Exhibit 99.4

                           LEASE TERMINATION AGREEMENT

         This Lease Termination Agreement ("Agreement") is made and entered into
effective as of the 13th day of January, 2005 by and between PHARMAFRONTIERS
CORP., Assignee of OPEXA PHARMACEUTICALS, INC., ("Tenant") and STEBBINS GREEN
CORNER, L.P. ("Landlord") with reference to the following:

RECITALS:

         Reference is here made to that Tenant and Landlord entered into a lease
agreement (the same, as heretofore renewed, modified and amended from time to
time, is herein called the "Lease") for office/warehouse space located at 835
Greens Parkway, Suite 150, Houston, Texas dated on or about May 31, 2002,
executed by and between Landlord and Tenant. Words with initial capital letters
used but not defined herein shall have the respective meanings assigned to them
in the Lease.

         Tenant has expressed a desire to terminate the Lease. Landlord and
Tenant hereby agree to terminate the Lease prior to the scheduled expiration of
the term thereof and they enter into this Agreement to set forth their
understandings and agreements in respect thereto.

AGREEMENTS:

         NOW, THEREFORE, for and in consideration of the mutual covenants and
agreements set forth herein Landlord and Tenant hereby agree as follows:

         1.       Termination Date. The Lease, including all rights and options
                  of Tenant, its subtenants, successors and assigns thereunder
                  including, without limitation, Tenant's right to use and
                  occupy the Premises and any and all other rights of Tenant or
                  any other party, if any, to use and occupy the Premises shall
                  terminate at 5:00 p.m., Houston, Texas local time, on February
                  28, 2005 (the "Lease Termination Date").

                  In this regard, Tenant represents and warrants that it has not
                  assigned or sublet or in any way transferred its rights or
                  interest in the Lease as of this date.

         2.       No Reimbursement of Expenses; Termination Fee and Other
                  Consideration to Landlord. Tenant acknowledges that no sums
                  shall be due and payable by Landlord to Tenant in connection
                  with the termination of the Lease or for losses to Tenant
                  resulting therefrom including, without limitation,
                  interruption of Tenant's business, moving costs and expenses,
                  and increased rental or other operating expenses incurred by
                  Tenant due to or arising out of the relocation of Tenant's
                  business.

                  In consideration of Landlord's agreements set forth herein,
                  Tenant (a) shall pay to Landlord a "Termination Fee" on or
                  before the Lease Termination Date as follows: the sum of (i)
                  $56,762.54 in cash or certified funds if payment is received
                  on or before February 28, 2005, or (ii) $65,967.28 if payment
                  is received after February 28, 2005; (b) hereby surrenders to



                  Landlord the Tenant's Security Deposit in the amount of
                  $15,379.69 and all other monies previously paid; and (c) shall
                  convey all modular furniture (eight (8) stations installed in
                  offices and eight (8) stations stored in warehouse) to
                  Landlord as part of this Agreement.

         3.       Personal Property. Tenant acknowledges that it shall have no
                  right to remove any fixture, or property from the Premises
                  other than Personal Property of Tenant removed prior to Lease
                  Termination.

         4.       Obligations Which Survive; Mutual Release. Notwithstanding the
                  termination of the Lease, the obligations of Landlord and
                  Tenant which, by the provisions of the Lease, survive the
                  expiration or sooner termination of the same, shall survive,
                  including without limitation, operating expense
                  reconciliations for 2004, however, Tenant shall not be
                  obligated to pay any such prorated operating expense
                  reconciliations for 2005. Subject to the preceding sentence
                  hereof, Landlord and Tenant each hereby release one another
                  from any and all claims, demands, suits, and liabilities each
                  may hold against the other as of the date hereof and which
                  arise out of, or are related to, the Lease.

         5.       Miscellaneous. This Agreement shall be governed by and
                  construed in accordance with the laws of the state of Texas.
                  The prevailing party in any litigation or other similar action
                  arising out of or related to this Agreement shall be entitled
                  to collect reasonable attorneys' fees and other costs incurred
                  in such action from the other party hereto in addition to all
                  other awards in such action. This Agreement may only be
                  amended in a writing signed by all parties hereto. All sums of
                  whatever nature owed by Tenant to Landlord under this
                  Agreement shall bear interest from the date due thereof until
                  paid at the lesser of eighteen percent (18%) per annum or the
                  maximum interest rate per annum allowed by law.

         EXECUTED effective as of the date and year first above written.

                                  STEBBINS GREEN CORNER, L.P.

                                  By: /s/Fred Caldwell
                                      -----------------------------------------
                                      Name: Fred Caldwell
                                      Title: President
                                                                      "Landlord"


                                  PHARMAFRONTIERS CORP.

                                  By: /s/ C.W. Rouse
                                      ------------------------------------------
                                      Name: C.W. Rouse
                                      Title: C.F.O.
                                                                        "Tenant"


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