Allos Therapeutics’ FOLOTYN Shows Activity and Tolerability in Phase 1 Dose Finding Study in Patients with Relapsed or Refractory CTCL

Allos Therapeutics, Inc. (NASDAQ: ALTH) today announced updated data from its ongoing dose finding Phase 1 study of FOLOTYN^® (pralatrexate injection) in patients with relapsed or refractory cutaneous T-cell lymphoma (CTCL), a group of often slow-growing non-Hodgkins lymphomas that primarily manifest in the skin. These data were presented during a poster presentation at the European Hematology Association (EHA) meeting being held June 10-13, 2010 in Barcelona, Spain.

Of the 54 patients enrolled in this dose de-escalation study, data were available for 48 patients with relapsed or refractory CTCL who received a median of 4 prior systemic therapies. FOLOTYN administered at 15 mg/m² via IV push weekly for three weeks out of a four-week cycle was determined to be the optimal starting dose and schedule that provided activity with tolerability. Of the 29 patients who received FOLOTYN at the optimal dose, 22 were evaluable for efficacy and 23 were evaluable for safety. The response rate for patients treated at the optimal dose was 45% (10/22). Of the patients who received FOLOTYN at the optimal dose or higher, 53% (18/34) achieved a response, including one complete response and 17 partial responses. In a subgroup analysis, responses to FOLOTYN were observed in patients who had failed key prior systemic therapies, including 42% (10/24) of patients who failed prior oral bexarotene, 40% (4/10) of methotrexate failures, 35% (7/20) of patients who failed HDAC inhibitors, and 24% (4/17) of interferon failures. FOLOTYN was well tolerated at the optimal dose, with forty-eight percent (11/23) of patients experiencing at least one adverse event. The only grade 3 adverse event observed was mucositis in 17% (4/23) of patients. No grade 4 adverse events were observed at the optimal dose. The most common adverse events, any grade, were mucositis (39% grade 1-3), nausea (22% grade 1-2) and fatigue (17% grade 1-2).

"CTCL is often an indolent disease, thus the goal of this trial was to identify an optimal dose with good activity and acceptable toxicity to allow continuous or maintenance treatment,” said Charles Morris, MB ChB, MRCP, chief medical officer at Allos Therapeutics, Inc. "We are encouraged by the consistent, high response rates and tolerability achieved at the optimal dose in this heavily pre-treated relapsed or refractory CTCL patient population. We look forward to completing patient follow up in this study and to further clinical evaluation of FOLOTYN as a potential treatment option for patients with CTCL."

About the Study

This ongoing, open-label, multi-center, dose finding Phase 1 study is evaluating FOLOTYN in patients with relapsed or refractory cutaneous T-cell lymphoma (CTCL) who received at least one prior systemic therapy. The first phase of the study employed a dose de-escalating strategy to determine an active, well-tolerated dose and schedule of FOLOTYN in this population. Patients were randomized into various dosing regimens to determine the optimal dose and schedule. Once the maximum tolerated dose (MTD) was determined at 15 mg/m² weekly for three weeks out of a four-week cycle, this MTD cohort was expanded to include a total of 29 patients. Patient enrollment in the expanded cohort has been completed and patient follow-up is ongoing to assess final efficacy and tolerability.

About Cutaneous T-Cell Lymphoma (CTCL)

Cutaneous T-cell lymphomas, or CTCLs, are comprised of a number of indolent non-Hodgkin's T-cell lymphomas, including mycosis fungoides and Sézary syndrome, which have their primary manifestations in the skin. According to the Lymphoma Research Foundation, CTCL accounts for approximately 2% to 3% of the estimated 66,000 new cases of non-Hodgkin's lymphoma diagnosed each year in the United States. According to the Cutaneous Lymphoma Foundation, the estimated annual prevalence of CTCL in the United States is between 16,000 and 20,000 cases.¹

About Allos Therapeutics

Allos Therapeutics, Inc. (Nasdaq: ALTH) is a biopharmaceutical company committed to the development and commercialization of innovative anti-cancer therapeutics. Allos is currently focused on the development and commercialization of FOLOTYN^® (pralatrexate injection), a folate analogue metabolic inhibitor. FOLOTYN is the first and only drug approved in the U.S. for the treatment of patients with relapsed or refractory peripheral T-cell lymphoma. The FDA approved FOLOTYN under the agency’s accelerated approval process. Allos is also developing FOLOTYN in other potential indications. Allos retains exclusive worldwide rights to FOLOTYN for all indications. Allos is headquartered in Westminster, Colo. For additional information, please visit www.allos.com.

Important Safety Information

Warnings and Precautions:

FOLOTYN may suppress bone marrow function, manifested by thrombocytopenia, neutropenia, and anemia. Monitor blood counts and omit or modify dose for hematologic toxicities.

Mucositis may occur. If = Grade 2 mucositis is observed, omit or modify dose.

Patients should be instructed to take folic acid and receive vitamin B₁₂ to potentially reduce treatment-related hematological toxicity and mucositis.

FOLOTYN can cause fetal harm. Women should avoid becoming pregnant while being treated with FOLOTYN, and pregnant women should be informed of the potential harm to the fetus.

Use caution and monitor patients when administering FOLOTYN to patients with moderate to severe renal function impairment.

Elevated liver function test abnormalities may occur and require monitoring. If liver function test abnormalities are = Grade 3, omit or modify dose.

Dermatologic reactions may occur. Patients with dermatologic reactions should be monitored closely.

Adverse Reactions:

The most common adverse reactions observed were mucositis (70%), thrombocytopenia (41%), nausea (40%), and fatigue (36%). The most common serious adverse events were pyrexia, mucositis, sepsis, febrile neutropenia, dehydration, dyspnea and thrombocytopenia.

Use in Specific Patient Population:

Nursing mothers should be advised to discontinue nursing or the drug, taking into consideration the importance of the drug to the mother.

Drug Interactions:

Co-administration of drugs subject to renal clearance (e.g., probenecid, NSAIDs, and trimethoprim/sulfamethaxazole) may result in delayed renal clearance.

For additional important safety information, please see the full prescribing information for FOLOTYN at www.allos.com.

Safe Harbor Statement

This press release contains forward-looking statements that are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements include, but are not limited to, statements regarding the estimated incidence of CTCL in the U.S.; Allos' future product development and regulatory strategies, including its intent to develop or seek regulatory approval for FOLOTYN in CTCL and other additional indications; and other statements that are other than statements of historical facts. In some cases, you can identify forward-looking statements by terminology such as "may," "will," "should," "expects," "intends," "plans," "anticipates," "believes," "estimates," "predicts," "projects," "potential," "continue," and other similar terminology or the negative of these terms, but their absence does not mean that a particular statement is not forward-looking. Such forward-looking statements are not guarantees of future performance and are subject to risks and uncertainties that may cause actual results to differ materially from those anticipated by the forward-looking statements. Important factors that may cause actual results to differ materially include, but are not limited to, that Allos may experience difficulties or delays in the initiation, progress or completion of its clinical trials, whether caused by competition, adverse events, investigative site initiation rates, patient enrollment rates, regulatory issues or other factors; and that Allos may lack the financial resources and access to capital to support its future operations, including its product development and commercialization plans for FOLOTYN. Additional information concerning these and other factors that may cause actual results to differ materially from those anticipated in the forward-looking statements is contained in the "Risk Factors" section of the Company's Quarterly Report on Form 10-Q for the quarter ended March 31, 2010, and in the Company's other periodic reports and filings with the Securities and Exchange Commission. The Company cautions investors not to place undue reliance on the forward-looking statements contained in this press release. All forward-looking statements are based on information currently available to Allos on the date hereof, and Allos undertakes no obligation to revise or update these forward-looking statements to reflect events or circumstances after the date of this presentation, except as required by law.

Note: The Allos logo and FOLOTYN name are trademarks of Allos Therapeutics, Inc.

References:

^1. Cutaneous Lymphoma Foundation. CTCL-MF fast facts http://clfoundation.org/publications/CL_fast_facts.pdf. Accessed June 4, 2010.