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                                                                   EXHIBIT 10.10

                              Pharmion Corporation
                                2525 28th Street
                             Boulder, Colorado 80301

April 2, 2003

Celgene Corporation
7 Powder Horn Drive
Warren, New Jersey 07059
Attention: John W. Jackson

Gentlemen:

On March 3, 2003, Pharmion GmbH ("Pharmion"), Pharmion Corporation ("Guarantor")
and Celgene Corporation ("Celgene") entered into Amendment No.1 (the
"Amendment") to the License Agreement among such parties dated November 16, 2001
(as amended, the "License Agreement"). Capitalized terms that are not defined
herein shall have the meaning ascribed thereto in the License Agreement.

Celgene, Pharmion and Guarantor mutually acknowledge and agree that the further
clinical development of Thalomid, including registration studies for, among
other indications, newly diagnosed multiple myeloma, is in the interest of the
parties, and that it is also in the interest of the parties that such studies
should include centers in the Territory. In order to insure that such studies
are consistent across centers in the United States and the Territory, and are
designed to enroll patients as rapidly as possible, Pharmion, Guarantor and
Celgene hereby agree as follows:

(1)      Promptly following the execution of this letter agreement, Celgene and
         Pharmion shall establish a Thalomid Clinical Development Committee
         ("TCDC") consisting of an equal number of representatives from both
         parties, which will meet (in person, telephonically or via
         videoconference) quarterly and, as may be agreed upon by Celgene and
         Pharmion from time to time, at other times, to review the design,
         development, enrollment and progress of Thalomid clinical trials in the
         Territory (the "Trials"). Through TCDC, Celgene and Pharmion each shall
         (a) afford the other the opportunity to confer concerning the
         initiation and conduct of Trials, including matters relating to the
         oversight of the clinical sites involved in Trials, (b) keep apprised
         on a regular basis concerning the progress of Trials, and (c) consider
         in good faith the views of the other with respect to Trials, including
         the views concerning possible adjustments of any Trials that may be
         appropriate to address the requirements of regulatory authorities in
         connection with obtaining Regulatory Approval of Thalomid. If requested
         by either Celgene or Pharmion, any material matter as to which the
         parties' representatives on the TCDC have opposing views shall be
         referred to the chief executive officer of Pharmion and the chief
         operating officer of Celgene for consideration by them. Notwithstanding
         anything to the contrary in this letter agreement, the party initiating
         a Trial shall have sole authority with respect to, and control of, such
         Trial.

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Celgene Corporation
April 2, 2003
Page 2

(2)      During the period commencing on the date of this letter agreement and
         ending December 31, 2005, Pharmion shall provide Celgene an aggregate
         of $8 million (the "Funding") for the expenses and internal costs
         incurred and/or to be incurred by Celgene for the conduct of Trials.
         The Funding shall be provided as follows: (a) in 2003 in three
         installments of $1 million each, payable upon execution of this letter
         agreement, September 30, 2003 and December 31, 2003; (b) in 2004 in
         four installments of $750,000 each, payable on the last day of each
         calendar quarter in 2004; and (c) in 2005 in four installments of
         $500,000 each, payable on the last day of each calendar quarter in
         2005. Celgene shall, within 45 days after the end of each calendar
         quarter in the period from the date of this letter to December 31,
         2006, provide Pharmion copies of invoices and other documentation
         available to Celgene reflecting up to $8 million of expenses and
         internal costs incurred by Celgene with respect to clinical trials of
         Thalomid.

(3)      To the extent there is any conflict between the terms of this letter
         agreement and the License Agreement, this Agreement shall control.

(4)      This letter agreement shall be governed by and construed in accordance
         with the laws of the State of New York.

Please indicate your acceptance of, and agreement with, the foregoing by signing
the enclosed copy of this letter and returning it to us.

Very truly yours,

Pharmion Corporation
Pharmion GmbH

By:  /s/ Patrick J. Mahaffy
     ---------------------------------
     Patrick J. Mahaffy
     President and CEO

ACCEPTED AND AGREED:

Celgene Corporation

By:  /s/ John W. Jackson
     ------------------------------------
     John W. Jackson
     Chairman and Chief Executive Officer<PAGE>

                                                                   EXHIBIT 10.11

                               Amendment No. 2 to
                                License Agreement

         This Amendment No. 2, dated April 8, 2003, to the License Agreement,
dated as of November 16, 2001, as amended by Amendment No. 1 dated as of March
3, 2003, by and among Pharmion GmbH, a Swiss limited liability company
("Pharmion"), Pharmion Corporation, a Delaware corporation ("Guarantor") and
Celgene Corporation, a Delaware corporation ("Celgene").

         WHEREAS, Pharmion, Guarantor and Celgene are parties to the License
Agreement, dated as of November 16, 2001, as amended by Amendment No. 1 dated as
of March 3, 2003 (the "Agreement"); and

         WHEREAS, Guarantor and Celgene have entered into a Securities Purchase
Agreement (the "Securities Purchase Agreement") whereby Guarantor will sell and
issue to Celgene a senior convertible promissory note in the principal amount of
$12,000,000 and a warrant to purchase shares of Celgene's common stock for an
aggregate purchase price of $12,000,000 (the "Securities Transaction"); and

         WHEREAS, pursuant to Section 5.4 of the Securities Purchase Agreement,
the obligation of Celgene to complete the Securities Transaction is subject to
the execution and delivery of this Amendment No. 2 to the Agreement;

         NOW, THEREFORE, in consideration of the premises and the mutual
covenants contained herein, Pharmion, Guarantor and Celgene hereby agree that
the Agreement be amended as follows:

         1.       Definitions. All terms not otherwise expressly defined in this
Amendment shall have the meanings ascribed to such terms in the Agreement.

         2.       Termination by Either Party in the Event of Bankruptcy.
Section 9.3(a) of the Agreement is hereby amended to read in its entirety as
follows:

                           "(a) Celgene may terminate this Agreement on 60 days
                  prior written notice to Pharmion following (i) a material
                  breach by Pharmion of any covenant, duty or undertaking
                  herein, or in the letter agreement of even date entered into
                  among Pharmion, Guarantor and Celgene (the "Letter
                  Agreement"), which is not cured within 60 days of written
                  notice thereof; or (ii) if any of Pharmion, Guarantor or
                  Pharmion BV, a wholly owned subsidiary of Guarantor, shall
                  become insolvent or shall file or have filed by its creditors
                  a petition in bankruptcy or similar proceeding, if a court of
                  competent jurisdiction appoints a receiver over the business
                  or assets of the other party, or the making by the party of a
                  general assignment for the benefit of creditors. Pharmion may
                  terminate this Agreement on 60 days prior written notice to
                  Celgene following (i) a material breach by Celgene of any
                  covenant, duty or undertaking herein, or in the Letter
                  Agreement, which is not cured within 60 days of written notice
                  thereof; or (ii) if Celgene shall become insolvent or shall
                  file or have filed by its creditors a petition

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                  in bankruptcy or similar proceeding, if a court of competent
                  jurisdiction appoints a receiver over the business or assets
                  of the other party, or the making by the party of a general
                  assignment for the benefit of creditors."

         3.       Consequences of Termination by Celgene. Section 9.5(d) of the
Agreement is hereby amended to read in its entirety as follows:

                           "(d) Pharmion shall, to the extent legally
                  permissible, take all additional action reasonably necessary
                  to assign all of its right, title and interest in and transfer
                  possession and control to Celgene of the regulatory filings
                  prepared by Pharmion, and regulatory approvals received by
                  Pharmion, and all clinical and other research data related to
                  such regulatory filings or approvals, to the extent that such
                  filings and approvals relate to the Product."

         4.       Unmodified Provisions. The provisions of this Amendment No. 2
shall be deemed to be incorporated in the Agreement and, except as expressly
modified by this Amendment, all terms and conditions of the Agreement shall
remain in full force and effect.

         5.       Governing Law. The parties agree that this Amendment shall be
governed by and construed in accordance with the laws of the State of New York.

         6.       Captions. All captions herein are for convenience only and
shall not be interpreted as having any substantive meaning.

         IN WITNESS WHEREOF, the parties have caused this Amendment No. 2 to be
duly executed by their authorized representatives, in duplicate as of the date
first written above.

Pharmion GmbH                                  Celgene Corporation

By: /s/ Patrick J. Mahaffy                    By: /s/ Robert J. Hugin
    -----------------------------------           -----------------------------
    Patrick J. Mahaffy                            Robert J. Hugin
    Chief Executive Officer                       SVP & Chief Financial Officer

Pharmion Corporation

By: /s/ Patrick J. Mahaffy
    ----------------------------------
    Patrick J. Mahaffy
    Chief Executive Officer

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