This discussion and analysis should be read in conjunction with our financial statements and accompanying notes included elsewhere in this report. Operating results are not necessarily indicative of results that may occur in future periods.

This document contains forward-looking statements that are based upon current expectations, within the meaning of the Private Securities Reform Act of 1995. We intend that such statements be protected by the safe harbor created thereby. Forward-looking statements involve risks and uncertainties and our actual results and the timing of events may differ significantly from the results discussed in the forward-looking statements. Examples of such forward-looking statements include, but are not limited to statements concerning:

• the timing of the proposed meeting between King Pharmaceuticals, Inc., or King, and the U.S. Food and Drug Administration, or FDA, with respect to the New Drug Application, or NDA for Remoxy;

• potential submission of additional non-clinical data with respect to the Remoxy NDA;

• collaboration, milestone and royalty revenue that may be received from King and other payments we may receive from our strategic alliances;

• the duration of the development period for all four expected drug candidates under our collaboration with King;

• potential sources of clinical and commercial supply of Remoxy and its components;

• expansion of our product line, including the formulation of additional dosage forms of Remoxy;

• expected amounts of, or fluctuations in, collaboration revenue and payments;

• future operating losses and anticipated operating and capital expenditures;

• uses of proceeds from our securities offerings;

• the potential benefits of our drug candidates;

• the sufficiency of materials required for the clinical development of our drug candidates;

• the utility of protection of our intellectual property;

• expected future sources of revenue and capital;

• potential competitors or competitive products;

• future market acceptance of our drug candidates;

• fluctuations in our expenses and operating results;

• future expectations regarding trade secrets, technological innovations, licensing agreements and outsourcing of certain business functions;

• anticipated hiring and development of our internal systems and infrastructure;

• potential non-realization of deferred tax assets; and

• the sufficiency of our current resources to fund our operations over the next twelve months.

Such forward-looking statements involve risks and uncertainties, including, but not limited to, those risks and uncertainties relating to:

• difficulties or delays in regulatory approval, production, commercialization, development, testing and clinical trials (including patient enrollment) of our drug candidates;

• the successful development of drug candidates pursuant to our collaboration agreements, including our collaboration agreement with King, and the continuation of such agreements;

• unexpected adverse side effects or inadequate therapeutic efficacy of our drug candidates that could slow or prevent product approval (including the risk that results of clinical trials may not indicate that our drug candidates are safe and effective) or market acceptance of such products, if approved;

• the uncertainty of patent protection for our intellectual property or trade secrets;

• potential infringement of the intellectual property rights or trade secrets of third parties;

• pursuing in-license and acquisition opportunities;

• hiring and retaining personnel; and

• our financial position and our ability to obtain additional financing if necessary.

In addition, such statements are subject to the risks and uncertainties discussed in the "Risk Factors" section and elsewhere in this document.

Overview

We are a biopharmaceutical company that develops novel drugs. In December 2008, we received from the FDA a Complete Response Letter for the NDA for Remoxy in which the FDA determined that the NDA was not approved. The FDA indicated additional non-clinical data will be required to support the approval of Remoxy. The FDA has not requested or recommended additional clinical efficacy studies prior to approval. Primary responsibility for the regulatory approval of REMOXY was recently assumed by King under our strategic alliance. King assumed all future regulatory and other activities for Remoxy and we continue to conduct development activities for three other product candidates under our strategic alliance with King. There are no changes to any economic terms of our strategic alliance to develop and commercialize REMOXY and three other abuse-resistant pain medications. Upon approval of REMOXY, we will receive a $15.0 million cash milestone payment from King. King is obligated to pay us a 20% royalty on net sales of drugs developed in connection with the strategic alliance, except as to the first $1.0 billion in cumulative net sales of such drugs, for which the royalty is set at 15%. We believe King plans to meet with the FDA in mid-2009 regarding the NDA for Remoxy. We believe this FDA meeting will provide King and us with a more reliable context in which to make projections about Remoxy.

We also have the following investigational drug candidates in clinical programs:

• PTI-202 and PTI-721, which are proprietary, abuse-resistant forms of opioid drugs.

We and King are engaged in a strategic alliance to develop and commercialize Remoxy, PTI-202, PTI-721 and another abuse-resistant opioid painkiller.

All of our collaboration, contract and milestone revenues are recognized pursuant to our strategic alliance with King. King made an upfront cash payment of $150.0 million to us in 2005. King has made milestone payments to us of $25.0 million related to clinical and regulatory milestones under the strategic alliance. We could also receive from King up to $125.0 million in additional milestone payments in the course of clinical development of the abuse-resistant opioid painkillers under the strategic alliance. Subject to certain limitations, King is also obligated to fund development expenses incurred by us pursuant to the collaboration agreement. King is obligated to fund the commercialization expenses of, and has the exclusive right to market and sell, drugs developed in connection with the strategic alliance. King is obligated to pay us a 20% royalty on net sales of drugs developed in connection with the strategic alliance, except as to the first $1.0 billion in cumulative net sales of such drugs, for which the royalty is set at 15%.

Although we were profitable in 2008 based on payments received from King and interest income, we have yet to generate any revenues from product sales. Through March 31, 2009, we have recorded an accumulated deficit of approximately $115.9 million. These losses have resulted principally from costs incurred in connection with research and development activities, salaries and other personnel-related costs and general corporate expenses. Research and development activities include costs of preclinical and clinical trials as well as clinical supplies associated with our drug candidates. Salaries and other personnel-related costs include non-cash stock-based compensation associated with options and other equity awards granted to employees and non-employees. Our operating results may fluctuate substantially from period to period as a result of the timing and enrollment rates of clinical trials for our drug candidates and our need for clinical supplies.

We expect to continue to use significant cash resources in our operations for the next several years and expect that our cash requirements for operating activities and capital expenditures may increase substantially in the future as we:

• continue to conduct preclinical and clinical trials for our drug candidates;

• seek regulatory approvals for our drug candidates;

• develop, formulate, manufacture and commercialize our drug candidates;

• implement additional internal systems and develop new infrastructure;

• acquire or in-license additional products or technologies, or expand the use of our technology;

• maintain, defend and expand the scope of our intellectual property; and

• hire additional personnel.

Product revenue will depend on the ability to receive regulatory approvals for, and successfully market, our drug candidates. If development efforts result in regulatory approval and successful commercialization of drug candidates, we will generate revenue from direct sales of our drugs and, for those of our drugs that are licensed to collaborators, from the receipt of license fees and royalties from sales of licensed products. We conduct our research and development programs through a combination of internal and collaborative programs. We rely on arrangements with universities, our collaborators, contract research organizations and clinical research sites for a significant portion of our product development efforts.

The following table summarizes expenses by category for all of our research and development efforts (in thousands):

                                         Three Months Ended March 31,
                                           2009              2008
               Compensation            $       3,176    $         3,047
               Contractor fees(1)              3,134              6,945
               Supplies(2)                       506              1,336
               Other common costs(3)             820              1,156

                                       $       7,636    $        12,484

(1) Contractor fees generally include expenses for preclinical studies and clinical trials.

(2) Supplies generally include costs for formulation and manufacturing activities.

(3) Other common costs generally include the allocation of common costs such as facilities.

Our technology has been applied across certain of our portfolio of drug candidates. Data, know-how, personnel, clinical results, research results and other matters related to the research and development of any one of our drug candidates may also relate to, and further the development of, our other drug candidates. For example, we expect that results of non-clinical studies, such as pharmacokinetics, toxicology and other studies, regarding certain components of our drug candidate Remoxy to be applicable to the other potential drug candidates that may arise out of our collaboration with King since all such potential drug candidates are expected to utilize such components. As a result, costs allocated to a specific drug candidate may not necessarily reflect the actual costs surrounding research and development of that drug candidate due to cross application of the foregoing. We are also developing a novel antibody drug candidate to treat metastatic melanoma. Research and development expenses related to this technology include approximately $0.8 million and $0.7 million in the three months ended March 31, 2009 and 2008, respectively, primarily in contractor fees and compensation. Research and development expenses related to hemophilia and other product candidates include approximately $1.6 million and $1.1 million in the three months ended March 31, 2009 and 2008, respectively, primarily in contractor fees and compensation.

Estimating the dates of completion of clinical development, and the costs to complete development, of our drug candidates would be highly speculative, subjective and potentially misleading. Pharmaceutical products take a significant amount of time to research, develop and commercialize. The clinical trial portion of the development of a new drug alone usually spans several years. We expect to reassess our future research and development plans based on our review of data we receive from our current research and development activities. The cost and pace of our future research and development activities are linked and subject to change.

Critical Accounting Policies

The preparation of our financial statements in accordance with United States generally accepted accounting principles requires us to make estimates and assumptions that affect the reported amounts of assets, liabilities, revenues, expenses and interest income in our financial statements and accompanying notes. We evaluate our estimates on an ongoing basis, including those estimates related to agreements, research collaborations and investments. We base our estimates on historical experience and various other assumptions that we believe to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. The following items in our financial statements require significant estimates and judgments:

• Expenses for clinical trials. We incur expenses for clinical trials from the planning phase through patient enrollment to reporting of the underlying data. We estimate expenses incurred for clinical trials that are in process based on patient enrollment and based on clinical data collection and management. Costs that are associated with patient enrollment are recognized as each patient in the clinical trial completes enrollment. Estimated clinical trial costs related to enrollment can vary based on numerous factors, including expected number of patients in trials, the number of patients that do not complete participation in a trial, and when a patient drops out of a trial. Information about patient enrollment can become available significantly after we report our expenses for clinical trials, in which case we would change our estimate of the remaining cost of a trial. Costs that are based on clinical data collection and management are recognized based on estimates of unbilled goods and services received. In the event of early termination of a clinical trial, we would accrue an amount based on estimates of the remaining non-cancelable obligations associated with winding down the clinical trial.

• Stock-based compensation. We recognize expense in the income statement for the fair value of all share-based payments to employees and directors, including grants of employee stock options and other share based awards. For stock options, we use the Black-Scholes option valuation model and the single-option award approach and straight-line attribution method. Using this approach, the compensation cost is amortized on a straight-line basis over the vesting period of each respective stock option, generally four years. We estimate forfeitures and adjust this estimate periodically based on the extent to which future actual forfeitures differ, or are expected to differ, from such estimates.

We have granted share-based awards that vest upon achievement of certain performance criteria, or Performance Awards. The value of these awards is the product of the number of shares of our common stock to be issued under the award multiplied by the fair market value of a share of our common stock on the date of grant. These awards include future performance conditions. We estimate an implicit service period for achieving these performance conditions. Performance Awards vest and common stock is issued on

achieving performance conditions. We recognize stock-based compensation expense for Performance Awards when we conclude that achieving a performance condition is probable. We periodically review and update as appropriate our estimates of the implicit service periods and the likelihood of achieving the performance conditions.

• Revenue recognition and deferred program fee revenue. We recognize program fee revenue, collaboration revenue and milestone revenue in connection with our strategic alliance with King. Program fee revenue is derived from the upfront payment from King received in December 2005 and is recognized ratably over our estimate of the development period of four drug candidates expected to be developed under the strategic alliance with King. We currently estimate the development period for all four expected drug candidates to extend through September 2014. We review the estimated development period on a quarterly basis and change it if appropriate based upon our latest expectations. Collaboration revenues from reimbursement of development expenses are generally recognized when King has completed its review of the expenses invoiced to them. King is obligated to pay us milestone payments contingent upon the achievement of certain substantive events in the development of Remoxy and the other abuse-resistant opioid painkillers under the strategic alliance. We recognize milestone payments from King as revenue when we achieve the underlying developmental milestone as the milestone payments are not dependent upon any other future activities or achievement of any other future milestones and the achievement of each of the developmental milestones were substantively at risk and contingent at the effective date of the collaboration. Substantial effort is involved in achieving each of the developmental milestones. These milestones represent the culmination of discrete earnings processes and the amount of each milestone payment is reasonable in relation with the level of effort associated with the achievement of the milestone. Each milestone payment is non-refundable and non-creditable when made. The ongoing research and development services being provided to King under the collaboration are priced at fair value based upon the reimbursement of expenses incurred pursuant to the collaboration with King.

• Taxes. We make estimates and judgments in determining the need for a provision for income taxes, including the estimation of our taxable income or loss for each full fiscal year. We have accumulated significant deferred tax assets. Deferred income taxes reflect the tax effects of net operating loss and tax credit carryovers and temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Realization of deferred tax assets is dependent upon future earnings, if any. We are uncertain of the timing and amount of any future earnings. Accordingly, except for $1.3 million of net deferred tax assets recognized on our balance sheet included in other assets as of March 31, 2009, we offset the net deferred tax assets with a valuation allowance. We may in the future determine that more of our deferred tax assets will likely be realized, in which case we will reduce our valuation allowance in the quarter in which such determination is made. If the valuation allowance is reduced, we may recognize a benefit from income taxes in our statement of operations in that period.

Results of Operations

Three months ended March 31, 2009 and 2008

Revenue - Collaboration revenue

Collaboration revenues were $3.2 million and $11.1 million in the three months ended March 31, 2009 and 2008, respectively. These revenues related to reimbursement of our development expenses incurred pursuant to the King strategic alliance. Collaboration revenues were lower in the first quarter of 2009 as compared to the first quarter of 2008 primarily because the reimbursable expenses we incurred pursuant to the strategic alliance with King were lower in the first quarter of 2009 as compared to the first quarter of 2008. We incurred expenses of $1.4 million in the first quarter of 2009 for which we expect King to complete their review and to reimburse us in the second quarter of 2009.

We expect the amount and timing of collaboration revenue to fluctuate in relation to the amount and timing of the underlying research and development expenses, as well as the timing of completion of King's review of submitted expenses.

Revenue - Program fee revenue

King paid us a $150.0 million upfront fee in connection with the closing of our strategic alliance with them in December 2005. Program fee revenues recognized from this upfront fee were $3.6 for both of the three months ended March 31, 2009 and 2008. We expect to recognize the remainder of the program fee ratably over our estimate of the development period under the strategic alliance with King. We currently estimate the development period for all four expected drug candidates to extend through September 2014.

Research and Development Expense

Research and development expense consists primarily of costs of drug development work associated with our drug candidates, including:

• preclinical testing,

• clinical trials,

• clinical supplies and related formulation and design costs, and

• salaries and other personnel-related expenses.

Research and development expense decreased to $7.6 million from $12.5 million in the three months ended March 31, 2009 and 2008, respectively. The decrease was primarily due to decreases in clinical and other development activities for Remoxy, partially offset by increased activities in metastatic melanoma, hemophilia and other projects. Research and development expenses included non-cash stock-based compensation expense of $1.1 million and $1.0 million in the three months ended March 31, 2009 and 2008, respectively.

We expect research and development expenses to fluctuate over the next several years as we continue our development efforts. In particular, with King assuming most development activities for Remoxy, we expect our related reimbursable expenses for Remoxy will be lower in the future. We expect our development efforts to result in our drug candidates progressing through various stages of clinical trials, including current and potential clinical trials for our other abuse-resistant drug candidates, as well as further clinical development of our product candidates in metastatic melanoma and hemophilia. King is obligated to reimburse development expenses for our abuse-resistant drug candidates pursuant to our strategic alliance. Our research and development expenses may fluctuate from period to period due to the timing and scope of our development activities and the results of clinical trials and preclinical studies.

General and Administrative Expense

General and administrative expenses consist primarily of compensation and other general corporate expenses. General and administrative expenses decreased to $1.7 million from $1.8 million in the three months ended March 31, 2009 and 2008, respectively. The decrease was primarily due to decreases in professional fees and operating expenses. General and administrative expenses included non-cash stock-based compensation expense of $0.5 million for both the three months ended March 31, 2009 and 2008. We expect general and administrative expenses to increase over the next several years in connection with support of pre-commercialization and commercialization activities for our drug candidates. The increase may fluctuate from period to period due to the timing and scope of these activities and the results of clinical trials and preclinical studies.

Interest Income

Interest income decreased to $0.4 million from $2.2 million for the three months ended March 31, 2009 and 2008, respectively, primarily due to decreases in prevailing interest rates on investments in marketable securities and, to a lesser extent, decreased average balances of marketable securities. We expect our interest income to decrease in the future as we use cash to fund our operations.

Liquidity and Capital Resources

Since inception, we have financed our operations primarily through public and private stock offerings, payments received under our strategic alliance with King, and interest earned on our investments. We intend to continue to use our capital resources to fund research and development activities, capital expenditures, working capital requirements and other general corporate purposes. As of March 31, 2009, cash, cash equivalents and marketable securities were $185.6 million.

Net cash used in operating activities was $3.8 million for the three months ended March 31, 2009 compared to net cash provided by operating activities of $1.6 million for the three months ended March 31, 2008. The change was primarily due to decreased activity related to reimbursable expenses for our abuse resistant products candidates and increased activities in our other product candidates.

Net cash provided by investing activities was $23.4 million in the three months ended March 31, 2009 and $58.6 million for the three months ended March 31, 2008. Cash from investing activities for the three months ended March 31, 2009 and March 31, 2008 consisted of sales and maturities of marketable securities. We did not use any cash for purchases of property, equipment and leasehold improvements during the three months ended March 31, 2009 or 2008. We expect to continue to invest in our infrastructure to support our operations.

Net cash provided by financing activities was $39,000 in the three months ended March 31, 2009 and net cash used by financing activities was $16.0 million in the three months ended March 31, 2008. In the three months ended March 31, 2008, we repurchased stock under a stock buyback plan that was completed in the three months ended June 30, 2008. Other cash from financing activities in both 2009 and 2008 consisted of proceeds received from the issuance of our common stock pursuant to stock option exercises.

We had $43.5 million of total deferred tax assets at December 31, 2008. Realization of these deferred tax assets is dependent on future earnings, if any. We are uncertain about the timing and amount of any future earnings. We have concluded that it is more likely than not that such deferred tax assets will not be realized. Accordingly, except for $1.3 million of deferred tax assets included in other assets as of March 31, 2009, we offset the deferred tax asset with a valuation allowance. There is a high degree of uncertainty regarding the timing of future cash outflows associated with our FASB Interpretation No. 48, "Accounting for Uncertainty in Income Taxes," or Interpretation 48. Our net Interpretation 48 liability at March 31, 2009 does not result in a material contractual obligation.

We currently lease approximately 41,200 square feet of general office space pursuant to non-cancelable operating leases that will expire in 2010 and 2012. Future minimum lease payments are as follows as of December 31, 2008 (in thousands):

2009 2010 2011 2012 Total Future minimum lease payments $ 743 $ 713 $ 570 $ 339 $ 2,365

We have license agreements that require us to make milestone payments upon the successful achievement of milestones, including clinical milestones. Our license agreements also require us to pay certain royalties to our licensors if we . . .