**UNITED
      STATES**


**SECURITIES
      AND EXCHANGE COMMISSION**


**Washington,
      DC 20549**





**FORM
      10-QSB**





x
            QUARTERLY
                REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF
                1934 For the quarterly period ended March
              31,
              2006




OR





o
            TRANSITION
                REPORT UNDER SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF
                1934 For the transition period from _______
              to
              _______




Commission
      file number 000-51473





**Cougar
      Biotechnology, Inc.**


(Exact
      Name of Registrant as Specified in Its Charter)





Delaware
              (State
                or other jurisdiction of
              incorporation
                or organization)
            20-2903204
              (I.R.S.
                Employer Identification No.)




10990
      Wilshire Boulevard, Suite 1200, Los Angeles, CA 90024


(Address
      of principal executive offices)





(310)
      943-8040


(Issuer’s
      telephone number)


Check
      whether the issuer: (1) filed all reports required to be filed by Section 13
      or
      15(d) of the Securities Exchange Act of 1934 during the preceding 12 months
      (or
      for such shorter period that the issuer was required to file such reports),
      and
      (2) has been subject to such filing requirements for the past 90 days. Yes
xNo o





Indicate
      by check mark whether the registrant is a shell company (as defined by Rule
      12b-2 of the Exchange Act). Yeso  Nox


As
      of May
      8, 2006 there were 4,607,105 shares of the issuer’s common stock, $.0001 par
      value, outstanding.





Traditional
      Small Business Disclosure Format (check one): Yes oNo x












**INDEX**




Page**PART
                I**
            **FINANCIAL
                INFORMATION**Item
                1.
            Unaudited
                Condensed Consolidated Balance Sheets
            3Unaudited
                Condensed Consolidated Statements of Operations
            4Unaudited
                Condensed Consolidated Statement of Stockholders’ Equity
                (Deficiency)
            5Unaudited
                Condensed Consolidated Statements of Cash Flows
            6Notes
                to Unaudited Condensed Consolidated Financial Statements
            7Item
                2.
            Management’s
                Discussion and Analysis of Financial Condition and Results of
                Operations
            9Item
                3.
            Controls
                and Procedures
            12**PART
                II**
            **OTHER
                INFORMATION**Item
                5.
            Other
                Information
            13Item
                6.
            Exhibits
            13Signatures
            15





2


**PART
      I - FINANCIAL INFORMATION:**





**Item
      1. UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS**








**SRKP
      4, INC. AND SUBSIDIARY**





**(A
      DEVELOPMENT STAGE COMPANY)**





**CONDENSED
      CONSOLIDATED BALANCE SHEETS**


**(Unaudited)**




**March
                31,**
            
            **December
                31,****2006**
            
            **2005****ASSETS**  Current
                  assets:Cash
                  and cash equivalents
              
              $
              --
              
              $
              4,628Totals
              
              $
              --
              
              $
              4,628**LIABILITIES
                  AND STOCKHOLDERS' DEFICIENCY**Current
                  liabilities:Advance
                  from stockholders
              
              $
              12,500
              
              $
              12,500Total
                  liabilities
              
              
              12,500
              
              
              12,500Commitments
                  and contingenciesStockholders'
                  deficiency:Preferred
                  stock - $.0001 par value; 10,000,000 sharesauthorized;
                  none issued or outstanding
              
              
              --
              
              
              --Common
                  stock - $.0001 par value; 100,000,000 sharesauthorized;
                  2,700,000 shares issued and outstanding
              
              
              270
              
              
              270Additional
                  paid-in capital
              
              
              24,730
              
              
              24,730Deficit
                  accumulated during the development stage
              
              
              (37,500
              )
              
              (32,872
              )Total
                  stockholders' deficiency
              
              
              (12,500
              )
              
              (7,872
              )Totals
              
              $
              --
              
              $
              4,628




SEE
        ACCOMPANYING NOTES TO THE CONDENSED CONSOLIDATED
        FINANCIAL STATEMENTS
  3




**SRKP
      4, INC. AND SUBSIDIARY**





**(A
      DEVELOPMENT STAGE COMPANY)**





**CONDENSED
      CONSOLIDATED STATEMENTS OF OPERATIONS**


(Unaudited)


Period
                  FromMay
                  24, 2005Three
                  Months Ended
              
              (date
                  of inception) toMarch
                  31, 2006
              
              March
                  31, 2006Operating
                  expenses:General
                  and administrative
              
              $
              4,628
              
              $
              37,500Totals
              
              
              4,628
              
              
              37,500Net
                  loss
              
              $
              (4,628
              )
              $
              (37,500
              )Net
                  loss per share
              
              $
              (.00
              )Weighted-average
                  common sharesoutstanding
                  - basic
              
              
              2,700,000




SEE ACCOMPANYING NOTES TO THE CONDENSED
      CONSOLIDATED FINANCIAL STATEMENTS




4


**SRKP
      4, INC. AND SUBSIDIARY**





**(A
      DEVELOPMENT STAGE COMPANY)**





**CONDENSED
      CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ DEFICIENCY**


(Unaudited)





Period
      from **** May
      24,
      2005 (date of inception) through March 31, 2006






DeficitAdditional
            
            
            AccumulatedCommon
                Stock
            
            
            Paid-in
            
            
            During
                theShares
            
            
            Amount
            
            
            Capital
            
            
            Development
                Stage
            
            
            TotalIssuance
                of shares of common stock at $.0093 per share
            
            
            2,700,000
            
            $
            270
            
            $
            24,730
            
            
            
            
            $
            25,000Net
                loss
            
            
            
            
            
            
            
            
            
            
            $
            (32,872
            )
            
            (32,872
            )Balance
                at December 31, 2005
            
            
            2,700,000
            
            
            270
            
            
            24,730
            
            
            (32,872
            )
            
            (7,872
            )Net
                loss
            
            
            
            
            
            
            
            
            
            
            
            (4,628
            )
            
            (4,628
            )**Balance
                at March 31, 2006**
            
            
            **2,700,000**
            
            **$**
            **270**
            
            **$**
            **24,730**
            
            **$**
            **(37,500**
            **)**
            **$**
            **(12,500**
            **)**







SEE
      ACCOMPANYING NOTES TO THE CONDENSED CONSOLIDATED
      FINANCIAL STATEMENTS




5


**SRKP
      4, INC. AND SUBSIDIARY**





**CONDENSED
      CONSOLIDATED STATEMENTS OF CASH FLOWS**


**THREE
      MONTHS ENDED MARCH 31, 2006 AND THE PERIOD FROM**


**MAY
      24, 2005 (DATE OF INCEPTION) TO MARCH 31, 2006**




CumulativePeriodFromMay
                  24, 2005Three
                  Months
              
              (date
                  ofEnded
              
              inception)
                  toMarch
                  31, 2006
              
              March
                  31, 2006Operating
                  activities:Net
                  loss
              
              $
              (4,628
              )
              $
              (37,500
              )Net
                  cash used in operating activities
              
              
              (4,628
              )
              
              (37,500
              )Financing
                  activities:Net proceeds from issuance of common stock
              
              
              
              
              
              25,000Advances
                  from stockholders
              
              
              --
              
              
              12,500Net
                  cash provided by financing activities
              
              
              --
              
              
              37,500Net
                  decrease in cash and cash equivalents
              
              
              (4,628
              )
              
              --Cash
                  and cash equivalents, beginning of period
              
              
              4,628
              
              
              --Cash
                  and cash equivalents, end of period
              
              $
              --
              
              $
              --




SEE ACCOMPANYING NOTES TO THE CONDENSED
      CONSOLIDATED FINANCIAL STATEMENTS


6


**SRKP
      4, INC. AND SUBSIDIARY**


**(A
      DEVELOPMENT STAGE COMPANY)**





**NOTES
      TO UNAUDITED CONDENSED CONSOLIDATED FINANCIAL STATEMENTS**





**NOTE
      1. BUSINESS DESCRIPTION**





SRKP
      4,
      Inc. (the “Company”), a development stage company, was organized under the laws
      of the State of Delaware on May 24, 2005 for the purpose of acquiring an
      operating business. The Company has had limited activities and has not generated
      any revenue as of March 31, 2006 and, accordingly, is in the development stage
      as defined in Financial Accounting Standards Board Statement No. 7.





**NOTE
      2. BASIS OF PRESENTATION:**





The
      accompanying unaudited condensed financial statements have been prepared in
      accordance with accounting principles generally accepted in the United States
      of
      America, pursuant to the rules and regulations of the Securities and Exchange
      Commission for interim financial information. Accordingly, the financial
      statements do not include all information and footnotes required by accounting
      principles generally accepted in the United States of America for complete
      annual financial statements. In the opinion of management, the accompanying
      unaudited condensed financial statements reflect all adjustments, consisting
      of
      only normal recurring adjustments, considered necessary for a fair presentation.
      Interim operating results are not necessarily indicative of results that may
      be
      expected for the year ending December 31, 2006 or for any subsequent period.
      These statements should be read in conjunction with the audited financial
      statements for SRKP 4, Inc. and notes thereto for the year ended December 31,
      2005 and filed with Form 10-KSB dated March 3, 2006.





**NOTE
      3. LIQUIDITY AND CAPITAL RESOURCES**





The
      Company reported a net loss of $4,628 for the three months ended March 31,
      2006.
      The net loss from date of inception, May 24, 2005 to March 31, 2006 amounted
      to
      $37,500. We have financed our operations since inception primarily through
      equity debt financing and from stockholder advances. The Company’s ability to
      continue as a going concern is dependent upon its ability to develop additional
      sources of capital, locate and complete a merger with another company, and
      ultimately, achieve profitable operations. We can give no assurances that any
      additional capital that we are able to obtain will be sufficient to meet our
      needs.





**NOTE
      4. SUMMARY OF SIGNIFICENT ACCOUNTING POLICIES**





**Use
      of estimates**





The
      preparation of financial statements in conformity with accounting principles
      generally accepted in the United States of America requires management to make
      estimates and assumptions that affect reported amounts of assets and liabilities
      as of the date of the balance sheet and reported amounts of expenses for the
      periods presented. Accordingly, actual results could differ from those
      estimates.





**Net
      loss per share**





Basic
      net
      loss per share is computed by dividing net loss by the weighted-average number
      of common shares outstanding during the periods presented as required by SFAS
      No. 128, “Earnings Per Share”.


**PRINCIPLES
        OF CONSOLIDATION**
 
 The
        accompanying Consolidated Financial Statements include the accounts **of** SRKP
        4,
        Inc. and SRKP Acquisition Corp. All significant intercompany accounts and
        transactions have been eliminated in consolidation.


**NOTE
      5. SUBSEQUENT EVENTS**





**Acquisition
      of Cougar Biotechnology, Inc.**





Pursuant
      to an Agreement and Plan of Merger dated February 27, 2006 (the “Merger
      Agreement”) by and among us, SRKP Acquisition Corp., a Delaware corporation and
      our wholly-owned subsidiary, and Cougar Biotechnology, Inc., a Delaware
      corporation (“Cougar”), SRKP Acquisition Corp. merged with and into Cougar, with
      Cougar remaining as the surviving corporation and our wholly-owned subsidiary.
      Cougar in-licenses or acquires clinical stage products that have previously
      been
      tested in clinical trials for the treatment of cancer. This transaction is
      referred to throughout this report as the “Merger.” The Merger was effective as
      of April 3, 2006, upon the filing of a certificate of merger with the Delaware
      Secretary of State. In consideration for their shares of Cougar capital stock,
      and in accordance with the Agreement, the stockholders of Cougar at March 31,
      2006 received an aggregate of 3,553,021 shares of our common stock. Upon
      completion of the Merger and the Redemption (as defined below), Cougar
      stockholders held 100% of our capital stock. In addition, we assumed all of
      the
      rights and obligations relating to all other securities convertible into and
      exercisable for shares of Cougar capital stock outstanding immediately prior
      to
      the Merger, which constitute, on a fully-diluted basis, the rights to acquire
      an
      aggregate 2,327,299 shares of our common stock. The Merger will be accounted
      for
      as a reverse merger in which Cougar will be the accounting
      acquirer.





7


As
      a
      condition to the Merger, we entered into an Indemnity Agreement dated April
      3,
      2006 with our former officers and directors, pursuant to which we agreed to
      indemnify such former officers and directors for actions taken by such officers
      and directors in their official capacities relating to the consideration,
      approval and consummation of the Merger.




On
      April
      6, 2006, our board of directors approved a transaction pursuant to which Cougar
      merged with and into us, and we remained as the surviving corporation. In
      connection with this parent-subsidiary merger, we relinquished our prior
      corporate name, SRKP 4, Inc., and assumed in its place the name “Cougar
      Biotechnology, Inc.” The parent-subsidiary merger and name change became
      effective on April 6, 2006.





**Redemption
      Agreement**





Contemporaneously
      with the closing of the Merger, pursuant to the terms of a Redemption Agreement
      dated February 27, 2006 by and among the Company and its then-current
      stockholders, the Company completed a redemption of an aggregate of 2,700,000
      shares of common stock (the “Redemption”) from its former stockholders in
      consideration of an aggregate of $200,000 paid by Cougar, less (i) the aggregate
      amount of fees, costs and expenses of our attorneys, accountants and other
      service providers incurred by the Company on or prior to the effective time
      and
      (ii) an aggregate of $12,500 to be paid to such former stockholders on a pro
      rata basis in satisfaction of an outstanding obligation of the Company to such
      former stockholders. The 2,700,000 shares constituted all of the issued and
      outstanding shares of the Company’s capital stock, on a fully-diluted basis,
      immediately prior to the Merger.




8


**Item
      2. MANAGEMENT’S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION
      AND**


**RESULTS
      OF OPERATION**





**Note
      Regarding Forward-Looking Statements**





The
      following discussion of our financial condition and results of operations should
      be read in conjunction with the financial statements and the notes to those
      statements included elsewhere in the Quarterly Report. This Quarterly Report
      contains statements that are not historical, but are forward-looking in nature,
      including statements regarding the expectations, beliefs, intentions or
      strategies regarding the future. In particular, the “Management’s Discussion and
      Analysis or Plan of Operation” section in Part I, Item 2 of this quarterly
      report includes forward-looking statements that reflect our current views with
      respect to future events and financial performance. We use words such as we
      “expect,” “anticipate,” “believe,” and “intend” and similar expressions to
      identify forward-looking statements. A number of important factors could,
      individually or in the aggregate, cause actual results to differ materially
      from
      those expressed or implied in any forward-looking statements. Such factors
      include, but are not limited to, our ability to obtain additional financing,
      our
      ability to develop and maintain customer relationships, regulatory developments
      relating to and the general success of our product and product candidates,
      and
      our ability to protect our proprietary technology. Other risks are described
      under the section entitled “Risk Factors” in our Current Report on Form 8-K
      filed on April 7, 2006.





Further,
      any forward-looking statement speaks only as of the date on which it is made,
      and we undertake no obligation to update any forward-looking statement or
      statements to reflect events or circumstances after the date on which such
      statement is made or to reflect the occurrence of unanticipated events. New
      factors emerge from time to time, and it is not possible for us to predict
      which
      factors will arise. In addition, we cannot assess the impact of each factor
      on
      our business or the extent to which any factor, or combination of factors,
      may
      cause actual results to differ materially from those contained in any
      forward-looking statements.





**Overview**





The
      Company incurred a net loss of $4,628 for the three months ended March 31,
      2006
      and $37,500 for the period from May 24, 2005 (inception) to March 31, 2006,
      respectively. Combined with the fact that the Company has no working capital
      and
      an accumulated deficit of $37,500 as of March 31, 2006, it is management's
      assertion that these circumstances may hinder the Company’s ability to continue
      as a going concern.





**Liquidity
      and Capital Resources**





As
      of
      March 31, 2006, the Company had no assets. This compares to assets of $4,628
      in
      cash and cash equivalents as of December 31, 2005. On April 3, 2006,
      contemporaneously with the closing of the Merger, Cougar completed a private
      placement offering with gross proceeds of $39,650,000.





**Results
      of Operations**





The
      Company has not conducted any active operations since inception, except for
      its
      efforts to locate suitable acquisition candidates. No revenue has been generated
      by the Company from May 24, 2005 (inception) to March 31, 2006. Effective April
      3, 2006, SRKP Acquisition Corp. acquired Cougar (see Note 5 of the financial
      statements).





**Plan
      of Operation**




Contemporaneously
      with the closing of the Merger, our plan of operation for the year ending
      December 31, 2006 is to continue implementing Cougar’s business strategy,
      including the clinical development of their three product candidates. We also
      intend to expand the drug candidate portfolio by acquiring additional drugs
      for
      development. We expect principal expenditures during the next 9 months to
      include:





·
            Operating
                expenses, including expanded research and development and general
                and
                administrative expenses; and




·
            product
                development expenses, including the costs incurred with respect to
                applications to conduct clinical trials in the United States and
                Europe
                for our three products.




As
      part
      of our planned expansion, we anticipate hiring up to 7 additional full-time
      employees devoted to research and development activities and up to 3 additional
      full-time employees for general and administrative activities. In addition,
      we
      intend to use clinical research organizations and third parties to perform
      our
      clinical studies and manufacturing. As indicated above, at our current and
      desired pace of clinical development of our three product candidates, during
      2006 we expect to spend approximately $12.8 million on clinical development
      and
      research and development activities and expend approximately $2.5 million on
      general and administrative expenses and $242,000 on facilities
      rent.





9


*Research
      and Development Projects*




CB-7630 .
      In
      April 2004, Cougar exclusively licensed the worldwide rights to CB-7630
      ( abiraterone
      acetate) from BTG plc. CB-7630 is an orally active targeted inhibitor of the
      steroidal enzyme 17α-hydroxylase/C17,20 lyase, a cytochrome p450 complex that is
      involved in testosterone production. In preclinical studies, CB-7630 has
      demonstrated the
      ability to selectively inhibit the target enzyme, reducing levels of
      testosterone production in both the adrenals and the testes that is believed
      to
      stimulate the growth of prostrate cancer cells.




In
      Phase
      I trials performed by the Centre for Cancer Therapeutics, Institute of Cancer
      Research (Sutton, United Kingdom), and Royal Marsden NHS Trust (Sutton, United
      Kingdom), CB-7630 was administered as a single agent to 26 patients with
      prostate cancer. We believe that the data from these clinical studies indicate
      that: 1) CB-7630, at an oral dose of 800mg, can successfully suppress
      testosterone levels to the castrate range; 2) CB-7630 can suppress testosterone
      produced by both the testes and the adrenals; and 3) CB-7630 is well tolerated
      with an acceptable toxicity profile. The results from these Phase I studies
      of
      CB-7630 were published in the British Journal of Cancer in June
      2004.




In
      December 2005, Cougar initiated a Phase I/II trial of CB-7630 for the treatment
      of advanced prostate cancer. The Phase I/II trial is being conducted at The
      Institute of Cancer Research, in the Cancer Research UK Centre for Cancer
      Therapeutics, and at The Royal Marsden Hospital in the United Kingdom. The
      Phase
      I/II study is an open label, dose escalating study to evaluate the safety and
      efficacy of CB-7630 administered daily to patients with chemotherapy-naïve
      hormone refractory prostate cancer (HRPC) with a rising PSA (prostate specific
      antigen) despite hormonal therapy.




Through
      March 2006, Cougar has incurred approximately $7,041,500 of cost related to
      the
      development of CB-7630. Currently, we anticipate that we will need to expend
      approximately an additional $3,900,000 to $4,400,000 in development costs in
      fiscal 2006 and at least an aggregate of approximately $50,000,000 to
      $75,000,000 until we receive FDA approval for CB-7630. Should we choose to
      continue development we expect that it will take an additional 6 to 8 years
      before we complete development and obtain FDA approval of CB-7630, if
      ever.




CB-3304 .
      In
      March 2004, Cougar exclusively licensed the worldwide rights to CB-3304
      (noscapine), an orally active alkaloid derived from opium. Preclinical studies
      have demonstrated that CB-3304 has anti-tumor activity and acts as an inhibitor
      of microtubule dynamics. Therefore, we believe that CB-3304 has potential
      applications in the treatment of a number of different tumor types where tubulin
      binding agents are known to have activity. These tumor types include, but are
      not limited to, non-Hodgkin’s lymphoma, multiple myeloma, breast cancer, lung
      cancer, ovarian cancer and prostate cancer.




In
      December 2005, Cougar announced positive interim data from an ongoing
      investigator sponsored Phase I trial of CB-3304 in patients with relapsed or
      refractory non-Hodgkin’s lymphoma. The trial is an open label dose escalating
      study, being conducted at the University of Southern California Norris
      Comprehensive Cancer Center, where cohorts of patients with relapsed/refractory
      non-Hodgkin’s lymphoma (NHL) or chronic lymphocytic leukemia (CLL/SLL) were
      treated at one of three different dose levels involving total daily doses of
      1
      g, 2 g, and 3 g per day. At each dose level, noscapine was administered orally
      on a three times a day schedule for 49 days. In the trial, responses for NHL
      patients were evaluated using the International Working Group Response Criteria
      for NHL and responses for CLL patients were evaluated using the NCI Working
      Group criteria. For both NHL and CLL patients, toxicity was graded according
      to
      the NCI common toxicity criteria (CTC).




At
      this
      interim analysis, 12 patients with a median age of 65 years (range 38-71) have
      been accrued. Four subjects had CLL/SLL, 2 had mantle cell lymphoma, one had
      follicular grade III lymphoma, 4 had diffuse large cell lymphoma (DLC), and
      one
      had lymphoplasmacytic low grade lymphoma. These interim results
      suggest:




·
            Of
                the 10 patients that are evaluable for response, one patient with
                follicular grade III disease has had a partial response. This patient
                initially demonstrated stabilization of their disease for a period
                of
                approximately four years before achieving a partial response. In
                addition,
                two patients, one with mantle cell lymphoma and one with DLC have
                demonstrated stable disease of duration 30 days and 77 days,
                respectively.




10


·
            CB-3304
                has been well tolerated, with no grade 3 or 4 hematological toxicities.
                One grade 3 neurotoxicity consisting of depressed level of consciousness
                was experienced at the 3 gram dose
                level.




·
            A
                larger study of noscapine is warranted to evaluate the efficacy of
                the
                compound in patients with lymphoma.




In
      December 2005, Cougar also announced results from preclinical experiments that
      we believe demonstrates the effectiveness of CB-3304 for the treatment of NHL
      and multiple myeloma and that warrant our continued development of the drug
      in
      hematological malignancies. The preclinical studies demonstrate that CB-3304
      exhibits potent antitumor activity against NHL and myeloma in vitro, as well
      as
      in vivo in xenograft models. More specifically, the in vitro studies
      demonstrated that following exposure to CB-3304, the OPM2 (multiple myeloma),
      H9
      (T cell lymphoma) and RL (B cell lymphoma) tumor cell lines exhibited an IC50
      of
      approximately 30 nM, 700 nM, and 500 nM for the OPM2, H9 and RL lines,
      respectively. Treatment with noscapine resulted in the induction of apoptosis
      in
      each of the cell lines tested. Additionally, in vivo studies demonstrated that
      in xenograft models, daily administration of noscapine resulted in tumor growth
      delays of between 30-80% of the control tumor volumes.




Through
      March 2006, Cougar has incurred approximately $838,800 of cost related to the
      development of CB-3304. Currently, we anticipate that we will need to expend
      approximately an additional $2,000,000 to $2,600,000 in development costs in
      fiscal 2006 and at least an aggregate of approximately $50,000,000 to
      $75,000,000 until we receive FDA approval for CB-3304. Should we choose to
      continue development we expect that it will take an additional 6 to 8 years
      before we complete development and obtain FDA approval of CB-3304, if
      ever.




CB-1089 .
      In June
      2005, Cougar exclusively licensed the worldwide rights to CB-1089 (seocalcitol),
      a synthetic vitamin D analog. In prostate cancer, clinical studies of a
      metabolite of vitamin D (calcitriol) given in combination with chemotherapy
      suggested that patients that received the combination of calcitriol plus
      chemotherapy had an improvement in their survival over the patients that
      received chemotherapy plus placebo without an increase in the toxicity of the
      chemotherapy. Preclinical studies in prostate cancer have shown that CB-1089
      is
      a more potent anti-cancer drug than calcitriol, which may result in better
      efficacy when used in combination therapy to treat prostrate cancer as opposed
      to calcitriol. We anticipate beginning clinical trials of CB-1089 in prostate
      cancer in the second half of 2006.




Through
      March 2006, Cougar has incurred approximately $375,000 of cost related to the
      development of CB-1089. Currently, we anticipate that we will need to expend
      approximately an additional $1,900,000 to $2,400,000 in development costs in
      fiscal 2006 and at least an aggregate of approximately $50,000,000 to
      $75,000,000 until we receive FDA approval for CB-1089. Should we choose to
      continue development we expect that it will take an additional 6 to 8 years
      before we complete development and obtain FDA approval of CB-1089, if
      ever.




*License
      Agreement Obligations*




CB-3304 .
      On
      February 23, 2004, Cougar entered into a license agreement (the “License
      Agreement”) with Emory University (“Emory”) for the worldwide, exclusive rights
      to discover, develop, have made, use, sell, have sold, offer for sale and import
      the products described in Emory’s intellectual property portfolio for noscapine
      and analogs of noscapine. The License Agreement terminates upon the date of
      the
      last to expire patent contained in the licensed technology. In consideration
      for
      the rights under the License Agreement, Cougar paid Emory an initial license
      fee
      of $72,435 in 2004. Cougar sponsored a research project involving the licensed
      technology in the amount of $114,000 of which $28,688 and $85,312 were paid
      in
      2005 and 2004, respectively. In connection with the license agreement, Cougar
      agreed to future milestone payments to Emory for the first technology from
      the
      intellectual property portfolio in the aggregate of up to $3,500,000, payable
      upon the achievement of certain clinical and regulatory milestones. Should
      a
      product incorporating the licensed technology be commercialized, we will be
      obligated to pay to Emory an annual royalty based on net sales of the product.
      In the event that we sublicense the licensed technology to a third party, we
      will be obligated to pay royalties to Emory based on a fixed rate of fees or
      royalties received from the sublicense.




CB-7630 .
      Effective April 20, 2004, Cougar entered into a license agreement with BTG
      International, LTD. (“BTG”) for the exclusive worldwide rights to make, use,
      lease and sell abiraterone acetate. The agreement terminates upon the date
      of
      the last to expire patent contained in the licensed technology. In consideration
      for the rights under the BTG license agreement, Cougar paid BTG an initial
      license fee of £500,000 (currently, approximately $923,100) in 2004 and agreed
      to pay BTG an annual license maintenance fee of £150,000 ($288,000) until the
      first commercial sale of the licensed product. In addition, the license
      agreement requires us to make aggregate milestone payments of up to £9,000,000
      ($16,614,000), payable upon the achievement of certain clinical and regulatory
      milestones. Should abiraterone acetate become commercialized, we will be
      obligated to pay to BTG an annual royalty based on net sales of the product.
      In
      the event that we sublicenses abiraterone acetate to a third party, we are
      obligated to pay royalties to BTG based on a fixed rate of fees or royalties
      received from the sublicense.




11


CB-1089 .
      Effective June 27, 2005, Cougar entered into a license agreement with LEO Pharma
      A/S (“LEO”) for the exclusive worldwide right to make, use, lease and sell
      seocalcitol. The agreement terminates upon the later of the date of the last
      patent contained in the licensed technology to expire or twenty years. In
      consideration for the rights under the LEO license agreement, Cougar paid LEO
      an
      initial license fee of $250,000 in 2005. In addition, the license agreement
      requires us to make aggregate milestone payments of up to $13,000,000, payable
      upon the achievement of certain clinical and regulatory milestones. Should
      seocalcitol become commercialized, we will be obligated to pay to LEO an annual
      royalty based on net sales of the product. In the event that we sublicenses
      seocalcitol to a third party, we are obligated to pay royalties to LEO based
      on
      a fixed rate of fees or royalties received from the sublicense.




**Off-Balance
      Sheet Arrangements**




We
      do not
      have any “off-balance sheet arrangements,” as that term is defined by SEC
      regulations.




**Item
      3. CONTROLS AND PROCEDURES.**





**Evaluation
      of disclosure controls and procedures**





We
      maintain disclosure controls and procedures that are designed to ensure that
      information required to be disclosed in our reports filed pursuant to the
      Securities Exchange Act of 1934, as amended (the “Exchange Act”), is recorded,
      processed, summarized and reported within the time periods specified in the
      Securities and Exchange Commission’s rules, regulations and related forms, and
      that such information is accumulated and communicated to our principal executive
      officer and principal financial officer, as appropriate, to allow timely
      decisions regarding required disclosure.





As
      of the
      end of the period covered by this quarterly report, we carried out an
      evaluation, under the supervision and with the participation of our management,
      including our principal executive officer and principal financial officer,
      of
      the effectiveness of the design and operation of our disclosure controls and
      procedures. Based on this evaluation, our principal executive officer and
      principal financial officer concluded that our disclosure controls and
      procedures were effective.





**Changes
      in internal controls**





During
      the quarter ended March 31, 2006, there has been no change in our internal
      control over financial reporting that has materially affected, or is reasonably
      likely to materially affect, our internal control over financial reporting.




12


**PART
      II - OTHER INFORMATION**








**Item
      5. OTHER INFORMATION**





*Merger
      with Cougar Biotechnology, Inc.*





On
      April
      3, 2006, a wholly-owned subsidiary of SRKP merged with and into Cougar
      Biotechnology, Inc. (“Cougar”), with Cougar remaining as the surviving
      corporation and a wholly owned subsidiary of SRKP. Upon the effective time
      of
      the merger, the business of SRKP was abandoned and the business plan of Cougar
      was adopted. The transaction was therefore accounted for as a reverse
      acquisition with Cougar as the acquiring party and SRKP as the acquired party.
      On April 6, 2006, our board of directors approved a transaction pursuant to
      which Cougar merged with and into us, and we remained as the surviving
      corporation. In connection with this parent-subsidiary merger, we relinquished
      our prior corporate name, SRKP 4, Inc., and assumed in its place the name
“Cougar Biotechnology, Inc.” The parent-subsidiary merger and name change became
      effective on April 6, 2006.





The
      Company disclosed these events in its Current Report on Form 8-K filed with
      the
      Commission on April 7, 2006, incorporating in such filing the audited financial
      statements of Cougar Biotechnology, Inc. for the years ended December 31, 2005
      and 2004, and for the period May 14, 2003 (Cougar’s inception) to December 31,
      2005. The unaudited condensed financial statements of Cougar for the three
      months ended March 31, 2006 and Cougar's management discussion and analysis
      for
      the three months ended March 31, 2006 are attached hereto as Exhibit 99.1,
      and are incorporated herein by reference.





*Correction
      of 8-K Disclosure*





On
      April
      19, 2006, the Company erroneously disclosed in its Current Report on Form 8-K
      that, on April 10, 2006, David M. Tanen tendered his resignation as a member
      of
      the Company’s board of directors effective May 1, 2006. The Company
      received  Mr. Tanen's notice of intended resignation on April 15, 2006, not
      April 10, 2006 as disclosed.





**Item
      6. EXHIBITS**





Exhibit
      No. Description




2.1
            Agreement
              and Plan of Merger dated February 27, 2006, by and among Cougar
              Biotechnology, Inc., SRKP 4, Inc., and SRKP Acquisition
              Corp.(incorporated by reference to exhibit 10.1 of the Company's Current
              Report on Form 8-K filed on March 2, 2006).  3.1
            Certificate
                of Incorporation (incorporated by reference to Exhibit 3.1 of the
                Company's Registration Statement on Form 10SB filed on August 3,
                2005)





3.2
            Certificate
                of Merger relating to the merger of SRKP Acquisition Corp. with and
                into
                Cougar Biotechnology, Inc. (incorporated by reference to Exhibit
                3.1 of
                the Company's Current Report Form 8-K dated April 3, 2006 and filed
                on
                April 7, 2006)





3.3
            Certificate
                of Ownership relating to the merger of Cougar Biotechnology, Inc.
                with and
                into SRKP4, Inc. (incorporated by reference to Exhibit 3.2 of the
                Company's Current Report Form 8-K dated April 3, 2006 and filed on
                April
                7, 2006)





3.4
            Certificate
                of Designation of Series A Convertible Preferred Stock of the Company
                (incorporated by reference to Exhibit 3.1 to the Company's current
                report
                on form 8-K dated March 31, 2006 and filed by April 6,
                2006).




4.1
            Form
                of Warrant - Related to the Sale of Bridge Notes (incorporated by
                reference to Exhibit 4.2 of the Company’s Registration Statement on Form
                SB-2 (SEC File No.: 333-133779) filed on May 3,
                2006)





4.2
            Form
                of Warrant issued in relation to guaranty of credit facility and
                issuance of certain promissory notes  (incorporated by reference to
                Exhibit 4.3 of the Company’s Registration Statement on Form SB-2 (SEC File
                No.: 333-133779) filed on May 3,
                2006)





13


4.3
            Form
                of Warrant issued in relation to Bridge
                Notes Financing (incorporated by reference to Exhibit 4.3 of the
                Company’s Registration Statement on Form SB-2 (SEC File No.: 333-133779)
                filed on May 3, 2006)





31.1
            Certification
                of Chief Executive Officer




31.2
            Certification
                of Chief Financial Officer




32.1
            Certifications
                of Chief Executive Officer and Chief Financial Officer pursuant to Section
                906 of the Sarbanes-Oxley Act of
                2002.




99.1
            Condensed
                Financial Statements and Management Discussion and Analysis of Cougar
                Biotechnology, Inc.




14


**SIGNATURES**





In
      accordance with the requirements of the Exchange Act of 1934, the registrant
      caused this report to be signed on its behalf by the undersigned, thereunto
      duly
      authorized.




COUGAR
              BIOTECHNOLOGY, INC.Date:
              May 17, 2006
            By:
            /s/ Alan
              H.
              AuerbachAlan
              H. AuerbachPresident
              and
              Chief Executive Officer


Date: May
              17,
              2006
            By:
            /s/ Charles
              R. EylerCharles
              R. EylerTreasurer


15







**Index
      to Exhibits Filed with this Report**






Exhibit
        No. Description


31.1
            Certification
                of Chief Executive Officer  31.2
              Certification
                  of Principal Financial Officer
  32.1
              Certifications
                  of Chief Executive Officer and Principal Financial Officer pursuant
                  to Section 906 of the Sarbanes-Oxley Act of
                  2002.
  99.1
              Condensed
                  Financial Statements of Cougar Biotechnology,
                  Inc




16