Item 1.01.  Entry into a Material Definitive Agreement.

On March 13, 2013, Pacira Pharmaceuticals, Inc. (“PPI-CA”), a California corporation and wholly-owned subsidiary of Pacira Pharmaceuticals, Inc., a Delaware corporation (“Pacira” and, collectively with PPI-CA, the “Company”) entered into (i) a Third Amendment (the “Third Amendment”) to its Industrial Real Estate Lease, dated December 8, 1994 with Lasdk Limited Partnership, a Delaware limited partnership (and successor-in-interest to Lankford & Associates, Inc., a Colorado corporation) (the “Lasdk Landlord”) for the property located at 10450 Science Center Drive, San Diego, California; and (ii) a Fifth Amendment (the “Fifth Amendment”) to its Industrial Real Estate Triple Net Lease, dated August 17, 1993 with HCP TPSP, LLC, a Delaware limited liability company (and successor-in-interest to Equitable Life Assurance Society of the United States, a New York corporation) (the “HCP Landlord”) for the property located at 11011 North Torrey Pines Road, La Jolla, California.

The Third Amendment extends the lease term from September 11, 2015 to August 31, 2020. In addition, the Third Amendment grants the Company the option to extend the lease for a period of five years (the “Option Term”) on written notice by the Company to the Lasdk Landlord not earlier than twelve (12) months and not later than nine (9) months prior to August 31, 2020, provided that the Company satisfies certain conditions set forth in the lease.  The annual rent payable during the Option Term is equal to the fair rental value for the premises as of the commencement date of the Option Term, subject to certain concessions, as described in further detail in the Third Amendment attached hereto as Exhibit 99.1 and incorporated herein by reference. Pursuant to the Third Amendment, the annual basic monthly rent ranges from $278,381.40 for each month in the year ending December 31, 2013 to $342,374.01 for each month in the year ending August 31, 2020.

In addition, the Third Amendment provides that the Lasdk Landlord will pay a one-time tenant improvement allowance (the “Tenant Improvement Allowance”) of $1,265,370 for costs relating to the initial design and construction of the Company’s improvements that are permanently affixed to the premises.  The Third Amendment further provides that the Company can increase the Tenant Improvement Allowance by an amount not to exceed $1,149,000 for base building work (the “Base Building Allowance”).  Monthly Basic Rent is not adjusted on account of any portion of the Base Building Allowance paid to the Company.  The Third Amendment further provides that, if exercised prior to October 1, 2013, the Company can increase the Tenant Improvement Allowance by an amount not to exceed $2,530,740 (the “Additional Allowance”). In the event the Company exercises its right to use all or any portion of the Additional Allowance, the monthly basic rent for the premises shall be increased by an amount equal to the “Additional Monthly Basic Rent,” as that term is defined in the Third Amendment and incorporated herein by reference, in order to repay the Additional Allowance to the Lasdk Landlord.

If the Company fails to utilize the Tenant Improvement Allowance by June 30, 2015, any unused amounts will revert back to the Lasdk Landlord and the Company will have no further rights with respect thereto.

2

Details regarding the items covered by the Tenant Improvement Allowance, the mechanics of disbursement of the Tenant Improvement Allowance and the manner in which disputes are settled are set forth in a Tenant Work Letter attached to the Third Amendment as Exhibit A and incorporated by reference herein.

The above description of the Third Amendment is qualified in its entirety by reference to the terms of the Third Amendment, filed as Exhibit 99.1 hereto and incorporated herein by reference.

The Fifth Amendment extends the lease term from August 1, 2015 to August 31, 2020. In addition, the Fifth Amendment grants the Company the option to extend the lease for a period of five years (the “Building 6 Option Term”) on written notice by the Company to the HCP Landlord not earlier than twelve (12) months and not later than nine (9) months prior to August 31, 2020, provided that the Company satisfies certain conditions set forth in the lease.  The annual rent payable during the Building 6 Option Term is equal to the fair rental value for the premises as of the commencement date of the Building 6 Option Term, subject to certain concessions, as described in further detail in the Fifth Amendment attached hereto as Exhibit 99.2 and incorporated herein by reference.

Pursuant to the Fifth Amendment, the annual basic monthly rent ranges from $66,456.60 for each month in the year ending December 31, 2013 to $81,733.24 for each month in the year ending August 31, 2020. In addition, the Fifth Amendment provides that the HCP Landlord will pay a one-time tenant improvement allowance (the “Building 6 Tenant Improvement Allowance”) of $326,190 for costs relating to the initial design and construction of the Company’s improvements that are permanently affixed to the premises.  The Fifth Amendment further provides that the Company can increase the Building 6 Tenant Improvement Allowance by an amount not to exceed $300,000 for base building work (the “Building 6 Base Building Allowance”).  Monthly Basic Rent is not adjusted on account of any portion of the Building 6 Base Building Allowance paid to the Company.  The Fifth Amendment further provides that, if exercised prior to October 1, 2013, the Company can increase the Building 6 Tenant Improvement Allowance by an amount not to exceed $652,380 (the “Building 6 Additional Allowance”). In the event the Company exercises its right to use all or any portion of the Building 6 Additional Allowance, the monthly basic rent for the premises shall be increased by an amount equal to the “Additional Monthly Basic Rent,” as that term is defined in the Fifth Amendment and incorporated herein by reference, in order to repay the Building 6 Additional Allowance to the HCP Landlord.

If the Company fails to utilize the Building 6 Tenant Improvement Allowance by June 30, 2015, any unused amounts will revert back to the HCP Landlord and the Company will have no further rights with respect thereto.

Details regarding the items covered by the Building 6 Tenant Improvement Allowance, the mechanics of disbursement of the Building 6 Tenant Improvement Allowance and the manner in which disputes are settled are set forth in a Tenant Work Letter attached to the Fifth Amendment as Exhibit A and incorporated by reference herein.

The above description of the Fifth Amendment is qualified in its entirety by reference to the terms of the Fifth Amendment, filed as Exhibit 99.2 hereto and incorporated herein by reference.

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

On March 13, 2013, Pacira Pharmaceuticals, Inc. (“PPI-CA”), a California corporation and wholly-owned subsidiary of Pacira Pharmaceuticals, Inc., a Delaware corporation (“Pacira” and, collectively with PPI-CA, the “Company”) entered into amendments to the employment agreements with the officers set forth below. The amendments modify the compensation such officers will receive in the event that Pacira terminates the officer’s employment without cause (as defined in the applicable officer’s employment agreement) or in the event the officer terminates his or her employment for good reason (as defined in the applicable officer’s employment agreement) within thirty (30) days prior to, or twelve (12) months following, the consummation of a change of control of the Company as follows:

3

4

In addition to the payments described above, each officer’s original employment agreement provided him or her with one hundred percent (100%) acceleration of vesting of the then unvested option shares held by such officer in the event of a termination without cause or for good reason in connection with a change of control. The amendments described above did not modify such acceleration provisions, which remain in full force and effect.

The above descriptions of the amendments to the employment agreements are qualified in their entirety by reference to such amendments, filed as Exhibits 99.3-99.7 hereto and incorporated herein by reference.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

5

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX

7