Exhibit 10(vv)

                 AMENDMENT AND WAIVER

            This AMENDMENT AND WAIVER (this "Amendment and Waiver"), dated as of
January 31, 2002, between SIGA Technologies, Inc., a Delaware corporation (the
"Corporation"), and Thomas N. Konatich ("Konatich"), amends and waives certain
provisions of the Employment Agreement, dated as of October 6, 2000, between the
Corporation and Konatich (the "Existing Agreement"). Capitalized terms used but
not defined herein shall have the respective meanings assigned to them in the
Existing Agreement.

            WHEREAS, an event which could be deemed to constitute a Change of
      Control has occurred;

            WHEREAS, under the Existing Agreement, the Initial Term ends on
      April 1, 2002; and

            WHEREAS, the Corporation and Konatich desire to amend the Existing
      Agreement as provided in this Amendment and Waiver.

            NOW THEREFORE, in consideration of the premises and for other good
and valuable consideration, the receipt and sufficiency of which is hereby
acknowledged, the undersigned, intending legally to be bound, hereby agree as
follows:

            1. Section 1 of the Existing Agreement shall be amended to read in
its entirety as follows:

                  1. Employment for Term. The Corporation hereby employs
      Konatich and Konatich hereby accepts employment with the Corporation for
      the period beginning on January 19, 2000 and ending December 31, 2002 (the
      "Initial Term"), or upon the earlier termination of the Term pursuant to
      Section 6. The termination of Konatich's employment under this Agreement
      shall end the Term but shall not terminate Konatich's or the Corporation's
      other agreements in this Agreement, except as otherwise provided herein.

            2. Section 3(a) of the Existing Agreement shall be amended to add
the following sentence at the end thereof:

      From and after January 31, 2002, the Base Salary shall be not less than
      $182,500 per annum, and the Corporation shall make the appropriate
      adjustments to its payroll as soon as reasonably practicable thereafter.

            3. (a) Any event occurring prior to January 31, 2002 that would
otherwise constitute a Change of Control, including, without limitation, the
execution of the letter agreement among Donald G. Drapkin, the Corporation,
Gabriel M. Cerrone, Thomas E. Constance, Eric A. Rose, M.D., Judson A. Cooper
and Joshua D. Schein, Ph.D., dated March 30, 2001, and the consummation of the
transactions contemplated thereby, shall not be deemed a Change of Control for
purposes of the Agreement.

<PAGE>

               (b) All stock options that were granted to Konatich by the
Corporation prior to March 30, 2001, shall, irrespective of any provisions of
the relevant option agreements, immediately vest and become exerciseable as of
the date hereof.

            4. Section 8 of the Existing Agreement shall be amended to add a
Subsection (f) that reads follows:

            (f). Satisfactory Alternative. Notwithstanding anything to the
            contrary herein, Konatich shall have no rights and the Corporation
            shall have no obligation under this Section 8 with respect to a
            Termination Due to Change in Control; if, prior to or simultaneously
            with such Termination Due to Change in Control, Konatich is offered
            employment within the Metro New York area by another business as its
            Chief Financial Officer at a level of compensation equal to or
            greater than his compensation hereunder (a "Satisfactory
            Alternative").

            5. Notices to the Corporation, as described in Section 13 of the
Existing Agreement shall be sent to:

                            SIGA Technologies, Inc.
                            420 Lexington Avenue, Suite 620
                            New York, New York 10170
                            Attention: President

                   with a copy to:

                            Kramer Levin Naftalis & Frankel LLP
                            919 Third Avenue
                            New York, New York 10022
                            Attention: Thomas E. Constance, Esq.

                      [Signature page follows immediately]

<PAGE>

            IN WITNESS WHEREOF, the parties hereto have executed this Amendment
and Waiver as of January 31, 2002.

                                                       SIGA TECHNOLOGIES, INC.


                                                       By:
                                                          ----------------------
                                                         Name:
                                                         Title:


                                                      /s/ Thomas N. Konatich
                                                      --------------------------
                                                      Thomas N. Konatich