EXHIBIT 10.1

VIAGEN, INC.

SERIES A PREFERRED STOCK PURCHASE
AGREEMENT

THIS SERIES A PREFERRED STOCK
PURCHASE AGREEMENT (thisAgreement) is made as
of September 16, 2009 (the Effective Date) by and between ViaGen, Inc., an
Arizona corporation (ViaGen or the Company), and Geron Corporation, a
Delaware corporation (Geron).

Geron desires to purchase, and
ViaGen desires to sell, ViaGen Series A Preferred Stock.

THEREFORE, the parties hereby agree
as follows:

**1.****Purchase and Sale of Stock**

**1.1****Sale and Issuance of Series A
Preferred Stock**

(a)On or prior to the Closing, ViaGen will have authorized (i) the sale and
issuance to Geron of 2,434,122 shares of Series A Preferred Stock (the New
Equity) equal to an aggregate total of $3,602,500 (the Aggregate Purchase
Price) and (ii) the issuance of the shares of the Companys Common Stock (as
defined below) to be issued upon conversion of the New Equity (the Conversion
Shares). Collectively, the New Equity and the Conversion Shares are referred to
herein as the Securities. The New Equity will have all rights, preferences,
privileges and restrictions accorded Series A Preferred Stock in the Companys
Amended and Restated Articles of Incorporation, a copy of which has been
provided to Geron.

(b)Subject to the terms and conditions of this Agreement, Geron agrees to
purchase the New Equity at a price of $1.48 per share (as adjusted for any stock
dividends paid in common stock, and any combinations, stock splits,
recapitalizations and the like each with respect to the Series A Preferred Stock
occurring on or after the date hereof and prior to the Closing) (the Purchase
Price per Share). In connection with this purchase by Geron, ViaGen agrees (i)
to accelerate the maturity date of that certain Convertible Promissory Note
dated September 4, 2008, by and between Viagen and Geron (the Note), with
ViaGen as maker and Geron as payee, in the amount of $1,500,000 plus applicable
interest, from December 31, 2009 to the Effective Date (the Accelerated
Maturity Date), and (ii) pay to Geron the Outstanding Amount (as such term is
defined in the Note) under the Note upon the Accelerated Maturity Date.

**1.2****Closing**

(a)The purchase and sale of the New Equity will take place at the offices of
Exeter Life Sciences, Inc. at 2390 E. Camelback Rd., Suite 440, Phoenix, AZ
85085, at 10:00 a.m. on September 16, 2009, or at such other time and place as
mutually agreed orally or in writing by Geron and ViaGen (such time and place,
the Closing).

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(b)Delivery. At Closing, ViaGen will
issue and deliver to Geron certificate(s) representing the New Equity. In
addition, prior to the Closing, each of ViaGen and Geron shall deliver all
documents, instruments and writings required to be delivered by either of them
pursuant to this Agreement in order to implement and effect the transactions
contemplated herein.

**2.****Representations and Warranties
of ViaGen**

ViaGen hereby represents, covenants
and warrants to Geron that:

**2.1****Organization, Good Standing and
Qualification**

ViaGen is a
corporation duly organized, validly existing and in good standing under the laws
of the State of Arizona and has all requisite corporate power and authority to
carry on its business as now conducted. ViaGen is duly qualified to transact
business and is in good standing in each jurisdiction in which the failure to so
qualify would have a material adverse effect on its business or properties.

**2.2****Capitalization and Voting Rights**

The
authorized capital of ViaGen consists, or will consist immediately prior to the
Closing, of:

(a)Preferred Stock. 150,000,000 shares of
preferred stock, no par value (Preferred Stock), of which 20,000,000 shares
have been designated Series A Preferred Stock (Series A Preferred Stock),
11,038,300 of which are issued and outstanding as of the date immediately before
the Closing. The rights, privileges and preferences of the Series A Preferred
Stock are as stated in ViaGens Amended and Restated Articles of Incorporation.

(b)Common Stock. 150,000,000 shares of
common stock, no par value (Common Stock), of which none are issued and
outstanding.

(c)Valid Issuance. The outstanding shares
of Preferred Stock are all duly and validly authorized and issued, fully paid
and nonassessable, and were issued in accordance with the registration or
qualification provisions of the Securities Act of 1933, as amended (the Act),
and any relevant state securities laws, or pursuant to valid exemptions
therefrom.

(d)Other Rights. Except for (i) the
conversion privileges of the Series A Preferred Stock, (ii) warrants
contemplated to be issued prior to December 31, 2009 for 506,757 shares of
ViaGen Series A Preferred Stock at $1.48 per share, and (iii) 1,535,500
outstanding options pursuant to the ViaGen, Inc. 2009 Stock Plan (the 2009
Stock Plan), there are no outstanding options, warrants, rights (including
conversion or preemptive rights) or agreements for the purchase or acquisition
from the Company of any shares of its capital stock. The Company has reserved an
aggregate of 2,500,000 shares of Common Stock, for issuance upon exercise of
options or restricted stock purchase awards granted to employees and other
service providers pursuant to the Companys 2009 Stock Plan. ViaGen is not a
party or subject to any agreement or understanding, and, to ViaGens knowledge,
there is no agreement or understanding between any persons and/or entities,
which affects or relates to the voting or giving of written consents with
respect to any security or by a director of ViaGen.

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**2.3****Authorization**

All
corporate action on the part of ViaGen, its officers, directors and shareholders
necessary for the authorization, execution and delivery of this Agreement, the
performance of all obligations of ViaGen hereunder, and the authorization,
issuance (or reservation for issuance), sale and delivery of the New Equity
being sold hereunder and the Common Stock issuable upon conversion of such New
Equity has been taken or will be taken prior to the Closing. This Agreement
constitutes valid and legally binding obligations of ViaGen, enforceable against
ViaGen in accordance with its terms.

**2.4****Valid Issuance of Series A
Preferred Stock and Common Stock**

The New
Equity that is being purchased hereunder, when issued, sold and delivered in
accordance with the terms of this Agreement for the consideration expressed
herein, will be duly and validly issued, fully paid, and nonassessable, and will
be free of restrictions on transfer other than restrictions on transfer under
this Agreement and under applicable state and federal securities laws. The
Common Stock issuable upon conversion of the Series A Preferred Stock purchased
hereunder has been duly and validly reserved for issuance and, upon issuance in
accordance with the terms of the Amended and Restated Articles of Incorporation,
will be duly and validly issued, fully paid, and nonassessable and will be free
of restrictions on transfer other than restrictions on transfer under this
Agreement and under applicable state and federal securities laws.

**2.5****Legal Proceedings and
Orders**

To the
knowledge of the Company, there is no action, suit, proceeding or investigation
pending or threatened against the Company that questions the validity of this
Agreement or the right of the Company to enter into this Agreement or to
consummate the transaction contemplated hereby, nor is the Company aware of any
basis for any of the forgoing. The Company is neither a party nor subject to the
provisions of any order, writ, injunction, judgment or decree of any court or
government agency or instrumentality that would affect the ability of the
Company to enter into this Agreement or to consummate the transaction
contemplated hereby.

**2.6****Consents.**

Except for
filings under federal and applicable state securities laws and except for
Permits (as defined below), the absence of which either individually or in the
aggregate would not have a material adverse effect on the Company, all permits,
consents, approvals, orders, authorizations of, or declarations to
(collectively, Permits) or filings with any federal, state, local or foreign
court, governmental or regulatory authority, or other person (including third
party consents) required on the part of the Company in connection with the
execution, delivery or performance of this Agreement and the consummation of the
transaction contemplated herein have been obtained or will be obtained prior to
the Closing, and will be effective as of the Closing.

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**3.****Representations and Warranties
of Geron**

Geron hereby represents, covenants
and warrants to ViaGen that:

**3.1****Authorization**

Geron has
full power and authority to enter into this Agreement, and this Agreement
constitutes a valid and legally binding obligation of Geron, enforceable against
it in accordance with its terms except (i) as limited by applicable bankruptcy,
insolvency, reorganization, moratorium and other laws of general application
affecting enforcement of creditors rights generally, (ii) as limited by laws
relating to the availability of specific performance, injunctive relief or other
equitable remedies.

**3.2****Purchase Entirely for Own
Account**

The New
Equity to be received by Geron and the Conversion Shares, if no registration
statement under the Act is in effect upon conversion of the New Equity, are
being acquired for investment for Gerons own account not as a nominee or agent,
and not with a view to the resale or distribution of any part thereof, and Geron
has no present intention of selling, granting any participation in, or otherwise
distributing the same. The acquisition by Geron of any of the New Equity and the
Conversion Shares, if no registration statement under the Act is in effect upon
conversion of the New Equity, shall constitute confirmation of the
representation by Geron that it does not have any contract, undertaking,
agreement or arrangement with any person to sell, transfer or grant
participations to such person or to any third person, with respect to any of the
New Equity or the Conversion Shares, if no registration statement under the Act
is in effect upon conversion of the New Equity.

**3.3****Disclosure of Information**

Geron has
had an opportunity to ask questions and receive answers from ViaGen regarding
the terms and conditions of the offering of the New Equity and the business,
properties, prospects and financial condition of ViaGen. The foregoing, however,
does not limit or modify the representations and warranties of ViaGen in Section
2 of this Agreement or the right Geron to rely thereon.

**3.4****Investment Experience**

Geron has
such knowledge and experience in financial or business matters that it is
capable of evaluating the merits and risks of the investment in the New Equity.
Geron acknowledges that any investment in the Securities involves a high degree
of risk, and represents that it is able, without materially impairing its
financial condition, to hold the Securities for an indefinite period of time and
to suffer a complete loss of its investment.

**3.5****Accredited Investor; Non-U.S.
Persons**

Geron either
(A) is an accredited investor within the meaning of Securities and Exchange
Commission (SEC) Rule 501 of Regulation D, as presently in effect, or (B) (i)
certifies that it is not a U.S. person within the meaning of SEC Rule 902 of
Regulation S, as presently in effect, and that it is not acquiring the
Securities for the account or benefit of any such U.S. person, (ii) agrees to
resell the Securities only in accordance with the provisions of Regulation S,
pursuant to registration under the Act, or pursuant to an available exemption
from registration and agrees not to engage in hedging transactions with regard
to such Securities unless in compliance with the Act, (iii) agrees that any
certificates for any Securities issued to Geron shall contain a legend to the
effect that transfer is prohibited except in accordance with the provisions of
Regulation S, pursuant to registration under the Act or pursuant to an available
exemption from registration and that hedging transactions involving such
Securities may not be conducted unless in compliance with the Act, or (iv)
agrees that ViaGen is hereby required to refuse to register any transfer of any
Securities issued to Geron not made in accordance with the provisions of
Regulation S, pursuant to registration under the Act, or pursuant to an
available exemption from registration.

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**3.6****Restricted Securities**

Geron
understands that the New Equity is characterized as a restricted security
under the federal securities laws inasmuch as it is being acquired from ViaGen
in a transaction not involving a public offering and that under such laws and
applicable regulations such securities may be resold without registration under
the Act only in certain limited circumstances. In this connection, Geron
represents that it is familiar with SEC Rule 144, as presently in effect, and
understands the resale limitations imposed thereby and by the Act. GERON
UNDERSTANDS AND ACKNOWLEDGES HEREIN THAT AN INVESTMENT IN VIAGENs SECURITIES
INVOLVES AN EXTREMELY HIGH DEGREE OF RISK AND MAY RESULT IN A COMPLETE LOSS OF
ITS INVESTMENT. Geron understands that the Securities have not been and may
never be registered under the Act and have not been and may never be registered
or qualified in any state in which they are offered, and thus Geron will not be
able to resell or otherwise transfer its Securities unless they are registered
under the Act and registered or qualified under applicable state securities
laws, or an exemption from such registration or qualification is available.
Geron has no immediate need for liquidity in connection with this investment.

**3.7****Further Limitations on
Disposition**

Without in
any way limiting the representations set forth above, Geron further agrees not
to make any disposition of all or any portion of the Securities unless:

(a)There is then in effect a registration statement under the Act covering
such proposed disposition and such disposition is made in accordance with such
registration statement; or

(b)(i) Geron shall have notified ViaGen of the proposed disposition and
shall have furnished ViaGen, in confidence, with a detailed statement of the
circumstances surrounding the proposed disposition, and (ii) if reasonably
requested by ViaGen, Geron shall have furnished ViaGen with an opinion of
Gerons counsel that such disposition will not require registration of such
shares under the Act. It is agreed that ViaGen will not require opinions of
counsel for transactions made pursuant to Rule 144.

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**3.8****Legends**

It is
understood that the certificates evidencing the New Equity shall, and the
Conversion Shares may, if no registration statement under the Act is in effect
upon conversion of the New Equity, bear the following legend:

THESE
SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED. THEY MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE
ABSENCE OF A REGISTRATION STATEMENT IN EFFECT WITH RESPECT TO THE SECURITIES
UNDER SUCH ACT OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT SUCH
REGISTRATION IS NOT REQUIRED OR UNLESS SOLD PURSUANT TO RULE 144 OF SUCH ACT.

**3.9****No Reliance on Others**

Geron
acknowledges that it is not relying upon any person, firm or corporation, other
than ViaGen and its officers and directors, in making its investment or decision
to invest in ViaGen.

4.Conditions to Gerons Obligations at the Closings

The
obligations of Geron under subsection 1.1(b) of this Agreement are subject to
the fulfillment on or before Closing of each of the following conditions:

**4.1****Representations and Warranties**

The
representations and warranties of ViaGen contained in Section 2 shall be true on
and as of Closing with the same effect as though such representations and
warranties had been made on and as of the date of Closing.

**4.2****Performance**

ViaGen shall
have performed and complied with all agreements, obligations and conditions
contained in this Agreement that are required to be performed or complied with
by it on or before Closing.

**4.3****Compliance
Certificate**

ViaGen shall
deliver to Geron at Closing a certificate, executed by the President of ViaGen,
stating that the conditions specified in Sections 4.1 and 4.2 have been
fulfilled.

**4.4****Secretarys Certificate**

ViaGen shall
deliver to Geron a certificate, executed by the Secretary of ViaGen, affirming
the effectiveness of the Amended and Restated Articles of Incorporation, Bylaws
and the resolutions of ViaGens Board of Directors and shareholders relating to
the transactions contemplated hereby.

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**4.5****Permits, Qualifications and
Consents**

All permits,
authorizations, approvals, consents or permits, if any, of any governmental
authority or regulatory body of the United States or of any state that are
required in connection with the lawful issuance and sale of the securities
pursuant to this Agreement shall be duly obtained and effective as of Closing.

**4.6****Proceedings and Documents**

All
corporate and other proceedings in connection with the transactions contemplated
at Closing hereby and all documents incident thereto shall be reasonably
satisfactory in form and substance to Geron, and Geron shall have received all
such counterpart original and certified or other copies of such documents as
they may reasonably request.

**5.****Conditions to ViaGens
Obligations at Closing**

The
obligations of ViaGen to Geron are subject to the fulfillment on or before
Closing of each of the following conditions by Geron:

**5.1****Representations and Warranties**

The
representations and warranties of Geron contained in Section 3 shall be true on
and as of Closing with the same effect as though such representations and
warranties had been made on and as of the date of Closing.

**5.2****Payment of Purchase Price**

Geron shall have delivered the
Aggregate Purchase Price to ViaGen.

**5.3****Permits, Qualifications and
Consents**

All permits,
authorizations, approvals, consents or permits, if any, of any governmental
authority or regulatory body of the United States or of any state that are
required in connection with the lawful issuance and sale of the securities
pursuant to this Agreement shall be duly obtained and effective as of Closing.

**6.****Miscellaneous**

**6.1****Indemnification**

Each party agrees to indemnify and hold
harmless the other party and each officer, director and person, if any, who
controls the other party from and against losses, claims, damages or liabilities
(or actions or proceedings in respect thereof), joint or several, directly or
indirectly, based upon or arising out of any failure of the first party to
comply with the covenants and obligations of the first party contained in this
Agreement. Promptly after receipt by any indemnified party or person of a notice
of a claim or the beginning of any action in respect of which indemnity is to be
sought against an indemnifying party pursuant to this Section 6.1, such
indemnified party or person shall notify the indemnifying party in writing of
such claim or of the commencement of such action, but the omission to so notify
the indemnifying party will not relieve it from any liability which it may have
to any indemnified party or person under this Section 6.1 (except to the extent
that such omission materially and adversely affects the indemnifying partys
ability to define such action) or from any liability otherwise than under this
Section 6.1.

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Subject to the provisions hereinafter
stated, in case any such action shall be brought against an indemnified party or
person, the indemnifying party shall be entitled to participate therein, and, to
the extent that it shall elect by written notice delivered to the indemnified
party or person promptly after receiving the aforesaid notice from such
indemnified party or person, shall be entitled to assume the defense thereof,
with counsel reasonably satisfactory to such indemnified party or person. After
notice from the indemnifying party to such indemnified party or person of its
election to assume the defense thereof, such indemnifying party shall not be
liable to such indemnified party or person for any legal expense subsequently
incurred by such indemnified party or person in connection with the defense
thereof, provided, however, that if there exists or shall exist a conflict of
interest that would make inappropriate, in the reasonable opinion of counsel to
the indemnified party or person, for the same counsel to represent both the
indemnified party or person and such indemnifying party or any affiliate or
associate thereof, the indemnified party or person shall be entitled to retain
its own counsel at the expense of such indemnifying party; provided, however,
that no indemnifying party shall be responsible for the fees and expenses of
more than one separate counsel (together with appropriate local counsel) for all
indemnified parties or persons. In no event shall any indemnifying party be
liable in respect to any amounts paid in settlement of any action unless the
indemnifying party or person shall have approved the terms of such settlement.
No indemnifying party shall, without the prior written consent of the
indemnified party or person, effect any settlement of any pending or threatened
proceeding in respect of which any indemnified party or person is a party,
unless such settlement includes an unconditional release of such indemnified
person from all liability on claims that are the subject matter of such
proceeding. The provisions of this Section 6.1 shall survive the termination of
this Agreement.

**6.2****Successors and Assigns**

Except as
otherwise provided herein, the terms and conditions of this Agreement shall
inure to the benefit of and be binding upon the respective successors and
assigns of the parties (including transferees of any Securities). Nothing in
this Agreement, express or implied, is intended to confer upon any party other
than the parties hereto or their respective successors and assigns any rights,
remedies, obligations, or liabilities under or by reason of this Agreement,
except as expressly provided in this Agreement.

**6.3****Governing Law; Venue**

This
Agreement is to be construed in accordance with and governed by the internal
laws of the State of Delaware without giving effect to any choice of law rule
that would cause the application of the laws of any jurisdiction other than the
internal laws of the State of Delaware to the rights and duties of the
parties.

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**6.4****Waiver of Right to Jury Trial**

GERON AND VIAGEN, TO THE FULLEST
EXTENT PERMITTED BYAPPLICABLE LAW, HEREBY
IRREVOCABLY WAIVE ALL RIGHT TO TRIAL BY JURY AS TO ANY ISSUE RELATING HERETO IN
ANY ACTION, PROCEEDING ORCOUNTERCLAIM ARISING
OUT OF OR RELATING TO THIS AGREEMENT.

**6.5****Counterparts**

This
Agreement may be executed in two or more counterparts, each of which shall be
deemed an original, but all of which together shall constitute one and the same
instrument.

**6.6****Notices**

Except as
may be otherwise provided herein, all notices, requests, waivers and other
communications made pursuant to this Agreement shall be in writing and shall be
conclusively deemed to have been duly given (a) when hand delivered to the other
party; (b) when sent by facsimile to the number set forth below each partys
signature if sent between 8:00 a.m. and 5:00 p.m. recipients local time on a
business day, or on the next business day if sent by facsimile to the number set
forth below if sent other than between 8:00 a.m. and 5:00 p.m. recipients local
time on a business day; (c) if to an address within the United States, three
business days after deposit in the U.S. mail with first class or certified mail
receipt requested postage prepaid and addressed to the other party at the
address set forth below; (d) if to an address outside the United States, seven
business day after deposit in the U.S. mail with first class postage prepaid and
addressed to the other party at the address set forth below; or (e) the next
business day after deposit with a national overnight delivery service, postage
prepaid, addressed to the parties as set forth below with next business day
delivery guaranteed, provided that the sending party receives a confirmation of
delivery from the delivery service provider. Each person making a communication
hereunder by facsimile shall promptly confirm by telephone to the person to whom
such communication was addressed each communication made by it by facsimile
pursuant hereto but the absence of such confirmation shall not affect the
validity of any such communication. A party may change or supplement the
addresses given above, or designate additional addresses, for purposes of this
Section 6.6 by giving the other party written notice of the new address in the
manner set forth above.

**6.7****Expenses**

Irrespective
of whether the Closing is effected, each of ViaGen and Geron shall pay all costs
and expenses that it incurs with respect to the negotiation, execution, delivery
and performance of this Agreement.

**6.8****Amendments and Waivers**

Any term of
this Agreement may be amended and the observance of any term of this Agreement
may be waived (either generally or in a particular instance and either
retroactively or prospectively), only upon written consent made by an authorized
representative of the consenting party(ies). Any amendment or waiver effected in
accordance with this paragraph shall be binding upon each holder of any
securities purchased under this Agreement at the time outstanding (including
securities into which such securities are convertible), each future holder of
all such securities, and ViaGen.

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**6.9****Severability**

If one or
more provisions of this Agreement are held to be unenforceable under applicable
law, such provision shall be excluded from this Agreement and the balance of the
Agreement shall be interpreted as if such provision were so excluded and shall
be enforceable in accordance with its terms.

**6.10****Further Assurances**

Each of
Geron and ViaGen shall from time to time and at all times hereafter make, do,
execute, or cause or procure to be made, done and executed such further acts,
deeds, conveyances, consents and assurances without further consideration, which
may reasonably be required to effect the transactions contemplated by this
Agreement.

**6.11****Entire Agreement**

This
Agreement and the documents referred to herein constitute the entire agreement
among the parties with respect to the subject matter hereof and no party shall
be liable or bound to any other party in any manner by any warranties,
representations or covenants except as specifically set forth herein or therein.

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*    *

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IN WITNESS
WHEREOF, the parties have executed this Agreement as of the date first above
written.

VIAGEN, INC.By:
    /s/ Mark
  WaltonMark Walton, PresidentAddress:
    Attn:
      President12357-A Riata
      Trace Pkwy, Ste 100Austin, TX
      78727Facsimile:
    (512)652-3698


GERON CORPORATIONBy:
    /s/ David J.
  EarpDavid J. Earp, Ph.D., J.D.Title:
    Chief Patent
      Counsel and Senior VicePresident,
      Business DevelopmentAddress:
    Attn: Chief
      Executive Officer230 Constitution
      Dr.Menlo Park, CA
      94025Facsimile:
    (650)
      473-8654


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