Kos Submits Supplemental New Drug Application To FDA For New Niaspan(R) CF Range of Products

-- Includes new optimized 1000mg Niaspan(R) CF formulation that has demonstrated an improved overall flushing profile vs. currently commercialized Niaspan, with a 42 percent reduction in severity, and a 43 percent reduction in duration of flushing

-- Niaspan CF launch planned for first quarter 2007

-- Plans in place to incorporate optimized Niaspan CF in future products over time

Kos Pharmaceuticals, Inc. (Nasdaq: KOSP) announced today that ithas submitted a supplemental New Drug Application for a completedosage range of Niaspan Caplet Formulation (CF) products for review tothe U.S. Food and Drug Administration (FDA). The Company has begunplanning for a first quarter 2007 launch of this new product.

The new range of Niaspan CF products include an optimized 1000mgformulation of the Kos HDL-boosting therapy Niaspan (niacinonce-daily, extended-release tablets). As previously announced, arecent clinical study demonstrated a significantly improved (p greaterthan 0.0001) overall flushing profile of optimized Niaspan CF versuscommercialized Niaspan, with a 42 percent reduction in flushingseverity and 43 percent reduction in the duration of flush. Notably,the significant reductions in flushing severity and duration wereachieved in the absence of aspirin or other NSAID co-administration,which is often recommended to mitigate flushing during the first weeksof therapy when the side effect is most likely to occur. Flushing is arelatively common and transient side effect reported by patients whentaking Niaspan to increase their HDL-C, or "good" cholesterol, andreduce LDL and triglycerides.

"This complete dosage range of Niaspan CF products draws upon theproven efficacy and safety of Niaspan, and could further enhancepatient acceptance and compliance in addition to improving tabletaesthetics and mechanical strength," said Adrian Adams, President andCEO of Kos Pharmaceuticals. "Our planned and evolving lifecyclemanagement initiatives further leverage our expertise in formulationdevelopment and continue to help address a significant clinical need.The potential for improved tolerability of Niaspan CF could thereforeincrease the number of patients who can benefit from this highlydifferentiated and potentially life-saving therapy."

Niaspan is the only FDA-approved once-daily prescription niacinformulation for the treatment of lipid disorders with the ability toelevate HDL by up to 26 percent. It is also indicated for thesecondary prevention of heart attacks, and in combination with abile-acid binding resin, to promote regression of coronaryatherosclerosis in patients with high cholesterol.

Based on the demonstrated patient benefits of the optimizedNiaspan CF product, Kos is planning to develop other optimizedproducts as part of a fully integrated development program designed tofurther enhance Kos' pioneering and leading position in the HDLraising area.

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.

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(R) 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 Teveten HCT 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 anticipated launch date for Niaspan CF, thedevelopment of future optimized Niaspan products, the potentialincrease in the number of patients and enhancement of patientacceptance and compliance as a result of improved tolerability ofNiaspan CF, the further enhancement of the Company's pioneering andleading position in the HDL raising area, the Company's strong andgrowing research 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 includemarket acceptance of Niaspan CF and optimized Niaspan CF, theprotection afforded by the Company's patents and those related to itsacquired and licensed products, the ability to build awareness for theCompany's products, including Niaspan CF and optimized Niaspan CF,within the medical community, the continuing growth of thecardiovascular, respiratory and allergy markets, the Company's abilityto increase the size of its sales force and to attract and retainsales professionals, the Company's and its licensors' ability toachieve regulatory approvals for products under development and tosuccessfully launch such products in a timely manner, the ability ofthird party suppliers to the Company continuing to be able to performtheir supply obligations, the Company's ability to entered intoadditional new business development opportunities, the progress of theCompany's research and development pipeline, the effect of conditionsin the pharmaceutical industry and the economy in general, as well ascertain other risks. A more detailed discussion of risks attendant tothe forward-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 July 12, 2006 and theCompany undertakes no duty to update this information.