**EXHIBIT 4.6**

THESECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACTOF 1933, AS AMENDED (THE “ACT”), OR UNDER THE SECURITIES LAWS OF ANYSTATE.  THESE SECURITIES ARE SUBJECT TORESTRICTIONS ON TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR RESOLDEXCEPT AS PERMITTED UNDER THE ACT AND THE APPLICABLE STATE SECURITIES LAWS,PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM.  THE ISSUER OF THESE SECURITIES MAY REQUIRE ANOPINION OF COUNSEL IN FORM AND SUBSTANCE SATISFACTORY TO THE ISSUER TO THEEFFECT THAT ANY PROPOSED TRANSFER OR RESALE IS IN COMPLIANCE WITH THE ACT ANDANY APPLICABLE STATE SECURITIES LAWS.

**COMMON STOCK PURCHASE WARRANT**
| **Warrant No. CS-[   ]** |   | 100,000 Shares |
|-----------------------------------------|--------|----------------|

July 24, 2006

**RIGEL PHARMACEUTICALS, INC.**

**WARRANT FORTHE PURCHASE OF SHARES OF COMMON STOCK**

**1.             Issuance**.  For value received, this Warrant is issued to**KWACKER LIMITED**,a corporation organized and existing under the laws of England, by **RIGEL PHARMACEUTICALS, INC.**,a Delaware corporation (hereinafter with its successors called the *“Company”*), in partial consideration forthat certain Amendment No. Three to Build-to-Suit Lease, dated as of thedate hereof, between the Company and Slough BTC, LLC, as landlord (*“Amendment Three”*).

**2.             PurchasePrice; Number of Shares**. The registered holder of this Warrant (the *“Holder”*), commencing on the date hereof, is entitled uponsurrender of this Warrant with the subscription form annexed hereto dulyexecuted, at the principal office of the Company, to purchase from the Companyone hundred thousand (100,000) fully paid and nonassessable shares (the “*Shares*”) of common stock, $.001 par valueper share, of the Company (the *“Common Stock”*),at a price per share of $0.57 (the *“PurchasePrice”*).  Until such time asthis Warrant is exercised in full or expires, the Purchase Price and thesecurities issuable upon exercise of this Warrant are subject to adjustment ashereinafter provided.  The person orpersons under whose name or names any certificate representing shares of CommonStock is issued hereunder shall be deemed to have become the holder of recordof the shares represented thereby as at the close of business on the date thisWarrant is exercised with respect to such shares, whether or not the transferbooks of the Company shall be closed.

**3.             Paymentof Purchase Price**.  ThePurchase Price may be paid (i) in cash or by check; (ii) by thesurrender by the Holder to the Company of any promissory notes or otherobligations issued by the Company, with all such notes and obligations sosurrendered being credited against the Purchase Price in an amount equal to theprincipal amount thereof plus accrued interest to the date of surrender; or(iii) by any combination of the foregoing.

**4.             NetIssue Election**.  TheHolder may elect to receive, without the payment by the Holder of anyadditional consideration, shares of Common Stock equal to the value of thisWarrant or any portion hereof by the surrender of this Warrant or such portionto the Company, with the net issue election notice annexed hereto dulyexecuted, at the principal office of the Company.  Thereupon, the Company shall issue to theHolder such number of fully paid and nonassessable shares of Common Stock as iscomputed using the following formula:
|     | *X*=   | *Y*(*A*– *B*) |   |
|-----|--------|--------------------|--------|
| *A* |   |

 
| where: |   | X =    | the number of shares of Common Stock to be issued to  the Holder pursuant to this Section 4. |
|--------|--------|--------|---------------------------------------------------------------------------------------------------|
|   |   |   |                                                                                              |
|   |   | Y =    | the number of shares of Common Stock covered by this  Warrant in respect of which the             |

 

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|        |   |   | net issue election is made pursuant to this  Section 4.                                                                                                    |
|--------|--------|--------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
|   |   |   |                                                                                                                                                            |
|   |   | A =    | the Fair Market Value (defined below) of one share  of Common Stock, as determined at the time the net issue election is made  pursuant to this Section 4. |
|   |   |   |                                                                                                                                                            |
|   |   | B =    | the Purchase Price in effect under this Warrant at  the time the net issue election is made pursuant to this Section 4.                                    |

 

*“FairMarket Value”* of a share of Common Stock as of a particulardate (the *“Determination Date”*) shall mean theaverage of the closing or last reported sale prices of the Common Stock asreported on the Nasdaq National Market over the 30-day period ending fivebusiness days prior to the Determination Date;*provided, however,* that (i) if the Common Stock is neithertraded on the Nasdaq National Market nor on a national securities exchange,then Fair Market Value shall be the average of the closing or last reportedsale prices of the Common Stock over the 30-day period ending five businessdays prior to the Determination Date reflected in the over-the-counter market,as reported by the National Quotation Bureau, Inc. or any organizationperforming a similar function, or if closing prices are not then routinelyreported for the over-the-counter market, the average of the last bid and askedprices of the Common Stock over the 30-day period ending five business daysprior to the Determination Date, and (ii) if there is no public market forthe Common Stock, then Fair Market Value shall be determined in good faith bythe Company’s Board of Directors.

**5.             PartialExercise**.  This Warrantmay be exercised in part, and the Holder shall be entitled to receive a newwarrant, which shall be dated as of the date of this Warrant, covering thenumber of shares in respect of which this Warrant shall not have beenexercised.

**6.             FractionalShares**.  In no eventshall any fractional share of Common Stock be issued upon any exercise of thisWarrant.  If, upon exercise of thisWarrant as an entirety, the Holder would, except as provided in thisSection 6, be entitled to receive a fractional share of Common Stock, thenthe Company shall pay in lieu thereof, the Fair Market Value of such fractionalshare in cash.

**7.             ExpirationDate**.  This Warrant orany Successor Warrant (as defined in Section 10 below) shall remainexercisable until the close of business on July 24, 2013, when it shall expireand thereafter be void.

**8.             ReservedShares; Valid Issuance**. The Company covenants that it will at all times from and after the datehereof reserve and keep available such number of its authorized shares ofCommon Stock, free from all preemptive or similar rights therein, as will besufficient to permit the exercise of this Warrant in full into shares of CommonStock upon such exercise.  The Companyfurther covenants that such shares as may be issued pursuant to such exercisewill, upon issuance, be duly and validly issued, fully paid and nonassessableand free from all taxes, liens and charges with respect to the issuancethereof.

**9.             StockSplits and Dividends**. If after the date hereof the Company shall subdivide the Common Stock,by split-up or otherwise, or combine the Common Stock, or issue additionalshares of Common Stock in payment of a stock dividend on the Common Stock, thenumber of shares of Common Stock issuable on the exercise of this Warrant shallforthwith be proportionately increased in the case of a subdivision or stockdividend, or proportionately decreased in the case of a combination, and the PurchasePrice shall forthwith be proportionately decreased in the case of a subdivisionor stock dividend, or proportionately increased in the case of a combination.

**10.          Mergers and Reclassifications**.

**(a)**           If after the date hereof the Companyshall enter into any Reorganization (as hereinafter defined), then, as acondition of such Reorganization, lawful provisions shall be made, and dulyexecuted documents evidencing the same from the Company or its successor shallbe delivered to the Holder (a *“Successor Warrant”*),so that the Holder shall thereafter have the right to purchase, at a totalprice not to exceed that payable upon the exercise of this Warrant in full, thekind and amount of shares of stock and other securities and property receivableupon such Reorganization by a holder of the number of shares of Common Stockwhich might have been purchased by the Holder immediately prior to suchReorganization, and in any such case appropriate provisions shall be made

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with respect to the rights and interest of the Holderto the end that the provisions hereof (including without limitation, provisionsfor the adjustment of the Purchase Price and the number of shares issuablehereunder and the provisions relating to the net issue election) shallthereafter be applicable in relation to any shares of stock or other securitiesand property thereafter deliverable upon exercise hereof.

* ***(b)**          For thepurposes of this Section 10:

(i)            the term *“AcquisitionTransaction”* shall include without limitation any consolidation of theCompany with, or merger of the Company into, another corporation or otherbusiness organization (other than a merger in which the Company is thesurviving corporation and which does not result in any reclassification orchange of the outstanding Common Stock); and

(ii)           the term *“Reorganization”*shall include without limitation any reclassification, capital reorganizationor change of the Common Stock (other than as a result of a subdivision,combination or stock dividend provided for in Section 9 hereof), anAcquisition Transaction, or any sale or conveyance to another corporation orother business organization of all or substantially all of the assets of theCompany.

**11.          Certificateof Adjustment**. Whenever the Purchase Price is adjusted, as herein provided, the Companyshall promptly deliver to the Holder a certificate of the Company’s ChiefFinancial Officer setting forth the Purchase Price after such adjustment andsetting forth a brief statement of the facts requiring such adjustment.

**12.          Notices of Record Date, Etc**.  In the event of:

**(a)          **anytaking by the Company of a record of the holders of any class of securities forthe purpose of determining the holders thereof who are entitled to receive anydividend or other distribution, or any right to subscribe for, purchase, sellor otherwise acquire or dispose of any shares of stock of any class or anyother securities or property, or to receive any other right;

**(b)          **anyreclassification of the capital stock of the Company, capital reorganization ofthe Company, consolidation or merger involving the Company, or sale orconveyance of all or substantially all of its assets; or

**(c)          **anyvoluntary or involuntary dissolution, liquidation or winding-up of the Company;

thenin each such event the Company will provide or cause to be provided to theHolder a written notice thereof.  Suchnotice shall be provided at least fifteen (15) calendar days prior to thedate specified in such notice on which any such action is to be taken.

**13.          Representations,Warranties and Covenants**. This Warrant is issued and delivered by the Company and accepted by eachHolder on the basis of the following representations, warranties and covenantsmade by the Company:

**(a)          **TheCompany has all necessary authority to issue, execute and deliver this Warrantand to perform its obligations hereunder. This Warrant has been duly authorized, issued, executed and delivered bythe Company and is the valid and binding obligation of the Company, enforceablein accordance with its terms, except as enforceability may be limited bybankruptcy, insolvency, reorganization or other similar laws of generalapplication affecting the enforcement of Holder’s rights or by general equityprinciples or public policy concerns.

**(b)          **Theshares of Common Stock issuable upon the exercise of this Warrant have beenduly authorized and reserved for issuance by the Company and, when issued inaccordance with the terms hereof, will be validly issued, fully paid andnonassessable.

**(c)          **Theissuance, execution and delivery of this Warrant do not, and the issuance ofthe shares of Common Stock upon the exercise of this Warrant in accordance withthe terms hereof will not, (i) violate or contravene the Company’s Amendedand Restated Certificate of Incorporation or by-laws, or any law, statute,

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regulation, rule, judgment or order applicable to theCompany, (ii) violate, contravene or result in a breach or default underany material contract, agreement or instrument to which the Company is a partyor by which the Company or any of its assets are bound or (iii) requirethe consent or approval of or the filing of any notice or registration with anyperson or entity.

**14.          Amendmentand Waiver**.  The termsof this Warrant may be amended, modified or waived only with the writtenconsent of the party against which enforcement of the same is sought.

**15.          Representationsand Covenants of the Holder**. This Common Stock Purchase Warrant has been entered into by the Companyin reliance upon the following representations and covenants of the Holder, whichby its acceptance hereof the Holder hereby confirms:

**(a)           InvestmentPurpose**.  The right toacquire Common Stock or the Common Stock issuable upon exercise of the Holder’srights contained herein will be acquired for investment and not with a view tothe sale or distribution of any part thereof, and the Holder has no presentintention of selling or engaging in any public distribution of the same exceptpursuant to a registration or exemption.

**(b)           AccreditedInvestor**.  Holder is an“accredited investor” within the meaning of the Securities and ExchangeCommission’s Rule 501 of Regulation D, as presently in effect.

**(c)           PrivateIssue**.  The Holderunderstands (i) that the Common Stock issuable upon exercise of the Holder’srights contained herein is not registered under the 1933 Act or qualified underapplicable state securities laws on the ground that the issuance contemplatedby this Warrant will be exempt from the registration and qualificationsrequirements thereof and (ii) that the Company’s reliance on suchexemption is predicated on the representations set forth in thisSection 15.

**(d)           FinancialRisk**.  The Holder hassuch knowledge and experience in financial and business matters as to becapable of evaluating the merits and risks of its investment and has theability to bear the economic risks of its investment.

**16.          Notices, Transfers, Etc.**

**(a)          **Anynotice or written communication required or permitted to be given to the Holdermay be given by certified mall or delivered to the Holder at the address most recentlyprovided by the Holder to the Company.

**(b)          **Subjectto compliance with applicable federal and state securities laws, this Warrantmay be transferred by the Holder with respect to any or all of the sharespurchasable hereunder.  Upon surrender ofthis Warrant to the Company, together with the assignment notice annexed heretoduly executed, for transfer of this Warrant as an entirety by the Holder, theCompany shall issue a new warrant of the same denomination to the assignee.  Upon surrender of this Warrant to theCompany, together with the assignment hereof properly endorsed, by the Holderfor transfer with respect to a portion of the shares of Common Stockpurchasable hereunder, the Company shall issue a new warrant to the assignee,in such denomination as shall be requested by the Holder hereof, and shallissue to such Holder a new warrant covering the number of shares in respect ofwhich this Warrant shall not have been transferred.

**(c)          **Incase this Warrant shall be mutilated, lost, stolen or destroyed, the Companyshall issue a new warrant of like tenor and denomination and deliver the same(i) in exchange and substitution for and upon surrender and cancellationof any mutilated Warrant or (ii) in lieu of any Warrant lost, stolen ordestroyed, upon receipt of an affidavit of the Holder or other evidencereasonably satisfactory to the Company of the loss, theft or destruction ofsuch Warrant and an indemnification of loss by the Holder in favor of theCompany.

**17.          Transferto Comply with the Securities Act of 1933.**   This Warrant may not be exercised and neitherthis Warrant nor any of the Shares, nor any interest in either, may be offered,sold, assigned, pledged, hypothecated, encumbered or in any other mannertransferred or disposed of, in whole or in part, except in

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compliance with applicable United States federal andstate securities laws and the terms and conditions hereof.  Each Warrant shall bear a legend insubstantially the same form as the legend set forth on the first page of thisWarrant.  Each certificate for Sharesissued upon exercise of this Warrant, unless at the time of exercise suchShares are acquired pursuant to a registration statement that has been declaredeffective under the Securities Act of 1933, as amended (the “Securities Act”),and applicable blue sky laws, shall bear a legend substantially in thefollowing form:

THE SECURITIESREPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933,AS AMENDED (THE “ACT”), OR UNDER THE SECURITIES LAWS OF ANY STATE.  THESE SECURITIES ARE SUBJECT TO RESTRICTIONSON TRANSFERABILITY AND RESALE AND MAY NOT BE TRANSFERRED OR RESOLD EXCEPT ASPERMITTED UNDER THE ACT AND THE APPLICABLE STATE SECURITIES LAWS, PURSUANT TOREGISTRATION OR EXEMPTION THEREFROM.  THEISSUER OF THESE SECURITIES MAY REQUIRE AN OPINION OF COUNSEL IN FORM ANDSUBSTANCE SATISFACTORY TO THE ISSUER TO THE EFFECT THAT ANY PROPOSED TRANSFEROR RESALE IS IN COMPLIANCE WITH THE ACT AND ANY APPLICABLE STATE SECURITIESLAWS.

Any certificate for any Shares issued at any time in exchange orsubstitution for any certificate for any Shares bearing such legend (except anew certificate for any Shares issued after the acquisition of such Sharespursuant to a registration statement that has been declared effective under theSecurities Act) shall also bear such legend unless, in the opinion of counselfor the Company, the Shares represented thereby need no longer be subject tothe restriction contained herein.  Theprovisions of this Section 17 shall be binding upon all subsequent holdersof certificates for Shares bearing the above legend and all subsequent holdersof this Warrant, if any.

**18.          Rightsof Holder.**  Holder shall not, by virtue hereof, beentitled to any rights of a stockholder of the Company, either at law or equity,and the rights of Holder are limited to those expressed in this Warrant.  Nothing contained in this Warrant shall beconstrued as conferring upon Holder hereof the right to vote or to consent orto receive notice as a stockholder of the Company on any matters or withrespect to any rights whatsoever as a stockholder of the Company.  No dividends or interest shall be payable oraccrued in respect of this Warrant or the interest represented hereby or theShares purchasable hereunder until, and only to the extent that, this Warrantshall have been exercised in accordance with its terms.

**19.  “Market Stand Off” Agreement**.  Holder hereby agrees not to sell, transfer,make any short sale of, grant any option for the purchase of, or enter into anyhedging or similar transaction with the same economic effect as a sale of, anyCommon Stock (or other securities) of the Company held by Holder for a periodspecified by a representative of the underwriters of Common Stock (or othersecurities) of the Company not to exceed ninety (90) days following theeffective date of a registration statement of the Company filed under theSecurities Act; *provided*that allofficers and directors of the Company and each holder of that number of sharesof Common Stock equal to or greater than the number of Shares then issuableupon exercise of this Warrant enter into similar agreements.

**20.          NoImpairment**.  TheCompany will not, by amendment of its Certificate or through anyreclassification, capital reorganization, consolidation, merger, sale orconveyance of assets, dissolution, liquidation, issue or sale of securities orany other voluntary action, avoid or seek to avoid the observance orperformance of any of the terms of this Warrant, but will at all times in goodfaith assist in the carrying out of all such terms and in the taking of allsuch action as may be necessary or appropriate in order to protect the rightsof the Holder.

**21.          GoverningLaw**.  The provisionsand terms of this Warrant shall be governed by and construed in accordance withthe internal laws of the State of California.

**22.          Successorsand Assigns**.  ThisWarrant shall be binding upon the Company’s successors and assigns and shallinure to the benefit of the Holder’s successors, legal representatives andpermitted assigns.

**23.          BusinessDays**.  If the last orappointed day for the taking of any action required or the expiration of anyrights granted herein shall be a Saturday or Sunday or a legal holiday inCalifornia, then such action may be

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taken or right may be exercised on the next succeedingday which is not a Saturday or Sunday or such a legal holiday.

**IN WITNESS WHEREOF,** the Company has duly caused this Warrant tobe signed by its duly authorized officer and to be dated as of the date firstwritten above.
|        | **Company:******                 |
|--------|----------------------------------|
|   | ** **                       |
|   | **RIGEL  PHARMACEUTICALS, INC.** |
|   |                             |
|   | By:                              | /s/ James M. Gower |
|   |                             | James M. Gower |
|   |                             | Chief Executive Officer |

 

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**SUBSCRIPTION**
| To: |   |   | Date: |   |
|-----|--------|--------|-------|--------|

 

The undersigned hereby subscribes for                shares of Common Stock covered by this Warrant. The certificate(s) for such shares shall be issued in the name of theundersigned or as otherwise indicated below:
|        |                  |
|--------|-----------------------|
|   | Signature             |
|   |                  |
|   |                  |
|   | Name for Registration |
|   |                  |
|   |                  |
|   | Mailing Address       |

 

 

**NET ISSUEELECTION NOTICE**
| To: |   |   | Date: |   |
|-----|--------|--------|-------|--------|

 

The undersigned hereby elects under Section 4 tosurrender the right to purchase                    shares of Common Stock pursuant to this Warrant.  The certificate(s) for such shares issuableupon such net issue election shall be issued in the name of the undersigned oras otherwise indicated below:
|        |                  |
|--------|-----------------------|
|   | Signature             |
|   |                  |
|   |                  |
|   | Name for Registration |
|   |                  |
|   |                  |
|   | Mailing Address       |

 

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**ASSIGNMENT**
| For value received                                           hereby sells, assigns and transfers unto                                                       |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| [Please print or  type the name and address of Assignee]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| the within Warrant, and does  hereby irrevocably constitute and appoint                                        its attorney to transfer the within Warrant on the books of the within named  Company with full power of substitution on the premises.                                                                                                                                                                                                    |

 
| **Dated:**              | ** ** | ** ** | ** ** | ** ** |
|-------------------------|------------|------------|------------|------------|
| ** **              |
| ** **              |
| ** **              |
| ** **              |
| **In the Presence of:** |
| ** **              |
| ** **              | ** ** |

 

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