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                                                                    EXHIBIT 1.13


                                  ALTAREX CORP.

                                STOCK OPTION PLAN

1.   PURPOSE OF THE PLAN

     The purpose of this stock option plan (the "Plan") is to develop the
interest of the directors, officers, employees and other persons who provide
on-going services (collectively, "Optionees") to AltaRex Corp. (the
"Corporation") and its subsidiaries in the growth and development of the
Corporation by providing such persons with the opportunity to acquire an
increased proprietary interest in the Corporation and to better enable the
Corporation and its subsidiaries to attract and retain persons of desired
experience and ability.

2.   ADMINISTRATION

     This Plan shall be administered by the board of directors of the
Corporation (the "Directors").

3.   GRANTING

     The Directors may from time to time and in their discretion grant by way of
resolution one or more stock options ("Stock Options") to purchase voting common
shares of the Corporation ("Common Shares") to any one or more Optionees.

4.   NUMBER

     The number of Common Shares reserved for issuance at any time pursuant to
this Plan shall be 2,480,000.

     The number of Common Shares reserved for issuance pursuant to this Plan, or
any other previously established or proposed share compensation arrangement of
the Corporation, in respect of all Stock Options granted to any one Optionee at
any one time shall not exceed five percent (5%) of the issued and outstanding
Common Shares in the capital of the Corporation.

     Common Shares optioned under Stock Options that expire or otherwise
terminate in accordance with the terms of the Plan shall be available to be
optioned under subsequent grants of Stock Options.

5.   EXERCISE PRICE

     At the time of grant of a Stock Option, the Directors shall fix the
exercise price thereof (the "Exercise Price"), which such price shall not be
less than the closing price of the Common Shares

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on The Toronto Stock Exchange (the "Exchange"), on the first date preceding the
date of grant on which the Common Shares traded on the Exchange. Alternatively,
the Directors may fix the Exercise Price at the weighted average of the trading
prices of the Common Shares on the Exchange on the five (5) days preceding the
date of grant of the Stock Option. In the event that the Common Shares are
listed on another stock exchange or stock exchanges, the references in this Plan
to The Toronto Stock Exchange shall be deemed to be references to such stock
exchange as shall be designated by the Directors. In the event that the Common
Shares are not listed for trading on any stock exchange at the time of the grant
of a Stock Option, the Exercise Price of such Stock Option shall be such price
as is determined by the Directors.

6.   VESTING

     At the time of grant of a Stock Option, the Directors shall fix the date or
dates on which the Optionee shall be entitled to exercise part or all of such
Stock Option (the "Vesting Dates").

7.   EXPIRY DATE

     At the time of grant of a Stock Option, the Directors shall fix the date on
which such Stock Option shall expire (the "Expiry Date"), provided that such
date shall be no later than five (5) years from the date of grant.

8.   STOCK OPTION AGREEMENT

     A written agreement shall be entered into between the Corporation and each
Optionee to whom a Stock Option has been granted under this Plan, which such
agreement shall set out the number of Common Shares under option, the Exercise
Price, the Vesting Dates, the Expiry Date and such other terms as the Directors
determine to be necessary or desirable, all of which shall be in accordance with
the provisions of this Plan (the "Stock Option Agreement"). The Stock Option
Agreement will be substantially in the form attached as Schedule "A" to this
Plan or in such other form as the Directors may from time to time approve (and
which other form is approved by the Exchange, if required) and may be executed
and delivered for and on behalf of the Corporation by any one of the President,
Chief Financial Officer or Vice-President of the Corporation or such other
officer or director of the Corporation as the Directors may authorize.

9.   NO RIGHT OF ASSIGNMENT

     All Stock Options granted pursuant to this Plan shall be personal to the
Optionee and shall not be assignable or otherwise transferable except by will or
the laws of descent and distribution.



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10.  NO RIGHT AS SHAREHOLDER

     An Optionee shall have no rights whatsoever as a shareholder in respect of
any Common Shares under option to such Optionee unless and until he/she has
exercised the related Stock Option in respect of such Common Shares.

11.  EXERCISE

     A Stock Option may be exercised in whole or in part by the delivery to the
Corporation at its head office of a written notice (the "Notice") that specifies
the number of Common Shares in respect of which such Stock Option is being
exercised together with payment in an amount equal to the Exercise Price thereof
multiplied by such number of Common Shares.

     Upon the exercise of a Stock Option in whole or in part, the Corporation
shall cause to be delivered to the Optionee a certificate registered in the name
of such Optionee representing the number of Common Shares specified in the
Notice.

     Common Shares issued upon the valid exercise of a Stock Option shall be
validly issued as fully paid and non-assessable. The issuance of such Common
Shares shall not require any further resolution or approval of the Directors and
shall be deemed to have occurred on the date that the related Stock Option was
exercised.

12.  VARIATIONS IN NUMBER

     In the event that the Corporation:

     (a)  declares a stock dividend or makes a distribution on the Common Shares
          in Common Shares;

     (b)  subdivides or consolidates the issued and outstanding Common Shares
          into a greater or smaller number of Common Shares;

     (c)  issues rights to all or substantially all of the holders of the Common
          Shares to purchase additional Common Shares at a price below the
          closing trading price of the Common Shares on the record date
          associated with such issuance; or

     (d)  effects any transaction through which the Common Shares as a class are
          converted into or rendered exchangeable for any other securities

then either or both of the number of Common Shares optioned under outstanding
Stock Options and the Exercise Price thereof shall be adjusted by resolution of
the Directors if the Directors determine that such an adjustment is required to
prevent substantial dilution or enlargement of the rights granted to Optionees.



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13.  VARIATIONS IN VESTING

     In the event that an Optionee dies, such Optionee's executor or executrix
shall have the right to exercise part or all of all then outstanding and vested
Stock Options on behalf of the Optionee's estate until the earlier of the date
set by the Directors at the time of the grant of such Stock Options (such date
not to exceed one year after the date of death of the Optionee) or the Expiry
Date. All Stock Options not exercised by such date shall immediately and
automatically terminate. The Directors shall have the right, in their sole
discretion, to provide at the time of the grant of the Stock Options of an
Optionee, that all Stock Options granted to such Optionee shall be deemed to
fully vest on the day prior to the Optionee's death. If the Directors do so,
such Optionee's executor or executrix shall have the right to exercise all of
the outstanding Stock Options of such Optionee in accordance with the above.

     In the event that an Optionee retires or resigns from his or her office and
employment with the Corporation and all of its subsidiaries or is removed from
such office and employment (whether with or without cause) or otherwise ceases
to hold such office or employment for any reason (otherwise than as a result of
the death of the Optionee) all then outstanding and unvested Stock Options
granted to such Optionee shall immediately and automatically terminate. Such
Optionee shall have the right to exercise part or all of his or her then
outstanding and vested Stock Options until the earlier of the date set by the
Directors at the time of the grant of such Stock Options (such date not to
exceed 90 days after the date such Optionee retires or is removed from such
office) or the Expiry Date. All such Stock Options not exercised by such date
shall immediately and automatically terminate. The Directors shall have the
right, in their sole discretion, to provide at the time of the grant of the
Stock Options of an Optionee, that all Stock Options granted to such Optionee
shall be deemed to fully vest on the day prior to the resignation or removal of
the Optionee from such office or employment. If the Directors do so, such
Optionee shall have the right to exercise all of the outstanding Stock Options
of such Optionee in accordance with the above.

     In the event that:

     (a)  the Directors determine that there is a reasonable probability that
          the Corporation will be reorganized, amalgamated or merged with,
          consolidated into or in any way combined with, another corporation;

     (b)  the shareholders of the Corporation approve the liquidation,
          dissolution or winding-up of the Corporation or the sale, lease,
          exchange or other disposition of all or substantially all of the
          property of the Corporation;

     (c)  a take-over bid, which is a "formal bid" (as that term is defined by
          the Securities Act (Alberta)), is made for any voting or equity
          securities of the Corporation; or

     (d)  the Directors determine that there is a reasonable probability that
          the Corporation will experience a change of control (as determined by
          the Directors)




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then the Directors may by resolution determine that all or any part of the
outstanding and unvested Stock Options granted to any one or more Optionees
shall vest on a date specified by such resolution and all such Stock Options
shall be deemed to have vested on the date so specified.

14.  AMENDMENT OR DISCONTINUANCE OF PLAN

     This Plan is subject to the rules of the Exchange and of any other stock
exchange or exchange facility through which the Common Shares may at any time be
traded (the "Rules"). To the extent that any provision of this Plan conflicts
with any Rule, such Rule shall govern and this Plan shall be deemed to be
amended to be consistent therewith.

     The Directors may amend or discontinue this Plan at any time (upon receipt
of the approval of the Exchange), provided that no such amendment or
discontinuance may, without the consent of any affected Optionee, alter or
impair any Stock Options previously granted to such Optionee under this Plan.

15.  TRANSITION

     A stock option agreement entered into prior to the effective date of this
Plan that remains outstanding on the effective date of this Plan shall continue
in full force and effect under the terms of this Plan. Upon the approval of this
Plan by the shareholders of the Corporation, all previous stock option plans, if
any, shall be rescinded.

16.  EFFECTIVE DATE

     This Plan shall be come effective as of the date set out below.

     DATED April 1, 1998

                                 ALTAREX CORP.


                                 Per:  "Richard E. Bagley"
                                       --------------------------------------
                                       RICHARD E. BAGLEY
                                       President


                                 Per:  "Blaine J. Schamber"
                                       --------------------------------------
                                       BLAINE J. SCHAMBER
                                       Vice-President, Finance and Corporate
                                       Development


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                                                                    EXHIBIT 1.13


                                  SCHEDULE "A"

                         AMENDMENT TO STOCK OPTION PLAN

     BE IT RESOLVED THAT:

1.   The stock option plan of the Corporation (the "Plan") be and is hereby
     amended such that the maximum number of Common Shares which may be reserved
     for issuance for all purposes at any time pursuant to the Plan shall be
     increased from 2,480,000 to 4,180,000.

2.   Any officer or director of the Corporation is hereby authorized, for an on
     behalf of the Corporation, to execute and deliver such documents and
     instruments and to take such other actions as such officer or director may
     determine to be necessary or advisable to implement this resolution and the
     matters authorized hereby, such determination to be conclusively evidenced
     by the execution and delivery of such documents or instruments and the
     taking of any such actions.


                                      A-1
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                                                                    EXHIBIT 1.13


                                  SCHEDULE "B"

                         AMENDMENT TO STOCK OPTION PLAN

     BE IT RESOLVED THAT:

1.   The stock option plan of the Corporation (the "Plan") be and is hereby
     amended such that the maximum date after which an option granted under the
     Plan shall expire is extended from five years from the date of grant to ten
     years from the date of grant.

2.   Any officer or director of the Corporation is hereby authorized, for and on
     behalf of the Corporation, to execute and deliver such documents and
     instruments and to take such other actions as such officer or director may
     determine to be necessary or advisable to implement this resolution and the
     matters authorized hereby, such determination to be conclusively evidenced
     by the execution and delivery of such documents or instruments and the
     taking of any such actions.


                                      B-1
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                                  SCHEDULE "C"

                         AMENDMENT TO STOCK OPTION PLAN

BE IT RESOLVED THAT:

1.  The stock option plan of the Corporation (the "Plan") be and is hereby
    amended such that the maximum number of Common Shares which may be reserved
    for issuance for all purposes at any time pursuant to the Plan shall be
    increased from 4,180,000 to 11,500,000.

2.  Any officer or director of the Corporation is hereby authorized, for and on
    behalf of the Corporation, to execute and deliver such documents and
    instruments and to take such other actions as such officer or director may
    determine to be necessary or advisable to implement this resolution and the
    matters authorized hereby, such determination to be conclusively evidenced
    by the execution and delivery of such documents or instruments and the
    taking of any such actions.