Exhibit 10.1

FIRST AMENDMENT TO PATENT LICENSE AGREEMENT

THIS AMENDMENT (the "Amendment") is made and entered into as of May 30, 2000
(the "Effective Date"), to the Patent License Agreement between Pharmacyclics,
Inc. ("LICENSEE") and the Board of Regents ("BOARD") of the University of Texas
System ("SYSTEM"), effective May 19, 1992 (the "Agreement," all capitalized
terms having the meanings as defined in the Agreement).

WHEREAS, BOARD and SYSTEM, on behalf of its component institution the University
of Texas at Austin ("UNIVERSITY"), and LICENSEE desire to enter into this
Amendment in order to resolve certain ambiguities in the original language of
the Agreement and to better reflect the parties' understanding given the
development status of the LICENSED SUBJECT MATTER;

NOW, THEREFORE, in consideration of the mutual covenants and agreement of terms
set forth herein, and for good and valuable consideration, the receipt and
sufficiency of which is hereby acknowledged, the parties hereto agree as
follows:

 A. Sections 2.8 and 2.10 of the Agreement are deleted in their entirety and
    replaced, and new Sections 2.11, 2.12 and 2.13 are added, as follows:

2.8 SALE(S), SELL or SOLD shall mean the transfer or disposition of a LICENSED
PRODUCT for value to a party other than LICENSEE, or a SUBSIDIARY or
SUBLICENSEE, but, shall not include any transfer of LICENSED PRODUCT between
LICENSEE and a SUBSIDIARY or SUBLICENSEE. Goods placed in inventory or on
consignment shall not be deemed SOLD until paid for by an independent third
party purchaser. SALES shall not include the distribution of reasonable and
customary quantities of complimentary samples and free "trade goods" including
those provided to indigent patient programs.

2.10 NET SALES shall mean the gross revenues collected by LICENSEE, its
SUBSIDIARY or SUBLICENSEE from the SALE of LICENSED PRODUCTS during a given
period, less deduction for:

(a) credits or allowances, if any, actually granted on account of price
adjustments, rejection or return of LICENSED PRODUCTS previously SOLD, whether
during the specific period or not, rebates, adjustments and discounts, including
charge backs;

(b) excise or ad valorem taxes, sales, use or other taxes or duties imposed upon
and paid with respect to such sales (excluding franchise, income, or other taxes
levied with respect to gross receipts);

(c) separately itemized insurance and transportation costs incurred in shipping
LICENSED PRODUCTS to independent parties; and

(d) promotional, cash, trade or volume discounts

(such deduction not to exceed the corresponding gross revenues).

2.11 SUBLICENSE shall mean a grant, by LICENSEE to an independent third party
that is not a SUBSIDIARY, of the commercial right to manufacture, use or SELL
(including, e.g., marketing, distribution and supply) under the LICENSED SUBJECT
MATTER.

2.12 SUBLICENSEE shall mean a party that has been granted a SUBLICENSE.

2.13 SUBLICENSING FEE(S) shall mean payments (in money, or money's worth as
described in Section 5.8(d) herein) received by LICENSEE from a SUBLICENSEE,
which payments are on account of the grant of a SUBLICENSE and are not otherwise
attributable to SALES of LICENSED PRODUCT. SUBLICENSING FEES excludes payments
in the nature of reimbursements and/or support for future expenditures on
research and development, technology transfer, the transfer of materials for
clinical and other research, manufacturing process development and scale-up and
the like).

B. Section 5.1 of the Agreement is deleted in its entirety and replaced with the
following:

5.1 Subject to the other terms of this Article V and in consideration of rights
granted by BOARD to LICENSEE under this Agreement, LICENSEE agrees to pay BOARD
the following:

(a) A running royalty as provided in paragraph 5.2 in the case of SALES by
LICENSEE, its SUBSIDIARIES and/or its SUBLICENSEES.

(b) As payment in full for any and all amounts due BOARD under Section 5.1(b) of
the Agreement (prior to the present Amendment), LICENSEE agrees to pay the
following fixed amounts:

 * One Hundred Thousand Dollars ($100,000), within thirty (30) days of
   LICENSEE's receipt of a fully executed original of this Amendment;
 * Fifty Thousand Dollars ($50,000) by August 14, 2001;
 * Fifty Thousand Dollars ($50,000) by August 14, 2002;
 * Fifty Thousand Dollars ($50,000) by August 14, 2003; and
 * Fifty Thousand Dollars ($50,000) by August 14, 2004.

(c) Commencing January 1, 2005 through termination of the Agreement, three
percent (3%) of any SUBLICENSING FEES (less any tax imposed or governmental
charge assessed against such fees) received by LICENSEE in a given calendar
year. The maximum amount payable to BOARD in any such calendar year on account
of such SUBLICENSING FEES shall not exceed Fifty Thousand Dollars ($50,000). The
amount of SUBLICENSING FEES received in any given calendar year, as used in
calculation of this payment and LICENSEE's corresponding maximum yearly payment
hereunder, shall be re-set to zero at the start of each calendar year; i.e.,
SUBLICENSING FEES in excess of $1.67 Million received in any calendar year
cannot be carried over nor serve as the basis for any payment hereunder in a
subsequent year.

C. Section 5.2 of the Agreement is deleted in its entirety and replaced with the
following:

5.2 Subject to Section 5.3, the royalty on SALES shall be:

(a) Five percent (5%) of NET SALES in respect of LICENSED PRODUCTS SOLD for use
as a human therapeutic (including without limitation in radiation or
photodynamic therapy); and

(b) Three percent (3%) of NET SALES in respect of LICENSED PRODUCTS SOLD for
other applications (including without limitation in vitro inactivation of
infectious agents, magnetic resonance imaging (MRI) and in vitro diagnostics).

D. Section 5.3 of the Agreement is deleted in its entirety and replaced with the
following:

5.3 During each calendar year, each royalty rate mentioned in Section 5.2 shall
be reduced by one percentage point (1%) for each $15,000,000 in the aggregate
NET SALES of LICENSEE and its SUBSIDIARIES and SUBLICENSES in that calendar
year; provided, however, that no such royalty rate shall be reduced so as to be
less than one (1%) percent. For example, immediately after the first $15,000,000
has been achieved during a given calendar year, the rates under Section 5.2(a)
and 5.2(b) will be four percent (4%) and two percent (2%), respectively.

E. The first sentence of Section 5.7 of the Agreement is deleted in its entirety
and replaced with the following:

5.7 During the term of this Agreement and for one (1) year thereafter LICENSEE
shall keep complete and accurate records of its and (as reported to it) its
SUBSIDIARIES' and SUBLICENSES' NET SALES, and of all SUBLICENSING FEES, in
sufficient detail to enable the amounts due BOARD hereunder to be determined.

F. Section 5.8 of the Agreement is deleted in its entirety and replaced with the
following:

5.8 LICENSEE shall provide the following reports and payments to BOARD.

(a) Within forty-five (45) days after March 31, June 30, September 30 and
December 31, LICENSEE shall deliver to BOARD at the address listed in paragraph
14.2 a true and accurate report, giving such particulars of the business
conducted by LICENSEE under this Agreement during the previous calendar quarter
as are pertinent to an accounting for payments hereunder, including at least:
any SUBLICENSING FEE received by LICENSEE, NET SALES received by LICENSEE and/or
its SUBSIDIARIES for each LICENSED PRODUCT, an accounting of any deduction(s)
taken in calculating NET SALES as permitted by the definition thereof, and the
calculation of the total amount owed BOARD hereunder for the period of such
report. Simultaneously with the delivery of each such report, LICENSEE shall pay
to BOARD the amount, if any, due for the period of such report. If no payments
are due it shall be so reported.

(b) LICENSEE shall impose on SUBLICENSEES, mutatis mutandis, reporting and
payment obligations similar to those of Section 5.8(a). LICENSEE shall provide
to BOARD such similar reports or excerpts therefrom as are pertinent to an
accounting for payments under paragraph 5.1(a), to the extent received by
LICENSEE during a calendar quarter or thereafter up until fifteen (15) business
days prior to the due date for LICENSEE's report under Section 5.8(a).
Simultaneously with the delivery of each such report on SUBLICENSEE activity,
LICENSEE shall pay to BOARD the corresponding royalty amount, if any, due for
the period of such report. If no payments are due it shall be so reported.

(c) Unless otherwise agreed in writing, LICENSEE's royalties hereunder will be
paid in U.S. Dollars as noted in Section 5.10 herein. Royalties with respect to
amounts other than U.S. Dollars shall be computed in U.S. Dollars by converting
such currency at the average exchange rate for U.S. Dollars prevailing over the
last business day of each month of the calendar quarter during which the SALES
were actually made. The exchange rates used shall be the rates published by the
Wall Street Journal, and if it does not publish any such rate or if it is no
longer published, a comparable publication to be agreed upon from time to time
by the parties.

(d) For the purposes of Section 5.1(c), the value of any SUB-LICENSING FEES
received other than in money shall be based upon a cash equivalent value to be
agreed upon in good faith between LICENSEE and the BOARD (any value recited in a
corresponding SUB-LICENSE agreement to be accorded significant weight), and the
BOARD's payment therefor shall, upon mutual agreement of BOARD, UNIVERSITY and
LICENSEE, be made in U.S. Dollars or in kind at such agreed-upon value.

G. Section 5.9 of the Agreement is deleted in its entirety and replaced with the
following:

5.9 Upon or before each January 1st throughout the term of the Agreement,
LICENSEE shall deliver to BOARD a written report as to LICENSEE's efforts and
accomplishments during the preceding year in commercializing LICENSED SUBJECT
MATTER in the LICENSED TERRITORY, and its commercialization plans for the coming
year.

H. Section 5.10 of the Agreement is deleted in its entirety and replaced with
the following:

5.10 All amounts payable hereunder by LICENSEE shall be payable in United States
funds, in accord with Section 5.8(c) herein, without deductions for taxes,
assessments, fees, or charges of any kind unless specifically permitted under
this Agreement. Checks shall be made payable to "The University of Texas at
Austin" and sent to the UNIVERSITY address noted in Section 14.2.

I. Section 14.2 of the Agreement is deleted in its entirety and replaced with
the following:

14.2 Any notice required by this Agreement shall be given in writing by prepaid,
first class, certified mail, return receipt requested, given in person or given
via nationally recognized overnight courier, and shall be effective upon
receipt, addressed as follows:

in the case of BOARD, to:

Board of Regents
The University of Texas System
201 West 7th Street
Austin, Texas 78701
Attention: Office of General Counsel

with a copy to UNIVERSITY at:

Office of Technology Licensing and Intellectual Property
The University of Texas at Austin
MCC Building, Suite 1.9A (R3500)
3925 West Braker Lane
Austin, Texas 78701
Attention: Director

in the case of LICENSEE, to:

Pharmacyclics, Inc.
995 East Arques Avenue
Sunnyvale, California 94086-4521
Attention: President and CEO

with a copy to:

Pharmacyclics, Inc.
995 East Arques Avenue
Sunnyvale, California 94086-4521
Attention: Office of General Counsel

or to such other addresses as may be given from time to time under the terms of
this notice provision.

J. In the case of any inconsistency between this Amendment and the Agreement,
this Amendment shall govern. Except as expressly provided in this Amendment, all
other terms, conditions and provisions of the Agreement shall continue in full
force and effect as provided therein.

IN WITNESS WHEREOF, the LICENSEE and BOARD have executed and delivered this
Amendment, effective as of the date first set forth above.

PHARMACYCLICS, INC.

 

BOARD OF REGENTS OF THE
UNIVERSITY OF TEXAS SYSTEM

By /s/ RICHARD A. MILLIER, M.D.
Richard A. Miller, M.D.
President and CEO

 

By /s/ JUAN M. SANCHEZ, Ph.D.
Juan M. Sanchez, Ph.D.
Vice President for Research

Date 5/30/00

 

Date 6/15/00

   

Approved as to Form:
UNIVERSITY OF TEXAS SYSTEM

   

By BETHLYNN MAXWELL, Ph.D.
BethLynn Maxwell, Ph.D.
Office of General Counsel
The University of Texas System

   

Date 6/14/00