher DNA dose compared with Groups A and B. All subjects were subsequently "boosted" by injection with a mixture of envelope protein antigens. In general, injection of the vaccine into muscle (Groups B and C) resulted in better cell mediated responses compared with injection under the skin (Group A).

The Phase I study was funded under a $16 million, five-year HIV Vaccine Design and Development Team contract from the National Institute of Allergy and Infectious Diseases.