Niaspan(R) Combined with Low/Moderate Dosed Statin Achieves Better Total Lipid Control vs. Higher Dose Statin Monotherapy or Zocor(R)/Zetia(R)

-- COMPELL study shows significantly greater reductions in triglycerides and Lp(a), as well as superior 2.5-3.5 fold increases in HDL-C and comparable lowering of LDL-C with Niaspan combination therapy versus Crestor(R) and Zocor/Zetia

-- Adding Niaspan to statin therapy achieves better total lipid control for patients at high risk for heart attack

Kos Pharmaceuticals, Inc. (Nasdaq: KOSP) commented today on theresults from the COMPELL (COMParative Effects on Lipid Levels ofNiaspan and Statins Versus Other Lipid Therapies) Phase IV efficacytrial presented at the XIV International Symposium on Atherosclerosis.The results demonstrated that adding the HDL-boosting therapy Niaspan(niacin extended-release tablets) to statin therapy (HMG-CoA reductaseinhibitors) achieved superior raising of high-density lipoproteincholesterol (HDL-C), or "good" cholesterol, and increased triglyceridelowering, with equivalent lowering of low-density lipoproteincholesterol (LDL-C), or "bad" cholesterol, for patients compared totreatment with a high dose statin or Zocor/Zetia (simvastatin andezetimibe).(1)

COMPELL was a 12-week, randomized, multicenter, open-label studyin 292 patients comparing the efficacy of combination therapy withNiaspan and low to moderate doses of Lipitor(R) and Crestor againstmoderate to high dose Crestor and Zocor/Zetia (sold as the fixed-dosecombination tablet, Vytorin(R)). One-half of the patients treated werewomen, who required LDL-C lowering therapy according to NCEP ATP IIIguidelines (LDL-C more than 100 mg/dL).(2) The primary endpoint waspercent change in LDL-C at week 12 from baseline compared across alltreatment groups.(3) In a dose-escalation study design, Niaspan 1000mg with Crestor 10 mg, and 20 mg, or, Niaspan 1000 mg and Lipitor 20mg, and Niaspan 2000 mg with Lipitor 40 mg were compared with Crestor20 mg and 40 mg or Zocor/Zetia 20mg/10mg and 40mg/10 mg.
Mean Percent Change from Baseline at Study End (Week 12)

LDL-C HDL-C TG Lp(a) +
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Atorvastatin 40mg/Niaspan 2000mg -56% +22% -47% -20%
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Rosuvastatin 20mg/Niaspan 1000mg -51% +24% -40% -6%
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Simvastatin 40mg/Ezetimibe 10mg -58% +10%* -33%* +7%*
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Rosuvastatin 40mg -54% +7%* -25%* +5%*
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* Significantly different (p is less than or equal to 0.05) versusatorvastatin/Niaspan

+ Lp(a) reported as median values

Study results showed that patients given Niaspan in combinationwith a low to moderate dose of Lipitor or Crestor achieved equivalentreduction in LDL-C (51-58%), 1.2 to 1.9-fold greater decreases intriglycerides and 2.5 to 3.5 fold greater increases in HDL-C, thanpatients who received high-dose Crestor or Zocor/Zetia.(4) Onlypatients receiving Niaspan experienced significant decreases inlipoprotein (a), referred to as Lp(a), which actually increased inpatients on Crestor and Zocor/Zetia.(5) Similar numbers of patientsreported adverse events and serious adverse events. No drug-relatedmyopathy was observed.

COMPELL was presented by Peter Jones, M.D., Associate Professor ofCardiology, Baylor University. "These results are particularlypowerful because they demonstrate that we can drive LDL-C levels downto goal and also raise the good cholesterol, HDL-C, without the needfor high doses of statin medications," said Dr. Jones. "The patientsin the study were at high risk for heart attack. For these patients,achieving optimal goal levels for all lipid parameters, includingHDL-C, LDL-C and triglycerides is essential. We found that bycombining the prescription form of niacin, called Niaspan, with a lowto moderate dose of a statin, we could achieve these results. Whenheart disease patients achieve these three goals, their risk of heartdisease goes down substantially."

"The COMPELL study puts broad dyslipidemic control and efficacy inappropriate perspective. Lowering LDL cholesterol to ultra-low levelsmay not be enough to protect against heart disease," said AdrianAdams, President and CEO of Kos Pharmaceuticals. "There seems to be adiminishing rate of return in reducing coronary events when LDL islowered progressively below 100 mg/dL. Most LDL-lowering trials showthat two-thirds to three-quarters of statin-treated patients who areat risk in fact progress to a cardiovascular event, despite treatment.This research points to combining statin therapy with Niaspan, themost effective drug available for increasing HDL, as the next clinicaladvance in risk reduction."

"Patients are currently being enrolled in the AIM-HIGH study,which is a landmark outcomes study sponsored in part by The NationalInstitutes of Health to evaluate the independent effect of treatingHDL-C and triglycerides with Niaspan and simvastatin versussimvastatin alone in the prevention of heart attack and stroke. Thisheightened awareness and recognition bodes extremely well for Kos'highly differentiated cholesterol products, Niaspan and Advicor(R) andpositions our optimized Niaspan CF and Simcor(TM)(Niaspan/simvastatin) well in what we believe is an under penetratedmarket with a growing emphasis on treating HDL cholesterol," Adamscontinued.

The HDL-C particle facilitates "reverse cholesterol transport,"and is like a "cleaning service", removing bad cholesterol (LDL-C) outof the arteries and back to the liver to be released into thegastrointestinal tract, where it is removed from the body.(6) Theprimary mechanism of statins is reducing levels of LDL-C throughinhibition of cholesterol synthesis and output from the liver, butthey have a much smaller effect on HDL-C levels.(7) Importantly,lowering LDL-C alone has only reduced events related to coronaryartery disease by approximately 30 - 35%.(8)

Previous studies have provided evidence that supports the role ofHDL-C in reducing risks associated with heart disease.

-- Evidence from a smaller clinical trial known as HATS (HDL Atherosclerosis Treatment Study) strongly suggested a correlation between raising HDL-C levels and the slowing or halting of atherosclerosis. HATS compared the combination of niacin and simvastatin versus placebo and showed a 60 to 90 percent reduction in cardiac events.

-- Another study, known as VA-HIT (VA High Density Lipoprotein Intervention Trial, conducted by the Department of Veteran Affairs), showed that raising HDL-C levels in patients with low HDL-C with a fibrate significantly reduced coronary heart disease events.

-- The ARBITER 2 (Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol) study showed that the combination of Niaspan and a statin slowed disease progression 68 percent more than statin monotherapy as measured by plaque build-up in the carotid artery. Additionally, the combination of Niaspan and statin therapy demonstrated a 60 percent reduction of coronary events compared with a statin used alone.

-- The findings of ARBITER 3 (Atherosclerosis Regression During Open-label Continuation of Extended-release Niacin following ARBITER 2) showed that raising HDL-C, with a moderate dose of Niaspan (1000 mg) removed existing plaque build-up from the carotid arteries in patients on statin therapy with well-controlled (less than 100 mg/dL) LDL-C. Carotid atherosclerosis was significantly reversed in study patients receiving Niaspan therapy for two years by an average of -0.04mm, which is equal to a 105 percent reduction in the rate of progression. Atherosclerosis regression was measured by the change in carotid intima-media thickness (CIMT), a recognized surrogate outcome marker in which a sub-millimeter increase in arterial wall thickness (plaque build-up) predicts an increase in heart disease risk. ARBITER 3 showed definite atherosclerosis regression 12-24 months following treatment with Niaspan, thereby confirming that sustained increases in HDL-C are independently associated with superior effects on atherosclerosis regression. These results reinforce the benefit of raising HDL-C in patients with well-controlled LDL-C levels.

About Niaspan

Available since 1997, Niaspan is the only FDA-approved, once-dailyextended-release prescription formulation of niacin for treatingabnormal cholesterol levels. Niaspan is indicated as an adjunct todiet when the response to a diet restricted in saturated fat andcholesterol and other nonpharmacologic measures alone has beeninadequate, to reduce elevated total cholesterol, LDL-C, Apo B, andtriglyceride levels, and to increase HDL-C in patients with primaryhypercholesterolemia and mixed dyslipidemia. In patients with ahistory of myocardial infarction and hypercholesterolemia, niacin isindicated to reduce the risk of recurrent non-fatal myocardialinfarction or coronary artery disease and hypercholesterolemia.Niacin, in combination with a bile acid binding resin, is indicated toslow progression or promote regression of atherosclerotic disease.

Niaspan is contraindicated in patients with allergies to any ofits ingredients, active peptic ulcer disease, significant orunexplained persistent liver dysfunction, or arterial bleeding.Niaspan should not be substituted for equivalent doses ofimmediate-release niacin. Niaspan should be prescribed with caution inpatients who consume substantial amounts of alcohol and/or have a pasthistory of liver disease. Liver function tests should be performed onall patients during therapy with Niaspan. Use of Niaspan with otherlipid-altering medications called statins may increase the risk ofrhabdomyolysis, a rare condition that causes muscles to breakdown. Themost common side effect with Niaspan is flushing of the skin. Othercommonly reported side effects include indigestion, headache, pain,abdominal pain, nausea, itching, diarrhea, running nose, vomiting andrash. Patients with diabetes should carefully monitor their bloodsugar and report changes to their doctor.(9)

About Kos Pharmaceuticals, Inc.

Kos Pharmaceuticals, Inc. is a fully integrated specialtypharmaceutical company engaged in developing, commercializing,manufacturing and marketing proprietary prescription products for thetreatment of chronic diseases with a particular focus on thecardiovascular, metabolic and respiratory disease areas. The Company'sprincipal product development strategy is to reformulate existingpharmaceutical products with large market potential to improve safety,efficacy, and patient compliance. Kos' strategy also includes makingmeasured investments in new chemical entity research through in-houseand sponsored research, scientific in-licensing and general corporatedevelopment activities. The Company currently markets Niaspan andAdvicor for the treatment of cholesterol disorders, Azmacort(R) forthe treatment of asthma, Cardizem(R)LA for the treatment ofhypertension and angina, and Teveten(R) and TevetenHCT for thetreatment of hypertension. Kos has a strong and growing research anddevelopment pipeline including proprietary drug delivery technologiesin solid-dose, inhalation and aerosol metered-dose deviceadministration to help fuel sustained, organic sales growth into thefuture.

Certain statements in this press release, including statementsrelating to Niaspan, the results of the COMPELL study and otherstudies, including but not limited to the HATS, VA-HIT, ARBITER 2 andARBITER 3 studies, the growing emphasis on the treatment of HDLcholesterol, the potential increase in market growth for cholesterolcombination therapies, the growth prospects of the markets in whichthe Company's products compete, the Company's strong and growingresearch and development pipeline and future sales growth areforward-looking and are subject to risks and uncertainties which maycause actual results to differ materially from those projected in aforward-looking statement. These risks and uncertainties include theprotection afforded by the Company's patents and those related to itsacquired and licensed products, the ability to build awareness for theCompany's products within the medical community, the continuing growthof the cardiovascular, respiratory and allergy markets, the Company'sability to increase the size of its sales force and to attract andretain sales professionals, the Company's and its licensors' abilityto achieve regulatory approvals for products under development and tosuccessfully launch such products in a timely manner, includingoptimized Niaspan CF and Simcor, the ability of third party suppliersto the Company continuing to be able to perform their supplyobligations, the Company's ability to entered into additional newbusiness development opportunities, the progress of the Company'sresearch and development pipeline, the effect of conditions in thepharmaceutical industry and the economy in general, as well as certainother risks. A more detailed discussion of risks attendant to theforward-looking statements included in this press release are setforth in the "Forward-Looking Information: Certain CautionaryStatements" section of the Company's Annual Report on Form 10-K forthe year ended December 31, 2005, filed with the Securities andExchange Commission, and in other reports filed with the SEC. Allinformation in this press release is as of June 20, 2006 and theCompany undertakes no duty to update this information.

(1)McKenney JM, Jones PH, Bays HE, Knopp RH, Kashyap ML, Ruoff GE,Stanek EJ, McGovern ME. Comparative Lipid Effects of CombinationTherapy with a Statin and Extended-Release Niacin Versus Statin PlusEzetimibe Versus a Statin Alone. (Abstract presented at the XIVInternational Symposium on Atherosclerosis.)

(2)McKenney JM, Jones PH, Bays HE, Knopp RH, Kashyap ML, Ruoff GE,Stanek EJ, McGovern ME. Comparative Lipid Effects of CombinationTherapy with a Statin and Extended-Release Niacin Versus Statin PlusEzetimibe Versus a Statin Alone. (Abstract presented at the XIVInternational Symposium on Atherosclerosis.)

(3)McKenney JM, Jones PH, Bays HE, Knopp RH, Kashyap ML, Ruoff GE,Stanek EJ, McGovern ME. Comparative Lipid Effects of CombinationTherapy with a Statin and Extended-Release Niacin Versus Statin PlusEzetimibe Versus a Statin Alone. (Abstract presented at the XIVInternational Symposium on Atherosclerosis.)

(4)McKenney JM, Jones PH, Bays HE, Knopp RH, Kashyap ML, Ruoff GE,Stanek EJ, McGovern ME. Comparative Lipid Effects of CombinationTherapy with a Statin and Extended-Release Niacin Versus Statin PlusEzetimibe Versus a Statin Alone. (Abstract presented at the XIVInternational Symposium on Atherosclerosis.)

(5)McKenney JM, Jones PH, Bays HE, Knopp RH, Kashyap ML, Ruoff GE,Stanek EJ, McGovern ME. Comparative Lipid Effects of CombinationTherapy with a Statin and Extended-Release Niacin Versus Statin PlusEzetimibe Versus a Statin Alone. (Abstract presented at the XIVInternational Symposium on Atherosclerosis.)

(6)The Difference Between LDL and HDL Cholesterol. American HeartAssociation. 2005. Available at www.americanheart.org; accessed data6/6/06

(7)Executive Summary of the Third Report of the NationalCholesterol Education Program (NCEP) Expert Panel on Detection,Evaluation, and Treatment of High Blood Cholesterol in Adults (AdultTreatment Panel III). Expert Panel on Detection, Evaluation, andTreatment of High Blood Cholesterol in Adults. JAMA2001;285:2486-2497.

(8)Bays, H. Existing and investigational combination drug therapyfor high-density lipoprotein cholesterol. Am J Cardiol2002;90(suppl):30K-43K.

(9)NIASPAN (prescribing information). Cranbury, NJ: KosPharmaceuticals, Inc. 2005