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                                                                EXHIBIT 10.20.1

            FIRST AMENDMENT TO EXCLUSIVE LICENSE AGREEMENT (UMass IP)

      This First Amendment to Exclusive License Agreement (UMass IP) ("First
Amendment") is made and entered into as of this 25th day of August, 2005 (the
"Amendment Effective Date"), by and between Advanced Cell, Inc. (formerly known
as Advanced Cell Technology, Inc.), a Delaware corporation with offices located
at 381 Plantation Street, Worcester, Massachusetts 01605 ("LICENSOR"), and
Lifeline Cell Technology, LLC (formerly known as PacGen Cellco, LLC), a
California limited liability company with offices located at 157 Surfview Drive,
Pacific Palisades, CA 90272 ("LICENSEE") (LICENSOR and LICENSEE sometimes
hereinafter referred to individually as a "Party" and collectively as the
"Parties").

      WHEREAS, the Parties previously entered into an Exclusive License
Agreement (UMass IP), dated May 14, 2004 (the "License Agreement"), which grants
LICENSEE defined rights to use certain intellectual property controlled by
LICENSOR; and

      WHEREAS, the Parties also entered into that certain Agreement to Amend
ACT/Cellco License Agreements dated September 7, 2004 (the "Agreement to
Amend"), which contemplates that the Parties will amend the License Agreement in
certain respects; and

      WHEREAS, the Parties have agreed to amend the License Agreement as
provided herein;

      NOW, THEREFORE, in consideration of the premises and terms of this First
Amendment, and in consideration of the payment to LICENSOR by LICENSEE of
$56,250, the receipt of which is hereby acknowledged by LICENSOR, the Parties
agree to amend the License Agreement as follows:

1.    Section 1.3 is deleted in its entirety and replaced with the following:

      1.3   "FIELD" shall mean (1) the research, development, manufacture and
            selling to third parties of human and non-human animal cells and ACT
            ANIMAL CELL LINES for commercial research use, including small
            molecule and other drug testing and basic research, (2) the
            manufacture and selling of human cells for therapeutic and
            diagnostic use in the treatment of human (a) diabetes, (b) liver
            diseases and (c) retinal diseases and retinal degenerative diseases,
            and (3) the use of ACT ANIMAL CELL LINES in the process of
            manufacturing and selling human cells for therapeutic and diagnostic
            use in the treatment of human (a) diabetes, (b) liver diseases and
            (c) retinal diseases and retinal degenerative diseases, but where
            the final marketed product does not include ACT ANIMAL CELL LINES
            (i.e. does not include the field of xenotransplantation); but FIELD
            shall exclude applications involving the use of cells in the
            treatment of tumors where the primary use of the cells is the
            destruction or reduction of tumors and does not involve regeneration
            of tissue or organ function.

2.    Section 1.4 is deleted in its entirety and replaced with the following:

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      1.4   "KNOW-HOW" means all compositions of matter, techniques and data and
            other know-how and technical inventions (whether or not patentable),
            improvements and developments, practices, methods, concepts, trade
            secrets, documents, computer data, computer code, apparatus,
            clinical and regulatory strategies, test data, analytical and
            quality control data, formulation, manufacturing, patent data or
            descriptions, development information, drawings, specifications,
            designs, plans, proposals and technical data and manuals and all
            other proprietary information that is owned or controlled by
            LICENSOR as of the Effective Date that relates to cloning technology
            or to any of the subject matter described in or claimed by the
            PATENT RIGHTS and is relevant to the FIELD. By way of illustration,
            but not in limitation, KNOW-HOW shall include commercial rights in
            the FIELD to any existing or potential research products, including
            reagents, developed by LICENSOR in the course of its in-house
            research as more fully described in Section 15.3 of this Agreement.
            An example of this is the proprietary culture medium developed by
            LICENSOR in the course of the development of LICENSOR's proprietary
            ooplasmic transfer technology.

3.    Section 1.10 is amended by deleting the text in Section 1.10 in its
      entirety and replacing it with the following: "Intentionally omitted".

4.    Section 2.6 is deleted in its entirety and replaced with the following:

            LICENSEE acknowledges and agrees that notwithstanding anything to
            the contrary in this Agreement, LICENSOR may: (i) practice the
            LICENSED TECHNOLOGY and develop and manufacture LICENSED PRODUCTS
            within the FIELD for research purposes, provided that LICENSOR may
            not market or sell LICENSED PRODUCTS in the FIELD to third parties
            in contravention of LICENSEE'S exclusive rights hereunder; (ii)
            distribute or otherwise transfer cells or cell lines or other
            reagents to collaborators for research purposes, and commercialize
            the results of such research (other than media and other reagents
            produced for sale to the commercial research market) outside the
            FIELD in connection with the research, development, manufacture or
            sale of therapeutic products that are not in contravention of
            LICENSEE'S exclusive rights hereunder; and (iii) distribute or
            otherwise transfer cells or cell lines to collaborators for the
            purposes of researching, developing and commercializing cell based
            therapeutics for purposes other than those exclusively licensed to
            LICENSEE hereunder.

            By way of illustration of subparagraph (ii) of Section 2.6 hereof,
            should LICENSOR partner with a biopharmaceutical company in order to
            produce skin cells for human therapeutic use, and in the process of
            basic research, preclinical, or clinical development find it
            necessary or useful to transfer cell lines or other reagents to that
            partner to facilitate the development of such dermatological
            product, such transfer, provided that the transferred material is
            not sold or marketed to such biopharmaceutical company for monetary
            compensation, shall be considered outside of the FIELD.

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            LICENSOR may make LICENSED PRODUCTS available to its collaborators.
            In the event LICENSOR requests that LICENSEE deliver to LICENSOR
            LICENSED PRODUCTS in the FIELD for use in connection with the
            purposes described in the above paragraph, LICENSEE shall make such
            LICENSED PRODUCTS available to LICENSOR on commercially reasonable
            terms. LICENSOR may make LICENSED PRODUCTS in the FIELD, whether
            developed and manufactured by LICENSOR or obtained from LICENSEE,
            available to its collaborators, provided that LICENSOR enters into a
            license with any such collaborator that expressly prohibits the
            collaborator from commercializing the LICENSED TECHNOLOGY in the
            FIELD or using the LICENSED PRODUCTS in the FIELD for any purpose
            other than in connection with the collaboration with LICENSOR for
            the purposes described above. LICENSOR shall provide LICENSEE with a
            copy of any such license entered into with a collaborator prior to
            delivering any LICENSED PRODUCTS in the FIELD; PROVIDED, HOWEVER,
            that LICENSOR may redact from such license agreements any financial
            terms LICENSOR considers proprietary or confidential and not
            relevant to LICENSEE'S exclusive rights hereunder, and PROVIDED
            FURTHER that any such licenses provided to LICENSEE shall be
            considered and treated as Confidential Information under Article 10
            of this Agreement. Any license by LICENSOR to a collaborator
            hereunder shall specifically provide that any intellectual property
            developed under such collaboration shall be treated as if developed
            by LICENSOR for purposes of determining if it is subject to any of
            the provisions of this Agreement.

5.    Section 4.3 is amended in part by deleting the text (including numbers)
      after the words "and the following minimum amounts:" and replacing such
      text with the following:

      (i)   At 12 months, $15,000
      (ii)  At 24 months, $30,000
      (iii) At 36 months, $45,000
      (iv)  Annually thereafter, $60,000

6.    Section 15.3 is amended by deleting the words "including any rights
      acquired under Section 15.18 hereof,".

7.    Section 15.18 is amended by deleting the text in said Section in its
      entirety and replacing it with the following:

      15.18 To support the grant of rights hereunder with respect to retinal
            disease, LICENSOR shall provide the services of Robert Lanza, M.D.,
            his assistants and the use of such lab space and equipment as they
            may need that LICENSOR can reasonable supply, understanding that Dr.
            Lanza, his assistants are the full-time

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            employees of LICENSOR and the equipment will be primarily used for
            LICENSOR research. Such assistance will be for a period of the
            earlier of one year from the date of this Amendment or until:

            (a)   the completion of preliminary animal studies to assess safety
                  and efficacy of applying cells for the treatment of retinitis
                  pigmentosa and/or macular degeneration (including any
                  contracts or rights already established for initial animal
                  studies);

            (b)   completion and submission of a scientific paper to a
                  peer-reviewed journal co-authored by LICENSOR and LICENSEE
                  scientists presenting animal data and analysis (subject to the
                  pre-approval of both parties prior to publication);

            (c)   completion of consultations with the FDA to assess the
                  suitability of animal data gathered to initiate the paperwork
                  for early stage human clinical trials;

            (d)   initiation of process of filing the paperwork for early stage
                  human trials.

            A committee composed of Michael West, Ph.D., Robert Lanza, M.D. and
            Irina Klimanskaya, Ph.D., as the LICENSOR representatives, and
            Jeffrey Janus and two additional representatives from LICENSEE that
            LICENSEE will promptly identify to LICENSOR in writing (the
            "Committee"), will meet periodically during the six-month period
            commencing on the Amendment Effective Date to discuss completion of
            the above-identified tasks.

            The LICENSEE Committee representatives may consult informally with
            the LICENSOR Committee representatives, both in person and by
            telephone, regarding issues of mutual interest identified by the
            Committee. The Committee shall meet during such six-month period at
            the facilities of LICENSOR or LICENSEE as shall be mutually
            determined; the time and place of such meetings, and the agenda for
            such meetings, shall be determined by mutual agreement. It is
            contemplated by the Parties that the Committee will meet three times
            during the six-month period. Either party may replace its
            representatives at any time, upon written notice and mutual
            agreement of the parties.

            The foregoing notwithstanding, if LICENSOR is unable or unwilling to
            complete the tasks outlined in this Section 15.18 above, LICENSEE
            shall have the right to manage and carry the work forward so long as
            LICENSEE provides funding for the project, in which case any
            intellectual property that is developed under LICENSEE's management
            and funding shall accrue to LICENSEE, and LICENSEE shall be entitled
            to treat as prepayment of future licensing requirements under this
            and other license agreements between LICENSOR and LICENSEE the
            actual costs incurred by LICENSEE in completing subsections (a)

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            through (d) above; PROVIDED, HOWEVER, that LICENSEE shall not be
            entitled to treat any such costs as prepayment of future licensing
            requirements under this and other license agreements between
            LICENSOR and LICENSEE if LICENSOR transfers to LICENSEE the
            technological protocols, techniques and training necessary for
            LICENSEE to replicate LICENSOR'S generation of retinal cells from
            stem cells. LICENSEE and LICENSOR agree that the transfer to
            LICENSEE of the technological protocols, techniques and training
            necessary for LICENSEE to replicate LICENSOR'S generation of retinal
            cells from stem cells shall be complete when LICENSOR provides
            LICENSEE with written copies of such protocols and techniques and
            two weeks of additional lab training at the Worcester facility by
            two qualified technicians within six months after the Amendment
            Effective Date.

8.    The Agreement is amended by replacing all references to the word "Product"
      with the term "Licensed Product".

9.    This First Amendment shall be governed by and construed in accordance with
      the laws of the State of Delaware, without regard to principles of
      conflicts of law thereof, and shall be binding upon and inure to the
      benefit of the Parties and their respective successors and assigns.

10.   The Parties agree that the Agreement to Amend is terminated by mutual
      agreement and that all of its provisions are superseded in their entirety
      by this First Amendment. The License Agreement, as amended hereby,
      contains the entire agreement of the Parties hereto and thereto with
      respect to the matters discussed herein and therein. This First Amendment
      may not be modified except in writing signed by the Parties.

11.   Except to the extent specifically amended hereby, the terms and provisions
      of the License Agreement are hereby ratified and affirmed in all respects
      and continue in full force and effect.

      IN WITNESS WHEREOF, this First Amendment has been executed by duly
authorized representatives of the Parties as of the Amendment Effective Date.

ADVANCED CELL, INC.

By:  /s/ William M. Caldwell, IV
   -----------------------------------------
Printed Name:  William M. Caldwell, IV
Title:         Chief Executive Officer

LIFELINE CELL TECHNOLOGY, LLC

By:  /s/ Kenneth Aldrich
   -----------------------------------------
Printed Name:  Kenneth Aldrich
Title:         Managing Member<Page>
                                                                EXHIBIT 10.21.1

             FIRST AMENDMENT TO EXCLUSIVE LICENSE AGREEMENT (ACT IP)

      This First Amendment to Exclusive License Agreement (ACT IP) ("First
Amendment") is made and entered into as of this 25th day of August, 2005 (the
"Amendment Effective Date"), by and between Advanced Cell, Inc. (formerly known
as Advanced Cell Technology, Inc.), a Delaware corporation with offices located
at 381 Plantation Street, Worcester, Massachusetts 01605 ("LICENSOR"), and
Lifeline Cell Technology, LLC (formerly known as PacGen Cellco, LLC), a
California limited liability company with offices located at 157 Surfview Drive,
Pacific Palisades, CA 90272 ("LICENSEE") (LICENSOR and LICENSEE sometimes
hereinafter referred to individually as a "Party" and collectively as the
"Parties").

      WHEREAS, the Parties previously entered into an Exclusive License
Agreement (ACT IP), dated May 14, 2004 (the "License Agreement"), which grants
LICENSEE defined rights to use certain intellectual property controlled by
LICENSOR; and

      WHEREAS, the Parties also entered into that certain Agreement to Amend
ACT/Cellco License Agreements dated September 7, 2004 (the "Agreement to
Amend"), which contemplates that the Parties will amend the License Agreement in
certain respects; and

      WHEREAS, the Parties have agreed to amend the License Agreement as
provided herein;

      NOW, THEREFORE, in consideration of the premises and terms of this First
Amendment, and in consideration of the payment to LICENSOR by LICENSEE of
$84,375, the receipt of which is hereby acknowledged by LICENSOR, the Parties
agree to amend the License Agreement as follows:

1.    Section 1.2 is deleted in its entirety and replaced with the following:

      1.2   "FIELD" shall mean (1) the research, development, manufacture and
            selling to third parties of human and non-human animal cells for
            commercial research use, including small molecule and other drug
            testing and basic research and (2) the manufacture and selling of
            human cells for therapeutic and diagnostic use in the treatment of
            human (a) diabetes, (b) liver diseases and (c) retinal diseases and
            retinal degenerative diseases; but FIELD shall exclude applications
            involving the use of cells in the treatment of tumors where the
            primary use of the cells is the destruction or reduction of tumors
            and does not involve regeneration of tissue or organ function.

2.    Section 1.3 is deleted in its entirety and replaced with the following:

      1.3   "KNOW-HOW" means all compositions of matter, techniques and data and
            other know-how and technical inventions (whether or not patentable),
            improvements and developments, practices, methods, concepts, trade
            secrets, documents, computer data, computer code, apparatus,
            clinical and regulatory strategies, test

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            data, analytical and quality control data, formulation,
            manufacturing, patent data or descriptions, development information,
            drawings, specifications, designs, plans, proposals and technical
            data and manuals and all other proprietary information that is owned
            or controlled by LICENSOR as of the Effective Date that relates to
            cloning technology or to any of the subject matter described in or
            claimed by the PATENT RIGHTS and is relevant to the FIELD. By way of
            illustration, but not in limitation, KNOW-HOW shall include
            commercial rights in the FIELD to any existing or potential research
            products, including reagents, developed by LICENSOR in the course of
            its in-house research as more fully described in Section 15.3 of
            this Agreement. An example of this is the proprietary culture medium
            developed by LICENSOR in the course of the development of LICENSOR's
            proprietary ooplasmic transfer technology.

3.    Section 1.9 is amended by deleting the text in Section 1.9 in its entirety
      and replacing it with the following: "Intentionally omitted".

4.    Section 2.5 is deleted in its entirety and replaced with the following:

      LICENSEE acknowledges and agrees that notwithstanding anything to the
      contrary in this Agreement, LICENSOR may: (i) practice the LICENSED
      TECHNOLOGY and develop and manufacture LICENSED PRODUCTS within the FIELD
      for research purposes, provided that LICENSOR may not market or sell
      LICENSED PRODUCTS in the FIELD to third parties in contravention of
      LICENSEE'S exclusive rights hereunder; (ii) distribute or otherwise
      transfer cells or cell lines or other reagents to collaborators for
      research purposes, and commercialize the results of such research (other
      than media and other reagents produced for sale to the commercial research
      market) outside the FIELD in connection with the research, development,
      manufacture or sale of therapeutic products that are not in contravention
      of LICENSEE'S exclusive rights hereunder; and (iii) distribute or
      otherwise transfer cells or cell lines to collaborators for the purposes
      of researching, developing and commercializing cell based therapeutics for
      purposes other than those exclusively licensed to LICENSEE hereunder.

      By way of illustration of subparagraph (ii) of Section 2.5 hereof, should
      LICENSOR partner with a biopharmaceutical company in order to produce skin
      cells for human therapeutic use, and in the process of basic research,
      preclinical, or clinical development find it necessary or useful to
      transfer cell lines or other reagents to that partner to facilitate the
      development of such dermatological product, such transfer, provided that
      the transferred material is not sold or marketed to such biopharmaceutical
      company for monetary compensation, shall be considered outside of the
      FIELD.

      LICENSOR may make LICENSED PRODUCTS available to its collaborators. In the
      event LICENSOR requests that LICENSEE deliver to LICENSOR LICENSED
      PRODUCTS in the FIELD for use in

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      connection with the purposes described in the above paragraph, LICENSEE
      shall make such LICENSED PRODUCTS available to LICENSOR on commercially
      reasonable terms. LICENSOR may make LICENSED PRODUCTS in the FIELD,
      whether developed and manufactured by LICENSOR or obtained from LICENSEE,
      available to its collaborators, provided that LICENSOR enters into a
      license with any such collaborator that expressly prohibits the
      collaborator from commercializing the LICENSED TECHNOLOGY in the FIELD or
      using the LICENSED PRODUCTS in the FIELD for any purpose other than in
      connection with the collaboration with LICENSOR for the purposes described
      above. LICENSOR shall provide LICENSEE with a copy of any such license
      entered into with a collaborator prior to delivering any LICENSED PRODUCTS
      in the FIELD; PROVIDED, HOWEVER, that LICENSOR may redact from such
      license agreements any financial terms LICENSOR considers proprietary or
      confidential and not relevant to LICENSEE'S exclusive rights hereunder,
      and PROVIDED FURTHER that any such licenses provided to LICENSEE shall be
      considered and treated as Confidential Information under Article 10 of
      this Agreement. Any license by LICENSOR to a collaborator hereunder shall
      specifically provide that any intellectual property developed under such
      collaboration shall be treated as if developed by LICENSOR for purposes of
      determining if it is subject to any of the provisions of this Agreement.

5.    Section 2.6 is deleted in its entirety.

6.    Section 4.3 is amended in part by deleting the text (including numbers)
      after the words "and the following minimum amounts:" and replacing such
      text with the following:

      (i)    At 12 months, $15,000
      (ii)   At 24 months, $37,500
      (iii)  At 36 months, $ 60,625
      (iv)   Annually thereafter, $75,000

7.    Section 15.3 is amended by deleting the words "including any rights
      acquired under Section 15.18 hereof,".

8.    Section 15.18 is amended by deleting the text in said Section in its
      entirety and replacing it with the following:

      15.18 To support the grant of rights hereunder with respect to retinal
            disease, LICENSOR shall provide the services of Robert Lanza, M.D.,
            his assistants and the use of such lab space and equipment as they
            may need that LICENSOR can reasonable supply, understanding that Dr.
            Lanza, his assistants are the full-time employees of LICENSOR and
            the equipment will be primarily used for LICENSOR research. Such
            assistance will be for a period of the earlier of one year from the
            date of this Amendment or until:

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            (a)   the completion of preliminary animal studies to assess safety
                  and efficacy of applying cells for the treatment of retinitis
                  pigmentosa and/or macular degeneration (including any
                  contracts or rights already established for initial animal
                  studies);

            (b)   completion and submission of a scientific paper to a
                  peer-reviewed journal co-authored by LICENSOR and LICENSEE
                  scientists presenting animal data and analysis (subject to the
                  pre-approval of both parties prior to publication);

            (c)   completion of consultations with the FDA to assess the
                  suitability of animal data gathered to initiate the paperwork
                  for early stage human clinical trials;

            (d)   initiation of process of filing the paperwork for early stage
                  human trials.

            A committee composed of Michael West, Ph.D., Robert Lanza, M.D. and
            Irina Klimanskaya, Ph.D., as the LICENSOR representatives, and
            Jeffrey Janus and two additional representatives from LICENSEE that
            LICENSEE will promptly identify to LICENSOR in writing (the
            "Committee"), will meet periodically during the six-month period
            commencing on the Amendment Effective Date to discuss completion of
            the above-identified tasks.

            The LICENSEE Committee representatives may consult informally with
            the LICENSOR Committee representatives, both in person and by
            telephone, regarding issues of mutual interest identified by the
            Committee. The Committee shall meet during such six-month period at
            the facilities of LICENSOR or LICENSEE as shall be mutually
            determined; the time and place of such meetings, and the agenda for
            such meetings, shall be determined by mutual agreement. It is
            contemplated by the Parties that the Committee will meet three times
            during the six-month period. Either party may replace its
            representatives at any time, upon written notice and mutual
            agreement of the parties.

            The foregoing notwithstanding, if LICENSOR is unable or unwilling to
            complete the tasks outlined in this Section 15.18 above, LICENSEE
            shall have the right to manage and carry the work forward so long as
            LICENSEE provides funding for the project, in which case any
            intellectual property that is developed under LICENSEE's management
            and funding shall accrue to LICENSEE, and LICENSEE shall be entitled
            to treat as prepayment of future licensing requirements under this
            and other license agreements between LICENSOR and LICENSEE the
            actual costs incurred by LICENSEE in completing subsections (a)
            through (d) above; PROVIDED, HOWEVER, that LICENSEE shall not be
            entitled to treat any such costs as prepayment of future licensing
            requirements under this and other license agreements between
            LICENSOR and LICENSEE if LICENSOR transfers to LICENSEE the
            technological protocols, techniques and training necessary for
            LICENSEE to replicate LICENSOR'S generation of retinal cells from
            stem cells. LICENSEE and LICENSOR agree that the transfer

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<Page>

            to LICENSEE of the technological protocols, techniques and
            training necessary for LICENSEE to replicate LICENSOR'S generation
            of retinal cells from stem cells shall be complete when LICENSOR
            provides LICENSEE with written copies of such protocols and
            techniques and two weeks of additional lab training at the Worcester
            facility by two qualified technicians within six months after the
            Amendment Effective Date.

9.    The Agreement is amended by replacing all references to the word "Product"
      with the term "Licensed Product".

10.   This First Amendment shall be governed by and construed in accordance with
      the laws of the State of Delaware, without regard to principles of
      conflicts of law thereof, and shall be binding upon and inure to the
      benefit of the Parties and their respective successors and assigns.

11.   The Parties agree that the Agreement to Amend is terminated by mutual
      agreement and that all of its provisions are superseded in their entirety
      by this First Amendment. The License Agreement, as amended hereby,
      contains the entire agreement of the Parties hereto and thereto with
      respect to the matters discussed herein and therein. This First Amendment
      may not be modified except in writing signed by the Parties.

12.   Except to the extent specifically amended hereby, the terms and provisions
      of the License Agreement are hereby ratified and affirmed in all respects
      and continue in full force and effect.

      IN WITNESS WHEREOF, this First Amendment has been executed by duly
authorized representatives of the Parties as of the Amendment Effective Date.

ADVANCED CELL, INC.

By:  /s/ William M. Caldwell, IV
   -----------------------------------------
Printed Name:  William M. Caldwell, IV
Title:         Chief Executive Officer

LIFELINE CELL TECHNOLOGY, LLC

By:  /s/ Kenneth Aldrich
   -----------------------------------------
Printed Name:  Kenneth Aldrich
Title:         Managing Member

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