<PAGE>   1

                                                                   EXHIBIT 10.11

                                GERON CORPORATION

                             SECURED LOAN AGREEMENT


     This Secured Loan Agreement (this "Agreement") is made as of August 10,
1999 by and between GERON CORPORATION, a California corporation (the "Company"),
and David J. Earp and Andrea L. Earp (each individually, a "Borrower" and
collectively, "Borrowers").


                                   BACKGROUND

     Borrowers desire to borrow from the Company, and the Company desires to
lend to Borrowers, an aggregate of $100,000 (the "Borrowed Amount") to purchase
a principal residence in the San Francisco Bay Area, located at 6766 Armour
Drive Oakland, CA 94611 (the "Principal Residence"). The parties desire that
such loan shall be secured pursuant to a Security Agreement of even date
herewith (the "Security Agreement") by a second deed of trust on Borrowers'
Principal Residence on the terms and conditions contained herein and in the
Security Agreement (the "Second Deed of Trust").

                                    AGREEMENT

     This agreement supercedes the Secured Loan Agreement dated August 9, 1999,
between us and shall be effective as of August 10, 1999.

     In consideration of the foregoing, and for other good and valuable
consideration, the receipt of which is hereby acknowledged, the parties agree as
follows:

     1.   AGREEMENT TO LEND. Subject to the terms and conditions contained in
this Agreement and upon execution of this Agreement, the Company agrees to issue
to Borrowers or for Borrowers' account, at the Company's option, a check or
other readily available funds in the Borrowed Amount (the "Loan") upon the date
of this Agreement.

     2.   PROMISSORY NOTE. In consideration of the Company's delivery of the
Borrowed Amount, Borrowers will execute a secured promissory note in the form
attached hereto as Exhibit A (the "Note"), in the principal amount of such
Borrowed Amount.

     3.   USE OF PROCEEDS OF THE LOAN. Borrowers agree that the proceeds of the
Loan shall be applied solely to the purchase of the Principal Residence.

     4.   REPAYMENT OF LOAN. Borrowers jointly and severally agree to repay in
full the principal amount of the Loan on the terms and conditions specified in
the Note.

     5.   BORROWER COVENANTS. Borrowers hereby covenant and agree for the
duration of this Agreement, the Loan and the Note: (i) to itemize their annual
federal and state tax returns;


<PAGE>   2

(ii) to use the Borrowed Amount solely to purchase Borrowers' Principal
Residence; and (iii) to indemnify and hold the Company harmless against any and
all expenses (including attorneys' fees) and all other costs, expenses and
obligations arising from any liability related to the Principal Residence.

     6.   SECURITY AGREEMENT. Borrowers will additionally execute the Security
Agreement in the form attached hereto as Exhibit B as security for Borrowers'
obligation to repay the Borrowed Amount, and will deliver, or cause to be
delivered, until the termination of this Agreement, the Security Agreement and
the Note, together with such other documents of assignment and other documents
as may be reasonably requested by the Company. Borrowers shall also deliver, or
cause to be delivered, to the Company the Second Deed of Trust, each executed by
Borrowers, to be recorded by the Company (if it so elects) with the official
records of the county in which the Principal Residence is located in accordance
with the terms of the Security Agreement.

     7.   NO EMPLOYMENT RIGHTS. Nothing in this Agreement or the Note is
intended or shall be construed to confer upon either Borrower any right to
employment or continued employment with the Company, or shall alter in any way
the nature of either Borrower's employment with the Company.

     8.   MISCELLANEOUS.

          (a)  SUCCESSORS AND ASSIGNS. 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. This Agreement may not be assigned by
Borrowers without the prior written consent of the Company. 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.

          (b)  GOVERNING LAW. This Agreement and all acts and transactions
pursuant hereto and the rights and obligations of the parties hereto shall be
governed, construed and interpreted in accordance with the laws of the State of
California, without giving effect to the principles of conflicts of law of such
state.

          (c)  SEVERABILITY. If one or more provisions of this Agreement are
held to be unenforceable under applicable law, the parties agree to renegotiate
such provision in good faith. In the event that the parties cannot reach a
mutually agreeable and enforceable replacement for such provision, then (i) such
provision shall be excluded from this Agreement, (ii) the balance of the
Agreement shall be interpreted as if such provision were so excluded and (iii)
the balance of the Agreement shall be enforceable in accordance with its terms.

          (d)  ADVICE OF LEGAL COUNSEL. Each party acknowledges and represents
that, in executing this Agreement, it has had the opportunity to seek advice as
to its legal rights from legal counsel and that the person signing on its behalf
has read and understood all of the terms


<PAGE>   3

and provisions of this Agreement. This Agreement shall not be construed against
any party by reason of the drafting or preparation thereof.

          (e)  COUNTERPARTS. This Agreement may be executed in counterparts,
each of which shall be deemed to be an original and all of which taken together
shall constitute one and the same instrument.

     The parties hereto have executed this Secured Loan Agreement as of the day
and year first above written.


                                        GERON CORPORATION


                                        By: /s/ DAVID L. GREENWOOD
                                           -------------------------------------

                                        Name:  David L. Greenwood
                                             -----------------------------------

                                        Title: Senior Vice President,
                                               Chief Financial Officer
                                              ----------------------------------

                                        Address: 230 Constitution Drive
                                                 Menlo Park, CA  94025


                                        /s/ DAVID J. EARP
                                        ----------------------------------------
                                        DAVID J. EARP


                                        /s/ ANDREA L. EARP
                                        ----------------------------------------
                                        ANDREA L. EARP

                                        Address: 6766 Armour Drive
                                                 Oakland, CA  94611

<PAGE>   4

                                    EXHIBIT A


                             SECURED PROMISSORY NOTE


$100,000.00                                                   August 10, 1999
                                                          Menlo Park, California

     FOR VALUE RECEIVED, DAVID J. EARP and ANDREA L. EARP (each, a "Borrower"
and collectively, "Borrowers") jointly and severally promise to pay to the order
of GERON CORPORATION (the "Company"), at its principal offices at 230
Constitution Drive, Menlo Park, CA 94025, the principal sum of One Hundred
Thousand Dollars ($100,000.00), upon the terms and conditions specified below.
Capitalized terms used but not otherwise defined herein shall have the meanings
given to such terms in that certain Secured Loan Agreement, dated as of August
10, 1999, by and between the Company and the Borrowers (the "Loan Agreement").

     1.   Payment. Borrowers jointly and severally promise to repay the
principal balance of this Note as follows: fifty percent (50%) of the principal
balance is due three years from the date of this Note and the second fifty
percent (50%) is due four years from the date of this Note. Borrowers also
jointly and severally promise to repay the entire principal balance of this Note
within ten days following the earliest to occur of (A) the closing of the sale
or other transfer of the Borrowers' new principal residence located at 6766
Armour Drive, Oakland, CA 94611, (B) termination of DAVID J. EARP'S employment
with the Company, or (C) the refinancing of the Borrowers' new principal
residence whereby additional equity is provided.

          Any payment to be made on a date that is not a business day may be
made on the next business day thereafter. The records of the Company shall be
conclusive evidence of the unpaid principal balance hereof, and of all payments
made in respect thereof, absent manifest error.

     2.   Application of Payments. Each payment shall be made in lawful tender
of the United States. Prepayment of principal may be made at any time without
penalty.

     3.   Events of Acceleration. The entire unpaid principal sum and accrued
but unpaid interest of this Note shall become immediately due and payable upon
one or more of the following events:

          A.   the failure of Borrowers to make any payment of any amount due
hereunder and the continuation of such default for a period of ten (10) days or
more;

          B.   the insolvency of either Borrower, the commission of any act of
bankruptcy by a Borrower, the execution by a Borrower of a general assignment
for the benefit of creditors, the filing by or against a Borrower of any
petition in bankruptcy or any petition for relief under the provisions of the
federal bankruptcy act or any other state or federal law for the relief of
debtors and the continuation of such petition without dismissal for a period of
thirty (30)

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days or more, the appointment of a receiver or trustee to take possession of any
property or assets of a Borrower, or the attachment of or execution against any
property or assets of a Borrower;

          C.   the sale, transfer, mortgage, assignment, further encumbrance or
lease, whether voluntarily or involuntarily or by operation of law or otherwise
of the Principal Residence covered by the Second Deed of Trust, or any portion
thereof or interest therein, without the prior written consent of the Company;

          D.   the occurrence of any event of default under the Security
Agreement or the Second Deed of Trust securing this Note or any obligation
secured thereby; or

          E.   Borrowers are unable to provide additional collateral if required
by Section 2 of the Security Agreement.

     4.   Employment Requirement. The benefits of the interest arrangement under
this Note are not transferable by Borrowers and are conditioned on the future
performance of substantial services by DAVID J. Earp. For purposes of applying
the provisions of this Note, DAVID J. EARP shall be considered to provide
substantial services to the Company for so long as he renders services as a
full-time employee of the Company or one or more of its subsidiaries.

     5.   Use of Proceeds; Security. The proceeds of the loan evidenced by this
Note may only be applied to the purchase of the Principal Residence. Payment of
this Note shall be secured by the Second Deed of Trust on the Principal
Residence under the terms of the Security Agreement and is subject to all the
provisions thereof. Borrowers, however, shall remain personally liable for
payment of this Note, and all of the assets of Borrowers, in addition to the
collateral under the Second Deed of Trust may be applied to the satisfaction of
Borrower's obligations hereunder. This Note is also subject to the terms of the
Loan Agreement.

     6.   Certification; Itemized Deductions. Borrowers certify that Borrowers
reasonably expect to be entitled to and will itemize deductions for federal
income tax purposes for each year the Note is outstanding.

     7.   Collection. If Borrowers fail to pay this Note as and when required
hereunder, Borrowers promise to pay all costs and expenses (including reasonable
attorney fees) incurred in connection with any proceedings to collect such
amounts in default whether or not an action is instituted.

     8.   Waiver. No previous waiver and no failure or delay by the Company in
acting with respect to the terms of this Note, the Second Deed of Trust or the
Loan Agreement shall constitute a waiver of any breach, default, or failure of
condition under this Note, the Second Deed of Trust, the Loan Agreement or the
obligations secured thereby. A waiver of any term of this Note, the Second Deed
of Trust, the Loan Agreement or of any of the obligations secured thereby must
be made in writing and shall be limited to the express terms of such waiver.
BORROWERS WAIVE PRESENTMENT; DEMAND; NOTICE OF DISHONOR; NOTICE OF DEFAULT OR
DELINQUENCY; NOTICE OF ACCELERATION; NOTICE OF PROTEST AND NONPAYMENT; NOTICE OF
COSTS, EXPENSES OR LOSSES AND INTEREST

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THEREON; NOTICE OF INTEREST ON INTEREST; AND DILIGENCE IN TAKING ANY ACTION TO
COLLECT ANY SUMS OWING UNDER THIS NOTE OR IN PROCEEDING AGAINST ANY OF THE
RIGHTS OR INTERESTS IN OR TO PROPERTIES SECURING PAYMENT OF THIS NOTE.

     9.   Conflicting Agreements. In the event of any inconsistencies between
the terms of this Note and the terms of any other document related to the loan
evidenced by the Note, the terms of this Note shall prevail.

     10.  Governing Law. This Note shall be construed in accordance with the
laws of the State of California, without giving effect to the principles of
conflicts of law of such state.


                                        ----------------------------------------
                                        BORROWER: DAVID J. EARP


                                        ----------------------------------------
                                        BORROWER: ANDREA L. EARP

                                        Address: 6766 Armour Drive
                                                 Oakland, CA 94611
<PAGE>   7

                                    EXHIBIT B

                               SECURITY AGREEMENT


     This Security Agreement (this "Agreement") is made as of August 10, 1999 by
and between GERON CORPORATION, a California corporation (the "Company"), and
DAVID J. EARP and ANDREA L. EARP (each individually, a "Borrower" and
collectively, "Borrowers").

                                    RECITALS

     The Company has loaned or will loan to Borrowers, and Borrowers have
borrowed or will borrow from the Company, an aggregate of $100,000 (the
"Borrowed Amount"), which loan is or shall be evidenced by a promissory note
(the "Note") and is to be secured by a second deed of trust on Borrowers'
principal residence (the "Second Deed of Trust"). The form of Note and the
obligations thereunder are as set forth in Exhibit A to the Secured Loan
Agreement between the Company and Borrowers, dated the date hereof (the "Loan
Agreement").

                                    AGREEMENT

     In consideration of the foregoing, and for other good and valuable
consideration, the receipt of which is hereby acknowledged, the parties to this
Agreement agree as follows (all capitalized terms used herein but not otherwise
defined shall have the meaning assigned to such terms in the Loan Agreement):

     1.   DEED OF TRUST.

          (a)  In consideration of the Loan to Borrowers under the Loan
Agreement, and to secure the Borrowed Amount, Borrowers are delivering herewith
the Second Deed of Trust in form and substance approved by the Company and duly
executed by Borrowers and properly notarized. The Company may, if the Company so
elects, but without obligation to do so, at any time record the Second Deed of
Trust against Borrowers' principal residence, located at 6766 Armour Drive,
Oakland, CA 94611 (the "Principal Residence"), in the official records of the
county in which the Principal Residence is located. Within five (5) days after
written demand, Borrowers shall furnish written evidence reasonably satisfactory
to the Company that (i) Borrowers hold good and marketable title to the
Principal Residence; (ii) there is no loan, deed of trust, mortgage or
encumbrance against the Principal Residence other than the first deed of trust
in an amount previously disclosed to the Company (the "First Deed of Trust");
and (iii) Borrowers are not in default under such First Deed of Trust or related
loan documents. Upon the sale, conveyance, assignment, alienation, encumbrance
or any other form of transfer of the Principal Residence, the Note shall be
immediately due and payable in full.

     2.   BORROWERS' REPRESENTATIONS, WARRANTIES AND COVENANTS. To induce the
Company to enter into this Agreement, Borrowers represent, warrant and covenant
to the Company, its successors and assigns, as follows:

<PAGE>   8

          (a)  Borrowers will jointly and severally pay the principal sum of the
Note secured hereby, together with interest thereon (if any), and perform all
other obligations required of the Borrowers under the Loan Agreement at the time
and in the manner provided therein.

          (b)  Borrowers have good and marketable title to the Principal
Residence free and clear of all security interests, liens, encumbrances and
rights of others other than the First Deed of Trust constituting a first lien
against the Principal Residence and the Second Deed of Trust. When duly
executed, delivered and recorded in the official land records of the county in
which the Principal Residence is located, the Second Deed of Trust will
constitute a valid, perfected security interest in the Principal Residence,
prior to all monetary liens or encumbrances other than the First Deed of Trust.

          (c)  The consent of no other party or entity is required to grant the
security interest in the Principal Residence (the "Existing Property") as
provided for in this Agreement. The creation of the security interest referenced
herein, and performance of the obligations of Borrowers hereunder, will not
violate or cause a conflict with any other agreement to which Borrowers are
parties, or to which the Principal Residence is subject. Borrowers will perform
all obligations of Borrowers in connection with the First Deed of Trust (and
related documents), and a default thereunder will constitute a default
hereunder.

          (d)  Other than the First Deed of Trust and the Second Deed of Trust,
there are no security interests or liens on the Existing Property that could be
perfected or obtained by filing a financing statement or notice with any state
filing office.

          (e)  There are no actions, proceedings, claims or disputes pending or,
to Borrowers' knowledge, threatened against or affecting Borrowers or the
Existing Property except as disclosed to the Company in writing prior to the
date of this Agreement.

          (f)  Borrowers shall not sell, convey, assign, alienate, further
encumber or otherwise transfer the Principal Residence, or enter into any
contract or other agreement to sell, convey, assign, alienate, encumber or
otherwise transfer the Principal Residence or any interest therein without the
prior written consent of the Company.

     3.   DEFAULT. Borrowers shall be deemed to be in default of the Note and of
this Agreement in the event:

          (a)  Payment of principal or interest on the Note shall be delinquent
for a period of 10 days or more; or

          (b)  Borrowers fail to perform any of the covenants contained in the
Loan Agreement (including exhibits thereto) for a period of 10 days after
written notice thereof from the Company; or

          (c)  Borrowers' representations and warranties to the Company
contained in this Agreement or the Second Deed of Trust were untrue or incorrect
as of the date of funding of the Loan Agreement; or

<PAGE>   9

          (d)  Any default under the First Deed of Trust.

     4.   REMEDIES IN THE EVENT OF DEFAULT. In the case of an event of default,
as set forth above, the Company shall have the right to accelerate payment of
the Note upon notice to Borrowers, and shall thereafter be entitled to pursue
any or all of its remedies under applicable law, including, without limitation,
(a) offsetting from Borrowers' salary, bonuses, vacation pay or other amounts
due to Borrowers from the Company, any amount due and payable by Borrowers under
the Note, and/or (b) proceeding against the Principal Residence under the Second
Deed of Trust.

     5.   INSOLVENCY. Borrowers agree that if a bankruptcy or insolvency
proceeding is instituted by or against either Borrower, or if a receiver is
appointed for the property of either Borrower, or if either Borrower makes an
assignment for the benefit of creditors, the entire amount unpaid on the Note
shall become immediately due and payable, and the Company may proceed as
provided in the case of default.

     6.   MISCELLANEOUS.

          (a)  SUCCESSORS AND ASSIGNS. 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. 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.

          (b)  GOVERNING LAW. This Agreement and all acts and transactions
pursuant hereto and the rights and obligations of the parties hereto shall be
governed, construed and interpreted in accordance with the laws of the State of
California, without giving effect to principles of conflicts of law.

          (c)  NOTICES. Any notice required or permitted by this Agreement shall
be in writing and shall be deemed sufficient upon receipt, when delivered
personally or by a nationally-recognized delivery service (such as Federal
Express or UPS) or confirmed facsimile, or forty-eight (48) hours after being
deposited in the U.S. mail as certified or registered mail with postage prepaid,
if such notice is addressed to the party to be notified at such party's address
or facsimile number as set forth below, or as subsequently modified by written
notice.

          (d)  SEVERABILITY. If one or more provisions of this Agreement are
held to be unenforceable under applicable law, the parties agree to renegotiate
such provision in good faith. In the event that the parties cannot reach a
mutually agreeable and enforceable replacement for such provision, then (i) such
provision shall be excluded from this Agreement, (ii) the balance of the
Agreement shall be interpreted as if such provision were so excluded and (iii)
the balance of the Agreement shall be enforceable in accordance with its terms.

          (e)  ADVICE OF LEGAL COUNSEL. Each party acknowledges and represents
that, in executing this Agreement, it has had the opportunity to seek advice as
to its legal rights from

<PAGE>   10

legal counsel and that the person signing on its behalf has read and understood
all of the terms and provisions of this Agreement. This Agreement shall not be
construed against any party by reason of the drafting or preparation thereof.

     The parties hereto have executed this Security Agreement as of the day and
year first above written.


                                        DAVID J. EARP


                                        ----------------------------------------
                                                       (Signature)


                                        ANDREA L. EARP


                                        ----------------------------------------
                                                       (Signature)


                                        Address: 6766 Armour Drive
                                                 Oakland, CA 94611


                                        GERON CORPORATION


                                        By:
                                           -------------------------------------


                                        Title:
                                              ----------------------------------