Spectrum Pharmaceuticals Completes Acquisition of Allos Therapeutics; Effective and Swift Integration Expected to Result In Significant Synergies

-- Spectrum Will Now Have Diversified Revenue from Three FDA-approved Anti-cancer Drugs

-- The Company Expects Pro-Forma Revenue of $300 Million in 2012

-- Significant Employment Changes Already Implemented

HENDERSON, Nev.--()--Spectrum Pharmaceuticals (NasdaqGS: SPPI), a biotechnology company with fully integrated commercial and drug development operations with a primary focus in hematology and oncology today announced the successful completion of the acquisition of Allos Therapeutics, Inc. (NasdaqGS: ALTH) (Allos), on September 5, 2012 through a “short-form” merger of Sapphire Acquisition Sub, Inc., a wholly-owned subsidiary of Spectrum, with and into Allos with Allos surviving the merger and continuing as a wholly-owned subsidiary of Spectrum.

Immediately prior to the merger, Spectrum successfully completed its cash tender offer to purchase all of the outstanding shares of common stock of Allos. Based on information provided by the depository for the tender offer, a total of 96,259,850 shares were validly tendered and not withdrawn at the expiration of the tender offer (including 2,368,421 shares tendered pursuant to the guaranteed delivery procedures set forth in the Offer to Purchase), representing approximately 89.98% of the outstanding shares of Allos common stock (or approximately 87.77% of such outstanding shares if none of the shares tendered pursuant to the guaranteed delivery procedures are actually delivered). Pursuant to the terms of the tender offer, Spectrum has accepted for payment all shares validly tendered and not validly withdrawn during the offering period, and has paid an amount equal to the aggregate consideration for all such shares to the depositary for the tender offer, to be disbursed to the Allos stockholders in accordance with the terms of the tender offer.

In order to effect the short-form merger and acquire 100% of the common stock of Allos, Spectrum exercised its “top-up” option, pursuant to the terms of the previously announced Agreement and Plan of Merger, dated as of April 4, 2012, among Spectrum, Allos and Sapphire Acquisition Sub, Inc., to purchase shares directly from Allos in an amount sufficient to enable Spectrum to acquire the remaining outstanding shares of Allos. As a result of the merger, all outstanding shares of common stock of Allos, other than shares held by Spectrum, Sapphire Acquisition Sub, Inc., Allos or its subsidiaries or shares held by Allos’ stockholders who have and validly exercise appraisal rights under Delaware law, will be canceled and converted into the right to receive a cash payment in an amount equal to the same offer price per share of $1.82 in cash, without interest and less any applicable withholding taxes, that was paid in the offer. September 5, 2012 was the last day that shares of Allos common stock trade on the NASDAQ Global Select Market.

“The completion of the Allos acquisition is a major milestone for Spectrum, meaningfully diversifying our revenues and bringing together programs and products that we believe will have significant synergies, both in the very near term and over ensuing years,” stated Rajesh C. Shrotriya, MD, Chairman, Chief Executive Officer, and President of Spectrum Pharmaceuticals. “We have had several months to prepare for this, and our integration plan is designed to be effective and swift. We will provide further updates on the acquisition and integration at upcoming investor conferences.”

About Spectrum Pharmaceuticals, Inc.

Spectrum Pharmaceuticals is a leading biotechnology company focused on acquiring, developing, and commercializing drug products, with a primary focus in oncology and hematology. Spectrum markets three oncology drugs ─ FUSILEV® (levoleucovorin) for Injection in the U.S.; FOLOTYN® (pralatrexate injection), also marketed in the U.S.; and ZEVALIN® (ibritumomab tiuxetan) Injection for intravenous use, for which the Company has worldwide marketing rights. Spectrum's strong track record in in-licensing and acquiring differentiated drugs, and expertise in clinical development have generated a robust, diversified, and growing pipeline of product candidates in advanced-stage Phase 2 and Phase 3 studies. More information on Spectrum is available at www.sppirx.com.

About ZEVALIN® and the ZEVALIN Therapeutic Regimen

ZEVALIN (ibritumomab tiuxetan) injection for intravenous use is indicated for the treatment of patients with relapsed or refractory, low-grade or follicular B-cell non-Hodgkin's lymphoma (NHL). ZEVALIN is also indicated for the treatment of patients with previously untreated follicular non-Hodgkin's Lymphoma who achieve a partial or complete response to first-line chemotherapy.

ZEVALIN is a CD20-directed radiotherapeutic antibody. The ZEVALIN therapeutic regimen consists of two components: rituximab, and Yttrium-90 (Y-90) radiolabeled ZEVALIN for therapy. ZEVALIN builds on the combined effect of a targeted biologic monoclonal antibody augmented with the therapeutic effects of a beta-emitting radioisotope.

Important ZEVALIN® Safety Information

Deaths have occurred within 24 hours of rituximab infusion, an essential component of the ZEVALIN therapeutic regimen. These fatalities were associated with hypoxia, pulmonary infiltrates, acute respiratory distress syndrome, myocardial infarction, ventricular fibrillation, or cardiogenic shock. Most (80%) fatalities occurred with the first rituximab infusion. ZEVALIN administration can result in severe and prolonged cytopenias in most patients. Severe cutaneous and mucocutaneous reactions, some fatal, can occur with the ZEVALIN therapeutic regimen.

Please see full Prescribing Information, including BOXED WARNINGS, for ZEVALIN and rituximab. Full prescribing information for ZEVALIN can be found at www.ZEVALIN.com.

About FOLOTYN®

FOLOTYN (pralatrexate injection), a folate analogue metabolic inhibitor, was discovered by Memorial Sloan-Kettering Cancer Center, SRI International and Southern Research Institute and developed by Allos Therapeutics. In September 2009, the U.S. Food and Drug Administration (FDA) granted accelerated approval for FOLOTYN for use as a single agent for the treatment of patients with relapsed or refractory PTCL. This indication is based on overall response rate. Clinical benefit such as improvement in progression-free survival or overall survival has not been demonstrated. FOLOTYN has been available to patients in the U.S. since October 2009. An updated analysis of data from PROPEL, the pivotal study of FOLOTYN in patients with relapsed or refractory PTCL, was published in the March 20, 2011 issue of the Journal of Clinical Oncology. FOLOTYN has patent protection through 2017 and potentially through July 2022, assuming a five-year patent term extension through the Hatch-Waxman Act. Please see full Prescribing Information for FOLOTYN at www.FOLOTYN.com.

Important FOLOTYN® 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 greater-than or equal to 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.

Fatal dermatologic reactions may occur. Dermatologic reactions may be progressive and increase in severity with further treatment. Patients with dermatologic reactions should be monitored closely, and if severe, FOLOTYN should be withheld or discontinued. Tumor lysis syndrome may occur. Monitor patients and treat if needed.

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 greater-than or equal to Grade 3, omit or modify dose.

Adverse Reactions

The most common adverse reactions were mucositis (70%), thrombocytopenia (41%), nausea (40%), and fatigue (36%). The most common serious adverse events are 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/sulfamethoxazole) may result in delayed renal clearance.

Please see FOLOTYN® Full Prescribing Information at www.FOLOTYN.com.

This press release may contain forward-looking statements regarding future events of Spectrum Pharmaceuticals and Allos Therapeutics that involve risks and uncertainties that could cause actual results to differ materially. These statements are based on management's current beliefs and expectations. Such forward-looking statements include statements regarding the success and strategic fit of the proposed combination of Spectrum Pharmaceuticals and Allos Therapeutics and the ability of Spectrum Pharmaceuticals to successfully integrate Allos Therapeutics. These forward-looking statements will depend on Spectrum Pharmaceuticals’ and Allos Therapeutics’ ability to identify, acquire, develop and commercialize a broad and diverse pipeline of late-stage clinical and commercial products, and to leverage the expertise of partners and employees around the world to assist us in the execution of our combined strategy. The forward-looking statements contained in this document are subject to risks and uncertainties which may cause actual results to differ materially from the forward-looking statements. These risks and uncertainties include, but are not limited to, risks and uncertainties are discussed in documents filed with the U.S. Securities and Exchange Commission by Allos Therapeutics, including the solicitation/recommendation statement, as well as the tender offer statement (including an offer to purchase, letter of transmittal, and related tender offer documents) that have been filed by Spectrum Pharmaceuticals and Sapphire Acquisition Sub, Inc.

Spectrum Pharmaceuticals and Allos Therapeutics do not plan to update any such forward-looking statements and expressly disclaim any duty to update the information contained in this press release except as required by law.

Contacts

Spectrum Pharmaceuticals
Shiv Kapoor, 702-835-6300
Vice President, Strategic Planning & Investor Relations
InvestorRelations@sppirx.com

Contacts

Spectrum Pharmaceuticals
Shiv Kapoor, 702-835-6300
Vice President, Strategic Planning & Investor Relations
InvestorRelations@sppirx.com