CytRx to Proceed with Arimoclomol Maximum Dose Study.

Intends to determine optimal dose for planned upcoming Phase IIB efficacy clinical trial for ALS 

LOS ANGELES -- CytRx Corporation (NASDAQ:CYTR) today announced its plans for completing the next step towards initiating its Phase IIb clinical trial for the treatment of amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), planned to begin in the third quarter of 2007. As an important step toward this goal, CytRx plans to determine the maximum safe and well-tolerated dose of orally-administered arimoclomol. CytRx intends to proceed with this maximum dose in the Phase IIb efficacy trial for ALS, subject to U.S. Food and Drug Administration (FDA) approval.

"In general, higher drug doses result in a greater opportunity for therapeutic benefit as long as the dose does not cause toxicity," said CytRx Chief Scientific Officer Jack Barber, Ph.D. "The favorable safety and tolerability profile observed for arimoclomol in our recent Phase IIa ALS trial, combined with previous and recent animal toxicology results, suggests that we may be able to safely increase the dose without causing significant side effects."

This European single-site, double-blind, placebo-controlled multiple rising/ascending dose study is designed to test the safety, tolerability and pharmacokinetics of increasing dosages of arimoclomol in healthy volunteers over a seven-day period. The plan includes enrolling a total of approximately 40 healthy volunteers, with 10 subjects in each of four groups. Within each group, seven subjects will receive arimoclomol and three will receive placebo (a capsule without drug). The first group will be dosed with 100 mg three times daily, the highest dose in the Phase IIa ALS clinical trial. Safety results from this group will provide a baseline that will be compared with subsequent higher dose groups. Dosing of the remaining three groups will proceed sequentially, with progressively higher doses to be administered to the next group only if the dosage in the prior lower dose group is determined to be safe and well-tolerated. If significant side effects occur at any dose level, the study will end and the previous dose level will be considered to be the maximum tolerated dose. If toxicity is not observed at lower doses, this cautious increase in dose is planned to reach a maximum dose at 600 mg three times a day, which is the maximum amount of drug that can fit into an easily-swallowed pill for oral delivery. After the maximum tolerated dose is determined, CytRx plans to evaluate the longer-term safety of this dose in a subsequent study to be described at a later time. CytRx believes that safety data from this latter study may support the use of this dose in the Phase IIb efficacy trial for ALS. CytRx believes that positive efficacy and safety results from the Phase IIb trial could be sufficient for arimoclomol product registration in the U.S. for this indication.

About Arimoclomol

Arimoclomol is one of CytRx's three orally-administered, small molecule compounds. This small molecule drug candidate is believed to function by stimulating a normal cellular protein repair pathway through the activation of "molecular chaperones." Since damaged proteins called aggregates are thought to play a role in many diseases, CytRx believes that activation of molecular chaperones could have therapeutic efficacy for a broad range of diseases.

About ALS

ALS is a progressive degeneration of the brain and spinal column nerve cells that control the muscles that allow movement. Over a period of months or years, ALS causes increasing muscle weakness, inability to control movement and problems with speaking, swallowing and breathing. According to the ALS Survival Guide, 50% of ALS patients die within 18 months of diagnosis and 80% die within five years. More than 120,000 people are living with ALS worldwide.

About CytRx Corporation

CytRx Corporation is a biopharmaceutical research and development company engaged in the development of high-value human therapeutics. In September 2006 CytRx announced that arimoclomol was shown to be safe and well tolerated at all three doses tested in its Phase IIa clinical trial in patients with ALS. The Company plans to enter a Phase IIb clinical trial with arimoclomol in ALS in the third quarter of 2007, subject to FDA approval. The FDA has granted Fast Track designation and Orphan Drug status to arimoclomol for the treatment of ALS. Also in September 2006, CytRx announced receipt of $24.5 million in a non-dilutive agreement with the privately funded ALS Charitable Remainder Trust to fund continued arimoclomol development for the treatment for ALS in return for a 1% royalty from potential worldwide sales of arimoclomol for the treatment of ALS. The Greater Los Angeles Chapter of The ALS Association is the charitable beneficiary of the ALS Charitable Remainder Trust.

CytRx's majority owned subsidiary, Worcester, Massachusetts-based RXi Pharmaceuticals, Inc., is a biopharmaceutical research and development company that will focus on developing RNAi-based therapeutics for the treatment of human disease. RXi's initial focus will be on neurodegenerative diseases, oncology, type 2 diabetes and obesity. RXi has licenses to a diverse series of early patents and patent applications that were filed from 1998 to 2006 in the areas of RNAi target sequences, RNAi chemistry and RNAi delivery.

For more information, visit www.cytrx.com.

Forward-Looking Statements

This press release contains forward-looking statements, including those related to the results and achievements of CytRx's clinical Phase IIa trial for arimoclomol, and plans for an upcoming multiple rising/ascending dose study and Phase IIb trial for arimoclomol, which involve known and unknown risks and uncertainties that may cause actual future results and achievements of CytRx to be materially different from those expressed or implied by these forward-looking statements. In particular, the results and achievements described may not be supported by further analysis of the results of any subsequent clinical trials. These risks and uncertainties also include risks and uncertainties regarding CytRx's ability to obtain regulatory approvals for further clinical testing of arimoclomol, the scope of clinical testing that may be required by regulatory authorities and the timing and outcome of further clinical trials. Additional uncertainties and risks regarding regulatory approval of CytRx's drug candidates, financing needs, reliance upon strategic relationships, intellectual property protections and other relevant matters are described in CytRx's reports filed with the Securities and Exchange Commission, including 10-K, 10-Q and 8-K reports. All forward-looking statements in this press release are based upon information available to CytRx as of the date of this press release. CytRx undertakes no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.