CytRx Reports Positive Preliminary Results from ENABLE Phase 2 Clinical Trial with Bafetinib in Patients with Relapsed B-Cell Chronic Lymphocytic Leukemia

LOS ANGELES--(BUSINESS WIRE)--CytRx Corporation (Nasdaq: CYTR), a biopharmaceutical company specializing in oncology, today announced that preliminary results from its ENABLE Phase 2 proof-of-concept trial demonstrated that bafetinib, the Company’s Bcr-Abl, Lyn and Fyn kinase inhibitor, was clinically active in a group of patients with relapsed or refractory B-cell chronic lymphocytic leukemia (B-CLL) who have failed several other treatments for their cancer. Based on this indication of clinical activity and the low incidence of adverse events, additional patients enrolled in the ENABLE Phase 2 clinical trial will receive bafetinib as a single agent at a higher dose.

“Due to the low incidence of adverse events, we are now able to increase the dose of bafetinib administered to newly enrolled patients, thus increasing the potential for greater efficacy.”

“We are highly optimistic about bafetinib’s prospects based on the preliminary results, which provide an initial indication that this drug candidate’s unique kinase inhibition could be efficacious in treating B-CLL and other cancers where approved therapies have failed,” said CytRx President and CEO Steven A. Kriegsman. “Due to the low incidence of adverse events, we are now able to increase the dose of bafetinib administered to newly enrolled patients, thus increasing the potential for greater efficacy.”

Of the 16 patients enrolled in the ENABLE Phase 2 clinical trial, 11 patients were evaluable for tumor response (patients who have received both baseline and follow-up tumor assessments). At the time of evaluation, the median duration of treatment for all patients was two months, and five of these 11 patients had received three to five months of bafetinib therapy; five patients either did not receive baseline or follow-up assessments. The median number of prior therapies for the full group is three, with a range between one and five prior therapies, and nine of 12 patients demonstrated unfavorable cytogenetics (del 17p; 13). This subgroup of patients typically has fast disease progression and shorter median overall survival.

All 11 evaluable patients demonstrated ≥50% elevation in their lymphocyte counts during the first two months of treatment, similar to other kinase inhibitors being tested in B-CLL patients. Six demonstrated >50% shrinkage in their lymph nodes and/or spleen, two patients had stable disease and three patients had progressive disease at their initial assessments. Lymph node softening also was noted in these patients. Only one grade 3 or 4 adverse event (grade 3 elevated liver enzymes) was noted, which resolved when bafetinib administration was ceased. Grade 1 and 2 adverse events included elevated liver enzymes with normal bilirubin, fatigue and gastrointestinal symptoms.

“These favorable initial Phase 2 clinical trial results of bafetinib’s activity and safety mark an important step in our goal to become a leading oncology therapeutics company. Further, we were able to obtain these results quickly after initiating enrollment in this clinical trial, validating our strategy to rapidly and cost-effectively conduct proof-of-concept trials in patients with advanced-stage cancers prior to moving into larger clinical trials,” Mr. Kriegsman added.

The ENABLE Phase 2 clinical trial, which is expected to enroll a total of 30 patients, is being performed at M.D. Anderson Cancer Center, City of Hope Medical Center and Cancer Care Centers of Texas. Patients self-administer bafetinib twice daily every day and continue treatment as long as their cancer is controlled and no intolerable side effects occur. The trial’s objectives are to assess preliminary efficacy of administration of bafetinib in B-CLL patients and evaluate its safety in this patient population.

“These results are very encouraging,” said Daniel Levitt, M.D., PhD, Chief Medical Officer at CytRx. “Lyn kinase, a primary target of bafetinib, is important to the activation and growth of B cells. It is upstream from both PI3kinase delta and Bruton’s tyrosine kinase in B-CLL and may regulate the activity of these other kinases in B cell malignancies.”

B-CLL is the most common form of leukemia in adults in Western countries. More than 17,000 new cases of B-CLL are reported in the U.S. each year; however up to an estimated 40% of cases may not be reported due to under-diagnosis and lack of placement in cancer registries. Virtually all patients are older than 55 years at presentation, with an average age of 70 years. Patients in the high-risk B-CLL have a median overall survival of one to five years.

About Bafetinib

CytRx holds rights to bafetinib (formerly known as INNO-406) in all territories except Japan. Bafetinib is a potent, orally available, rationally designed, Bcr-Abl, Lyn and Fyn kinase inhibitor, which was being developed as a third-line treatment for patients with CML and certain forms of acute myeloid leukemia (AML) that are refractory or intolerant of other approved treatments. In November 2008, CytRx announced that bafetinib demonstrated clinical responses in patients with CML in an international, open-label Phase 1 dose-ranging clinical trial conducted in patients with CML and other leukemias that have a certain mutation called the Philadelphia Chromosome (Ph+) and are intolerant of or resistant to Gleevec^® and, in some cases, second-line tyrosine kinase inhibitors such as dasatinib and nilotinib. In April 2010, the Company announced that bafetinib had received official notification from the Committee for Orphan Medicinal Products (COMP) of the European Medicines Agency (EMEA) that a positive opinion was made regarding the application for orphan medicinal product status for the treatment of chronic myeloid leukemia (CML). Bafetinib also has been granted Orphan Drug Status for the treatment of Ph+ CML by the U.S. Food and Drug Administration (FDA).

About CytRx Corporation

CytRx Corporation is a biopharmaceutical research and development oncology company engaged in the development of high-value human therapeutics. The CytRx oncology pipeline includes three programs in clinical development for cancer indications: bafetinib, tamibarotene and INNO-206. The Company is evaluating bafetinib in the ENABLE Phase 2 clinical trial in high-risk B-cell chronic lymphocytic leukemia (B-CLL) and the PROACT Phase 2 clinical trial in advanced prostate cancer, and is conducting a pharmacokinetic clinical trial in brain cancer. With its tumor-targeting oncology candidate INNO-206, CytRx plans to initiate a Phase 2 clinical trial as a treatment for soft tissue sarcomas, following a dose escalation safety trial. CytRx's pipeline also includes tamibarotene, which it is testing in a double-blind placebo-controlled Phase 2 clinical trial in patients with non-small-cell lung cancer, and which is in a registration clinical trial as a treatment for acute promyelocytic leukemia (APL). For more information on the Company, visit http://www.cytrx.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of Section 21E of the Securities Exchange Act of 1934, as amended. Such statements 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 outcome, timing and results of CytRx's clinical trials, including its clinical trial with bafetinib in patients with B-CLL, the risk that future results from the Company’s ENABLE clinical trial might not be consistent with the announced preliminary results, the risk that patients administered a higher dose of bafetinib might not respond favorably or might exhibit adverse events not seen at the lower dose, uncertainties regarding regulatory approvals for current and future clinical testing and the scope of the clinical testing that may eventually be required by regulatory authorities, the significant time and expense that will be incurred in developing any of the potential commercial applications for CytRx's oncology drug candidates, including bafetinib, risks related to CytRx's ability to manufacture its drug candidates in a timely fashion, cost-effectively or in commercial quantities in compliance with stringent regulatory requirements, risks related to CytRx's need for additional capital or strategic partnerships to fund its ongoing working capital needs and development efforts, and the risks and uncertainties described in the most recent annual and quarterly reports filed by CytRx with the Securities and Exchange Commission and current reports filed since the date of CytRx's most recent annual report. 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.