OSI Pharmaceuticals and Pfizer Announce Phase IV Macugen(R)(pegaptanib sodium injection) Maintenance Trial in Neovascular Age-Related Macular Degeneration (AMD)

OSI Pharmaceuticals, Inc. (NASDAQ: OSIP) and Pfizer Inc. (NYSE:PFE) today announced the initiation of LEVEL (EvaLuation of Efficacyand safety in maintaining Visual acuity with sEquential treatment ofneovascuLar AMD), a Phase IV trial that will explore the safety andefficacy of Macugen(R) (pegaptanib sodium injection) as a maintenancetherapy for patients who have received prior neovascular AMD treatmentand experienced improvement in macular disease. The 54-week trial,comprising up to 1000 patients at 100 sites across the country, isscheduled to enroll its first patient today.

Neovascular AMD is a chronic, progressive disease that may requireongoing management. Nearly 70,000 patients have already been treatedwith Macugen, which offers proven efficacy and safety for up to twoyears in the treatment of neovascular AMD with six-week dosing. Safetymay be an important consideration when choosing a maintenance therapy.According to retrospective Medicare data presented at the annualmeeting of the Association for Research in Vision and Ophthalmology,patients with neovascular AMD are typically older, with significantlymore co-morbid conditions such as hypertension, diabetes, lipiddisorders, stroke and heart attack than those who do not haveneovascular AMD.

"Armed with a growing number of treatment options, we shouldexplore new regimens that may be capable of providing beneficialpatient outcomes while addressing long-term safety and dosingconsiderations," said Thomas R. Friberg, MS, MD, Professor ofOphthalmology and Bioengineering University of Pittsburgh MedicalCenter and a lead investigator in the LEVEL trial. "For example,clinical data suggest that a non-selective anti-VEGF-A therapy canimprove vision in a significant portion of patients and that thisimprovement may stabilize after a few injections. It makes sense tostudy whether these gains can also be maintained using a selectiveanti-VEGF therapy."

Neovascular AMD research suggests that the chronic suppression ofVEGF (vascular endothelial growth factor) may be important inminimizing the risk of recurrent macular swelling and bleeding thatmay result in irreversible vision loss. By specifically targeting andsuppressing VEGF 165, Macugen has been shown to reduce blood vesselgrowth and preserve vision by slowing vision loss. In addition,Macugen has an excellent long-term safety profile that has beenevaluated in controlled clinical trials up to two years. Patients werethen followed for a third year of treatment in an uncontrolledextension study.

"The introduction of anti-VEGF therapy marked a new era in themanagement of neovascular AMD, yet we still have much to learn," saidAnthony P. Adamis, M.D., Chief Scientific Officer, (OSI) Eyetech."Macugen has proven efficacy and safety. The LEVEL trial will providefurther insight into Macugen's potential role in new treatmentregimens for neovascular AMD."

LEVEL STUDY DESIGN

In this open label, multi-center trial, subjects must have had atleast one, but no more than three treatments for neovascular AMDwithin 30 to 120 days prior to study entry leading to an improvementin macular disease. Macugen will be administered once every six weeksfor 48 weeks. Booster treatment with additional neovascular AMDtherapy may be employed if the investigator believes macular diseasehas progressed.

The primary endpoint is the percentage of subjects who remain atbaseline vision or gain (greater than or equal to 0 lines) vision frombaseline to 54 weeks. Secondary endpoints include the percentage ofsubjects maintaining or gaining one, two and three lines of visualacuity at week 54 compared to pre-enrollment baseline vision(treatment initiation baseline); the mean change of visual acuity frombaseline to Week 54; the percentage of subjects losing less than threelines of vision at 54 weeks; and anatomical outcomes on fluoresceinangiography and optical coherence tomography.

About Age-Related Macular Degeneration

AMD is a chronic, progressive disease of the central portion ofthe retina called the macula, resulting in the loss of central vision.The most common symptoms are a central blurred or blank spot,distortion of objects or simply blurred vision. Peripheral visionusually remains intact. AMD is classified into two forms: atrophic,referred to as dry AMD, and neovascular or wet AMD.

In neovascular AMD, abnormal blood vessels grow and leak into themacula, resulting in loss of vision. Neovascular AMD is the moresevere form of the disease and progresses more rapidly than the drytype. Although it accounts for only about 10-15 percent of all maculardegeneration cases, neovascular AMD is responsible for 90 percent ofblindness caused by the disease.

About Macugen

Macugen, a selective inhibitor of VEGF 165, is indicated in theUnited States for the treatment of neovascular age-related maculardegeneration (neovascular AMD) and is administered in a 0.3-mg doseonce every six weeks by intravitreal injection. Macugen is a pegylatedanti-VEGF aptamer, which binds to vascular endothelial growth factor(VEGF). VEGF is a protein that plays a critical role in angiogenesis(the formation of new blood vessels) and increased permeability(leakage from blood vessels), two pathological processes thatcontribute to the vision loss associated with neovascular AMD.

Macugen has been approved by regulatory authorities in the UnitedStates, European Union, Canada, Brazil, Argentina, Peru, Pakistan, thePhilippines and Switzerland, with filings submitted in 14 othercountries. OSI and Pfizer Inc. co-promote Macugen in the UnitedStates. OSI has granted Pfizer the exclusive rights to commercializeMacugen in countries outside the United States pursuant to aroyalty-bearing licensing agreement. Macugen is now available in theUnited States, Canada, United Kingdom, Germany, Sweden, Finland,Ireland, Austria, Philippines and Pakistan.

For full prescribing information about Macugen, please visithttp://www.macugen.com/.

Important Safety Information

Macugen is contraindicated in patients with ocular or periocularinfections or with known hypersensitivity to pegaptanib sodium or anyother excipient of this product.

Safety or efficacy of Macugen beyond two years has not beendemonstrated.

Intravitreal injections including those with Macugen have beenassociated with endophthalmitis. Proper aseptic injection technique --which includes use of sterile gloves, a sterile drape, and a sterileeyelid speculum (or equivalent) -- should always be utilized whenadministering Macugen. In addition, patients should be monitoredduring the week following the injection to permit early treatment,should an infection occur.

Increases in intraocular pressure (IOP) have been seen within 30minutes of injection with Macugen. Therefore, IOP as well as theperfusion of the optic nerve head should be monitored and managedappropriately.

Serious adverse events related to the injection procedureoccurring in less than 1% of intravitreal injections includedendophthalmitis, retinal detachment, and iatrogenic traumaticcataract.

Most frequently reported adverse events in patients treated for upto two years were anterior chamber inflammation, blurred vision,cataract, conjunctival hemorrhage, corneal edema, eye discharge, eyeirritation, eye pain, hypertension, increased IOP, ocular discomfort,punctate keratitis, reduced visual acuity, visual disturbance,vitreous floaters, and vitreous opacities. These events occurred inapproximately 10% to 40% of patients.

Rare cases of anaphylaxis/anaphylactoid reactions, includingangioedema, have been reported in postmarketing experience followingthe intravitreal administration procedure.

About OSI Pharmaceuticals

OSI Pharmaceuticals is committed to "shaping medicine and changinglives" by discovering, developing and commercializing high-quality andnovel pharmaceutical products that extend life or improve the qualityof life for patients with cancer, eye diseases, and diabetes. TheCompany operates through three business teams, (OSI) Oncology, (OSI)Eyetech and (OSI) Prosidion. (OSI) Oncology is focused on developingmolecular targeted therapies designed to change the paradigm of cancercare. (OSI) Eyetech specializes in the development andcommercialization of novel therapeutics to treat diseases of the eye.(OSI) Prosidion is committed to the generation of novel, targetedtherapies for the treatment of type 2 diabetes and obesity. OSI'sflagship product, Tarceva(R) (erlotinib), is the first drug discoveredand developed by OSI to obtain FDA approval and the only EGFRinhibitor to have demonstrated the ability to improve survival in bothnon-small cell lung cancer and pancreatic cancer patients. OSI marketsTarceva through partnerships with Genentech, Inc. in the United Statesand with Roche throughout the rest of the world. Macugen(R)(pegaptanib sodium injection) is approved in the United States for thetreatment of neovascular age-related macular degeneration. OSIcommercializes Macugen in partnership with Pfizer Inc. For additionalinformation about OSI, please visit http://www.osip.com.

This news release contains forward-looking statements. Thesestatements are subject to known and unknown risks and uncertaintiesthat may cause actual future experience and results to differmaterially from the statements made. Factors that might cause such adifference include, among others, the completion of clinical trials,the FDA review process and other governmental regulation, OSI's andits collaborators' abilities to successfully develop and commercializedrug candidates, competition from other pharmaceutical companies, theability to effectively market products, and other factors described inOSI Pharmaceuticals' filings with the Securities and ExchangeCommission.

About Pfizer Inc

Pfizer Inc discovers, develops, manufactures and markets leadingprescription medicines for humans and animals as well as many of theworld's best-known consumer brands. Pfizer Ophthalmics, a division ofPfizer Inc., is committed to preserving sight and eliminatingpreventable blindness through the discovery and development oftreatments for eye diseases. Pfizer Ophthalmics supports patients whoare at risk of blindness or suffering from vision impairment and thehealth care professionals who treat them. Its current product lineincludes the most prescribed treatment to lower elevated eye pressurein patients with ocular hypertension (abnormally high eye pressure) oropen-angle glaucoma. In collaboration with OSI Pharmaceuticals, thedivision also includes a treatment for neovascular age-related maculardegeneration.

For more information about Pfizer, please visithttp://www.pfizer.com.

PFIZER DISCLOSURE NOTICE

The information in this release is as of June 26, 2006.

Pfizer assumes no obligation to update any forward-lookingstatements contained in this release as a result of new information orfuture events or developments.

This release contains forward-looking information about certainpotential benefits of Macugen that involves substantial risks anduncertainties. Such risks and uncertainties include the uncertaintiesinherent in clinical trials, competitive developments and other risksand uncertainties set forth in Pfizer's Annual Report on Form 10-K forthe fiscal year ended December 31, 2005 and in its reports on Form10-Q and Form 8-K.