<PAGE>
                                                                   EXHIBIT 10.16


                            ALLOS THERAPEUTICS, INC.
                            EMPLOYMENT AGREEMENT FOR
                                 MICHAEL E. HART

THIS EMPLOYMENT AGREEMENT (the "Agreement") is made as of this 17th day of
December, 2001, by and between ALLOS THERAPEUTICS, INC., (the "Company"), and
MICHAEL E. HART ("Executive") (collectively, the "Parties").

WHEREAS, Executive is critical to the ongoing operation of the Company and the
commercialization of the Company's products; and

WHEREAS, the Company wishes to continue to employ Executive and to assure itself
of the continued services of Executive in his new assignment as President and
Chief Executive Officer, on the terms set forth herein;

WHEREAS, Executive is currently serving the Company under the terms of that
certain Employment Agreement, dated January 17, 2001, by and between the
Executive and the Company (the "Prior Agreement"); and

WHEREAS, Executive and the Company desire to terminate the Prior Agreement and
Executive wishes to be so employed under the terms set forth herein.

NOW, THEREFORE, in consideration of the promises, mutual covenants, the above
recitals, and the agreements herein set forth, and for other good and valuable
consideration, the sufficiency of which is hereby acknowledged, the Parties
agree to the following terms and conditions of the Executive's employment:

1. EMPLOYMENT. The Company hereby agrees to employ Executive as President and
Chief Executive Officer and Executive hereby accepts such employment upon the
terms and conditions set forth herein as of the date first written above.

2. TERMINATION OF PRIOR AGREEMENT. Executive and the Company hereby agree to
terminate the Prior Agreement in its entirety pursuant to Section 14(b) thereof.

3. AT-WILL EMPLOYMENT. It is understood and agreed by the Company and Executive
that this Agreement does not contain any promise or representation concerning
the duration of Executive's employment with the Company. Executive specifically
acknowledges that his employment with the Company is at-will and may be altered
or terminated by either Executive or the Company at any time, with or without
cause and/or with or without notice. The nature, terms or conditions of
Executive's employment with the Company cannot be changed by any oral
representation, custom, habit or practice, or any other writing. In addition,
that the rate of salary, any bonuses, paid time off, other compensation, or
vesting schedules are stated in units of years or months does not alter the
at-will nature of the employment, and does not mean and should not be
interpreted to mean that Executive is guaranteed employment to the end of any
period of time or for any period of time. In the event of conflict between this
disclaimer and any other statement, oral or written, present or future,
concerning terms and conditions of employment, the at-will relationship
confirmed by this disclaimer shall control. This at-will status cannot be
altered except in writing signed by Executive and the Chairman of the Board of
Directors.



                                       1
<PAGE>

4. DUTIES. Executive shall render full-time services to the Company as its
President and Chief Executive Officer. Executive shall devote his best efforts
and his full business time, skill and attention to the performance of his duties
on behalf of the Company.

5. POLICIES AND PROCEDURES. Executive agrees that he is subject to and will
comply with the policies and procedures of the Company, as such policies and
procedures may be modified, added to or eliminated from time to time at the sole
discretion of the Company, except to the extent any such policy or procedure
specifically conflicts with the express terms of this Agreement. Executive
further agrees and acknowledges that any written or oral policies and procedures
of the Company do not constitute contracts between the Company and Executive.

6. COMPENSATION. For all services rendered and to be rendered hereunder, the
Company agrees to pay to the Executive, and the Executive agrees to accept a
base salary of $300,000 per annum. Any such salary shall be payable in equal
biweekly installments and shall be subject to such deductions or withholdings as
the Company is required to make pursuant to law, or by further agreement with
the Executive. The Board of Directors may adjust the Executive's compensation
from time to time in its sole and complete discretion.

7. BONUS. Executive will be eligible for a discretionary bonus in an amount
equal to 35 % of Executive's base salary ("Bonus"). The decision to award the
Bonus and/or to modify the amount of any bonus given is within the sole and
complete discretion of the Board.

8. STOCK OPTIONS.

         (a) The Executive will receive an option to purchase 100,000 shares of
         the Company's Common Stock under the Company's 2000 Equity Incentive
         Plan (the "Plan") at an exercise price equal to the closing sale price
         of the Company's Common Stock as reported on the Nasdaq National Market
         on the date approved by the Compensation Committee of the Board of
         Directors. Such option will be subject to the terms and conditions of
         the Plan and will vest in accordance with the Company's standard
         vesting schedule.

         (b) If and when the Company's 2001 Broad Based Equity Incentive Plan
         (the "Broad Based Plan") is adopted by the Board of Directors, the
         Executive will receive an option to purchase 250,000 shares of the
         Company's Common Stock under the Broad Based Plan at an exercise price
         equal to the then current fair market value of the Company's Common
         Stock as reported on the Nasdaq National Market. Such option will be
         subject to terms and conditions of the Broad Based Plan and will vest
         in accordance with the Company's standard vesting schedule.



                                       2
<PAGE>

(c) If the Broad Based Plan is not adopted by the Board of Directors, then at
the next annual meeting of the Company's stockholders the Company shall seek
approval from the Company's stockholders for an increase in the number of shares
reserved under the plan of at least 250,000 shares; upon such approval, the
Company shall grant Executive an option to purchase 250,000 shares of the
Company's Common Stock under the Plan with an exercise price equal to the then
current fair market value as reported on the NASDAQ National Market and such
option shall vest in accordance with the Company's standard vesting schedule,
provided however, that the Vesting Commencement Date for such option shall be
the date hereof;

(d) If the Broad Based Plan is not adopted by the Board of the Directors and the
stockholders of the Company do not approve an increase in the Plan as set forth
in Section 8(c) hereof, the Executive will be entitled to receive (i) two (2)
additional grants under the Plan of 125,000 shares of the Company's Common Stock
each to occur on December 17, 2002 and December 17, 2003 with exercise
prices equal to the then current fair market values as reported on the NASDAQ
National Market on such dates and such options shall vest in accordance with the
Company's standard vesting schedule, provided however, that the Vesting
Commencement Date of each such option shall be the date hereof; or (ii) such
other alternative compensation that the Executive and the Company may agree
upon.

9. OTHER BENEFITS. While employed by the Company as provided herein:

         (a) Executive and Employee Benefits. The Executive shall be entitled to
         all benefits to which other executive officers of the Company are
         entitled, on terms comparable thereto, including, without limitation,
         participation in the 401(k) plan, group insurance policies and plans,
         medical, health, vision, and disability insurance policies and plans,
         and the like, which may be maintained by the Company for the benefit of
         its executives. The Company reserves the right to alter and amend the
         benefits received by Executive from time to time at the Company's
         discretion.

         (b) Additional Insurance. Subject to such insurance being available
         under the Company's plans, the Executive shall be entitled to and the
         Company shall pay for additional term life insurance up to a maximum of
         $3,000,000 (the beneficiary of which will be the Executive's immediate
         family directly or through a trust) and additional supplemental
         disability insurance up to the maximum available under the Company's
         plans.

         (c) Expense Reimbursement. The Executive shall receive, against
         presentation of proper receipts and vouchers, reimbursement for direct
         and reasonable out-of-pocket expenses incurred by him in connection
         with the performance of his duties hereunder, according to the policies
         of the Company.

         (d) Personal Time Off. The Executive shall be entitled to personal time
         off and sick leave according to the Company's benefits package.

         10. PROPRIETARY AND OTHER OBLIGATIONS. Executive agrees to continue to
         abide by Executive's previously executed Non-Competition, Proprietary
         Information and Inventions Agreement attached hereto as Exhibit A.

         11. TERMINATION. Executive and the Company each acknowledge that either
         party has the right to terminate Executive's employment with the
         Company at any time for any reason whatsoever, with or without cause or
         advance notice pursuant to the following:



                                       3
<PAGE>

         (a) Termination by Death or Disability. Subject to applicable state or
         federal law, in the event Executive shall die during the period of his
         employment hereunder or become permanently disabled, as evidenced by
         notice to the Company and Executive's inability to carry out his job
         responsibilities for a continuous period of more than three months,
         Executive's employment and the Company's obligation to make payments
         hereunder shall terminate on the date of his death, or the date upon
         which, in the sole determination of the Board of Directors, Executive
         has failed to carry out his job responsibilities for three months
         except the Company shall pay the Executive's estate any salary earned
         but unpaid prior to termination, all accrued but unused personal time
         and any business expenses that were incurred but not reimbursed as of
         the date of termination. Vesting of any unvested stock options shall
         cease on the date of termination.

         (b) Voluntary Resignation by Executive. In the event the Executive
         voluntarily terminates his employment with the Company (other than for
         Good Reason as defined below), the Company's obligation to make
         payments hereunder shall cease upon such termination, except the
         Company shall pay Executive any salary earned but unpaid prior to
         termination, all accrued but unused personal time and any business
         expenses that were incurred but not reimbursed as of the date of
         termination. Vesting of any unvested stock options shall cease on the
         date of termination.

         (c) Termination for Just Cause. In the event the Executive is
         terminated by the Company for Just Cause (as defined below), the
         Company's obligation to make payments hereunder shall cease upon the
         date of receipt by Executive of written notice of such termination (the
         "date of termination" for purposes of this paragraph 9(c)), except the
         Company shall pay Executive any salary earned but unpaid prior to
         termination, all accrued but unused personal time and any business
         expenses that were incurred but not reimbursed as of the date of
         termination. Vesting of any unvested stock options shall cease on the
         date of termination.

         (d) Termination by the Company without Just Cause Or Resignation for
         Good Reason (Other Than Change in Control). Company will have the right
         to terminate Executive's employment with Company at any time without
         Just Cause. In the event Executive is terminated without Just Cause or
         resigns for Good Reason (as defined below), and upon the execution of a
         full general release by Executive ("Release", attached as Exhibit B),
         releasing all claims known or unknown that Executive may have against
         Company as of the date Executive signs such release, and upon the
         written acknowledgment of his continuing obligations under the
         Confidentiality Agreement, attached as Exhibit A, Executive shall be
         entitled to receive the following Severance Benefits: (i) continuation
         of Executive's base salary, then in effect, for a period of twelve (12)
         months following the Termination Date, paid on the same basis and at
         the same time as previously paid; (ii) payment of any accrued but
         unused vacation and sick leave; (iii) the Company shall reimburse
         Executive, on a grossed-up basis, for the after-tax payment of the
         premiums of Executive's supplemental disability plan and supplemental
         life insurance plan for a period of 24 months following a Termination
         without Just Cause or for reasons other than Change in Control; and
         (iv) the Company shall pay the premiums of Executive's group health
         insurance COBRA continuation coverage, including coverage for
         Executive's eligible dependents, for a maximum period of twelve (12)
         months following a Termination without Just Cause or for reasons other
         than Change in Control; provided, however, that (a) the Company shall
         pay premiums for Executive's eligible dependents only for coverage for
         which those eligible dependents were enrolled immediately prior to the
         Change in Control Termination and (b) the Company's obligation to pay
         such premiums shall cease immediately upon Executive's eligibility for
         comparable group health insurance provided by a new employer of
         Executive.



                                       4
<PAGE>

         (e) Change in Control Severance Benefits. In the event that the Company
         terminates Executive's employment without Just Cause or Executive
         resigns for Good Reason within one (1) month prior to or thirteen (13)
         months following the effective date of a Change in Control (as defined
         below), ("Change in Control Termination"), and upon the execution of a
         Release (Exhibit B), Executive shall be entitled to receive the
         following Change in Control Severance Benefits: (i) continuation of
         Executive's base salary, then in effect, for a period of two (2) years
         following the Termination Date, paid on the same basis and at the same
         time as previously paid; (ii) payment of any accrued but unused
         vacation and sick leave; (iii) the Company shall reimburse Executive,
         on a grossed-up basis, for the after-tax payment of the premiums of
         Executive's supplemental disability plan and supplemental life
         insurance plan for a period of 24 months following a Termination
         without Just Cause or for reasons other than Change in Control; (iv) a
         bonus in the amount equal to the bonus amount paid in the year
         immediately preceding the Change in Control; and (v) the Company shall
         pay the premiums of Executive's group health insurance COBRA
         continuation coverage, including coverage for Executive's eligible
         dependents, for a maximum period of eighteen (18) months following a
         Change in Control Termination; provided, however, that (a) the Company
         shall pay premiums for Executive's eligible dependents only for
         coverage for which those eligible dependents were enrolled immediately
         prior to the Change in Control Termination and (b) the Company's
         obligation to pay such premiums shall cease immediately upon
         Executive's eligibility for comparable group health insurance provided
         by a new employer of Executive. If Executive obtains new employment
         pursuant to which he is employed on an average of 30 hours or more each
         week he may elect, upon written notification to the Company, to receive
         any unpaid severance benefits (subject to required deductions and tax
         withholdings) within 14 days after receipt by the company of such
         written notice. Executive agrees that the Company's payment of health
         insurance premiums will satisfy its obligations under COBRA for the
         period provided. No premium payments will be made following the
         effective date of Executive's coverage by a health insurance plan of a
         subsequent employer. For the balance of the period that Executive is
         entitled to coverage under federal COBRA law, if any, Executive shall
         be entitled to maintain such coverage at Executive's own expense.

         In addition, in the event the Company terminates Executive's employment
         without Just Cause or that Executive resigns for Good Reason within one
         (1) month prior to or thirteen (13) months following the effective date
         of a Change in Control, the vesting of Executive's then outstanding
         stock options shall be accelerated in full, and the time during which
         such options may be exercised shall be extended to 24 months following
         the date of such Change in Control.



                                       5
<PAGE>

10. DEFINITIONS.

         (a) Just Cause. As used in this Agreement, "Just Cause" shall mean the
         occurrence of one or more of the following: (i) Executive's conviction
         of a felony or a crime involving moral turpitude or dishonesty; (ii)
         Executive's participation in a fraud or act of dishonesty against the
         Company; (iii) Executive's intentional and material damage to the
         Company's property; (iv) material breach of Executive's employment
         agreement, the Company's written policies, or the Proprietary
         Information and Inventions Agreement that is not remedied by Executive
         within fourteen (14) days of written notice of such breach from the
         Board or conduct by Executive which demonstrates Executive's gross
         unfitness to serve the Company as President or Chief Executive Officer.
         Executive's physical or mental disability or death shall not constitute
         cause hereunder.

         (b) Good Reason. As used in this Agreement, "Good Reason" shall mean
         any one of the following events which occurs on or after the
         commencement of Executive's employment without Executive's consent: (i)
         any reduction of Executive's then existing annual salary base or annual
         bonus target by more than ten percent (10%), unless the Executive
         accepts such change in compensation opportunity; or, (ii) any request
         that the Executive relocate to a work site that would increase the
         Executive's one-way commute distance by more than thirty-five (35)
         miles from his then principal residence, unless the Executive accepts
         such relocation opportunity, or (iii) within 90 days of a Change in
         Control (as defined below) should the Company fail to offer the
         Executive a position that is equivalent in pay, benefits and
         responsibilities.

         (c) Change in Control. As used in this Agreement, a "Change in Control"
         is defined as; (a) a sale, lease, exchange or other transfer in one
         transaction or a series of related transactions of all or substantially
         all of the assets of the Company (other than the transfer of the
         Company's assets to a majority-owned subsidiary corporation); (b) a
         merger or consolidation in which the Company is not the surviving
         corporation (other than a merger or consolidation in which shareholders
         immediately before the merger or consolidation have, immediately after
         the merger or consolidation, greater stock voting power); (c) a reverse
         merger in which the Company is the surviving corporation but the shares
         of the Company's common stock outstanding immediately preceding the
         merger are converted by virtue of the merger into other property,
         whether in the form of securities, cash or otherwise (other than a
         reverse merger in which shareholders immediately before the merger
         have, immediately after the merger, greater stock voting power); or (d)
         any transaction or series of related transactions in which in excess of
         50% of the Company's voting power is transferred.

         11. TERMINATION OF COMPANY'S OBLIGATIONS. Notwithstanding any
         provisions in this Agreement to the contrary, the Company's
         obligations, and Executive's rights pursuant to Sections 9(d) and 9(e)
         herein, regarding salary continuation and the payment of COBRA
         premiums, shall cease and be rendered a nullity immediately should
         Executive fail to comply with the provisions of the Proprietary
         Information & Inventions Agreement attached hereto as Exhibit A or if
         Executive directly or indirectly competes with the Company.

         12. CONTINUATION OF EMPLOYMENT/RESTRICTIVE COVENANT. Executive
         acknowledges that he will be a member of executive and management
         personnel at the Company. Executive further acknowledges that during
         his employment at the Company, he will be privy to extremely sensitive,
         confidential and valuable commercial information, which constitutes
         trade secrets belonging to the Company, the disclosure of which
         information and secrets would greatly harm the Company. Accordingly,
         during the term of Executive's employment and for a period of twelve
         (12) months immediately following Executive's termination, Executive
         shall not without first obtaining the prior written approval of the
         Company, directly or indirectly engage or prepare to engage, in any
         activities in competition with the Company, or accept employment or
         establish a business relationship with a business that directly
         competes with the Company with regard to radiation sensitizers.



                                       6
<PAGE>

13. NONSOLICITATION. While employed by the Company, and for twelve (12) months
immediately following the Executive's termination of employment, Executive
agrees not to interfere with the business of the Company by soliciting,
attempting to solicit, inducing, or otherwise causing any employee of the
Company to terminate his or her employment in order to become an employee,
consultant or independent contractor to or for any competitor of the Company.

14. MISCELLANEOUS.

         (a) Taxes. Executive agrees to be responsible for the payment of any
         taxes due on any and all compensation, stock option, or benefits
         provided by the Company pursuant to this Agreement.

         (b) Modification/Waiver. This Agreement may not be amended, modified,
         superseded, canceled, renewed or expanded, or any terms or covenants
         hereof waived, except by a writing executed by each of the parties
         hereto or, in the case of a waiver, by the party waiving compliance.
         Failure of any party at any time or times to require performance of any
         provision hereof shall in no manner affect his or its right at a later
         time to enforce the same. No waiver by a party of a breach of any term
         or covenant contained in this Agreement, whether by conduct or
         otherwise, in any one or more instances shall be deemed to be or
         construed as a further or continuing waiver of agreement contained in
         the Agreement.

         (c) Severability. Whenever possible, each provision of this Agreement
         will be interpreted in such manner as to be effective and valid under
         applicable law, but if any provision of this Agreement is held to be
         invalid, illegal or unenforceable in any respect under any applicable
         law or rule in any jurisdiction, such invalidity, illegality or
         unenforceability will not affect any other provision or any other
         jurisdiction, but this Agreement will be reformed, construed and
         enforced in such jurisdiction as if such invalid, illegal or
         unenforceable provisions had never been contained herein.

         (d) Successors and Assigns. This Agreement is intended to bind and
         inure to the benefit of and be enforceable by Executive and the
         Company, and their respective successors, assigns, heirs, executors and
         administrators, except that Executive may not assign any of his duties
         hereunder and he may not assign any of his rights hereunder without the
         written consent of the Company, which shall not be withheld
         unreasonably.

         (e) Notices. All notices given hereunder shall be given by certified
         mail, addressed, or delivered by hand, to the other party at his or its
         address as set forth herein, or at any other address hereafter
         furnished by notice given in like manner. Executive promptly shall
         notify Company of any change in Executive's address. Each notice shall
         be dated the date of its mailing or delivery and shall be deemed given,
         delivered or completed on such date.

         (f) Governing Law; Personal Jurisdiction and Venue. This Agreement and
         all disputes relating to this Agreement shall be governed in all
         respects by the laws of the State of Colorado as such laws are applied
         to agreements between Colorado residents entered into and performed
         entirely in Colorado. The Parties acknowledge that this Agreement
         constitutes the minimum contacts to establish personal jurisdiction in
         Colorado and agree to Colorado court's exercise of personal
         jurisdiction. The Parties further agree that any disputes relating to
         this Agreement shall be brought in courts located in the State of
         Colorado.



                                       7
<PAGE>

         (g) Entire Agreement. This Agreement together with the Exhibits A and B
         attached hereto set forth the entire agreement and understanding of the
         parties hereto with regard to the employment of the Executive by the
         Company and supersede and any and all prior agreements, arrangements
         and understandings, written or oral, pertaining to the subject matter
         hereof. No representation, promise or inducement relating to the
         subject matter hereof has been made to a party that is not embodied in
         these Agreements, and no party shall be bound by or liable for any
         alleged representation, promise or inducement not so set forth.

         (h) Survival. The following provisions of this Agreement shall survive
         the termination of Executive's employment and the assignment of this
         Agreement by the Company to any successor in interest or other
         assignee: Section 8, Section 12 and Section 13.

         (i) Injunctive Relief. Executive acknowledges that the restrictions set
         forth in Sections 8, 12, and 13 above are necessary to protect the
         Company's confidential proprietary information and other legitimate
         business interests and are reasonable in all respects, including
         duration, territory and scope of activity restricted. Executive further
         acknowledges that the provisions of Sections 8, 12 and 13 hereof are
         essential to the Company, that the Company would not enter into this
         Agreement if it did not include these provisions and that damages
         sustained by the Company as a result of a breach of these provisions
         cannot be adequately remedied by damages, and Executive agrees that the
         Company, in addition to any other remedy it may have under this
         Agreement or at law, shall be entitled to injunctive and other
         equitable relief to prevent or curtail any breach of Sections 8, 12 and
         13 of this Agreement. Executive agrees that the existence of any claim
         or cause of action by Executive against the Company or its affiliates,
         whether predicated on this Agreement or otherwise, shall not constitute
         a defense to the enforcement by the Company of any of the provisions of
         Sections 8, 12 and 13 hereof. Executive shall have no right to enforce
         any of his rights under this Agreement by seeking or obtaining
         injunctive or other equitable relief and acknowledges that damages are
         an adequate remedy for any breach by the Company of this Agreement.



                                       8
<PAGE>

IN WITNESS WHEREOF, the parties have each duly executed this Restated Employment
Agreement as of the day and year first above written.

                                 ALLOS THERAPEUTICS, INC.

                                 By: /s/ STEPHEN HOFFMAN
                                 Its: Member of the Board of Directors

                                 EXECUTIVE:

                                 /s/ MICHAEL E. HART
                                 Michael E. Hart



                                       9
<PAGE>

                                    EXHIBIT A

                   MANAGER, EXECUTIVE PERSONNEL OR ASSISTANTS'
                      PROPRIETARY INFORMATION, INVENTIONS,
                 NON-COMPETITION, AND NON-SOLICITATION AGREEMENT
                                    Colorado

This Manager, Executive Personnel or Assistants' Proprietary Information,
Inventions, Non-competition, and Non-solicitation Agreement ("Agreement") is
made in consideration for my employment or continued employment by ALLOS
THERAPEUTICS, INC. or its subsidiaries or affiliates (the "Company"), and the
compensation now and hereafter paid to me. I hereby agree as follows:

1.            NONDISCLOSURE.

              1.1 Recognition of Company's Rights; Nondisclosure. At all times
              during my employment and thereafter, I will hold in strictest
              confidence and will not disclose, use, lecture upon or publish any
              of the Company's Proprietary Information (defined below), except
              as such disclosure, use or publication may be required in
              connection with my work for the Company, or unless an officer of
              the Company expressly authorizes such in writing. I will obtain
              Company's written approval before publishing or submitting for
              publication any material (written, verbal, or otherwise) that
              relates to my work at Company and/or incorporates any Proprietary
              Information. I hereby assign to the Company any rights I may have
              or acquire in such Proprietary Information and recognize that all
              Proprietary Information shall be the sole property of the Company
              and its assigns.

              1.2 Proprietary Information. The term "Proprietary Information"
              shall mean any and all confidential and/or proprietary knowledge,
              data or information of the Company. By way of illustration but not
              limitation, "Proprietary Information" includes (a) trade secrets,
              inventions, mask works, ideas, processes, formulas, source and
              object codes, data, programs, other works of authorship, know-how,
              improvements, discoveries, developments, designs and techniques
              (hereinafter collectively referred to as "Inventions"); and (b)
              information regarding plans for research, development, new
              products, marketing and selling, business plans, budgets and
              unpublished financial statements, licenses, prices and costs,
              suppliers and customers; and (c) information regarding the skills
              and compensation of other employees of the Company.
              Notwithstanding the foregoing, it is understood that, at all such
              times, I am free to use information which is generally known in
              the trade or industry, which is not gained as result of a breach
              of this Agreement, and my own, skill, knowledge, know-how and
              experience to whatever extent and in whichever way I wish.

              1.3 Third Party Information. I understand, in addition, that the
              Company has received and in the future will receive from third
              parties confidential or proprietary information ("Third Party
              Information") subject to a duty on the Company's part to maintain
              the confidentiality of such information and to use it only for
              certain limited purposes. During the term of my employment and
              thereafter, I will hold Third Party Information in the strictest
              confidence and will not disclose to anyone (other than Company
              personnel who need to know such information in connection with
              their work for the Company) or use, except in connection with my
              work for the Company, Third Party Information unless expressly
              authorized by an officer of the Company in writing.

              1.4 No Improper Use of Information of Prior Employers and Others.
              During my employment by the Company I will not improperly use or
              disclose any confidential information or trade secrets, if any, of
              any former employer or any other person to whom I have an
              obligation of


<PAGE>

              confidentiality, and I will not bring onto the premises of the
              Company any unpublished documents or any property belonging to any
              former employer or any other person to whom I have an obligation
              of confidentiality unless consented to in writing by that former
              employer or person. I will use in the performance of my duties
              only information which is generally known and used by persons with
              training and experience comparable to my own, which is common
              knowledge in the industry or otherwise legally in the public
              domain, or which is otherwise provided or developed by the
              Company.



<PAGE>

2.            ASSIGNMENT OF INVENTIONS.

              2.1 Proprietary Rights. The term "Proprietary Rights" shall mean
              all trade secret, patent, copyright, mask work and other
              intellectual property rights throughout the world.

              2.2 Prior Inventions. Inventions, if any, patented or unpatented,
              which I made prior to the commencement of my employment with the
              Company are excluded from the scope of this Agreement. To preclude
              any possible uncertainty, I have set forth on Exhibit A (Previous
              Inventions) attached hereto a complete list of all Inventions that
              I have, alone or jointly with others, conceived, developed or
              reduced to practice or caused to be conceived, developed or
              reduced to practice prior to the commencement of my employment
              with the Company, that I consider to be my property or the
              property of third parties and that I wish to have excluded from
              the scope of this Agreement (collectively referred to as "Prior
              Inventions"). If disclosure of any such Prior Invention would
              cause me to violate any prior confidentiality agreement, I
              understand that I am not to list such Prior Inventions in Exhibit
              A but am only to disclose a cursory name for each such invention,
              a listing of the party(ies) to whom it belongs and the fact that
              full disclosure as to such inventions has not been made for that
              reason. A space is provided on Exhibit A for such purpose. If no
              such disclosure is attached, I represent that there are no Prior
              Inventions. If, in the course of my employment with the Company, I
              incorporate a Prior Invention into a Company product, process or
              machine, the Company is hereby granted and shall have a
              nonexclusive, royalty-free, irrevocable, perpetual, worldwide
              license (with rights to sublicense through multiple tiers of
              sublicensees) to make, have made, modify, use and sell such Prior
              Invention. Notwithstanding the foregoing, I agree that I will not
              incorporate, or permit to be incorporated, Prior Inventions in any
              Company Inventions without the Company's prior written consent.

              2.3 Assignment of Inventions. Subject to Sections 2.4, and 2.6, I
              hereby assign and agree to assign in the future (when any such
              Inventions or Proprietary Rights are first reduced to practice or
              first fixed in a tangible medium, as applicable) to the Company
              all my right, title and interest in and to any and all Inventions
              (and all Proprietary Rights with respect thereto) whether or not
              patentable or registrable under copyright or similar statutes,
              made or conceived or reduced to practice or learned by me, either
              alone or jointly with others, during the period of my employment
              with the Company. Inventions assigned to the Company, or to a
              third party as directed by the Company pursuant to this Section 2,
              are hereinafter referred to as "Company Inventions."

              2.4 Nonassignable Inventions. I recognize that, in the event of a
              specifically applicable state law, regulation, rule, or public
              policy ("Specific Inventions Law"), this Agreement will not be
              deemed to require assignment of any invention which qualifies
              fully for protection under a Specific Inventions Law by virtue of
              the fact that any such invention was, for example, developed
              entirely on my own time without using the Company's equipment,
              supplies, facilities, or trade secrets and neither related to the
              Company's actual or anticipated business, research or development,
              nor resulted from work performed by me for the Company. In the
              absence of a Specific Inventions Law, the preceding sentence will
              not apply.


<PAGE>

              2.5 Obligation to Keep Company Informed. During the period of my
              employment and for six months after the last day of my employment
              with the Company, I will promptly disclose to the Company fully
              and in writing all Inventions authored, conceived or reduced to
              practice by me, either alone or jointly with others. In addition,
              I will promptly disclose to the Company all patent applications
              filed by me or on my behalf within a year after termination of
              employment. At the time of each such disclosure, I will advise the
              Company in writing of any Inventions that I believe fully qualify
              for protection under the provisions of a Specific Inventions Law;
              and I will at that time provide to the Company in writing all
              evidence necessary to substantiate that belief. The Company will
              keep in confidence and will not use for any purpose or disclose to
              third parties without my consent any confidential information
              disclosed in writing to the Company pursuant to this Agreement
              relating to Inventions that qualify fully for protection under a
              Specific Inventions Law. I will preserve the confidentiality of
              any Invention that does not fully qualify for protection under a
              Specific Inventions Law.

              2.6 Government or Third Party. I also agree to assign all my
              right, title and interest in and to any particular Invention to a
              third party, including without limitation the United States, as
              directed by the Company.

              2.7 Works for Hire. I acknowledge that all original works of
              authorship which are made by me (solely or jointly with others)
              within the scope of my employment and which are protectable by
              copyright are "works made for hire," pursuant to United States
              Copyright Act (17 U.S.C., Section 101).

              2.8 Enforcement of Proprietary Rights. I will assist the Company
              in every proper way to obtain, and from time to time enforce,
              United States and foreign Proprietary Rights relating to Company
              Inventions in any and all countries. To that end I will execute,
              verify and deliver such documents and perform such other acts
              (including appearances as a witness) as the Company may reasonably
              request for use in applying for, obtaining, perfecting,
              evidencing, sustaining and enforcing such Proprietary Rights and
              the assignment thereof. In addition, I will execute, verify and
              deliver assignments of such Proprietary Rights to the Company or
              its designee. My obligation to assist the Company with respect to
              Proprietary Rights relating to such Company Inventions in any and
              all countries shall continue beyond the termination of my
              employment, but the Company shall compensate me at a reasonable
              rate after my termination for the time actually spent by me at the
              Company's request on such assistance.

              In the event the Company is unable for any reason, after
              reasonable effort, to secure my signature on any document needed
              in connection with the actions specified in the preceding
              paragraph, I hereby irrevocably designate and appoint the Company
              and its duly authorized officers and agents as my agent and
              attorney in fact, which appointment is coupled with an interest,
              to act for and in my behalf to execute, verify and file any such
              documents and to do all other lawfully permitted acts to further
              the purposes of the preceding paragraph with the same legal force
              and effect as if executed by me. I hereby waive and quitclaim to
              the Company any and all claims, of any nature whatsoever, which I
              now or may hereafter have for infringement of any Proprietary
              Rights assigned hereunder to the Company.

              3. NO CONFLICTS OR SOLICITATION. I acknowledge that during my
              employment I will have access to and knowledge of Proprietary
              Information. I also acknowledge that during my employment with the
              Company, I have held and/or will hold a management or executive
              position or am, or will be, an assistant to a manager or
              executive. To protect the Company's Proprietary Information, I
              agree that during the period of my employment by the Company I
              will not, without the Company's express written consent, engage in
              any other employment or business activity directly related to the
              business in which the Company is now involved or becomes involved,
              nor will I engage in any other activities which conflict with my
              obligations to the Company. To protect the Company's Proprietary
              Information, and because of the position in the Company that I
              hold, I agree that during my employment with the Company whether
              full-time or part-time and for a period of one year after my last
              day of employment with the Company, I will not (a) directly or
              indirectly solicit or induce any employee of the Company to
              terminate or negatively alter his or her relationship with the
              Company or (b) directly or indirectly solicit the business of any
              client or customer of the Company (other than on behalf of the
              Company) or (c) directly or indirectly induce any client,
              customer, supplier, vendor, consultant or independent contractor
              of the Company to terminate or negatively alter his, her or its
              relationship with the Company. I agree that the geographic scope
              of the non-solicitation should include the "Restricted Territory"
              (as defined below).


<PAGE>

4. If any restriction set forth in this Section is found by any court of
competent jurisdiction to be unenforceable because it extends for too long a
period of time or over too great a range of activities or in too broad a
geographic area, it shall be interpreted to extend only over the maximum period
of time, range of activities or geographic area as to which it may be
enforceable.

5. COVENANT NOT TO COMPETE. I acknowledge that during my employment I will have
access to and knowledge of Proprietary Information. I also acknowledge that
during my employment with the Company, I have held and/or will hold a management
or executive position or am, or will be, an assistant to a manager or executive.
To protect the Company's Proprietary Information, and because of the position in
the Company that I may hold, I agree that during my employment with the Company
whether full-time or part-time and for a period of one year after my last day of
employment with the Company, I will not directly or indirectly engage in
(whether as an employee, consultant, proprietor, partner, director or
otherwise), or have any ownership interest in, or participate in the financing,
operation, management or control of, any person, firm, corporation or business
that engages in a "Restricted Business" in a "Restricted Territory" (as defined
below). It is agreed that ownership of (i) no more than one percent (1%) of the
outstanding voting stock of a publicly traded corporation, or (ii) any stock I
presently own shall not constitute a violation of this provision.

              5.1 Reasonable. I agree and acknowledge that the time limitation
              on the restrictions in this paragraph, combined with the
              geographic scope, is reasonable. I also acknowledge and agree that
              this paragraph is reasonably necessary for the protection of
              Company's Proprietary Information as defined in paragraph 1.2
              herein, that through my employment I shall receive adequate
              consideration for any loss of opportunity associated with the
              provisions herein, and that these provisions provide a reasonable
              way of protecting Company's business value which will be imparted
              to me. If any restriction set forth in this paragraph 4 is found
              by any court of competent jurisdiction to be unenforceable because
              it extends for too long a period of time or over too great a range
              of activities or in too broad a geographic area, it shall be
              interpreted to extend only over the maximum period of time, range
              of activities or geographic area as to which it may be
              enforceable.

              5.2 As used herein, the terms:

              (i) "Restricted Business" shall mean the development or
              commercialization of radiosensitizers.

              (ii) "Restricted Territory" shall mean any state, county, or
              locality in the United States in which the Company conducts
              business and any other country, city, state, jurisdiction, or
              territory in which the Company does business.

              6. RECORDS. I agree to keep and maintain adequate and current
              records (in the form of notes, sketches, drawings and in any other
              form that may be required by the Company) of all Proprietary
              Information developed by me and all Inventions made by me during
              the period of my employment at the Company, which records shall be
              available to and remain the sole property of the Company at all
              times.

              7. NO CONFLICTING OBLIGATION. I represent that my performance of
              all the terms of this Agreement and as an employee of the Company
              does not and will not breach any agreement to keep in confidence
              information acquired by me in confidence or in trust prior to my
              employment by the Company. I have not entered into, and I agree I
              will not enter into, any agreement either written or oral in
              conflict herewith.

              8. RETURN OF COMPANY MATERIALS. When I leave the employ of the
              Company, I will deliver to the Company any and all drawings,
              notes, memoranda, specifications, devices, formulas, and
              documents, together with all copies thereof, and any other
              material containing or disclosing any Company Inventions, Third
              Party Information or Proprietary Information of the Company,
              unless agreed to by the Company. I further agree that any property
              situated on the Company's premises and owned by the Company,
              including disks and other storage media, filing cabinets or other
              work areas, is subject to inspection by Company personnel at any
              time with or without notice.


<PAGE>

9. LEGAL AND EQUITABLE REMEDIES. Because my services are personal and unique and
because I may have access to and become acquainted with the Proprietary
Information of the Company, the Company shall have the right to enforce this
Agreement and any of its provisions by injunction, specific performance or other
equitable relief, without bond and without prejudice to any other rights and
remedies that the Company may have for a breach of this Agreement.

10. NOTICES. Any notices required or permitted hereunder shall be given to the
appropriate party at the address specified below or at such other address as the
party shall specify in writing. Such notice shall be deemed given upon personal
delivery to the appropriate address or if sent by certified or registered mail,
three days after the date of mailing.

11. NOTIFICATION OF NEW EMPLOYER. In the event that I leave the employ of the
Company, I hereby consent to the notification of my new employer of my rights
and obligations under this Agreement.

12.           GENERAL PROVISIONS.

              12.1 Governing Law; Consent to Personal Jurisdiction and Exclusive
              Forum. This Agreement will be governed by and construed according
              to the laws of the State of Colorado as such laws are applied to
              agreements entered into and to be performed entirely within
              Colorado between Colorado residents. I hereby expressly understand
              and consent that my employment is a transaction of business in the
              State of Colorado and constitutes the minimum contacts necessary
              to make me subject to the personal jurisdiction of the federal
              courts located in the State of Colorado, and the state courts
              located in the County of Denver, Colorado, for any lawsuit filed
              against me by Company arising from or related to this Agreement. I
              agree and acknowledge that any controversy arising out of or
              relating to this Agreement or the breach thereof, or any claim or
              action to enforce this Agreement or portion thereof, or any
              controversy or claim requiring interpretation of this Agreement
              must be brought in a forum located within the State of Colorado.
              No such action may be brought in any forum outside the State of
              Colorado. Any action brought in contravention of this paragraph by
              one party is subject to dismissal at any time and at any stage of
              the proceedings by the other, and no action taken by the other in
              defending, counter claiming or appealing shall be construed as a
              waiver of this right to immediate dismissal. A party bringing an
              action in contravention of this paragraph shall be liable to the
              other party for the costs, expenses and attorney's fees incurred
              in successfully dismissing the action or successfully transferring
              the action to the federal courts located in the State of Colorado,
              or the state courts located in the County of Denver, Colorado.

              12.2 Severability. In case any one or more of the provisions
              contained in this Agreement shall, for any reason, be held to be
              invalid, illegal or unenforceable in any respect, such invalidity,
              illegality or unenforceability shall not affect the other
              provisions of this Agreement, and this Agreement shall be
              construed as if such invalid, illegal or unenforceable provision
              had never been contained herein. If moreover, any one or more of
              the provisions contained in this Agreement shall for any reason be
              held to be excessively broad as to duration, geographical scope,
              activity or subject, it shall be construed by limiting and
              reducing it, so as to be enforceable to the extent compatible with
              the applicable law as it shall then appear.

              12.3 Successors and Assigns. This Agreement will be binding upon
              my heirs, executors, administrators and other legal
              representatives and will be for the benefit of the Company, its
              successors, and its assigns.

              12.4 Survival. The provisions of this Agreement shall survive the
              termination of my employment and the assignment of this Agreement
              by the Company to any successor in interest or other assignee.


<PAGE>

              12.5 Employment. I agree and understand that my employment is
              at-will which means I or the company each have the right to
              terminate my employment at will, with or without advanced notice
              and with or without cause. I further agree and understand that
              nothing in this Agreement shall confer any right with respect to
              continuation of employment by the Company, nor shall it interfere
              in any way with my right or the Company's right to terminate my
              employment at any time, with or without cause.


<PAGE>

              12.6 Waiver. No waiver by the Company of any breach of this
              Agreement shall be a waiver of any preceding or succeeding breach.
              No waiver by the Company of any right under this Agreement shall
              be construed as a waiver of any other right. The Company shall not
              be required to give notice to enforce strict adherence to all
              terms of this Agreement.

              12.7 Entire Agreement. The obligations pursuant to Sections 1
              through 4 and Sections 6 and 7 (including all subparts) of this
              Agreement shall apply to any time during which I was previously
              employed, or am in the future employed, by the Company as a
              consultant if no other agreement governs nondisclosure and
              assignment of inventions during such period. This Agreement is the
              final, complete and exclusive agreement of the parties with
              respect to the subject matter hereof and supersedes and merges all
              prior discussions between us. No modification of or amendment to
              this Agreement, nor any waiver of any rights under this Agreement,
              will be effective unless in writing and signed by the party to be
              charged. Any subsequent change or changes in my duties, salary or
              compensation will not affect the validity or scope of this
              Agreement.

              This Agreement shall be effective as of the _______________, 2001.

              I HAVE READ THIS AGREEMENT CAREFULLY AND UNDERSTAND ITS TERMS. I
              HAVE COMPLETELY FILLED OUT EXHIBIT A TO THIS AGREEMENT.


Dated:

Michael E. Hart

ACCEPTED AND AGREED TO:




<PAGE>

                                    EXHIBIT B

TO:                Allos Therapeutics, Inc.

FROM:              Michael E. Hart

DATE:

SUBJECT:           Previous Inventions

1. Except as listed in Section 2 below, the following is a complete list of all
inventions or improvements relevant to the subject matter of my employment by
Allos Therapeutics, Inc. that have been made or conceived or first reduced to
practice by me alone or jointly with others prior to my engagement by the
Company:

               [ ]          No inventions or improvements.

               [ ]          See below:

               [ ]          No inventions or improvements.

               [ ]          See below:

               [ ]          Additional sheets attached.

2. Due to a prior confidentiality agreement, I cannot complete the disclosure
under Section 1 above with respect to inventions or improvements generally
listed below, the proprietary rights and duty of confidentiality with respect to
which I owe to the following party(ies):

<Table>
<Caption>
          Invention or Improvement                       Party(ies)                             Relationship
<S>                                               <C>                                 <C>

1.
               -----------------------             -----------------------             -----------------------

2.
               -----------------------             -----------------------             -----------------------

3.
               -----------------------             -----------------------             -----------------------
</Table>


               [ ]          Additional sheets attached.


<PAGE>

                                    EXHIBIT B

                                RELEASE AGREEMENT

I understand that my position with Allos Therapeutics, Inc. (the "Company")
terminated effective ___________, _____ (the "Separation Date"). The Company has
agreed that if I choose to sign this Release, the Company will pay me certain
severance or consulting benefits pursuant to the terms of the Executive
Employment (the "Agreement") between myself and the Company, and any agreements
incorporated therein by reference. I understand that I am not entitled to such
benefits unless I sign this Release and it becomes fully effective. I understand
that, regardless of whether I sign this Release, the Company will pay me all of
my accrued salary and vacation through the Separation Date, to which I am
entitled by law.

In consideration for the severance benefits I am receiving under the Agreement,
I hereby release the Company and its officers, directors, agents, attorneys,
employees, shareholders, parents, subsidiaries, and affiliates from any and all
claims, liabilities, demands, causes of action, attorneys' fees, damages, or
obligations of every kind and nature, whether they are now known or unknown,
arising at any time prior to the date I sign this Release. This general release
includes, but is not limited to: all federal and state statutory and common law
claims, claims related to my employment or the termination of my employment or
related to breach of contract, tort, wrongful termination, discrimination, wages
or benefits, or claims for any form of equity or compensation. Notwithstanding
the release in the preceding sentence, I am not releasing any right of
indemnification I may have for any liabilities arising from my actions within
the course and scope of my employment with the Company.

If I am forty (40) years of age or older as of the Separation Date, I
acknowledge that I am knowingly and voluntarily waiving and releasing any rights
I may have under the federal Age Discrimination in Employment Act of 1967, as
amended ("ADEA"). I also acknowledge that the consideration given for the waiver
in the above paragraph is in addition to anything of value to which I was
already entitled. I have been advised by this writing, as required by the ADEA
that: (a) my waiver and release do not apply to any claims that may arise after
my signing of this Release; (b) I should consult with an attorney prior to
executing this Release; (c) I have twenty-one (21) days within which to consider
this Release (although I may choose to voluntarily execute this Release
earlier); (d) I have seven (7) days following the execution of this release to
revoke the Release; and (e) this Release will not be effective until the eighth
day after this Release has been signed both by me and by the Company ("Effective
Date").

Agreed:

ALLOS THERAPEUTICS.INC.                         MICHAEL E. HART

By:


Name:


Title:

Date:                                   Date: