EXHIBIT 10.18 OYSTER POINT MARINA PLAZA Sixth Amendment to Office Lease

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Exhibit 10.18

OYSTER POINT MARINA PLAZA
Sixth Amendment to Office Lease

THIS Sixth Amendment TO OFFICE LEASE (the "Sixth Amendment") is made and entered into as of August 1, 2002, by and between KASHIWA FUDOSAN AMERICA, INC., a California corporation ("Landlord") and TITAN PHARMACEUTICALS, INC., a Delaware corporation ("Tenant").

Recita1s

A.

Landlord and Tenant have heretofore entered into that certain lease dated February 14, 1996 (the "Lease") for premises originally described as Suite 505 (the "Premises"), initially containing approximately 3,866 rentable square feet of space in the building located at 400 Oyster Point Boulevard, South San Francisco, California (the "Building"), which forms part of the office building complex commonly known as Oyster Point Marina Plaza (the "Complex").

B.

The Lease has heretofore been amended by the following instruments (collectively the "Addenda"):

C.

The parties mutually desire to amend the terms of the Lease to extend its Term, expand the Premises, and in certain other respects, all on and subject to the terms and conditions hereof.

Agreement

Now, therefore, in consideration of the mutual terms and conditions herein contained and of other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties agree as follows:

1 EFFECT OF AMENDMENT. Landlord and Tenant agree that, notwithstanding anything contained in the Lease to the contrary, the provisions set forth below will be deemed to be part of the Lease and shall supersede, to the extent they differ, any contrary provisions in the Lease. Terms defined in the Lease shall have the same meanings in this Sixth Amendment, unless a different definition is set forth in this Sixth Amendment. The term Lease as used herein shall be deemed to include the Addenda, each of which may also be referred to separately herein.

2 EFFECTIVE DATE. The amendments and changes specified in this Sixth Amendment shall become effective on October 1, 2002 (the "Effective Date"). Notwithstanding the foregoing, this Sixth Amendment shall constitute the fully-binding agreement and contract of the parties from and after the date of the parties execution and delivery of this Sixth Amendment to each other.

1

3 SUMMARY TABLE. The Table set forth in ¶ 4 of Fifth Amendment is hereby superseded and replaced in its entirety by the following table, which shall constitute the Table under § 1.2 of the Lease for all purposes from and after the Effective Date of this Sixth Amendment:

In the event of any conflict between the terms contained in the Table and the terms contained in subsequent paragraphs of this Sixth Amendment, the terms of the Table shall control, except as may be expressly varied in any subsequent paragraph of this Sixth Amendment.

4 EXPANSION OF PREMISES. Upon Substantial Completion of the Work specified in the Work Letter Agreement, as described in ~8 below, the Premises shall be expanded to include approximately 3,821 rentable square feet of space known as Suite 504 in the Building ("Suite 504") for all purposes under the Lease. The parties anticipate that Substantial Completion of Landlord's Work in Suite 504 will occur on or before October 1, 2002 (the "Target Date"). From and after the later to occur of the Target Date or Substantial Completion of Landlord's Work under the Work Letter Agreement specified in ¶ 8 below, Suite 504 shall become part of the Premises pursuant to the basic terms specified in the Table above regarding term, Base Rent, Tenant's Share of increases in Operating Expenses and Taxes, and the Base Year for the purposes of calculating Additional Rentable payable with respect to Suite 504.

5 EXTENSION OF LEASE TERM. The Term of the Lease specified in § 1.4 of the Lease, as heretofore modified in the Addenda, is hereby extended for an additional period of one (1) year commencing on July 1, 2006, and the Expiration Date of the Lease is hereby amended accordingly to June 30, 2007, for the entire Premises (including Suite 504).

6 EXTENSION TERM BASE RENT. The Base Rent for the Premises specified in § 1.5 of the Lease, as heretofore modified in the Addenda, shall be the amounts specified as Monthly Base Rent in the Table above for the various periods and spaces set forth in the