**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-23 |   | 100,000 Shares |
|-------------------|--------|----------------|
| July 24, 2006     |   |           |

 

**RIGEL PHARMACEUTICALS, INC.**

**WARRANTFOR THE PURCHASE OF SHARES OF COMMON STOCK**

**1.             Issuance**. For value received, this Warrant is issued to **KWACKER LIMITED**, a corporationorganized and existing under the laws of England, by **RIGEL PHARMACEUTICALS, INC.**, a Delaware corporation (hereinafterwith its successors called the *“Company”*),in partial consideration for that certain Amendment No. Three toBuild-to-Suit Lease, dated as of the date hereof, between the Company andSlough BTC, LLC, as landlord (*“Amendment Three”*).

**2.             PurchasePrice; Number of Shares**.  The registered holder of thisWarrant (the *“Holder”*),commencing on the date hereof, is entitled upon surrender of this Warrant withthe subscription form annexed hereto duly executed, at the principal office ofthe Company, to purchase from the Company one hundred thousand (100,000) fullypaid and nonassessable shares (the “*Shares*”)of common stock, $.001 par value per share, of the Company (the *“Common Stock”*), at a price per share of$10.57 (the *“Purchase Price”*).  Until such time as this Warrant is exercisedin full or expires, the Purchase Price and the securities issuable uponexercise of this Warrant are subject to adjustment as hereinafterprovided.  The person or persons underwhose name or names any certificate representing shares of Common Stock isissued hereunder shall be deemed to have become the holder of record of theshares represented thereby as at the close of business on the date this Warrantis exercised with respect to such shares, whether or not the transfer books ofthe Company shall be closed.

**3.             Paymentof Purchase Price**.  The Purchase Price may be paid (i) incash or by check; (ii) by the surrender by the Holder to the Company ofany promissory notes or other obligations issued by the Company, with all suchnotes and obligations so surrendered being credited against the Purchase Pricein an amount equal to the principal amount thereof plus accrued interest to thedate of surrender; or (iii) by any combination of the foregoing.

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**4.             NetIssue Election**.  The Holder may elect to receive, without thepayment by the Holder of any additional consideration, shares of Common Stockequal to the value of this Warrant or any portion hereof by the surrender ofthis Warrant or such portion to the Company, with the net issue election noticeannexed hereto duly executed, 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 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 Warrant may be exercised in part, andthe Holder shall be entitled to receive a new warrant, which shall be dated asof the date of this Warrant, covering the number of shares in respect of whichthis Warrant shall not have been exercised.

**6.             FractionalShares**.  In no event shall any fractional share ofCommon Stock be issued upon any exercise of this Warrant.  If, upon exercise of this Warrant as anentirety, the Holder would, except as provided in this Section 6, beentitled to receive a fractional share of Common Stock, then the Company shallpay in lieu thereof, the Fair Market Value of such fractional share in cash.

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**7.             ExpirationDate**.  This Warrant or any Successor Warrant (asdefined in Section 10 below) shall remain exercisable until the close ofbusiness on July 24, 2013, when it shall expire and thereafter be void.

**8.             ReservedShares; Valid Issuance**.  The Company covenants that itwill at all times from and after the date hereof reserve and keep availablesuch number of its authorized shares of Common Stock, free from all preemptiveor similar rights therein, as will be sufficient to permit the exercise of thisWarrant in full into shares of Common Stock upon such exercise.  The Company further covenants that such sharesas may be issued pursuant to such exercise will, upon issuance, be duly andvalidly issued, fully paid and nonassessable and free from all taxes, liens andcharges with respect to the issuance thereof.

**9.             StockSplits and Dividends**.  If after the date hereof the Company shallsubdivide the Common Stock, by split-up or otherwise, or combine the CommonStock, or issue additional shares of Common Stock in payment of a stockdividend on the Common Stock, the number of shares of Common Stock issuable onthe exercise of this Warrant shall forthwith be proportionately increased inthe case of a subdivision or stock dividend, or proportionately decreased inthe case of a combination, and the Purchase Price shall forthwith beproportionately decreased in the case of a subdivision or stock dividend, orproportionately increased in the case of a combination.

**10.          Mergers and Reclassifications**.

**(a)**           Ifafter the date hereof the Company shall enter into any Reorganization (ashereinafter defined), then, as a condition of such Reorganization, lawfulprovisions shall be made, and duly executed documents evidencing the same fromthe Company or its successor shall be delivered to the Holder (a *“Successor Warrant”*), so that the Holder shall thereafterhave the right to purchase, at a total price not to exceed that payable uponthe exercise of this Warrant in full, the kind and amount of shares of stockand other securities and property receivable upon such Reorganization by aholder of the number of shares of Common Stock which might have been purchasedby the Holder immediately prior to such Reorganization, and in any such caseappropriate provisions shall be made with respect to the rights and interest ofthe Holder to the end that the provisions hereof (including without limitation,provisions for the adjustment of the Purchase Price and the number of sharesissuable hereunder 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)**           Forthe purposes of this Section 10:

(i)            the term *“AcquisitionTransaction”* shall include without limitation any consolidation ofthe Company 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

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a subdivision, combination or stock dividend providedfor in Section 9 hereof), an Acquisition Transaction, or any sale orconveyance to another corporation or other business organization of all orsubstantially all of the assets of the Company.

**11.          Certificateof Adjustment**.  Whenever the Purchase Price is adjusted, asherein provided, the Company shall promptly deliver to the Holder a certificateof the Company’s Chief Financial Officer setting forth the Purchase Price aftersuch adjustment and setting forth a brief statement of the facts requiring suchadjustment.

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

**(a)          **any taking by the Company of a record ofthe holders of any class of securities for the purpose of determining theholders thereof who are entitled to receive any dividend or other distribution,or any right to subscribe for, purchase, sell or otherwise acquire or disposeof any shares of stock of any class or any other securities or property, or toreceive any other right;

**(b)          **any reclassification of the capital stockof the Company, capital reorganization of the Company, consolidation or mergerinvolving the Company, or sale or conveyance of all or substantially all of itsassets; or

**(c)          **any voluntary 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 anddelivered by the Company and accepted by each Holder on the basis of thefollowing representations, warranties and covenants made by the Company:

**(a)          **The Company has all necessary authorityto issue, execute and deliver this Warrant and to perform its obligationshereunder.  This Warrant has been dulyauthorized, issued, executed and delivered by the Company and is the valid andbinding obligation of the Company, enforceable in accordance with its terms,except as enforceability may be limited by bankruptcy, insolvency,reorganization or other similar laws of general application affecting theenforcement of Holder’s rights or by general equity principles or public policyconcerns.

**(b)          **The shares of Common Stock issuable uponthe exercise of this Warrant have been duly authorized and reserved for issuanceby the Company and, when issued in accordance with the terms hereof, will bevalidly issued, fully paid and nonassessable.

**(c)          **The issuance, execution and delivery ofthis Warrant do not, and the issuance of the shares of Common Stock upon theexercise of this Warrant in accordance with the terms hereof will not,(i) violate or contravene the Company’s Amended and Restated Certificateof Incorporation or by-laws, or any law, statute, regulation, rule, judgment ororder applicable to the Company, (ii) violate, contravene or result in abreach or default under any

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material contract, agreement or instrument to whichthe Company is a party or by which the Company or any of its assets are boundor (iii) require the consent or approval of or the filing of any notice orregistration with any person or entity.

**14.          Amendmentand Waiver**.  The terms of this Warrant may be amended,modified or waived only with the written consent of the party against whichenforcement of the same is sought.

**15.          Representationsand Covenants of the Holder**.  This CommonStock Purchase Warrant has been entered into by the Company in reliance uponthe following representations and covenants of the Holder, which by itsacceptance hereof the Holder hereby confirms:

**(a)           InvestmentPurpose**.  The right to acquire Common Stock or theCommon Stock issuable upon exercise of the Holder’s rights contained hereinwill be acquired for investment and not with a view to the sale or distributionof any part thereof, and the Holder has no present intention of selling orengaging in any public distribution of the same except pursuant to aregistration or exemption.

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

**(c)           PrivateIssue**.  The Holder understands (i) that theCommon Stock issuable upon exercise of the Holder’s rights contained herein isnot registered under the 1933 Act or qualified under applicable statesecurities laws on the ground that the issuance contemplated by this Warrantwill be exempt from the registration and qualifications requirements thereofand (ii) that the Company’s reliance on such exemption is predicated onthe representations set forth in this Section 15.

**(d)           FinancialRisk**.  The Holder has such knowledge and experiencein financial and business matters as to be capable of evaluating the merits andrisks of its investment and has the ability to bear the economic risks of itsinvestment.

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

**(a)          **Any notice or written communicationrequired or permitted to be given to the Holder may be given by certified mallor delivered to the Holder at the address most recently provided by the Holderto the Company.

**(b)          **Subject to compliance with applicablefederal and state securities laws, this Warrant may be transferred by theHolder with respect to any or all of the shares purchasable hereunder.  Upon surrender of this Warrant to theCompany, together with the assignment notice annexed hereto duly executed, fortransfer of this Warrant as an entirety by the Holder, the Company shall issuea 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

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be requested by the Holder hereof, and shall issue tosuch Holder a new warrant covering the number of shares in respect of whichthis Warrant shall not have been transferred.

**(c)          **In case this Warrant shall be mutilated,lost, stolen or destroyed, the Company shall issue a new warrant of like tenorand denomination and deliver the same (i) in exchange and substitution forand upon surrender and cancellation of any mutilated Warrant or (ii) inlieu of any Warrant lost, stolen or destroyed, upon receipt of an affidavit ofthe Holder or other evidence reasonably satisfactory to the Company of theloss, theft or destruction of such Warrant and an indemnification of loss bythe Holder in favor of the Company.

**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 compliance withapplicable United States federal and state securities laws and the terms andconditions hereof.  Each Warrant shallbear a legend in substantially the same form as the legend set forth on thefirst page of this Warrant.  Eachcertificate for Shares issued upon exercise of this Warrant, unless at the timeof exercise such Shares are acquired pursuant to a registration statement thathas been declared effective under the Securities Act of 1933, as amended (the “SecuritiesAct”), 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.          Rights of Holder.**  Holder shallnot, by virtue hereof, be entitled to any rights of a stockholder of theCompany, either at law or equity, and the rights of Holder are limited to thoseexpressed in this Warrant.  Nothingcontained in this Warrant shall be construed as conferring upon Holder hereofthe right to vote or to consent or to receive notice as a stockholder of the

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Company on any matters or with respect to any rightswhatsoever as a stockholder of the Company. No dividends or interest shall be payable or accrued in respect of thisWarrant or the interest represented hereby or the Shares purchasable hereunderuntil, and only to the extent that, this Warrant shall have been exercised inaccordance 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 any hedging or similartransaction with the same economic effect as a sale of, any Common Stock (orother securities) of the Company held by Holder for a period specified by arepresentative of the underwriters of Common Stock (or other securities) of theCompany not to exceed ninety (90) days following the effective date of aregistration statement of the Company filed under the Securities Act; *provided*that all officers and directorsof the Company and each holder of that number of shares of Common Stock equalto or greater than the number of Shares then issuable upon exercise of thisWarrant enter into similar agreements.

**20.          NoImpairment**.  The Company will not, by amendment of itsCertificate or through any reclassification, capital reorganization,consolidation, merger, sale or conveyance of assets, dissolution, liquidation,issue or sale of securities or any other voluntary action, avoid or seek toavoid the observance or performance of any of the terms of this Warrant, butwill at all times in good faith assist in the carrying out of all such termsand in the taking of all such action as may be necessary or appropriate inorder to protect the rights of the Holder.

**21.          GoverningLaw**.  The provisions and terms of this Warrantshall be governed by and construed in accordance with the internal laws of theState of California.

**22.          Successorsand Assigns**.  This Warrant shall be binding upon theCompany’s successors and assigns and shall inure to the benefit of the Holder’ssuccessors, legal representatives and permitted assigns.

**23.          Business Days**. If the last or appointed day for the taking of any action required orthe expiration of any rights granted herein shall be a Saturday or Sunday or alegal holiday in California, then such action may be taken or right may beexercised on the next succeeding day which is not a Saturday or Sunday or sucha legal holiday.

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**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       |

 

**NETISSUE ELECTION 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 ofAssignee]

thewithin Warrant, and does hereby irrevocably constitute and appoint                                                              its attorney to transfer the within Warrant on the books of the within namedCompany with full power of substitution on the premises.
| **DATED****:**           | ** ** | ** ** | ** ** | ** ** |
|--------------------------|------------|------------|------------|------------|
| ** **               |
| ** **               |
| **IN THE  PRESENCE OF:** |
| ** **               |
| ** **               | ** ** |

 

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