Common use of CONSENT TO ACT AS REPRESENTATIVE Clause in Contracts

CONSENT TO ACT AS REPRESENTATIVE. Xxxxxx & Xxxxxxx, LLC ("Xxxxxx") consents and agrees that XX Xxxxx Securities Corporation ("XX Xxxxx") will act as Representative of the Placement Agents under this Agreement and with respect to the sale of the Stock. Accordingly, Xxxxxx authorizes XX Xxxxx to manage the Offering and sale of the Stock and to take such action in connection therewith as XX Xxxxx in its sole discretion deems appropriate or desirable, consistent with the provisions of the Agreement Among Underwriters previously entered into between XX Xxxxx and Xxxxxx, taking into account that the Offering of the Stock will be in the form of a best efforts placement and not a firm commitment underwriting. If the foregoing is in accordance with your understanding of the agreement between the Company and the Placement Agents, kindly indicate your acceptance in the space provided for that purpose below. Very truly yours, GTC BIOTHERAPEUTICS, INC. By: /s/ XXXXXXXX X. XXX Name: Xxxxxxxx X. Xxx Title: Chairman, President & Chief Executive Officer Accepted as of the date first above written: XX XXXXX SECURITIES CORPORATION By: /s/ XXXXXXX X. XXXXXXX Name: Xxxxxxx X. Xxxxxxx Title: Managing Director XXXXXX & XXXXXXX, LLC By: /s/ XXXXXX X. XXXXX Name: Xxxxxx X. Xxxxx Title: Chief Financial Officer Xxxxxxx X Xxxx-Xx Xxxxxxxxx Xxxxx , 0000 XX XXXXX SECURITIES CORPORATION XXXXXX & XXXXXXX, LLC c/o XX Xxxxx Securities Corporation 0000 Xxxxxx xx xxx Xxxxxxxx Xxx Xxxx, Xxx Xxxx 00000 Re: GTC Biotherapeutics, Inc.—Offering of Common Stock Dear Sirs: In order to induce XX Xxxxx Securities Corporation ("XX Xxxxx") and Xxxxxx & Xxxxxxx, LLC to enter in to a certain placement agent agreement with GTC Biotherapeutics, Inc., a Massachusetts corporation (the "Company"), with respect to the offering of shares of the Company's Common Stock, par value $.01 per share ("Common Stock"), the undersigned hereby agrees that for a period of 90 days following the date of the final prospectus (the "Final Prospectus") filed by the Company with the Securities and Exchange Commission in connection with such offering, the undersigned will not, without the prior written consent of XX Xxxxx, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, any shares of Common Stock (including, without limitation, Common Stock which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933 (the "Securities Act") and the Securities Exchange Act of 1934, as the same may be amended or supplemented from time to time (such shares, the "Beneficially Owned Shares")) or securities convertible into or exercisable or exchangeable for Common Stock, (ii) enter into any swap, hedge or similar agreement or arrangement that transfers in whole or in part, the economic risk of ownership of the Beneficially Owned Shares or securities convertible into or exercisable or exchangeable in Common Stock or (iii) engage in any short selling of the Common Stock. Notwithstanding the foregoing, nothing contained herein will be deemed to restrict or prohibit the transfer of shares of Common Stock, Beneficially Owned Shares or securities convertible into or exercisable or exchangable for shares of Common Stock (i) as a bona fide gift, provided the recipient thereof agrees in writing to be bound by the terms thereof or (ii) as a distribution to partners, retired partners or the estates of such partners or retired partners or shareholders of the undersigned, provided that the distributees thereof agree in writing to be bound by the terms thereof. If (i) the Company issues an earnings release or material news or a material event relating to the Company occurs during the last 17 days of the lock-up period, or (ii) prior to the expiration of the lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the lock-up period, the restrictions imposed by this Agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. Anything contained herein to the contrary notwithstanding, any person to whom shares of Common Stock or Beneficially Owned Shares are transferred from the undersigned from and after the date hereof shall be bound by the terms of this Agreement. In addition, the undersigned hereby confirms that the undersigned does not have the right to request or demand registration pursuant to the Securities Act of any shares of Common Stock that are registered in the name of the undersigned or that are Beneficially Owned Shares. In order to enable the aforesaid covenants to be enforced, the undersigned hereby consents to the placing of legends and/or stop-transfer orders with the transfer agent of the Common Stock with respect to any shares of Common Stock or Beneficially Owned Shares. SIGNATURE BLOCK FOR A NATURAL PERSON Name: Please Print Date: SIGNATURE BLOCK FOR A CORPORATION, PARTNERSHIP, TRUST OR OTHER ENTITY Name of corporation, partnership, trust or other entity, including type of entity and jurisdiction of organization: Please Print By: Name: Please Print Title: Please Print Date: Exhibit B Legal Opinion of Xxxxxx & Dodge LLP

CONSENT TO ACT AS REPRESENTATIVE. Xxxxxx CIBC World Market Corp. (“CIBC”) and Xxxxx, Xxxxxxxx & XxxxxxxXxxx, LLC Inc. ("Xxxxxx"“Xxxxx”) each consents and agrees that XX Xxxxx Securities Corporation ("“XX Xxxxx"”) will act as Representative of the Placement Agents under this Agreement and with respect to the sale of the Stock. Accordingly, Xxxxxx authorizes CIBC and Xxxxx authorize XX Xxxxx to manage the Offering and sale of the Stock and to take such action in connection therewith as XX Xxxxx in its sole discretion deems appropriate or desirable, consistent with the provisions of the Agreement Among Underwriters previously entered into between XX Xxxxx Xxxxx, CIBC and XxxxxxXxxxx, taking into account that the Offering of the Stock will be in the form of a best efforts placement and not a firm commitment underwriting. If the foregoing is in accordance with your understanding of the agreement between the Company and the Placement Agents, kindly indicate your acceptance in the space provided for that purpose below. Very truly yours, GTC BIOTHERAPEUTICS, INC. KOSAN BIOSCIENCES INCORPORATED By: /s/ XXXXXXXX Xxxxxxx X. XXX Xxxxxxx Name: Xxxxxxxx Xxxxxxx X. Xxx Xxxxxxx Title: Chairman, President & Chief Executive Officer Coo Accepted as of the date first above written: XX XXXXX SECURITIES CORPORATION By: /s/ XXXXXXX Xxxxxxx X. XXXXXXX Xxxxxxx Name: Xxxxxxx X. Xxxxxxx Title: Managing Director XXXXXX & XXXXXXX, LLC CIBC WORLD MARKETS CORP. By: /s/ XXXXXX X. XXXXX Xxxxxxx Xxxxxxxx Name: Xxxxxx X. Xxxxx Xxxxxxx Xxxxxxxx Title: Chief Financial Officer Managing Director XXXXX, XXXXXXXX & XXXX, INC. By: /s/ Xxxxxxx X Xxxx-Xx Xxxxxxxxx Xxxxx , 0000 XX XXXXX SECURITIES CORPORATION XXXXXX & XXXXXXX, LLC c/o X. Xxxxxx Name: Xxxxxxx X. Xxxxxx Title: Managing Director Schedule I Placement Agents XX Xxxxx Securities Corporation 0000 Xxxxxx xx xxx CIBC World Markets Corp. Xxxxx, Xxxxxxxx Xxx & Xxxx, Inc. Exhibit A Form of Subscription Agreement SUBSCRIPTION AGREEMENT Kosan Biosciences Incorporated 0000 Xxx Xxxx 00000 Re: GTC Biotherapeutics, Inc.—Offering of Common Stock Dear Sirs: In order to induce XX Xxxxxx Xxxxx Securities Corporation ("XX Xxxxx") and Xxxxxx & Xxxxxxx, LLC to enter in to a certain placement agent XX 00000 The undersigned (the “Investor”) hereby confirms its agreement with GTC Biotherapeutics, Inc., a Massachusetts corporation (the "Company"), with respect to the offering of shares of the Company's Common Stock, par value $.01 per share ("Common Stock"), the undersigned hereby agrees that for a period of 90 days following the date of the final prospectus (the "Final Prospectus") filed by the Company with the Securities and Exchange Commission in connection with such offering, the undersigned will not, without the prior written consent of XX Xxxxx, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, any shares of Common Stock (including, without limitation, Common Stock which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933 (the "Securities Act") and the Securities Exchange Act of 1934, you as the same may be amended or supplemented from time to time (such shares, the "Beneficially Owned Shares")) or securities convertible into or exercisable or exchangeable for Common Stock, (ii) enter into any swap, hedge or similar agreement or arrangement that transfers in whole or in part, the economic risk of ownership of the Beneficially Owned Shares or securities convertible into or exercisable or exchangeable in Common Stock or (iii) engage in any short selling of the Common Stock. Notwithstanding the foregoing, nothing contained herein will be deemed to restrict or prohibit the transfer of shares of Common Stock, Beneficially Owned Shares or securities convertible into or exercisable or exchangable for shares of Common Stock (i) as a bona fide gift, provided the recipient thereof agrees in writing to be bound by the terms thereof or (ii) as a distribution to partners, retired partners or the estates of such partners or retired partners or shareholders of the undersigned, provided that the distributees thereof agree in writing to be bound by the terms thereof. If (i) the Company issues an earnings release or material news or a material event relating to the Company occurs during the last 17 days of the lock-up period, or (ii) prior to the expiration of the lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the lock-up period, the restrictions imposed by this Agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. Anything contained herein to the contrary notwithstanding, any person to whom shares of Common Stock or Beneficially Owned Shares are transferred from the undersigned from and after the date hereof shall be bound by the terms of this Agreement. In addition, the undersigned hereby confirms that the undersigned does not have the right to request or demand registration pursuant to the Securities Act of any shares of Common Stock that are registered in the name of the undersigned or that are Beneficially Owned Shares. In order to enable the aforesaid covenants to be enforced, the undersigned hereby consents to the placing of legends and/or stop-transfer orders with the transfer agent of the Common Stock with respect to any shares of Common Stock or Beneficially Owned Shares. SIGNATURE BLOCK FOR A NATURAL PERSON Name: Please Print Date: SIGNATURE BLOCK FOR A CORPORATION, PARTNERSHIP, TRUST OR OTHER ENTITY Name of corporation, partnership, trust or other entity, including type of entity and jurisdiction of organization: Please Print By: Name: Please Print Title: Please Print Date: Exhibit B Legal Opinion of Xxxxxx & Dodge LLPfollows:

CONSENT TO ACT AS REPRESENTATIVE. Xxxxxx & XxxxxxxXxxx Capital Partners, LLC ("Xxxxxx"“Xxxx”) consents and agrees that XX Xxxxx Securities Corporation ("“XX Xxxxx"”) will act as Representative of the Placement Agents under this Agreement and with respect to the sale of the Stock. Accordingly, Xxxxxx Xxxx authorizes XX Xxxxx to manage the Offering and sale of the Stock and to take such action in connection therewith as XX Xxxxx in its sole discretion deems appropriate or desirable, consistent with the provisions of the Agreement Among Underwriters previously entered into between XX Xxxxx and XxxxxxXxxx, taking into account that the Offering of the Stock will be in the form of a best efforts placement and not a firm commitment underwriting. If the foregoing is in accordance with your understanding of the agreement between the Company and the Placement Agents, kindly indicate your acceptance in the space provided for that purpose below. Very truly yours, GTC BIOTHERAPEUTICS, INC. TARGETED GENETICS CORPORATION By: /s/ XXXXXXXX X. XXX H. Xxxxxxx Xxxxxx Name: Xxxxxxxx X. Xxx H. Xxxxxxx Xxxxxx Title: Chairman, President Pres. & Chief Executive Officer CEO Accepted as of the date first above written: XX XXXXX SECURITIES CORPORATION By: /s/ XXXXXXX Xxxxxxx X. XXXXXXX Xxxxxxx Name: Xxxxxxx X. Xxxxxxx Title: Managing Director XXXXXX & XXXXXXXXXXX CAPITAL PARTNERS, LLC By: /s/ XXXXXX Xxxx X. XXXXX Delfonse Name: Xxxxxx Xxxx X. Xxxxx Delfonse Title: Chief Financial Officer Xxxxxxx X Xxxx-Xx Xxxxxxxxx Xxxxx , 0000 XX XXXXX SECURITIES CORPORATION XXXXXX & XXXXXXX, LLC c/o Managing Director Schedule I Placement Agents XX Xxxxx Securities Corporation 0000 Xxxxxx xx xxx Xxxxxxxx Xxx Xxxx, Xxx Xxxx 00000 Re: GTC Biotherapeutics, Inc.—Offering of Common Stock Dear Sirs: In order to induce XX Xxxxx Securities Corporation ("XX Xxxxx") and Xxxxxx & XxxxxxxCapital Partners, LLC to enter in to a certain placement agent agreement with GTC Biotherapeutics, Inc., a Massachusetts corporation (the "Company"), with respect to the offering Exhibit A Form of shares of the Company's Common Stock, par value $.01 per share ("Common Stock"), the undersigned hereby agrees that for a period of 90 days following the date of the final prospectus (the "Final Prospectus") filed by the Company with the Securities and Exchange Commission in connection with such offering, the undersigned will not, without the prior written consent of XX Xxxxx, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, any shares of Common Stock (including, without limitation, Common Stock which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933 (the "Securities Act") and the Securities Exchange Act of 1934, as the same may be amended or supplemented from time to time (such shares, the "Beneficially Owned Shares")) or securities convertible into or exercisable or exchangeable for Common Stock, (ii) enter into any swap, hedge or similar agreement or arrangement that transfers in whole or in part, the economic risk of ownership of the Beneficially Owned Shares or securities convertible into or exercisable or exchangeable in Common Stock or (iii) engage in any short selling of the Common Stock. Notwithstanding the foregoing, nothing contained herein will be deemed to restrict or prohibit the transfer of shares of Common Stock, Beneficially Owned Shares or securities convertible into or exercisable or exchangable for shares of Common Stock (i) as a bona fide gift, provided the recipient thereof agrees in writing to be bound by the terms thereof or (ii) as a distribution to partners, retired partners or the estates of such partners or retired partners or shareholders of the undersigned, provided that the distributees thereof agree in writing to be bound by the terms thereof. If (i) the Company issues an earnings release or material news or a material event relating to the Company occurs during the last 17 days of the lock-up period, or (ii) prior to the expiration of the lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the lock-up period, the restrictions imposed by this Subscription Agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. Anything contained herein to the contrary notwithstanding, any person to whom shares of Common Stock or Beneficially Owned Shares are transferred from the undersigned from and after the date hereof shall be bound by the terms of this Agreement. In addition, the undersigned hereby confirms that the undersigned does not have the right to request or demand registration pursuant to the Securities Act of any shares of Common Stock that are registered in the name of the undersigned or that are Beneficially Owned Shares. In order to enable the aforesaid covenants to be enforced, the undersigned hereby consents to the placing of legends and/or stop-transfer orders with the transfer agent of the Common Stock with respect to any shares of Common Stock or Beneficially Owned Shares. SIGNATURE BLOCK FOR A NATURAL PERSON Name: Please Print Date: SIGNATURE BLOCK FOR A CORPORATION, PARTNERSHIP, TRUST OR OTHER ENTITY Name of corporation, partnership, trust or other entity, including type of entity and jurisdiction of organization: Please Print By: Name: Please Print Title: Please Print Date: 33 Exhibit B Form of Lock-Up Agreement 34 Exhibit C-1 Legal Opinion of Xxxxxx & Dodge Whitney LLP Legal Opinion of Xxxxxxxx & Xxxxxxxx LLP

CONSENT TO ACT AS REPRESENTATIVE. Xxxxxx & Xxxxxxx, LLC RBC Capital Markets Corporation ("XxxxxxRBC") consents and agrees that XX Xxxxx Securities Corporation SG Cowen & Co., LLC ("XX XxxxxSG COWEN") will act as Representative of the Placement Plxxxxxxx Agents under this Agreement txxx Xxxxement and with respect to the sale of the Stock. Accordingly, Xxxxxx RBC authorizes XX Xxxxx SG Cowen to manage the Offering and the sale of the Stock and to take such action xxxx xxtion in connection therewith as XX Xxxxx SG Cowen in its sole discretion deems appropriate or desirable, consistent with consixxxxx xxth the provisions of the Agreement Among Underwriters previously entered into between XX Xxxxx SG Cowen and XxxxxxRBC, taking into account that the Offering of the Stock will be xxxx xx in the form of a best efforts placement and not a firm commitment underwriting. If the foregoing is in accordance with your understanding of the agreement between the Company and the Placement Agents, kindly indicate your acceptance in the space provided for that purpose below. Very truly yours, GTC BIOTHERAPEUTICSSANTARUS, INC. By: /s/ XXXXXXXX X. XXX Gerald T. Proehl Name: Xxxxxxxx Xxxxxx X. Xxx Xxxehl Title: Chairman, President & Xxxxxxxxx xxx Chief Executive Officer Accepted as of the date first above written: XX XXXXX SECURITIES CORPORATION By: /s/ XXXXXXX X. XXXXXXX Name: Xxxxxxx X. Xxxxxxx Title: Managing Director XXXXXX SG COWEN & XXXXXXXCO., LLC By: /s/ XXXXXX X. XXXXX Richard E. Gormley Name: Xxxxxx Richarx X. Xxxxx Xxxmley Title: Chief Financial Officer Xxxxxxx X Xxxx-Xx Xxxxxxxxx Xxxxx , 0000 XX XXXXX SECURITIES CORPORATION XXXXXX Managxxx Xxxxxxxx XXX CAPITAL MARKETX XXXXXXXXXXX Xx: /s/ Michael J. Rosso Name: Michael J. Rosso Title: Managing Dixxxxxx SCHEDULE I Placement Agents SG COWEN & XXXXXXXCO., LLC c/o XX Xxxxx Securities Corporation 0000 Xxxxxx xx xxx Xxxxxxxx Xxx Xxxx, Xxx Xxxx 00000 Re: GTC Biotherapeutics, Inc.—Offering of Common Stock Dear Sirs: In order to induce XX Xxxxx Securities Corporation ("XX Xxxxx") and Xxxxxx RBC CAPITAL MARKETS CORPORATION EXHIBIT A FORM OF SUBSCRIPTION AGREEMENT EXHIBIT B FORM OF LOCK-UP AGREEMENT EXHIBIT C-1 LEGAL OPINION OF LATHAM & Xxxxxxx, LLC to enter in to a certain placement agent agreement with GTC Biotherapeutics, Inc., a Massachusetts corporation (the "Company"), with respect to the offering of shares of the Company's Common Stock, par value $.01 per share ("Common Stock"), the undersigned hereby agrees that for a period of 90 days following the date of the final prospectus (the "Final Prospectus") filed by the Company with the Securities and Exchange Commission in connection with such offering, the undersigned will not, without the prior written consent of XX Xxxxx, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, any shares of Common Stock (including, without limitation, Common Stock which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933 (the "Securities Act") and the Securities Exchange Act of 1934, as the same may be amended or supplemented from time to time (such shares, the "Beneficially Owned Shares")) or securities convertible into or exercisable or exchangeable for Common Stock, (ii) enter into any swap, hedge or similar agreement or arrangement that transfers in whole or in part, the economic risk of ownership of the Beneficially Owned Shares or securities convertible into or exercisable or exchangeable in Common Stock or (iii) engage in any short selling of the Common Stock. Notwithstanding the foregoing, nothing contained herein will be deemed to restrict or prohibit the transfer of shares of Common Stock, Beneficially Owned Shares or securities convertible into or exercisable or exchangable for shares of Common Stock (i) as a bona fide gift, provided the recipient thereof agrees in writing to be bound by the terms thereof or (ii) as a distribution to partners, retired partners or the estates of such partners or retired partners or shareholders of the undersigned, provided that the distributees thereof agree in writing to be bound by the terms thereof. If (i) the Company issues an earnings release or material news or a material event relating to the Company occurs during the last 17 days of the lock-up period, or (ii) prior to the expiration of the lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the lock-up period, the restrictions imposed by this Agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. Anything contained herein to the contrary notwithstanding, any person to whom shares of Common Stock or Beneficially Owned Shares are transferred from the undersigned from and after the date hereof shall be bound by the terms of this Agreement. In addition, the undersigned hereby confirms that the undersigned does not have the right to request or demand registration pursuant to the Securities Act of any shares of Common Stock that are registered in the name of the undersigned or that are Beneficially Owned Shares. In order to enable the aforesaid covenants to be enforced, the undersigned hereby consents to the placing of legends and/or stop-transfer orders with the transfer agent of the Common Stock with respect to any shares of Common Stock or Beneficially Owned Shares. SIGNATURE BLOCK FOR A NATURAL PERSON Name: Please Print Date: SIGNATURE BLOCK FOR A CORPORATION, PARTNERSHIP, TRUST OR OTHER ENTITY Name of corporation, partnership, trust or other entity, including type of entity and jurisdiction of organization: Please Print By: Name: Please Print Title: Please Print Date: Exhibit B Legal Opinion of Xxxxxx WATKINS LLP EXHIBIT C-2 NEGATIVE ASSURANCES STATEMENT OF COUNSEL TO THE COMPANY EXHIBIT C-3 LEGAL OPINION OF WILSON SONSINI GOODRICH & Dodge LLPROSATI

CONSENT TO ACT AS REPRESENTATIVE. Xxxxxx & Xxxxxxx, LLC RBC Capital Markets Corporation ("Xxxxxx"“RBC”) consents and agrees that XX Xxxxx Securities Corporation & Co., LLC ("“XX Xxxxx"”) will act as Representative of the Placement Agents under this Agreement and with respect to the sale of the Stock. Accordingly, Xxxxxx RBC authorizes XX Xxxxx to manage the Offering and sale of the Stock and to take such action in connection therewith as XX Xxxxx in its sole discretion deems appropriate or desirable, consistent with the provisions of the Agreement Among Underwriters previously entered into between XX Xxxxx and XxxxxxRBC, taking into account that the Offering of the Stock will be in the form of a best efforts placement and not a firm commitment underwriting. If the foregoing is in accordance with your understanding of the agreement between the Company and the Placement Agents, kindly indicate your acceptance in the space provided for that purpose below. Very truly yours, GTC BIOTHERAPEUTICSPOINT THERAPEUTICS, INC. By: /s/ XXXXXXXX Xxxxxxx X. XXX Xxxxx Name: Xxxxxxxx Xxxxxxx X. Xxx Xxxxx Title: Chairman, Senior Vice President & Chief Executive Officer Accepted as of the date first above written: XX XXXXX SECURITIES CORPORATION & CO., LLC By: /s/ XXXXXXX Xxxxxxx X. XXXXXXX Xxxxxxx Name: Xxxxxxx X. Xxxxxxx Title: Managing Director XXXXXX & XXXXXXX, LLC RBC CAPITAL MARKETS CORPORATION By: /s/ XXXXXX Xxxxxxx X. XXXXX Xxxxx Name: Xxxxxx Xxxxxxx X. Xxxxx Title: Chief Financial Officer Xxxxxxx X Xxxx-Xx Xxxxxxxxx Xxxxx , 0000 Head of Private Placements Managing Director SCHEDULE I Placement Agents XX XXXXX SECURITIES CORPORATION XXXXXX & XXXXXXXCO., LLC c/o XX Xxxxx Securities Corporation 0000 Xxxxxx xx xxx Xxxxxxxx Xxx Xxxx, Xxx Xxxx 00000 Re: GTC Biotherapeutics, Inc.—Offering of Common Stock Dear Sirs: In order to induce XX Xxxxx Securities Corporation ("XX Xxxxx"RBC CAPITAL MARKETS CORPORATION Schedule 2(d)(i) and Xxxxxx & Xxxxxxx, LLC to enter in to a certain placement agent agreement with GTC BiotherapeuticsSubsidiaries Point Therapeutics Massachusetts, Inc., a Massachusetts corporation Schedule 2(d)(ii) Subsidiaries Hemapharm Inc., a Delaware corporation Hemasure A/S, a Denmark corporation Schedule 2(m) Pursuant to the Engagement Agreement between the Company and RBC Capital Markets Corporation (“RBC”) dated February 24, 2004 in connection with the Company’s March 2004 private placement (the "Company"“Private Placement”), with respect the Company agreed to pay RBC a cash fee in the offering amount of shares 6.0% of any additional purchases by any Private Placement investors of the Company's Common Stock’s shares between the Private Placement closing and March 26, par value $.01 per share ("Common Stock"), the undersigned hereby agrees that for a period of 90 days following the date of the final prospectus (the "Final Prospectus") filed by the Company with the Securities and Exchange Commission in connection with 2005. Any such offering, the undersigned will not, without the prior written consent of XX Xxxxx, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, any shares of Common Stock (including, without limitation, Common Stock which may be deemed fee is to be beneficially owned by paid in its entirety at the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933 (the "Securities Act") and the Securities Exchange Act of 1934, as the same may be amended or supplemented from time to time (such shares, the "Beneficially Owned Shares")) or securities convertible into or exercisable or exchangeable for Common Stock, (ii) enter into any swap, hedge or similar agreement or arrangement that transfers in whole or in part, the economic risk of ownership of the Beneficially Owned Shares or securities convertible into or exercisable or exchangeable in Common Stock or (iii) engage in any short selling of the Common Stock. Notwithstanding the foregoing, nothing contained herein will be deemed to restrict or prohibit the transfer of shares of Common Stock, Beneficially Owned Shares or securities convertible into or exercisable or exchangable for shares of Common Stock (i) as a bona fide gift, provided the recipient thereof agrees in writing to be bound by the terms thereof or (ii) as a distribution to partners, retired partners or the estates of such partners or retired partners or shareholders of the undersigned, provided that the distributees thereof agree in writing to be bound by the terms thereof. If (i) the Company issues an earnings release or material news or a material event relating to the Company occurs during the last 17 days of the lock-up period, or (ii) prior to the expiration of the lock-up period, the Company announces that it will release earnings results during the 16-day period beginning on the last day of the lock-up period, the restrictions imposed by this Agreement shall continue to apply until the expiration of the 18-day period beginning on the issuance of the earnings release or the occurrence of the material news or material event. Anything contained herein to the contrary notwithstanding, any person to whom shares of Common Stock or Beneficially Owned Shares are transferred from the undersigned from and after the date hereof shall be bound by the terms of this Agreement. In addition, the undersigned hereby confirms that the undersigned does not have the right to request or demand registration pursuant to the Securities Act of any shares of Common Stock that are registered in the name of the undersigned or that are Beneficially Owned Shares. In order to enable the aforesaid covenants to be enforced, the undersigned hereby consents to the placing of legends and/or stop-transfer orders with the transfer agent of the Common Stock with respect closing related to any shares of Common Stock or Beneficially Owned Shares. SIGNATURE BLOCK FOR A NATURAL PERSON Name: Please Print Date: SIGNATURE BLOCK FOR A CORPORATION, PARTNERSHIP, TRUST OR OTHER ENTITY Name of corporation, partnership, trust or other entity, including type of entity and jurisdiction of organization: Please Print By: Name: Please Print Title: Please Print Date: Exhibit B Legal Opinion of Xxxxxx & Dodge LLPsuch additional purchase.