LORUS THERAPEUTICS
INC.




2003 SHARE OPTION PLAN




OCTOBER 9, 2003


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TABLE OF CONTENTS


|      |  |  |  | ARTICLE 1. INTERPRETATION                  |  |  |   | 
|----- |  |  |  | ------------------------------------------ |  |  | - | 
|1.1.  |  |  |  | Purpose of the Plan                        |  |  | 1 | 
|1.2.  |  |  |  | Definitions                                |  |  | 1 | 
|1.3.  |  |  |  | Schedules                                  |  |  | 1 | 
|1.4.  |  |  |  | Headings and Table of Contents             |  |  | 1 | 
|1.5.  |  |  |  | Gender and Number                          |  |  | 1 | 
|1.6.  |  |  |  | Currency                                   |  |  | 1 | 
|1.7.  |  |  |  | Invalidity of Provisions                   |  |  | 2 | 
|1.8.  |  |  |  | Entire Agreement                           |  |  | 3 | 
|1.9.  |  |  |  | Governing Law                              |  |  | 2 | 
|1.10. |  |  |  | Effective Date                             |  |  | 2 | 
|      |  |  |  |                                            |  |  |   | 
|      |  |  |  | ARTICLE 2.ADMINISTRATION                   |  |  |   | 
|2.1.  |  |  |  | Administration by the Board of Directors 2 |  |  | 1 | 
|2.2.  |  |  |  | Authority of the Board of Directors        |  |  | 2 | 
|2.3.  |  |  |  | Grants by CEO                              |  |  | 3 | 
|2.4.  |  |  |  | Shares Subject to the Plan                 |  |  | 3 | 
|2.5.  |  |  |  | Restrictions on Issuances                  |  |  | 3 | 
|2.6.  |  |  |  | Compliance with Law                        |  |  | 4 | 
|      |  |  |  |                                            |  |  |   | 
|      |  |  |  | ARTICLE 3.FAIR VALUE                       |  |  |   | 
|3.1.  |  |  |  | Definition                                 |  |  | 4 | 
|      |  |  |  |                                            |  |  |   | 
|      |  |  |  | ARTICLE 4.GRANT OF OPTIONS                 |  |  |   | 
|4.1.  |  |  |  | Grants                                     |  |  | 5 | 
|4.2.  |  |  |  | Participation Voluntary                    |  |  | 5 | 
|4.3.  |  |  |  | General Terms of the Option                |  |  | 5 | 
|4.4.  |  |  |  | Option Exercise Price                      |  |  | 5 | 
|4.5.  |  |  |  | Exercise Period of Option                  |  |  | 5 | 
|4.6.  |  |  |  | Option Agreements                          |  |  | 6 | 
|4.7.  |  |  |  | Prohibition on Transfer of Options         |  |  | 6 | 
|      |  |  |  |                                            |  |  |   | 
|      |  |  |  | ARTICLE 5.EXERCISE OF OPTIONS              |  |  |   | 
|5.1.  |  |  |  | Method of Exercise of Option               |  |  | 7 | 

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|5.2.           |  |  |  | Payment of Option Price                            |  |  | 7  | 
|-------------- |  |  |  | -------------------------------------------------- |  |  | -- | 
|5.3.           |  |  |  | Withholding of Tax                                 |  |  | 7  | 
|               |  |  |  |                                                    |  |  |    | 
|               |  |  |  | ARTICLE 6.SHARES                                   |  |  |    | 
|6.1.           |  |  |  | Shareholder Rights                                 |  |  | 8  | 
|               |  |  |  |                                                    |  |  |    | 
|               |  |  |  | ARTICLE 7.REORGANIZATIONS AND ADJUSTMENTS          |  |  |    | 
|7.1.           |  |  |  | Reorganization or Sale of the Company              |  |  | 8  | 
|7.2.           |  |  |  | Substitute Options upon Acquisition by the Company |  |  | 8  | 
|7.3.           |  |  |  | Capital Adjustments                                |  |  | 8  | 
|               |  |  |  |                                                    |  |  |    | 
|               |  |  |  | ARTICLE 8.EMPLOYMENT AND COMPENSATION              |  |  |    | 
|8.1.           |  |  |  | No
Special Employment Rights                       |  |  | 9  | 
|8.2.           |  |  |  | Other Employee Benefits                            |  |  | 9  | 
|8.3.           |  |  |  | Non-Exclusivity                                    |  |  | 9  | 
|               |  |  |  |                                                    |  |  |    | 
|               |  |  |  | ARTICLE 9.AMENDMENTS                               |  |  |    | 
|9.1.           |  |  |  | Amendment or Termination Without Consent           |  |  | 9  | 
|9.2.           |  |  |  | Amendment With Individual Consent                  |  |  | 10 | 
|               |  |  |  |                                                    |  |  |    | 
|               |  |  |  | ARTICLE 10.GENERAL MATTERS                         |  |  |    | 
|10.1.          |  |  |  | Notices                                            |  |  | 10 | 
|10.2.          |  |  |  | Submission to Jurisdiction                         |  |  | 10 | 
|10.3.          |  |  |  | Language of Plan                                   |  |  | 10 | 
|10.4.          |  |  |  | Further Assurances                                 |  |  | 10 | 
|               |  |  |  |                                                    |  |  |    | 
|SCHEDULES      |  |  |  |                                                    |  |  |    | 
|Schedule
1.2.1 |  |  |  |  Definitions                                      |  |  |    | 
|Schedule
1.2.2 |  |  |  |  Incorporated Definitions                         |  |  |    | 
|Schedule
2.2.5 |  |  |  |  Regulations                                      |  |  |    | 
|Schedule
2.6.4 |  |  |  |  Company Obligations Required By Law              |  |  |    | 
|Schedule
4.6   |  |  |  |  Form of Option Agreement                         |  |  |    | 
|Schedule
5.1   |  |  |  |  Exercise Form                                    |  |  |    | 

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LORUS THERAPEUTICS INC. 2003 OPTION
PLAN




ARTICLE 1. INTERPRETATION


|1.1. |  | Purpose of the Plan
|---- |  | -------------------



The purpose of this Plan is to advance
the interests of the Company by increasing its ability to attract, retain and reward Eligible Persons who are involved in the development of the
Company by providing those Eligible Persons with an opportunity to acquire an ownership interest in the Company and aligning further the interests of
those Eligible Persons with the interests of the Companys security holders.


|1.2. |  | Definitions
|---- |  | -----------



1.2.1.  In this Plan and its
Schedules, the terms set out in Schedule 1.2.1 (Definitions) will have the meanings given to those terms in that schedule.




1.2.2.  Certain terms, whose
definitions are incorporated by reference from other material, are set out in Schedule 1.2.2 (Incorporated Definitions).


|1.3. |  | Schedules
|---- |  | ---------

|The
following are the schedules attached to this Plan:
|------------------------------------------------------
|Schedule
1.2.1                                        
|Schedule
1.2.2                                        
|Schedule
2.2.5                                        
|Schedule
4.6                                          
|Schedule
5.1                                          

|1.4. |  | Headings and Table of Contents
|---- |  | ------------------------------



The inclusion of headings and a table
of contents in this Plan is for convenience of reference only and will not affect the construction or interpretation of the Plan.


|1.5. |  | Gender and Number
|---- |  | -----------------



In this Plan, unless the context
otherwise requires, words importing the singular include the plural and vice versa and words importing gender include all genders.


|1.6. |  | Currency
|---- |  | --------



Except where otherwise expressly
provided, all amounts in this Plan are stated and will be paid in Canadian currency.


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|1.7. |  | Invalidity of Provisions
|---- |  | ------------------------



Each of the provisions contained in
this Plan is distinct and severable and a declaration of invalidity or unenforceability of any provision or part by a court of competent jurisdiction
will not affect the validity or enforceability of any other provision of the Plan. To the extent permitted by applicable law, the Company and all
Participants waive any provision of law which renders any provision of this Plan invalid or unenforceable in any respect.


|1.8. |  | Entire Agreement
|---- |  | ----------------



This Plan and each Option Agreement
constitutes the entire agreement between the parties pertaining to the subject matter of those documents. There are no warranties, conditions, or
representations (including any that may be implied by statute) and there are no agreements in connection with the subject matter except as specifically
set out or referred to in those documents.


|1.9. |  | Governing Law
|---- |  | -------------



This Plan will be governed by and
interpreted in accordance with the laws of the Province of Ontario and the laws of Canada applicable in Ontario.


|1.10. |  | Effective Date
|----- |  | --------------



This Plan is effective as of October 9,
2003.




ARTICLE 2. Administration


|2.1. |  | Administration by the Board of
Directors
|---- |  | ----------------------------------------



This Plan will be administered by the
board of directors of the Company or a committee of the board of directors duly appointed for this purpose by the board of directors and consisting of
not less than 2 directors. If a committee is appointed for this purpose, all references to the term Board will be deemed to be
references to the committee.


|2.2. |  | Authority of the Board of Directors
|---- |  | -----------------------------------



Subject to this Plan, the Board has the
authority to:




2.2.1.  grant Options to
Eligible Persons;




2.2.2.  determine the terms
of Option grants, including any limitations, restrictions and conditions upon those grants, which terms may differ by grant and by
Participant;




2.2.3.  issue Shares upon the
exercise of Options;




2.2.4.  effect any repurchase
of Shares, Options or other rights contemplated by this Plan;


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2.2.5.  interpret this Plan
and adopt, amend or rescind any administrative guideline and other rule or Regulation relating to this Plan as it may from time to time consider
advisable, subject to the Law; and




2.2.6.  make all other
determinations and take all other actions in connection with the implementation and administration of this Plan as it may consider necessary or
advisable.




The Boards guidelines, rules, Regulations, interpretations
and determinations will be final and binding upon the Company and all Participants and their legal representatives. No member of the Board will be
liable for any act or omission (whether or not negligent) taken or omitted in good faith, or for the exercise of an authority or discretion granted in
connection with the Plan to the Board, or for the acts or omission of any other members of the Board.


|2.3. |  | Grants by CEO
|---- |  | -------------



The Chief Executive Officer of the Company is authorized to grant
Options from time to time to Eligible Persons between meetings of the Board, subject to the ratification and approval of those grants by the Board at
the next meeting of the Board; provided those grants are made in accordance with (1) the terms of the Plan and (2) any guidelines set out by the Board.
The exercise price of Options granted in this manner will in all cases be established on the date of grant by the Chief Executive Officer, in
accordance with section 4.4.


|2.4. |  | Shares Subject to the Plan
|---- |  | --------------------------



2.4.1.  Effective from
September 13, 2005 the maximum total number of Shares available for issuance from treasury upon exercise of Options granted under the Plan is 10% of
the issued and outstanding Shares of the Corporation, being 25,920,797 Shares as at September 13, 2005, less any Shares issued pursuant to options
exercised under the Previous Stock Option Plan. Any Share subject to an Option that, for any reason, has been cancelled or terminated without having
been exercised under the Plan or the Previous Plan, will again be available for issuance under this Plan.




2.4.2.  No fractional Shares
may be issued or purchased under the Plan and the Board will determine the manner in which any fractional Shares or rights to acquire fractional Shares
are to be addressed.


|2.5. |  | Restrictions on Issuances
|---- |  | -------------------------



The issuing of Options is subject to the following
restrictions:




2.5.1.  that the number of
Shares reserved for issuance under Options granted to Insiders or under Stock Options granted to Insiders under this and any other Share Compensation
Arrangement of the Company may not exceed 15% of the Outstanding Issue;




2.5.2.  that Insiders may
not, within a 12 month period, be issued a number of Shares under the Plan and/or under any other Share Compensation Arrangement of the Company
exceeding 10% of the Outstanding Issue; and


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2.5.3.  that any one Insider
and that Insiders Associates may not, within a 12 month period, be issued a number of Shares under the Plan and/or under any other Share
Compensation Arrangement of the Company exceeding 10% of the Outstanding Issue.




2.5.4.  that the number of
Shares reserved for issuance under Options to any one Person may not exceed 5% of the Outstanding Issue.


|2.6. |  | Compliance with Law
|---- |  | -------------------



2.6.1.  The Company is not
obligated by this Plan or any grant under it to, and will not, take any action required, permitted or otherwise contemplated by this Plan except in
accordance with Law. The Board may postpone or adjust any exercise of any Option or the issue of any Shares under this Plan or refrain from taking any
action or exercising any right required, permitted or contemplated by the Plan as the Board in its discretion may deem necessary in order to permit the
Company to ensure that this Plan and the issuance of Shares under it comply with Law.




2.6.2.  If the Shares are
listed on a Stock Market, the Company will have no obligation to issue any Shares under this Plan unless the Shares have been duly listed, upon
official notice of issuance, on that Stock Market.




2.6.3.  If Law prevents the
exercise of an Option or the issue of a Share, the Board may, in addition to the rights referred to in this Plan, choose to address the economic value
of a Participants rights in whatever manner it deems to be reasonable in the circumstances, and action taken by the Company in consequence of
that determination will be deemed to have satisfied the Companys obligations as they would otherwise have existed.




2.6.4.  The Company will
comply with all reporting obligations required by Law.




ARTICLE 3. FAIR VALUE


|3.1. |  | Definition
|---- |  | ----------



Fair Value for the
purposes of this Plan will be equal to the weighted average of the trading prices of the Shares on the Stock Market for the five trading days ending on
the last trading date preceding the date on which the calculation of Fair Value is to be made, provided that:




3.1.1.  Fair
Value for the purpose of determining the exercise price of all Options (other than Incentive Options) under section 4.4 will be equal to the
closing market price of the Shares on the Stock Market on the last trading date preceding the date of the grant. If there is no trading on that date,
the exercise price will be the average of the bid and ask on the Stock Market on the last trading date preceding the date of the
grant.


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Article 4. Grant of Options


|4.1. |  | Grants
|---- |  | ------



The Board may grant Options to Eligible
Persons. An Eligible Person may receive Options on more than one occasion under this Plan and may receive differing Options on any one
occasion.


|4.2. |  | Participation Voluntary
|---- |  | -----------------------



The participation of an Eligible Person
in the Plan and the purchase of Shares by a Participant upon exercise of an Option is voluntary, and neither the participation nor any purchase will
have any effect, positively or negatively, on the employment or continuing employment of an Eligible Person or Participant who is an Employee, the
appointment or continuing appointment of an Eligible Person or Participant who is an Executive or the engagement or continuing engagement of an
Eligible Person or Participant who is a Consultant or Consultant Entity.


|4.3. |  | General Terms of the Option
|---- |  | ---------------------------



4.3.1.  In respect of each
Option, the Board will determine the Eligible Person who will receive the Option, the number of Shares subject to the Option, the expiration date of
the Option, the extent to which each Option is exercisable from time to time during the term of the Option and other terms and conditions relating to
each Option.




4.3.2.  If not otherwise
determined by the Board, an Option will vest as to 50% on the first annual anniversary of the date of grant of the Option and an additional 25% on the
second and third annual anniversaries after the date of the grant of the Option.


|4.4. |  | Option Exercise Price
|---- |  | ---------------------



The Board will, in accordance with Law,
establish the exercise price of an Option when each Option is granted equal to the Fair Value of the Shares as of the date of grant.


|4.5. |  | Exercise Period of Option
|---- |  | -------------------------



4.5.1.  Maximum
Period. Options granted must be exercised no later than 10 years after the date of grant (or within any lesser period that the applicable grant,
this Plan, Regulations or any Law may require). No Option may be exercised after its stated expiration.




4.5.2.  Termination.




4.5.2.1.  a Participant ceases
to be an Eligible Person as a result of:


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4.5.2.1.1.  the termination
of the Participants appointment, employment or engagement by the Company (and/or its Affiliates) without Cause,




4.5.2.1.2.  the resignation
of the Participant, or




4.5.2.1.3.  the retirement of
the Participant,




each Option held by the Participant, to
the extent which it has vested on or prior to the Termination Date in accordance with the Option Agreement and this Plan, will cease to be exercisable
3 months after the Termination Date unless it expires sooner or unless otherwise determined by the Board.




4.5.2.2.  If a Participant
ceases to be an Eligible Person as a result of the termination of the Participants appointment, employment or engagement by the Company (and/or
its Affiliates) because of Cause, each Option held by the Participant, to the extent which it has vested and not expired on or prior to the Termination
Date in accordance with the Option Agreement and this Plan, will cease to be exercisable immediately upon the Companys (and/or an
Affiliates) giving of notice of termination, unless otherwise determined by the Board.




4.5.2.3.  Effective the
Termination Date, any portion of an Option that has not vested on or prior to the Termination Date will no longer be exercisable.




4.5.3.  Death or
Disability. If a Participant ceases to be an Eligible Person as a result of the Participants death or Disability, each Option held by the
Participant, to the extent which it has vested and not expired on or prior to the date of the Participants death or Disability in accordance with
the Option Agreement and this Plan, will cease to be exercisable 9 months after the Termination Date unless otherwise determined by the Board. Any
portion of a Participants Option that has not vested on or prior to the date of the Participants death or Disability will no longer be
exercisable.


|4.6. |  | Option Agreements
|---- |  | -----------------



Each Option must be confirmed, and will
be governed, by an Option Agreement signed by the Company and by the Participant, substantially in the form attached as Schedule 4.6 (Form of Option
Agreement).


|4.7. |  | Prohibition on Transfer of Options
|---- |  | ----------------------------------



Options are personal to the
Participant. No Participant may deal with an Option or any interest in it or Transfer an Option except in accordance with this Plan. A purported
Transfer of an Option in violation of this Plan will not be valid and the Company will not issue any Share upon the attempted exercise of that Option.
Subject to Law, the Board may establish rules, Regulations and procedures permitting the Transfer of Options in circumstances and on terms determined
by the Board. If Options have been granted to a Participants Subsidiary or a Consultants Consultant Entity and the related Subsidiary
ceases to be a Subsidiary or the related


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Consultant Entity ceases to so qualify, then the Participant will
be deemed to have Transferred any Option held by that entity to the entity, and that Transfer will be subject to the requirements and sanctions set out
in this section. Notwithstanding anything to the contrary in the Plan, Options cannot be Transferred other than by will or the laws of descent and
distribution and will be exercisable during a Participants lifetime only by the Participant




ARTICLE 5. EXERCISE OF OPTIONS


|5.1. |  | Method of Exercise of Option
|---- |  | ----------------------------



A Participant may exercise all or a
portion of an Option by delivering to the Company, to the address and person set out in section 10.1, a completed exercise form in the form attached as
Schedule 5.1 (Exercise Form) and, if exercised under section 5.2, accompanied by payment of the exercise price multiplied by the number of Shares to be
purchased.


|5.2. |  | Payment of Option Price
|---- |  | -----------------------



The purchase price of each Share
purchased under an Option must be paid in full at the time of exercise by bank draft, certified cheque or in any other manner permitted by the Board
and by Law. Upon receipt of payment in full, but subject to this Plan, the number of Shares in respect of which the Option is exercised will be issued
as fully paid and non-assessable.


|5.3. |  | Withholding of Tax
|---- |  | ------------------



5.3.1.  If the Company
determines that under the requirements of taxation Law it is obliged to withhold for remittance to a taxing authority any amount upon exercise of an
Option or the sale of Shares acquired on exercise of an Option, the Company may, prior to and as a condition of issuing the Shares or at any other
later date, (1) require the Participant exercising the Option to pay to the Company, in addition to and in the same manner as the exercise price for
the Shares, (2) withhold from any other amounts payable by the Company to the Participant or (3) transfer from the Participant to the Company Shares
issuable upon exercise of the Option having a Fair Value equal to, any amount that the Company is obliged to remit to that taxing authority in respect
of the exercise of the Option or the sale of the Shares acquired on exercise of the Option. Any additional payment will, in any event, be due no later
than the date as of which any amount with respect to the Option exercised must be included in the gross income of the Participant for tax
purposes.




5.3.2.  Promptly after a
Participant sells any Shares acquired on exercise of an Option, the Participant will notify the Company in writing of the date and terms of the sale
and will provide all other information regarding the sale as the Company may reasonably require.


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ARTICLE 6. SHARES


|6.1. |  | Shareholder Rights
|---- |  | ------------------



A Participant will not have any rights
as a shareholder of the Company with respect to any Shares subject to an Option until that Participant has exercised the Option and the Company has
issued Shares in accordance with the Plan.




ARTICLE 7. Reorganizations and
adjustments


|7.1. |  | Reorganization or Sale of the Company
|---- |  | -------------------------------------



If there is:




7.1.1.  a
Combination,




7.1.2.  the sale, lease,
transfer or other disposition of all or substantially all of the assets of the Company, or




7.1.3.  a reorganization or
liquidation of the Company,




the Board, or the board of directors of any entity assuming the
obligations of the Company, having regard to its fiduciary duties and the best interests of the Company, will, as to unexercised Options, upon written
notice to Participants, provide that: (a) all unvested Options of Executives will vest immediately; (b) all unexercised Options (both vested and
unvested) will terminate immediately prior to the consummation of the merger, consolidation, acquisition, reorganization, liquidation, sale or transfer
unless those Options which have vested are exercised by respective Participants within 30 days following the date of the notice.


|7.2. |  | Substitute Options upon Acquisition by the
Company
|---- |  | --------------------------------------------------



The Company may grant Options under the
Plan in substitution for options held by directors, officers or employees of or consultants to another entity who become Eligible Persons as a result
of a merger or consolidation of the other entity with the Company or an Affiliate, or as a result of the acquisition by the Company of property or
securities of the other entity. The Company may direct that substitute Options be granted on any terms and conditions that the Board considers
appropriate in the circumstances, subject to Law.


|7.3. |  | Capital Adjustments
|---- |  | -------------------



If there is any change in the
outstanding Shares by reason of a share dividend or split, recapitalization, consolidation, combination or exchange of shares, special dividend or
other fundamental corporate change, other than the issuance of Shares by the Company for consideration, the Board will, subject to Law, make a
substitution or adjustment in




7.3.1.  the exercise price of
any unexercised Options;


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7.3.2.  the maximum number
and/or class of securities of the Company reserved for issuance under this Plan; or




7.3.3.  the number and/or
class of securities of the Company subject to unexercised Options previously granted,




as the Board determines is appropriate in the
circumstances.




ARTICLE 8. Employment and
Compensation


|8.1. |  | No Special Employment Rights
|---- |  | ----------------------------



Nothing contained in the Plan or in any
Option will confer upon any Participant any right with respect to the continuation of the Participants appointment, employment or engagement by
the Company or interfere in any way with the right of the Company at any time to terminate or change any terms of that appointment, employment or
engagement including any increase or decrease in the compensation of the Participant.


|8.2. |  | Other Employee Benefits
|---- |  | -----------------------



The amount of any compensation deemed
to be received by a Participant as a result of the exercise of an Option or the sale of Shares received upon an exercise of an Option will not
constitute compensation for the purpose of determining any other employee benefits of that Participant, including benefits under any bonus, pension,
profit-sharing, life insurance or salary continuation plan, except as otherwise specifically determined by the Board.


|8.3. |  | Non-Exclusivity
|---- |  | ---------------



Nothing contained in this Plan will
prevent the Board from adopting other or additional compensation arrangements for the benefit of any Participant or other Eligible Person, subject to
Law.




ARTICLE 9. Amendments


|9.1. |  | Amendment or Termination Without
Consent
|---- |  | ----------------------------------------



9.1.1.  The Board may amend,
suspend or terminate this Plan or any portion of it at any time in accordance with Law, provided that no amendment, suspension or termination may,
without the consent of the affected Participant or except as otherwise provided in the Plan, impair any Option, or any right under an Option,
previously granted to any Participant.




9.1.2.  If this Plan is
terminated, the provisions of this Plan, the Regulations and any administrative guidelines and other rules adopted by the Board and in force when this
Plan is terminated will continue in effect as long as any Option, or any right under an Option, remains outstanding. However, notwithstanding the
termination of this Plan, the


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Board may make any amendments to this
Plan, or to any outstanding Option, that it would be entitled to make if this Plan were still in effect.


|9.2. |  | Amendment With Individual Consent
|---- |  | ---------------------------------



With the consent of the affected
Participant, the Board may amend any outstanding Option in any manner to the extent that the Board would have had the initial authority to grant the
Option as so modified or amended, including to change the date or the price at which an Option becomes exercisable, subject to Law.




ARTICLE 10. GENERAL MATTERS


|10.1. |  | Notices
|----- |  | -------



Any notice or other communication
required or permitted to be given under this Plan will be in writing and will be given by prepaid first-class mail, by electronic mail or by
hand-delivery as provided below. Any notice or other communication, if mailed by prepaid first-class mail at any time other than during a general
discontinuance of postal service due to strike, lockout or otherwise, will be deemed to have been received on the fourth Business Day after the
post-marked date, or if sent by electronic mail, will be deemed to have been received on the Business Day following the sending, or if delivered by
hand will be deemed to have been received on the day on which it is delivered to the applicable address noted below either to the individual designated
below or to an individual at that address having apparent authority to accept deliveries on behalf of the addressee. Notice of change of address will
also be governed by this section. Notices and other communications will be addressed, if to the Company, to the head office of the Company, attention:
Corporate Secretary and, if to a Participant, at the last address which appears on the records of the Company.


|10.1. |  | Submission to Jurisdiction
|----- |  | --------------------------



The Company and each Participant
irrevocably submit to the non-exclusive jurisdiction of the courts of Ontario in respect of all matters relating to this Plan and any Option
Agreement.


|10.1. |  | Language of Plan
|----- |  | ----------------



The parties to this Plan have expressly
agreed that this Plan and related documents be drawn in the English language. Les parties aux présentes ont expressément convenu que le
présent plan et tous les documents y afférents soient rédigés en langue anglaise.


|10.1. |  | Further Assurances
|----- |  | ------------------



Each Participant will promptly do,
make, execute or deliver, or cause to be done, made, executed or delivered, all further acts, documents and things as the Company may reasonably
require from time to time for the purpose of giving effect to this Plan and will use


---



-11-




reasonable efforts and take all steps as may be reasonably within
the Participants power to implement to their full extent the provisions of this Plan.


---





SCHEDULE 1.2.1




Definitions


|1. |  | Affiliate has the meaning given to that term
in OSC Rule 45-105.
|-- |  | ------------------------------------------------------------------

|2. |  | Associate has the meaning given to that term
in the Securities Act (Ontario).
|-- |  | -------------------------------------------------------------------------------

|3. |  | Board means the board of directors of the
Company or a committee of the board of directors appointed to administer the Plan.
|-- |  | ------------------------------------------------------------------------------------------------------------------------------

|4. |  | Business Day means any day, other than
Saturday, Sunday or any statutory holiday in the Province of Ontario.
|-- |  | --------------------------------------------------------------------------------------------------------------

|5. |  | Cause, in respect of a Participant,
either
|-- |  | --------------------------------------------

|5.1. |  | has the meaning given to that term in any written employment or
consulting agreement between the Company or an Affiliate and the Participant or in any written employment policy or manual of the Company or an
Affiliate applicable to the Participant, or
|---- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|5.2. |  | if there is no written definition of this term applicable to the
Participant, means (1) the wilful failure of the Participant to properly carry out the Participants duties and responsibilities or to adhere to
the polices of the Company or its Affiliates after notice by the Company (or an Affiliate) of the failure to do so and an opportunity for the
Participant to correct the failure within a reasonable period from the date of receipt of that notice, (2) fraud, theft, dishonesty or wilful
misconduct by, or the gross incompetence of, the Participant involving the property, business or affairs of the Company or its Affiliates or the
carrying out of the Participants duties, as determined in good faith by the Company and (3) any other conduct that would constitute cause as that
term is interpreted by the courts of the Province of Ontario from time to time.
|---- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|6. |  | Combination means any acquisition of the
Company by means of any transaction or series of related transactions, including any consolidation, merger, amalgamation or similar form of corporate
reorganization, (1) in which the outstanding shares of the Company are exchanged for securities or other consideration issued, delivered or caused to
be issued or delivered, by the acquiring Person, its subsidiary or other Person and (2) under which the holders of the outstanding voting securities of
the Company immediately prior to the transaction fail to hold, directly or indirectly, equity securities representing a majority of the voting power of
the Company or surviving entity or its parent immediately following the transaction in substantially the same proportions as their ownership of the
voting power of the equity securities of the Company immediately prior to the transaction.
|-- |  | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|7. |  | Company means Lorus Therapeutics Inc., and
includes any successor company.
|-- |  | ----------------------------------------------------------------------------

SCHEDULE 1.2.1
- Page i

---

|8. |  | Consultant has the meaning given to that term
in OSC Rule 45-105 and excludes an individual whose services are in connection with the offer or sale or securities of the Company in a capital raising
transaction.
|-- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|9. |  | Consultant Entity means, for an individual
Consultant, a company of which the individual Consultant is an employee or shareholder or a partnership of which the individual Consultant is an
employee or partner.
|-- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|10. |  | Control (or Controlled) has the
meaning given to that term in OSC Rule 45-105.
|--- |  | ----------------------------------------------------------------------------------

|11. |  | Disability, in respect of a Participant,
either
|--- |  | -------------------------------------------------

|11.1. |  | has the meaning given to that term in any written employment or
consulting agreement between the Company or an Affiliate and the Participant or in any written employment policy or manual of the Company or an
Affiliate applicable to the Participant, or
|----- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|11.2. |  | if there is no written definition of this term applicable to the
Participant, means, subject to applicable human rights law, the mental or physical state of the Participant resulting in the Participant being unable
as a result of illness, disease, mental or physical disability or similar cause, as determined by a legally qualified medical practitioner selected by
the Company, to fulfil the Participants obligations to the Company or an Affiliate for any consecutive 180-day period or for any period of 180
days (whether or not consecutive) in any consecutive 365-day period.
|----- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|12. |  | Eligible Person, subject to the Regulations
and to Law, means (1) any Executive or Employee (including any of those persons who are on a leave of absence authorized by the board of directors of
the Company or of any Affiliate), (2) any Subsidiary of an Executive or Employee, (3) any Consultant or Consultant Entity or (4) any RRSP or RRIF
established by or for an Executive, Employee or Consultant or under which the Executive, Employee or Consultant is a beneficiary.
|--- |  | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|13. |  | Employee has the meaning given to that term
in in Schedule 1.2.2.
|--- |  | -------------------------------------------------------------------

|14. |  | Entity means any partnership, limited
partnership, joint venture, syndicate, company or corporation with or without share capital, unincorporated association, trust or other entity however
designated or constituted.
|--- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|15. |  | Executive has the meaning given to that term
in Schedule 1.2.2.
|--- |  | -----------------------------------------------------------------

|16. |  | Fair Value has the meaning given to that term
in section 3.1.
|--- |  | ---------------------------------------------------------------

|17. |  | including means including without
limitation.
|--- |  | -----------------------------------------------

|18. |  | Insider has the meaning given to the term
insider in the TSX Rules.
|--- |  | -----------------------------------------------------------------------

SCHEDULE 1.2.1
- Page ii

---

|19. |  | Law means all applicable law including all
applicable securities laws and the rules applicable to any stock exchange or quotation system on which the Shares are listed or quoted or on which the
Company wishes to list or quote its shares (including any required prior regulatory approval or shareholder consent).
|--- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|20. |  | Option means a right granted to an Eligible
Person to purchase Shares on the terms of this Plan.
|--- |  | --------------------------------------------------------------------------------------------------

|21. |  | Option Agreement means an agreement signed by
the Company and by a Participant with respect to a granted Option, as contemplated by section 4.6.
|--- |  | --------------------------------------------------------------------------------------------------------------------------------------------------

|22. |  | OSC Rule 45-105 means Ontario Securities
Commission Rule 45-105  Trades to Employees, Senior Officers, Directors and Consultants, as that rule may be amended, renumbered or reclassified
from time to time, and any successor to that rule.
|--- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|23. |  | Outstanding Issue has the meaning given to
the term outstanding issue in the TSX Rules.
|--- |  | -------------------------------------------------------------------------------------------

|24. |  | Participant means an Eligible Person to whom
an Option has been granted, and, as appropriate with respect to each individual Participant (including in calculating holdings of a Participant or
addressing termination of a Participant), also includes an RRSP, RRIF, Subsidiary or Consultant Entity related to that Participant.
|--- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|25. |  | Person means any individual, partnership,
limited partnership, joint venture, syndicate, sole proprietorship, company or corporation with or without share capital, unincorporated association,
trust, trustee, executor, administrator or other legal personal representative, regulatory body or agency, government or governmental agency, authority
or entity however designated or constituted.
|--- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|26. |  | Plan means this 2003 Share Option Plan of the
Company and all schedules attached to this Plan, in each case as they may be amended or supplemented from time to time, and unless otherwise indicated,
references to Articles, sections and Schedules are to the specified Articles, sections and Schedules in this Plan.
|--- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|27. |  | Previous Stock Option Plan means the stock
option plan of the Company established June 3, 1993, as amended. Issuances of options under this stock option plan ceased November 20,
2003.
|--- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|28. |  | Regulations means the regulations set out in
Schedule 2.2.5 (Regulations) made under this Plan, as they may be amended from time to time in accordance with the Plan.
|--- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------

|29. |  | RRIF means a registered retirement income
fund.
|--- |  | -------------------------------------------------

|30. |  | RRSP means a registered retirement savings
plan.
|--- |  | --------------------------------------------------

SCHEDULE 1.2.1
- Page iii

---

|31. |  | Share means a common share of the Company and
includes any class of securities into which the common shares of the Company as a whole class may be subsequently reclassified, converted or
exchanged.
|--- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|32. |  | Share Compensation Arrangement has the
meaning given to the term share compensation arrangement in the TSX Rules.
|--- |  | ---------------------------------------------------------------------------------------------------------------------

|33. |  | Stock Market means each stock exchange or
quotation system on which the Shares are listed or quoted and, in respect of any calculation or determination to be made under this Plan, means one
which is selected by the Board for the purposes of the calculation or determination, generally on the basis of volume of trading or other measure as to
the accuracy of the trading history. If the Shares are listed on the TSX, then Stock Market will mean the TSX for the purpose of any
calculation or determination, unless the trading volume of the Shares is materially higher on another stock exchange or quotation system.
|--- |  | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|34. |  | Stock Option has the meaning given to the
term stock option in the TSX Rules.
|--- |  | ---------------------------------------------------------------------------------

|35. |  | Subsidiary has the meaning given to that term
in Business Corporation Act (Ontario).
|--- |  | --------------------------------------------------------------------------------------

|36. |  | Termination Date means the date on which a
Participant ceases to be an Eligible Person in accordance with the Plan.
|--- |  | ---------------------------------------------------------------------------------------------------------------------

|37. |  | Transfer includes any sale, exchange,
assignment, gift, bequest, disposition, mortgage, hypothecate, charge, pledge, encumbrance, grant of security interest or other arrangement by which
possession, legal title, beneficial ownership or the right to receive proceeds or benefits of or from the subject matter passes from one Person to
another, or to the same Person in a different capacity, whether or not voluntary and whether or not for value, and any agreement to effect any of the
foregoing, and the words Transferred, Transferring and similar words have corresponding meanings.
|--- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|38. |  | TSX means the Toronto Stock
Exchange.
|--- |  | ---------------------------------------

|39. |  | TSX Rules means the rules of the Toronto
Stock Exchange Company Manual relating to changes in capital structure of listed companies in connection with employee stock option and stock purchase
plans, options for services, and related matters (currently sections 626 to 637.3), as those rules may be amended, renumbered or reclassified from time
to time, or any successors.
|--- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

SCHEDULE 1.2.1
- Page iv

---



SCHEDULE 1.2.2




Incorporated Definitions




The definitions in this schedule have
been substantially reproduced from the statutory, regulatory or other material in force as of October 9, 2003 and from which they have been
incorporated. This Schedule will be deemed to be updated from time to time, as applicable, as that material is updated, and a replacement version will
be distributed to Participants as soon as practicable after.


|1. |  | A person or company is considered to be an affiliated
entity of another person or company if one is a subsidiary entity of the other or if both are subsidiary entities of the same person or company, or
if each of them is controlled by the same person or company.
|-- |  | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2. |  | associate, where used to indicate a
relationship with any person or company means,
|-- |  | ------------------------------------------------------------------------------------

|2.1. |  | any company of which such person or company beneficially owns,
directly or indirectly, voting securities carrying more than 10 per cent of the voting rights attached to all voting securities of the company for the
time being outstanding,
|---- |  | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2.2. |  | any partner of that person or company,
|---- |  | --------------------------------------

|2.3. |  | any trust or estate in which such person or company has a
substantial beneficial interest or as to which such person or company serves as trustee or in a similar capacity,
|---- |  | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2.4. |  | any relative of that person who resides in the same home as that
person,
|---- |  | ------------------------------------------------------------------------

|2.5. |  | any person who resides in the same home as that person and to
whom that person is married, or any person of the opposite sex or the same sex who resides in the same home as that person and with whom that person is
living in a conjugal relationship outside marriage, or
|---- |  | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2.6. |  | any relative of a person mentioned in clause 2.5 who has the
same home as that person.
|---- |  | --------------------------------------------------------------------------------------

|3. |  | a person or company is considered to be controlled by a
person or company if
|-- |  | ----------------------------------------------------------------------------

|3.1. |  | in the case of a person or company
|---- |  | ----------------------------------

|3.1.1. |  | voting securities of the first-mentioned person or company
carrying more than 50 percent of the votes for the election of directors are held, otherwise than by way of security only, by or for the benefit of the
other person or company, and
|------ |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|3.1.2. |  | the votes carried by the securities are entitled, if exercised,
to elect a majority of the directors of the first-mentioned person or company;
|------ |  | ----------------------------------------------------------------------------------------------------------------------------------------------

SCHEDULE 1.2.2
- Page i

---

|3.2. |  | in the case of a partnership that does not have directors, other
than a limited partnership, the second-mentioned person or company holds more than 50 percent of the interests in the partnership; or
|---- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|3.3. |  | in the case of a limited partnership, the general partner is the
second-mentioned person or company.
|---- |  | ----------------------------------------------------------------------------------------------------

|4. |  | consultant means, for an issuer, an
individual, other than an employee or an executive of the issuer, that (1) is engaged to provide on a bona fide basis consulting, technical, management
or other services to the issuer or to an affiliated entity of the issuer under a written contract between the issuer or the affiliated entity and the
individual or a consultant company or consultant partnership of the individual, and (2) in the reasonable opinion of the issuer, spends or will spend a
significant amount of time and attention on the affairs and business of the issuer or an affiliated entity of the issuer.
|-- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|5. |  | employee means, for an issuer, an employee of
the issuer or of an affiliated entity of the issuer, other than an executive of the issuer.
|-- |  | -------------------------------------------------------------------------------------------------------------------------------------------

|6. |  | executive means, for an issuer, an
issuer-officer or an issuer-director.
|-- |  | --------------------------------------------------------------------------

|7. |  | incentive means a compensation or incentive
arrangement for an executive.
|-- |  | ---------------------------------------------------------------------------

|8. |  | incentive plan means a plan providing for
incentives.
|-- |  | -------------------------------------------------------

|9. |  | insider of a listed company
means:
|-- |  | ------------------------------------

|9.1. |  | an insider as defined in the Securities Act (Ontario),
other than a person who falls within that definition solely by virtue of being a director or senior officer of a subsidiary of the listed company,
and
|---- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|9.2. |  | an associate of any person who is an insider by virtue of
9.1.
|---- |  | --------------------------------------------------------------

|10. |  | outstanding issue means the number of shares
of the applicable class outstanding on a non-diluted basis, subject to any applicable adjustments provided for in Sections 628 to 630 of the TSX
Rules.
|--- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|11. |  | related person, for an issuer, means (1) a
director or senior officer of the issuer or (2) an associate of a director or senior officer of the issuer.
|--- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------

|12. |  | share compensation arrangement means a stock
option, stock option plan, employee stock purchase plan or any other compensation or incentive mechanism involving the issuance or potential issuance
of shares to one or more service providers, including a share purchase from treasury which is financially assisted by the company by way of a loan,
guaranty or otherwise.
|--- |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

SCHEDULE 1.2.2
- Page ii

---

|13. |  | stock option means an option to purchase
shares from treasury granted to a service provider as a compensation or incentive mechanism.
|--- |  | ---------------------------------------------------------------------------------------------------------------------------------------

|14. |  | a person or company is considered to be a subsidiary
entity of another person or company if
|--- |  | -------------------------------------------------------------------------------------------

|14.1. |  | it is controlled by
|----- |  | -------------------

|14.1.1. |  | that other, or
|------- |  | --------------

|14.1.2. |  | that other and one or more persons or companies, each of which
is controlled by that other, or
|------- |  | ----------------------------------------------------------------------------------------------

|14.1.3. |  | two or more persons or companies, each of which is controlled by
that other; or
|------- |  | -------------------------------------------------------------------------------

|14.2. |  | it is a subsidiary entity of a person or company that is that
others subsidiary entity.
|----- |  | ----------------------------------------------------------------------------------------

SCHEDULE 1.2.2
- Page iii

---



SCHEDULE 2.2.5




Regulations


|1. |  | Subject to the Law and upon notice to the Company, a Participant
may Transfer Options, or Shares received under the exercise of Options, to any RRSP or RRIF established by or for the Participant or under which the
Participant is a beneficiary. Upon death of a Participant, the Participants Option(s) will become part of the Participants estate, and any
right of the Participant may be exercised by the former Participants legal representatives, provided the legal representatives comply with all
obligations of the former Participant.
|-- |  | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2. |  | A Participant who is an Executive or Employee will cease to be
an Eligible Person on the earliest of:
|-- |  | -----------------------------------------------------------------------------------------------------

|2.1. |  | the end of the notice period, if the Company gives the
Participant notice of termination of appointment and/or employment or the Participant gives the Company notice of resignation and the Participant
continues to hold the appointment and/or work during the notice period,
|---- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2.2. |  | the date on which the Company gives the Participant notice of
termination of appointment and/or employment (with or without Cause), if the Participant does not continue to hold the appointment and/or work during
the notice period, and, for greater certainty, will not include any period of statutory or common law notice or severance,
|---- |  | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2.3. |  | the date on which the Participant gives the Company notice of
resignation, if the Participant does not continue to hold the appointment and/or work during the notice period,
|---- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|2.4. |  | the date of the Participants retirement,
|---- |  | -----------------------------------------

|2.5. |  | the date of the Participants death,
|---- |  | ------------------------------------

|2.6. |  | the date of the Participants Disability,
|---- |  | -----------------------------------------

|2.7. |  | the date on which the Participant otherwise fails to meet the
criteria set out under the definition of an Eligible Person, and
|---- |  | ------------------------------------------------------------------------------------------------------------------------------

|2.8. |  | in any other case, the actual date on which both the Participant
and the Company had actual notice that the Participants appointment and/or employment would cease on a particular date.
|---- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



For greater certainty, the above dates
will apply whether or not the Participant receives any payment in lieu of notice. For greater certainty, if, as a result of one or more of the events
listed above, a Participant no longer qualifies or will no longer qualify as an Eligible Person in one category but will remain an Eligible Person
under another category, then the Participant will remain an Eligible Person.


SCHEDULE 2.2.5
- Page i

---

|3. |  | The date of a Participants Disability will be the last day
of the applicable period during which the Participant is unable to fulfil the Participants obligations to the Company.
|-- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|4. |  | A Participant who is a Consultant will cease to be an Eligible
Person on the earliest of:
|-- |  | -----------------------------------------------------------------------------------------

|4.1. |  | the completion or substantial performance of the
Consultants engagement in accordance with the terms of the written contract,
|---- |  | ------------------------------------------------------------------------------------------------------------------------------

|4.2. |  | the expiration of the Consultants written
contract,
|---- |  | ----------------------------------------------------

|4.3. |  | the notice of termination by the Company of the contract whether
with or without Cause, or
|---- |  | ------------------------------------------------------------------------------------------

|4.4. |  | the services of any key individual referred to in the Consultant
Entitys contract no longer being available to the Company as required under the contract.
|---- |  | -----------------------------------------------------------------------------------------------------------------------------------------------------------

|5. |  | If the legal representative of a Participant who has died or has
a Disability purports to exercise any Options of the Participant, the Company will have no obligation to issue the Shares until evidence satisfactory
to the Company has been provided that the legal representative is entitled to exercise the Options.
|-- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

SCHEDULE 2.2.5
- Page ii

---



SCHEDULE 4.6




Form of Option Agreement




LORUS THERAPEUTICS INC. 2003 SHARE OPTION
PLAN




 [DATE]




PERSONAL & CONFIDENTIAL




 [NAME]




 [ADDRESS]




Dear  [NAME]:




Grant of Option




I am very pleased to advise you that
the Board of Directors of Lorus Therapeutics Inc. (the Company) has granted to you an option (the Option) to purchase common
shares (the Shares) of the Company. This Option was granted on the basis set out in this letter, and is subject to the 2003 Share Option
Plan of the Company (the Plan), a copy of which is enclosed. This letter and the Plan are referred to collectively as the Option
Documents. All capitalized terms not otherwise defined in this letter have the meanings given to them in the Plan.


|Date of grant of
Option:                             |  |  |  | ___________________________________ 
|---------------------------------------------------- |  |  |  | ------------------------------------
|                                                     |  |  |  |                                     
|The total number
of Shares subject to thisOption is: |  |  |  | ___________________________________ 
|                                                     |  |  |  |                                     
|The exercise
price of this Option is:                |  |  |  | $___________________________________



Vesting of Options




Your Options will vest or
become exercisable




in accordance with the table set out
below. Provided that you are an Eligible Person and have been an Eligible Person throughout the time period set out in Column 1, the number of Options
set out in Column 2 will vest at 11:59 p.m. on the last day of that time period. The number of Options you may exercise at any time (prior to the
expiry date set out below) will be equal to the total number of Options which have vested, less any Options which you have exercised or which have
expired in accordance with the Option Documents.


SCHEDULE 4.6
- Page i

---



|Column
1                      |  |  |  | Column 2                                           
|----------------------------- |  |  |  | ---------------------------------------------------
|Time
Period                   |  |  |  | Number of
Options vesting followingthat time period
|____________ to
_____________ |  |  |  | ____________________                               
|____________ to
_____________ |  |  |  | ____________________                               
|____________ to
_____________ |  |  |  | ____________________                               



 [OTHER CONDITIONS APPLICABLE TO
VESTING, SUCH AS ATTAINING CERTAIN PERFORMANCE GOALS]




Expiry of Option




Subject to earlier expiration in
accordance with the Option Documents, your rights to purchase Shares under this Option will expire at 11:59 p.m. on:









Exercise of Option




This Option may be exercised in whole
or in part in respect of the vested portion of the Option at any time prior to expiry of the Option by delivery of written notice in a form attached to
the Plan to the address and person set out in the Plan by exercising all or part of the vested portion of the Option for a number of Shares specified
to be purchased and enclosing payment by bank draft or certified cheque of the total purchase price of the Shares.




This Option may not be exercised or
surrendered in respect of amounts of less than 100 Shares in the case of any one exercise unless that exercise would exhaust the
Option.




Tax Consequences




Receiving a grant of an Option,
exercising an Option and selling Shares received upon exercise of an Option may all result in tax consequences, which will differ depending on your
jurisdiction of residence. The Company may impose requirements in relation to your exercise of an Option or subsequent sale of Shares issued upon
exercise of an Option, to ensure compliance with taxation laws related to withholdings and remittances. You are strongly urged to consult your tax
advisor as to the various tax consequences.




Options and Your Service to the Company




Nothing in the Option Documents will
affect the right of the Company to terminate your services, responsibilities or duties to the Company and its Affiliates at any time


SCHEDULE 4.6
- Page ii

---



for any reason. Regardless of the reason for your termination,
your rights to exercise this Option will be restricted to those rights which have vested and not expired on or prior to your Termination Date and, in
any claim for wrongful dismissal, no consideration will be given to any Options that might have vested during an appropriate notice period, all as
described in the Plan. As set out the Plan, your participation in the Plan and any purchase of Shares upon exercise of an Option is voluntary, and
neither the participation nor any purchase will have any effect, positively or negatively, on your appointment, employment or engagement by the
Company.




No Transfers




This Option is personal to you alone
and may not be sold or Transferred in any way, except as described in the Plan.




Decisions of Board Binding




All decisions made by the Board of
Directors with regard to any questions arising in connection with the Option Documents, whether of interpretation or otherwise, will be final and
binding on all parties.




Acceptance of Option




Please indicate acceptance of this
agreement by signing where indicated below on the enclosed copy of this letter and returning the signed copies to the Company to the attention of
Corporate Secretary.


SCHEDULE 4.6
- Page iii

---

|By signing and delivering this agreement, you are acknowledging
receipt of copies of the Plan and having been provided with an opportunity to consider the Plan and to seek independent legal advice with respect to
them, and are agreeing to be bound by all terms of this letter and the Plan.
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



Yours truly,




LORUS THERAPEUTICS
INC.


|By: |  | 
|--- |  | 



I have
read and agree to be bound by this letter and the Plan.


|Signature:           |  |  |  | ___________________________________
|-------------------- |  |  |  | -----------------------------------
|Name
(print):        |  |  |  | ___________________________________
|Address:             |  |  |  | ___________________________________
|                     |  |  |  | ___________________________________
|Date:                |  |  |  | ___________________________________
|Witness
Signature:   |  |  |  | ___________________________________
|Witness Name
print): |  |  |  | ___________________________________

SCHEDULE 4.6
- Page iv

---



SCHEDULE 5.1




Exercise Form




LORUS THERAPEUTICS INC. 2003 SHARE OPTION
PLAN




SHARE OPTION EXERCISE AND SUBSCRIPTION
FORM


|TO: |  | Lorus Therapeutics Inc. (the Company) 2 Meridian
Road Toronto, Ontario M9W 4Z7 Attention:        Corporate Secretary
|--- |  | ----------------------------------------------------------------------------------------------------------------------

|RE: |  | Share Option Exercise under the 2003 Share Option Plan of the
Company
|--- |  | ---------------------------------------------------------------------








Under an option agreement dated
, I was granted an option (the
Option) to purchase a total of  Shares. At this date, a portion of the Option has
vested entitling me to purchase  Shares, of which I have already purchased
 Shares in total under one or more prior exercise and subscription forms.




I give notice that I wish
to:


|[ ] |  | under section 5.1 of the Plan, exercise the vested portion of my
Option to purchase  Shares at the price of $  per Share, and I
hereby subscribe for that number of Shares at that price, enclose payment for those Shares in full by bank draft or certified cheque in the total
amount of $  and direct that
|--- |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|[ ] |  | a certificate representing the subscribed Shares be delivered to
me at the address set out below;
|--- |  | -------------------------------------------------------------------------------------------------

|[ ] |  | a certificate representing the subscribed Shares be delivered to
me at my office; or
|--- |  | ------------------------------------------------------------------------------------

|[ ] |  | the subscribed Shares be deposited directly into my broker
account (see account details below), and I hereby authorize Computershare Trust Company of Canada, or such other registrar and transfer agent as the
Company may appoint from time to time;
|--- |  | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



or


| |  | I am resident at the address set out below; and
|- |  | -----------------------------------------------

| |  | I have received copies of the Plan and the Option Agreement and
am agreeing to be bound by all terms of those agreements.
|- |  | -------------------------------------------------------------------------------------------------------------------------

SCHEDULE 5.1
- Page 5

---



All capitalized terms used in this
exercise and subscription form and not otherwise defined have the meanings given to them in the Plan.


|Signature:              |  |  |  | ___________________________________
|----------------------- |  |  |  | -----------------------------------
|Name
(print):           |  |  |  | ___________________________________
|Address:                |  |  |  | ___________________________________
|                        |  |  |  | ___________________________________
|Date:                   |  |  |  | ___________________________________
|Broker
account details: |  |  |  | ___________________________________
|                        |  |  |  | ___________________________________

SCHEDULE 5.1
- Page 6

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