EX-4.(F) 4 d55990_ex4-f.txt REGISTRATION RIGHTS AGREEMENT Exhibit 4(f) REGISTRATION RIGHTS AGREEMENT THIS REGISTRATION RIGHTS AGREEMENT, dated as of May 23, 2003 (this "Agreement"), is made by and between SIGA TECHNOLOGIES, INC., a Delaware corporation, having its principal place of business located at 420 Lexington Avenue, Suite 620, New York, NY 10170 (the "Company"), and Plexus Vaccines Inc., a California corporation, having its principal place of business located at 11770 Bernardo Plaza Court, Suite 370-B, San Diego, CA 92128 (the "Initial Investor"). W I T N E S S E T H: WHEREAS, upon the terms and subject to the conditions of the Asset Purchase Agreement, dated as of May 14, 2003, between the Initial Investor and the Company (the "Asset Purchase Agreement"), the Company has agreed to issue and sell to the Initial Investor 1,950,000 shares of common stock, par value $.0001 per share, of the Company (the "Shares"); and WHEREAS, to induce the Initial Investor to execute and deliver the Asset Purchase Agreement, the Company has agreed to provide certain registration rights under the Securities Act of 1933, as amended, and the rules and regulations thereunder, or any similar successor statute (collectively, the "Securities Act"), with respect to the Shares; NOW, THEREFORE, in consideration of the premises and the mutual covenants contained herein and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Company and the Initial Investor hereby agree as follows: 1. Definitions. Terms not otherwise defined herein shall have the meanings ascribed to them in the Asset Purchase Agreement. As used in this Agreement, the following terms shall have the following meanings: (a) "Common Stock" means common stock, par value $.0001 per share, of the Company. (b) "Investor" means the Initial Investor and any permitted transferee or assignee who agrees to become bound by the provisions of this Agreement in accordance with Section 9 hereof and who holds Registrable Securities. (c) "Investor Group" means the Investor and each "Investor" (as such term is defined in each registration rights agreement dated as of the date hereof between the Company and each party identified on Schedule I attached hereto and made a part hereof), as a group and not individually. (d) "Potential Material Event" means any of the following: (i) the possession by the Company of material information not ripe for disclosure in a registration statement, which shall be evidenced by a determination in good faith by the Board of Directors of the Company 1 that disclosure of such information in the registration statement would be detrimental to the business and affairs of the Company or (ii) any material engagement or activity by the Company which would, in the good faith determination of the Board of Directors of the Company, be adversely affected by disclosure in a registration statement at such time; in each case where such determination shall be accompanied by a good faith determination by the Board of Directors of the Company that the registration statement would be materially misleading absent the inclusion of such information. (e) "Register," "Registered," and "Registration" refer to a registration effected by preparing and filing a Registration Statement or Statements in compliance with the Securities Act and pursuant to Rule 415 under the Securities Act or any successor rule providing for offering securities on a continuous basis ("Rule 415"), and the declaration or ordering of effectiveness of such Registration Statement by the United States Securities and Exchange Commission (the "SEC"). (f) "Registrable Securities" means the Shares until the Shares are eligible for resale pursuant to Rule 144 under the Securities Act. (g) "Registration Statement" means a registration statement of the Company under the Securities Act covering Registrable Securities on Form S-3, if the Company is then eligible to file using such form, and if not eligible, on Form SB-2 or other appropriate form. (h) "Effective Date" means the date the SEC declares a Registration Statement covering Registrable Securities and otherwise meeting the conditions contemplated hereby to be effective. (i) "Restricted Sale Date" means the first date, other than during a Permitted Suspension Period (as defined below), on which the Investor is restricted from making sales of Registrable Securities covered by any previously effective Registration Statement. 2. Registration. The Company shall use its commercially reasonable best efforts to prepare and file with the SEC, as soon as practicable after the Closing Date, either a Registration Statement or an amendment to an existing Registration Statement, in either event registering for resale by the Investor a sufficient number of shares of Common Stock for the Initial Investor to sell the Registrable Securities, but in no event less than the number of shares equal to the Registrable Securities at the time of filing of such Registration Statement (or such lesser number as may be required by the SEC). The Registration Statement shall include only the Registrable Securities. The Company will use its commercially reasonable best efforts to cause such Registration Statement to be declared effective. 3. Obligations of the Company. In connection with the registration of the Registrable Securities, the Company shall do each of the following: (a) Use its commercially reasonable best efforts to prepare and file with the SEC a Registration Statement with respect to not less than the number of Registrable Securities provided in Section 2 above, and thereafter use its commercially reasonable best efforts to cause such Registration Statement relating to Registrable Securities to become effective and keep the Registration Statement effective at all times during the period (the "Registration Period") 2 continuing until the earlier of (i) the date that is two (2) years after the last day of the calendar month following the month in which the Effective Date occurs, or (ii) the date on which the Shares are no longer Registrable Securities, which Registration Statement (including any amendments or supplements thereto and prospectuses contained therein) shall not contain any untrue statement of a material fact or omit to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances in which they were made, not misleading; (b) Use its commercially reasonable best efforts to prepare and file with the SEC such amendments (including post-effective amendments) and supplements to the Registration Statement and the prospectus used in connection with the Registration Statement as may be necessary to keep the Registration Statement effective at all times during the Registration Period, and, during the Registration Period, comply with the provisions of the Securities Act with respect to the disposition of all Registrable Securities of the Company covered by the Registration Statement until such time as all of such Registrable Securities have been disposed of in accordance with the intended methods of disposition by the seller or sellers thereof as set forth in the Registration Statement; (c) Permit one firm of counsel designated by the Investor Group to review the Registration Statement and all amendments and supplements thereto a reasonable period of time (but not less than two (2) business days and not more than ten (10) days) prior to their filing with the SEC. (d) Notify each Investor promptly (and, in the case of (i)(A) below, not less than two (2) business days prior to such filing) (i)(A) when a prospectus or any prospectus supplement or post-effective amendment to the Registration Statement is proposed to be filed; (B) whenever the SEC notifies the Company whether there will be a "review" of such Registration Statement; (C) whenever the Company receives (or a representative of the Company receives on its behalf) any oral or written comments from the SEC in respect of a Registration Statement (copies or, in the case of oral comments, summaries of such comments shall be promptly furnished by the Company to the Investors); and (D) with respect to the Registration Statement or any post-effective amendment, when the same has become effective; (ii) of any request by the SEC or any other Federal or state governmental authority for amendments or supplements to the Registration Statement or prospectus or for additional information; (iii) of the issuance by the SEC of any stop order suspending the effectiveness of the Registration Statement covering any or all of the Registrable Securities or the initiation of any proceedings for that purpose; (iv) of the receipt by the Company of any notification with respect to the suspension of the qualification or exemption from qualification of any of the Registrable Securities for sale in any jurisdiction, or the initiation or threatening of any proceeding for such purpose; and (v) of the occurrence of any event that to the best knowledge of the Company makes any statement made in the Registration Statement or prospectus or any document incorporated or deemed to be incorporated therein by reference untrue in any material respect or that requires any revisions to the Registration Statement, prospectus or other documents so that, in the case of the Registration Statement or the prospectus, as the case may be, it will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading; 3 (e) Furnish or make available to each Investor (i) promptly after the same is prepared and publicly distributed, filed with the SEC, or received by the Company, one (1) copy of the Registration Statement, each preliminary prospectus and prospectus, and each amendment or supplement thereto, and (ii) such number of copies of a prospectus, and all amendments and supplements thereto and such other documents, as such Investor may reasonably request in order to facilitate the disposition of the Registrable Securities owned by such Investor; (f) As promptly as practicable after becoming aware thereof, notify each Investor of the happening of any event of which the Company has knowledge, as a result of which the prospectus included in the Registration Statement, as then in effect, includes an untrue statement of a material fact or omits to state a material fact required to be stated therein or necessary to make the statements therein, in light of the circumstances under which they were made, not misleading, and use its commercially reasonable efforts to promptly prepare a supplement or amendment to the Registration Statement or other appropriate filing with the SEC to correct such untrue statement or omission, and deliver or make available a number of copies of such supplement or amendment to each Investor as such Investor may reasonably request; (g) Notwithstanding the foregoing, if at any time or from time to time after the date of effectiveness of the Registration Statement, the Company notifies the Investors in writing of the existence of a Potential Material Event, the Investor shall not offer or sell any Registrable Securities, or engage in any other transaction involving or relating to the Registrable Securities, from the time of the giving of notice with respect to a Potential Material Event until such Investor receives written notice from the Company that such Potential Material Event either has been disclosed to the public or no longer constitutes a Potential Material Event; provided, however, that the Company may not so suspend the right to such holders of Registrable Securities during the periods the Registration Statement is required to be in effect other than during a Permitted Suspension Period. The term "Permitted Suspension Period" means one or more suspension periods during any consecutive 12-month period which suspension periods, in the aggregate, do not exceed one hundred eighty (180) days, provided, however, that no one such suspension period shall either (i) be for more than forty-five (45) days or (ii) begin less than ten (10) business days after the last day of the preceding suspension (whether or not such last day was during or after a Permitted Suspension Period); provided, further, that the Company shall, if lawful to do so, provide the Investor with at least two (2) business days' notice of the existence (but not the substance of) a Potential Material Event; (h) Use its commercially reasonable efforts to secure and maintain the designation of all the Registrable Securities covered by the Registration Statement on the "Nasdaq/Small Cap Market" of the National Association of Securities Dealers Automated Quotations System ("NASDAQ") within the meaning of Rule 11Aa2-1 of the SEC under the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the quotation of the Registrable Securities on The Nasdaq/Small Cap Market; (i) Provide a transfer agent and registrar, which may be a single entity, for the Registrable Securities not later than the initial Effective Date. (j) Cooperate with the Investor who holds Registrable Securities being offered to facilitate the timely preparation and delivery of certificates for the Registrable 4 Securities to be offered pursuant to the Registration Statement and enable such certificates for the Registrable Securities to be in such denominations or amounts as the case may be, as the Investor may reasonably request, and, within five (5) business days after a Registration Statement which includes Registrable Securities is ordered effective by the SEC, the Company shall deliver, and shall cause legal counsel selected by the Company to deliver, to the transfer agent for the Registrable Securities (with copies to the Investor whose Registrable Securities are included in such Registration Statement) an appropriate instruction and, if necessary, an opinion of such counsel; and (k) Take all other reasonable actions necessary to expedite and facilitate disposition by the Investor of the Registrable Securities pursuant to the Registration Statement. 4. Obligations of the Investor. In connection with the registration of the Registrable Securities, each Investor shall have the following obligations: (a) It shall be a condition precedent to the obligations of the Company to complete the registration pursuant to this Agreement with respect to the Registrable Securities of a particular Investor that such Investor shall furnish to the Company such information regarding itself, the Registrable Securities held by it, and the intended method of disposition of the Registrable Securities held by it, as shall be reasonably required to effect the registration of such Registrable Securities and shall execute such documents in connection with such registration as the Company may reasonably request. At least ten (10) business days prior to the first anticipated filing date of the Registration Statement, the Company shall notify each Investor of the information the Company requires from each such Investor (the "Requested Information") if such Investor has any Registrable Securities included in the Registration Statement. If at least two (2) business days prior to the filing date the Company has not received the Requested Information from an Investor (a "Non-Responsive Investor"), then the Company may file the Registration Statement without including Registrable Securities of such Non-Responsive Investor; (b) Each Investor, by such Investor's acceptance of the Registrable Securities, agrees to cooperate with the Company as reasonably requested by the Company in connection with the preparation and filing of the Registration Statement hereunder, unless such Investor has notified the Company in writing of such Investor's election to exclude all of such Investor's Registrable Securities from the Registration Statement; and (c) Each Investor agrees that, upon receipt of any notice from the Company of the happening of any event of the kind described in Section 3(f) or 3(g), above, such Investor will immediately discontinue disposition of Registrable Securities pursuant to the Registration Statement covering such Registrable Securities until such Investor's receipt of the copies of the supplemented or amended prospectus contemplated by Section 3(f) or 3(g) or such Investor is advised in writing by the Company that use of the applicable prospectus may be resumed and, if so directed by the Company, such Investor shall deliver to the Company (at the expense of the Company) or destroy (and deliver to the Company a certificate of destruction) all copies in such Investor's possession, of the prospectus covering such Registrable Securities current at the time of receipt of such notice. 5 5. Expenses of Registration. All reasonable expenses (other than underwriting discounts, commissions and fees of the Investor attributable to the sale of the Registrable Securities or more than one counsel, any accountants and other persons retained by the Investor Group in connection with the transactions contemplated by this Agreement) incurred in connection with registrations, filings or qualifications pursuant to Section 3, but including, without limitation, all registration, listing, and qualifications fees, printers and accounting fees, the fees and disbursements of counsel for the Company shall be borne by the Company. In addition, a fee for one counsel for the Investor Group up to $2,500 for the review of the Registration Statement and up to $1,500 for each post-effective amendment to a Registration Statement, shall be borne by the Company. 6. Indemnification. In the event any Registrable Securities are included in a Registration Statement under this Agreement: (a) To the extent permitted by law, the Company will indemnify and hold harmless each Investor who holds such Registrable Securities, the directors, if any, of such Investor, the officers, if any, of such Investor, each person, if any, who controls any Investor within the meaning of the Securities Act or the Exchange Act (each, an "Indemnified Person" or "Indemnified Party"), against any losses, claims, damages, liabilities or expenses (joint or several) incurred (collectively, "Claims") to which any of them may become subject under the Securities Act, the Exchange Act or otherwise, insofar as such Claims (or actions or proceedings, whether commenced or threatened, in respect thereof) arise out of or are based upon any of the following statements, omissions or violations in the Registration Statement, or any post-effective amendment thereof, or any prospectus included therein: (i) any untrue statement or alleged untrue statement of a material fact contained in the Registration Statement or any post-effective amendment thereof or the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein (in the case of a prospectus, in light of the circumstances in which they were made) not misleading, (ii) any untrue statement or alleged untrue statement of a material fact contained in the final prospectus (as amended or supplemented, if the Company files any amendment thereof or supplement thereto with the SEC) or the omission or alleged omission to state therein any material fact necessary to make the statements made therein, in light of the circumstances under which the statements therein were made, not misleading or (iii) any violation or alleged violation by the Company of the Securities Act, the Exchange Act, any state securities law or any rule or regulation under the Securities Act, the Exchange Act or any state securities law (the matters in the foregoing clauses (i) through (iii) being, collectively, "Violations"). Subject to clause (c) of this Section 6, the Company shall reimburse the Investors, promptly as such expenses are incurred and are due and payable, for any legal fees or other reasonable expenses incurred by them in connection with investigating or defending any such Claim. Notwithstanding anything to the contrary contained herein, the indemnification agreement contained in this Section 6(a) shall not (i) apply to a Claim arising out of or based upon a Violation which occurs in reliance upon and in conformity with information furnished in writing to the Company by or on behalf of any Indemnified Person expressly for use in connection with the preparation of the Registration Statement or any such amendment thereof or supplement thereto, after such prospectus was made available by the Company pursuant to Section 3(c) hereof; (ii) be available to the extent such Claim is based on a failure of the Investor to deliver or cause to be delivered the prospectus made available by the Company or the amendment or supplement thereto made available by the Company; (iii) be available to the 6 extent such Claim is based on the delivery of a prospectus by the Investor after receiving notice from the Company under Section 3(f), (g) or (h) hereof (other than a notice regarding the effectiveness of the Registration Statement or any amendment or supplement thereto), (iv) be available if any untrue statement or alleged untrue statement of a material fact contained in the final prospectus or the omission or alleged omission to state therein any material fact necessary to make the statements made therein, in light of the circumstances under which the statements therein were made, not misleading is corrected in all material respects in an amendment or supplement to the prospectus, or (v) apply to amounts paid in settlement of any Claim if such settlement is effected without the prior written consent of the Company, which consent shall not be unreasonably withheld or delayed. (b) In connection with any registration in which any Investor is participating, such Investor agrees to indemnify the Company, its directors and officers who sign the Registration Statement, each person, if any, who controls (within the meaning of either the Securities Act or of the Exchange Act) the Company, each other Investor and any prospective underwriters, as the case may be, and any of their respective affiliates, general partners, officers, employees, agents and controlling persons (each, an "Indemnified Person" or "Indemnified Party"), to the same extent as the foregoing indemnity from the Company to such Investor, but only with respect to information relating to such Investor furnished to the Company in writing by such Investor expressly for use in the Registration Statement, the prospectus, any amendment or supplement thereto, or any preliminary prospectus. Notwithstanding the foregoing, each Investor shall not be liable for an amount in excess of the proceeds of sale of such Investor's Registrable Securities (less applicable underwriting discounts and commissions). (c) Promptly after receipt by an Indemnified Person or Indemnified Party under this Section 6 of notice of the commencement of any action (including any governmental action), such Indemnified Person or Indemnified Party shall, if a Claim in respect thereof is to be made against any indemnifying party under this Section 6, deliver to the indemnifying party a written notice of the commencement thereof and the indemnifying party shall have the right to participate in, and, to the extent the indemnifying party so desires, jointly with any other indemnifying party similarly noticed, to assume control of the defense thereof with counsel mutually satisfactory to the indemnifying party and the Indemnified Person or the Indemnified Party, as the case may be. In case any such action is brought against any Indemnified Person or Indemnified Party, and it notifies the indemnifying party of the commencement thereof, the indemnifying party will be entitled to participate in, and, to the extent that it may wish, jointly with any other indemnifying party similarly notified, assume the defense thereof, subject to the provisions herein stated and after notice from the indemnifying party to such Indemnified Person or Indemnified Party of its election so to assume the defense thereof, the indemnifying party will not be liable to such Indemnified Person or Indemnified Party under this Section 6 for any legal or other reasonable out-of-pocket expenses subsequently incurred by such Indemnified Person or Indemnified Party in connection with the defense thereof other than reasonable costs of investigation, unless the indemnifying party shall not pursue the action to its final conclusion. The Indemnified Person or Indemnified Party shall have the right to employ separate counsel in any such action and to participate in the defense thereof, but the fees and reasonable out-of-pocket expenses of such counsel shall not be at the expense of the indemnifying party if the indemnifying party has assumed the defense of the action with counsel reasonably satisfactory to the Indemnified Person or Indemnified Party provided such counsel is of the opinion that all 7 defenses available to the Indemnified Party can be maintained without prejudicing the rights of the indemnifying party. The failure to deliver written notice to the indemnifying party within a reasonable time of the commencement of any such action shall not relieve such indemnifying party of any liability to the Indemnified Person or Indemnified Party under this Section 6, except to the extent that the indemnifying party is prejudiced in its ability to defend such action. The indemnification required by this Section 6 shall be made by periodic payments of the amount thereof during the course of the investigation or defense, as such expense, loss, damage or liability is incurred and is due and payable. 7. Contribution. To the extent any indemnification by an indemnifying party is prohibited or limited by law, the indemnifying party agrees to make the maximum contribution with respect to any amounts for which it would otherwise be liable under Section 6 to the fullest extent permitted by law; provided, however, that (a) no contribution shall be made under circumstances where the maker would not have been liable for indemnification under the fault standards set forth in Section 6; (b) no seller of Registrable Securities guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Securities Act) shall be entitled to contribution from any seller of Registrable Securities who was not guilty of such fraudulent misrepresentation; and (c) except where the seller has committed fraud or intentional misconduct, contribution by any seller of Registrable Securities shall be limited in amount to the net amount of proceeds received by such seller from the sale of such Registrable Securities. 8. Reports under Securities Act and Exchange Act. With a view to making available to Investor the benefits of Rule 144 promulgated under the Securities Act or any other similar rule or regulation of the SEC that may at any time permit Investor to sell securities of the Company to the public without Registration ("Rule 144"), the Company agrees to: (a) make and keep public information available, as those terms are understood and defined in Rule 144; and (b) file with the SEC in a timely manner all reports and other documents required of the Company under the Securities Act and the Exchange Act. 9. Assignment of the Registration Rights. The rights to have the Company register Registrable Securities pursuant to this Agreement shall be automatically assigned by the Investors to any transferee of the Registrable Securities only if: (a) the Investor agrees in writing with the transferee or assignee to assign such rights, and a copy of such agreement is furnished to the Company within a reasonable time after such assignment, (b) the Company is, within a reasonable time after such transfer or assignment, furnished with written notice of (i) the name and address of such transferee or assignee and (ii) the securities with respect to which such registration rights are being transferred or assigned, (c) immediately following such transfer or assignment the further disposition of such securities by the transferee or assignee is restricted under the Securities Act and applicable state securities laws, (d) at or before the time the Company received the written notice contemplated by clause (b) of this sentence the transferee or assignee agrees in writing with the Company to be bound by all of the provisions contained herein, and (e) such transfer of Registrable Securities is completed and disclosed to the Company prior to the initial Effective Date. In the event of any delay in filing or effectiveness of the 8 Registration Statement as a result of such assignment, the Company shall not be liable for any damages arising from such delay. 10. Amendment of Registration Rights. Any provision of this Agreement may be amended and the observance thereof may be waived (either generally or in a particular instance and either retroactively or prospectively), only with the written consent of the Company and Investors who hold a fifty-one percent (51%) interest of the Registrable Securities. Any amendment or waiver effected in accordance with this Section 10 shall be binding upon each Investor and the Company. 11. Miscellaneous. (a) A person or entity is deemed to be a holder of Registrable Securities whenever such person or entity owns of record such Registrable Securities. If the Company receives conflicting instructions, notices or elections from two or more persons or entities with respect to the same Registrable Securities, the Company shall act upon the basis of instructions, notice or election received from the registered owner of such Registrable Securities. (b) Notices required or permitted to be given hereunder shall be given in the manner contemplated by the Asset Purchase Agreement, (i) if to the Company or to the Initial Investor, to their respective address contemplated by the Asset Purchase Agreement, and (ii) if to any other Investor, at such address as such Investor shall have provided in writing to the Company, or at such other address as each such party furnishes by notice given in accordance with this Section 11(b). (c) This Agreement is intended for the benefit of the parties hereto and their respective permitted successors and assigns and is not for the benefit of, nor may any provision hereof be enforced by, any other person. (d) Failure of any party to exercise any right or remedy under this Agreement or otherwise, or delay by a party in exercising such right or remedy, shall not operate as a waiver thereof. (e) This Agreement shall be governed by and interpreted in accordance with the laws of the State of New York for contracts to be wholly performed in such state and without giving effect to the principles thereof regarding the conflict of laws. Each of the parties consents to the jurisdiction of the federal courts whose districts encompass any part of the City of New York or the state courts of the State of New York sitting in the City of New York in connection with any dispute arising under this Agreement and hereby waives, to the maximum extent permitted by law, any objection, including any objection based on forum non coveniens, to the bringing of any such proceeding in such jurisdictions. To the extent determined by such court, either party hereto shall reimburse the other party for any reasonable legal fees and disbursements incurred by such party in enforcement of or protection of any of its rights under this Agreement. (f) If any provision of this Agreement shall be invalid or unenforceable in any jurisdiction, such invalidity or unenforceability shall not affect the validity or enforceability of the remainder of this Agreement or the validity or enforceability of 9 this Agreement in any other jurisdiction. (g) Subject to the requirements of Section 9 hereof, this Agreement shall inure to the benefit of and be binding upon the successors and assigns of each of the parties hereto. (h) All pronouns and any variations thereof refer to the masculine, feminine or neuter, singular or plural, as the context may require. (i) The headings in this Agreement are for convenience of reference only and shall not limit or otherwise affect the meaning thereof. (j) This Agreement may be executed in one or more counterparts, each of which shall be deemed an original but all of which shall constitute one and the same agreement. This Agreement, once executed by a party, may be delivered to the other party hereto by telephone line facsimile transmission of a copy of this Agreement bearing the signature of the party so delivering this Agreement. (k) The Company acknowledges that any failure by the Company to perform its obligations under Section 3(a) hereof, or any delay in such performance could result in loss to the Investors, and the Company agrees that, in addition to any other liability the Company may have by reason of such failure or delay, the Company shall be liable for all direct damages caused by any such failure or delay, unless the same is the result of force majeure. Neither party shall be liable for consequential damages. (l) This Agreement constitutes the entire agreement among the parties hereto with respect to the subject matter hereof. There are no restrictions, promises, warranties or undertakings, other than those set forth or referred to herein. This Agreement supersedes all prior agreements and understandings among the parties hereto with respect to the subject matter hereof. This Agreement may be amended only by an instrument in writing signed by the party to be charged with enforcement thereof. [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK] 10 IN WITNESS WHEREOF, the parties have caused this Agreement to be duly executed by their respective officers thereunto duly authorized as of the day and year first above written. COMPANY: SIGA TECHNOLOGIES, INC. By: /s/ Thomas N. Konatich ------------------------------------ Name: Thomas N. Konatich Title: Acting Chief Executive Officer and Chief Financial Officer INITIAL INVESTOR: PLEXUS VACCINE INC. By: /s/ Susan K. Burgess ------------------------------------ Name: Susan K. Burgess Title: President and Chief Executive Officer 11