Exhibit 99.4

UNAUDITED PRO FORMA COMBINED FINANCIAL STATEMENTS OF CORNERSTONE THERAPUETICS INC.

On December 28, 2011, Cornerstone Therapeutics Inc. (“Cornerstone”) entered into an Agreement and Plan of Merger (the “Merger Agreement”) by and among Cornerstone; Cohesion Merger Sub, Inc., a Delaware corporation and wholly owned subsidiary of the Cornerstone; Cardiokine, Inc., a Delaware Corporation (“Cardiokine”); and Shareholder Representative Services LLC, a Colorado limited liability company, solely in its capacity as the indemnification representative of the Cardiokine security holders. On December 30, 2011, the merger contemplated by the Merger Agreement (the “Merger”) was completed. Pursuant to the Merger, Cornerstone acquired all of the outstanding shares of Cardiokine.

The accompanying unaudited pro forma combined financial statements present the pro forma consolidated financial position and results of operations of the combined company based upon Cornerstone’s and Cardiokine’s historical financial statements, after giving effect to Cornerstone’s acquisition of Cardiokine and adjustments described in the following footnotes, and are intended to reflect the impact of this acquisition on Cornerstone on a pro forma basis.

The unaudited pro forma combined balance sheet as September 30, 2011 reflects the acquisition of Cardiokine as if it had been consummated on that date and includes historical information as reported by the separate companies as well as adjustments that give effect to events that are directly attributable to the Merger and that are factually supportable.

The unaudited pro forma combined statement of operations for the nine months ended September 30, 2011 and statement of income for the year ended December 31, 2010 give effect to the Merger as if it had been consummated on January 1, 2010 and include historical information as reported by the separate companies as well as adjustments that give effect to events that are directly attributable to the Merger, are expected to have a continuing impact and are factually supportable.

The accompanying unaudited pro forma combined financial statements are presented for illustrative purposes only. They do not purport to represent what Cornerstone’s consolidated results of operations and financial position would have been had the Merger actually occurred as of the dates indicated, and they do not purport to project Cornerstone’s future consolidated results of operations or financial position. The unaudited pro forma combined statements of operations and income do not reflect any adjustments for the effect of non-recurring items that we may realize as a result of the Merger. The unaudited pro forma combined financial statements include certain reclassifications to conform the historical financial information of Cardiokine to the presentation of Cornerstone.

Pro forma adjustments are necessary to reflect the estimated purchase price and to reflect the amounts related to tangible and intangible assets and liabilities acquired at an amount equal to the preliminary estimate of their fair values. The pro forma adjustments reflecting the completion of the acquisition are based upon the acquisition method of accounting in accordance with Accounting Standards Codification 805, “Business Combinations” (“ASC 805”), and the assumptions set forth in the notes to the unaudited pro forma combined financial statements. The unaudited pro forma combined balance sheet has been adjusted to reflect the allocation of the estimated purchase price to identifiable assets and liabilities

acquired, including an amount for goodwill representing the difference between the purchase price and the fair value of the identifiable assets and liabilities. The estimated purchase price was calculated based upon identifying an intangible asset for in-process research and development as well as identifying a pre-acquisition contingency based upon future obligations. This calculation is highly subjective and is subject to change.

You should read this information in conjunction with:

CORNERSTONE THEREAPEUTICS INC.

UNAUDITED PRO FORMA COMBINED BALANCE SHEET

AS OF SEPTEMBER 30, 2011

(in thousands, except share and per share data)

CORNERSTONE THEREAPEUTICS INC.

UNAUDITED PRO FORMA COMBINED STATEMENT OF OPERATIONS

NINE MONTHS ENDED SEPTEMBER 30, 2011

(in thousands, except share and per share data)

CORNERSTONE THEREAPEUTICS INC.

UNAUDITED PRO FORMA COMBINED STATEMENT OF INCOME

YEAR ENDED DECEMBER 31, 2010

(in thousands, except share and per share data)

CORNERSTONE THEREAPEUTICS INC.

NOTES TO UNAUDITED PRO FORMA COMBINED FINANCIAL STATEMENTS

The unaudited pro forma combined financial statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission. Certain information and certain footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”) have been omitted pursuant to such rules and regulations; accordingly, these pro forma forma financial statements should be read in connection with Cornerstone’s and Cardiokine’s historical audited and unaudited financial statements referred to above.

The acquisition method of accounting under U.S. GAAP requires, among other things, that most assets acquired and liabilities assumed be recognized at their fair values at the acquisition date. Fair value is defined under U.S. GAAP as “the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date.” Market participants are assumed to be buyers and sellers in the principal (or most advantageous) market for the asset or liability. Fair value measurements for an asset assume the highest and best use by these market participants. Fair value measurements can be highly subjective and it is possible that other professionals, applying reasonable judgment to the same facts and circumstances, could develop and support a range of alternative estimated amounts. Accordingly, the assets acquired and liabilities assumed were recorded at their respective fair values and added to those of Cornerstone.

Description of Transaction

On December 30, 2011, Cornerstone Therapeutics Inc. (“Cornerstone”) acquired Cardiokine, Inc., a specialty pharmaceutical company focused on developing hospital products for cardiovascular indications (“Cardiokine”), pursuant to an Agreement and Plan of Merger (the “Merger Agreement”) by and among Cornerstone; Cohesion Merger Sub, Inc., a wholly owned subsidiary of Cornerstone; and Shareholder Representative Services LLC, a Colorado limited liability company, solely in its capacity as the indemnification representative of the Cardiokine security holders. Cornerstone acquired Cardiokine primarily to obtain Cardiokine’s pending new drug application (“NDA”) for a lixivaptan compound to be used, if approved, to treat hyponatremia. In connection with the transaction, Cardiokine’s stockholders received Cardiokine’s cash on hand at closing, less the amount of a $2.7 million escrow fund established by Cardiokine out of its cash on hand to secure Cornerstone’s indemnification rights pursuant to the Merger Agreement, and Cornerstone assumed approximately $2.0 million of Cardiokine’s current liabilities. In addition, Cornerstone agreed to pay consideration consisting of each of the following: (1) $1.0 million paid shortly following closing; (2) either $7.0 million or $8.5 million if Cardiokine’s pending NDA for its lixivaptan compound, CRTX 080, is approved for sale by the U.S. Food and Drug Administration (the “FDA”); (3) up to $147.5 million based on the achievement of certain sales related milestones ($7.5 million at $75 million, $15 million at $150 million, $25 million at $250 million and $100 million at $500 million, each payable at the first time the annual sales reach the relevant milestone); (4) quarterly earnout payments of 8% or 12% of net sales of the approved product, with such rate being

dependent upon the scope of the labeling which the FDA may approve for the product; and (5) one-half of any proceeds realized from the license of the approved product outside the United States (collectively, the “Purchase Consideration”). The Purchase Consideration will be paid first to a subsidiary of Pfizer Inc. (“Pfizer”), the licensor of certain rights to the lixivaptan compound, in satisfaction of Cardiokine’s payment obligations to Pfizer, until Pfizer has been paid a total of $20,000,000. Thereafter, any further Purchase Consideration will be paid in accordance with the Merger Agreement to certain other parties for which obligations existed and then directly to Cardiokine’s former security holders.

Fair Value of Consideration Transferred

A summary of the purchase price is as follows (in thousands):

Assets Acquired and Liabilities Assumed

The total purchase price was allocated to the acquired tangible and intangible assets and assumed liabilities of Cardiokine based on their estimated fair values as of December 30, 2011. The excess of the purchase price over the estimated fair values of the assets acquired and liabilities assumed was allocated to goodwill.

The allocation of the total fair value of consideration transferred, as shown above, to the acquired tangible and intangible assets and assumed liabilities of Cardiokine based on their estimated fair values as of the closing date of the transaction is as follows (in thousands):

Prepaid and other assets consist primarily of an anticipated income tax refund related to NOL carryback claims and Cardiokine’s 2011 final tax return. The refund is classified in other current assets offset by a liability to Cardiokine’s former stockholders classified in accrued expenses.

The estimated fair value of in-process research and development related to the development program for lixivaptan, or CRTX 080, was determined using the excess-earning method under the income approach. Projected cash flows from the anticipated sales of the product were adjusted for the probabilities of approved labeling and commercialization of the product.

At the closing of the acquisition, Cornerstone recorded an $8.8 million contingent liability for contingent consideration potentially payable under the Merger Agreement. The initial fair value of this liability was determined using a discounted cash flow analysis incorporating the estimated future cash flows from potential milestones and royalty payments. The liability will be periodically assessed based on events and circumstances related to the underlying milestones, and any change will be recorded in Cornerstone’s consolidated statement of operations. The carrying amount of the liability may fluctuate significantly and actual amounts paid to Pfizer may be materially different from the carrying value of the liability.

Goodwill is calculated as the difference between the fair value of the consideration and the provisional values assigned to the assets acquired and liabilities assumed. None of the goodwill is expected to be deductible for tax purposes.

The accompanying unaudited pro forma combined financial statements present the pro forma consolidated financial position and results of operations of the combined company based upon the historical financial statements of Cornerstone and Cardiokine, after giving effect to the Cardiokine acquisition and adjustments described in the following footnotes, and are intended to reflect the impact of this acquisition on Cornerstone on a pro forma basis.

The unaudited pro forma combined balance sheet reflects the acquisition of Cardiokine as if it has been consummated on September 30, 2011 and includes pro forma adjustments for preliminary valuations by Cornerstone management of certain tangible and intangible assets as of the acquisition date of December 30, 2011.

The unaudited pro forma combined statement of operations for the nine months ended September 30, 2011 and unaudited pro forma combined statement of income for the year ended December 31, 2010 combine Cornerstone’s historical results for the nine months ended September 30, 2011 and year ended December 31, 2010 with Cardiokine historical results for the same periods. The unaudited pro forma statement of operations and unaudited pro forma statement of income give effect to the acquisition as if it had taken place on January 1, 2010.

The accompanying unaudited pro forma combined financial statements are presented for illustrative purposes only.

Pro forma adjustments are necessary to reflect the estimated purchase price and to reflect amounts related to Cardiokine’s net tangible and intangible assets and liabilities at an amount equal to the preliminary estimate of the fair values. The only intangible asset identified was in-process research and development valued at $11.5 million. Under the guidance of ASC 805, the fair value of in-process research and development is capitalized on the balance sheet until the project is either abandoned and written off or successfully commercialized, at which time Cornerstone would begin amortizing the fair value over the estimated useful life.

The unaudited pro forma combined financial statements do not include any adjustments for liabilities that may result from integration activities related to the Cardiokine acquisition. Additional assets or liabilities may be recorded that could affect amounts in the unaudited pro forma combined financial statements. During the measurement period, any such adjustments to provisional amounts would increase or decrease goodwill. Adjustments that occur after the end of the measurement period will be recognized in the post-combination current period operations.

The pro forma adjustments included in the unaudited pro forma combined financial statements are as follows:

The estimated fair value of in-process research and development related to the development program for lixivaptan, or CRTX 080, was determined using the excess-earning method under the income approach. Projected cash flows from the anticipated sales of the product were adjusted for the probabilities of approved labeling and commercialization of the product.

At the closing of the acquisition, Cornerstone recorded an $8.8 million contingent liability for contingent consideration potentially payable under the Merger Agreement. The initial fair value of this liability was determined using a discounted cash flow analysis incorporating the estimated future cash flows from potential milestones and royalty payments. The liability will be periodically assessed based on events and circumstances related to the underlying milestones, and any change will be recorded in Cornerstone’s consolidated statement of operations. The carrying amount of the liability may fluctuate significantly and actual amounts paid to Pfizer may be materially different from the carrying value of the liability.

Goodwill is calculated as the difference between the fair value of the consideration and the provisional values assigned to the assets acquired and liabilities assumed. None of the goodwill is expected to be deductible for tax purposes.

Shares used to calculate unaudited pro forma combined basic and diluted net income (loss) per share are based on the number of Cornerstone weighted-average shares used in computing historical net income (loss) per share, basic and diluted.