Exhibit 10.68

AMENDMENT NO. 1

to

ASSIGNMENT AGREEMENT

This AMENDMENT TO ASSIGNMENT AGREEMENT("**Amendment**"), effective as of May 12, 2008 (the"**Amendment Date**"), is made and entered into by and between**PHARMACYCLICS, INC.**, a Delaware corporation having a place of business at995 East Arques Avenue, Sunnyvale, California 94085,("**Pharmacyclics**") and **APPLERA CORPORATION**, a Delawarecorporation, through its **CELERA GROUP** having a place of business at 45West Gude Drive, Rockville, Maryland 20850 ("**Celera**").Pharmacyclics and Celera may each be referred to herein individually as a"**Party**" or, collectively, as "**Parties**."

WHEREAS, Pharmacyclics and Celera are parties to theAssignment Agreement, effective as of April 7, 2006, whereby Celera assigned toPharmacyclics certain proprietary technology and know-how related to the CeleraPrograms, including but not limited to the **[*******]** (the "**AssignmentAgreement**");  

WHEREAS, Pharmacyclics desires that certain paymentterms of the Assignment Agreement relating to **[*******]** be amended; and 

WHEREAS, Celera desires that such payment terms shouldbe amended, subject to the terms and conditions set forth below.  

NOW, THEREFORE, in consideration of the mutualcovenants and obligations set forth herein, and for other good and valuableconsideration, the receipt and sufficiency of which is hereby acknowledged,Pharmacyclics and Celera hereby agree as follows: 

In General.

All terms defined in the Assignment Agreement shall have a meaning in thisAmendment as in the Assignment Agreement, unless otherwise expressly defined inthis Amendment.  
**Amendment of the Assignment Agreement.

2.1   Amendment of Section 6.3.  Section 6.3 of theAssignment Agreement is hereby amended to read in its entirety as follows;
**6.3	Product Milestones
(a)	Pharmacyclics will pay to Celera payments as setforth in this Section 6.3 within thirty (30) days after (i) under Section 6.3(b)and 6.3(c), Pharmacyclics' receipt of upfront and milestone payments from one ormore Third Parties upon the grant by Pharmacyclics of a sublicense to such ThirdParty under the Celera Technology and the Celera Patents to make, use, offer tosell, sell and import any Assigned Product which is an

**[*******]**, and(ii) under Section 6.3(d), the first achievement of the corresponding milestonefor an Assigned Product which is an **[*******]** or which is a**[*******]**.  Such payments shall be made in Dollars by wire transfer ofimmediately available funds into an account designated by Celera.  Noachievement milestone payment will be payable more than once, no matter how manytimes such milestone is achieved by a single Assigned Product or by multipleAssigned Products in each of the **[*******]** category or the**[*******]** category.  Such payments will be nonrefundable andnon-creditable against Royalties payable pursuant to Sections 6.4, and any otherfees, milestone payments or other payments due Celera under thisAgreement.
**(b)	Subject to the terms and conditions of thisAgreement, in the event that Pharmacyclics, within **[*******]** of theAmendment Date, grants a sublicense to one or more Third Parties under theCelera Technology and the Celera Patents to make, use, offer to sell, sell andimport any Assigned Product which is an **[*******]**, Pharmacyclics willpay to Celera the first **[*******]** Dollars ($**[*******]**)received by Pharmacyclics as upfront and milestone payments from such ThirdParties.  For purposes of this Section 6.3(b) and Section 6.3(c), the term"upfront and milestone payments" does not include amounts reasonablyand fairly attributable to bona fide (i) debt financing, (ii) sale of equity inPharmacyclics, (iii) reimbursement for the cost and expense of research,development and clinical services incurred by Pharmacyclics after the effectivedate of such sublicense and attributable to **[*******]**, or (iv)reimbursement of patent filing, prosecution and maintenance expenses incurred byPharmacyclics and attributable to **[*******]**.
**(c)  	Subject to the terms and conditions of thisAgreement, in the event that Pharmacyclics, at any time subsequent to**[*******]** after the Amendment Date, grants a sublicense to one or moreThird Parties under the Celera Technology and the Celera Patents to make, use,offer to sell, sell and import any Assigned Product which is an**[*******]**, Pharmacyclics will pay to Celera the greater of (i)**[*******]**% of the first $**[*******]** received by Pharmacyclicsas upfront and milestone payments from such Third Parties, up to a total of$**[*******]** or (ii) **[*******]**% of any Upfront Paymentsreceived from such Third Party. The foregoing amounts will be determined as andwhen Pharmacyclics receives such amounts and will take into account all paymentsreceived by Pharmacyclics as described in this Section 6.3(c). For purposes ofthis Section 6.3(c), the term "Upfront Payment" means any cash paymentthat, under the terms of the relevant sublicense, is a firm and certain paymentobligation as of the effective date of such sublicense, but not includingamounts reasonably and fairly attributable to bona fide (i) debt financing, (ii)sale of equity in Pharmacyclics, (iii) reimbursement for the cost and expense ofresearch, development and clinical services incurred by Pharmacyclics after theeffective date of such sublicense and attributable to **[*******]**, or(iv) reimbursement of patent filing, prosecution and maintenance expensesincurred by Pharmacyclics and attributable to
                                       2

**[*******]**, and isindependent of the achievement by Pharmacyclics of any performancemilestone.
**	For example: if Pharmacyclics has paid Celera$[*****] due to Celera from an initial Third Party sublicense agreementthrough 6.3(c)(i), but then enters into a second Third Party sublicenseagreement where Pharmacyclics receives from such Third Party an Upfront Paymentof $[*******], Pharmacyclics would pay Celera an additional $[*******](calculated $[*******] X [*******]% = $[*******], less $[*******]previously paid to Celera = $[*******]). 
(d)	Subject to the terms and conditions of thisAgreement, Pharmacyclics will pay Celera milestone payments in accordance withthe following table:

**Milestone Event**Milestone Payment Amount (Dollars) **[*****]****[*****]**
1.	**[*******]**
$**[*******]**
$**[*******]**
2.	**[*******]**
$**[*******]**
$**[*******]**
3.	**[*******]**
$**[*******]**
$**[*******]**
4.	**[*******]**
$**[*******]**
$**[*******]**
5.	**[*******]**
$**[*******]**
$**[*******]**
6.	**[*******]**
$**[*******]**
$**[*******]**
7.	**[*******]**
$**[*******]**
$**[*******]**
	**Total**
$**[*******]**
$**[*******]**

2.2 **Amendment of Section 6.4.**Section 6.4 of the Assignment Agreement is hereby amended to read in itsentirety as follows;**6.4	Royalties

(a)	Subject to the termsand conditions of this Agreement, Pharmacyclics will pay Celera a tiered Royaltyin accordance with the following table on worldwide Net Sales:

                                       3

**Total Net Sales of an************************