<PAGE>


                             AVAX TECHNOLOGIES, INC.

                   AMENDED AND RESTATED 1992 STOCK OPTION PLAN

Pursuant to resolutions passed by the Board of Directors of AVAX Technologies,
Inc., a Delaware corporation ("Company"), subject to stockholder approval, the
Company's 1992 Stock Option Plan was amended to provide for an increase in the
number of option shares from 437,500 (after giving effect to two separate
one-for-two reverse stock splits) to 1,500,000. Such amendment was duly approved
and authorized by the stockholders of the Company at the Annual Meeting of the
Company on June 3, 1998.

1. Purposes of the Plan. The purposes of this 1992 Stock Option Plan are to
provide incentive to Employees and Consultants of the Company, to encourage
Employee proprietary interest in the Company, to encourage Employees to remain
in the employ of the Company and to attract to the Company individuals of
experience and ability.

Options granted under this Plan may be either Incentive Stock Options or
Nonstatutory Stock Options, at the discretion of the Administrator and as
reflected in the terms of the written option agreement.

2. Definitions. As used in this Plan, the following definitions shall apply:

       (a) "Administrator" shall mean the Board or any of its Committees
       appointed pursuant to Section 4 of the Plan.

       (b) "Applicable Laws" shall have the meaning set forth in Section 4(a)
       below.

       (c) "Board" shall mean the Board of Directors of the Company.

       (d) "Code" shall mean the Internal Revenue Code of 1986, as amended.

       (e) "Committee" shall mean the Committee appointed by the Board of
       Directors in accordance with Section 4(a) below, if one is appointed.

       (f) "Common Stock" shall mean the $0.004 par value Common Stock of the
       Company.

       (g) "Company" shall mean AVAX Technologies, Inc. (formerly WALDEN
       LABORATORIES, INC. (formerly APPEX TECHNOLOGIES, INC.)), a Delaware
       corporation, or any successor corporation to the Company.

       (h) "Consultant" shall mean (i) any person who is engaged by the Company
       or any subsidiary to render consulting services and is compensated for
       such consulting services, and (ii) any director of the Company whether
       compensated for such services or not; provided, however, that if the
       Company registers any class of any equity security pursuant to Section 12
       of the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
       the term Consultant shall thereafter not include directors who are not
       compensated for their services or who are paid only a director's fee by
       the Company.

       (i) "Continuous Status as an Employee or Consultant" shall mean the
       absence of any interruption or termination of service as an Employee or
       Consultant. Continuous Status as an Employee or Consultant shall not be
       considered interrupted in the case of sick leave, military leave, or any
       other leave of absence approved by the Administrator; provided, however,
       either that such leave must be for a period of not more than ninety (90)
       days or that re-employment upon the expiration of such leave must be
       guaranteed by contract or by statute.

       (j) "Employee" shall mean any person, including officers and directors,
       employed by the Company or any Parent or Subsidiary of the Company. The
       payment of a director's fee by the Company shall not be sufficient to
       constitute "employment" by the Company.

       (k) "Fair Market Value" means, as of any date, the value of Common Stock
       determined as follows:
<PAGE>

       (i) If the Common Stock is listed on any established stock exchange or a
       national market system including without limitation the National Market
       System of the National Association of Securities Dealers, Inc. Automated
       Quotation ("NASDAQ") System, its Fair Market Value shall be the average
       of the closing sales prices for such stock as quoted on such system for
       the last five trading days before the date of determination (if for a
       given day no sales were reported, the closing bid on that day shall be
       used), as such prices are reported in The Wall Street Journal or such
       other source as the Administrator deems reliable;

       (ii) If the Common Stock is quoted on the NASDAQ System (but not on the
       National Market System thereof) or regularly quoted by a recognized
       securities dealer but selling prices are not reported, its Fair Market
       Value shall be the average of the mean between the bid and asked prices
       for the Common Stock for the last five days before the date of
       determination; or

       (iii) In the absence of an established market for the Common Stock, the
       Fair Market Value thereof shall be determined in good faith by the
       Administrator.

       (l) "Incentive Stock Option" shall mean an Option intended to qualify as
       an incentive stock option within the meaning of Section 422 of the Code.

       (m) "Nonstatutory Stock Option" shall mean an Option not intended to
       qualify as an Incentive Stock Option.

       (n) "Option" shall mean a stock option granted pursuant to the
       Plan.

       (o) "Optioned Stock" shall mean the Common Stock subject to an Option.

       (p) "Optionee" shall mean an Employee or Consultant who receives an
       Option.

       (q) "Parent" shall mean a "parent corporation," whether now or hereafter
       existing, as defined in Section 424(e) of the Code.

       (r) "Plan" shall mean this 1992 Stock Option Plan, as amended and
       restated.

       (s) "Share" shall mean a share of Common Stock, adjusted in accordance
       with Section 11 below.

       (t) "Subsidiary" shall mean a "subsidiary  corporation,"  whether now or
       hereafter existing,  as defined in Section 424(f) of the Code.

3. Stock Subject to the Plan. Subject to the provisions of Section 11 below, the
maximum aggregate number of shares that may be optioned and sold under the Plan
is 1,500,000 shares of Common Stock. The Shares may be authorized, but unissued,
or reacquired Common Stock.

If an Option should expire or become unexercisable for any reason without having
been exercised in full, then the unpurchased Shares that were subject to the
Option shall, unless the Plan has been terminated, become available for fixture
grant under the Plan.

Notwithstanding any other provision of the Plan, shares issued under the Plan
and later repurchased by the Company shall not become available for fixture
grant or sale under the Plan.

4. Administration of the Plan.

       (a) Composition of Administrator.

            (i) Multiple Administrative Bodies. If permitted by Rule 16b-3
            promulgated under the Exchange Act or any successor rule thereto, as
            in effect at the time that discretion is being exercised with
            respect to the Plan ("Rule 16b-3"), and by the legal requirements
            relating to the administration of incentive stock option plans, if
            any, of applicable securities laws and the Code (collectively, the
            "Applicable Laws"), the Plan may (but need not) be administered by
            different administrative bodies with respect to directors, officers
            who are not directors and Employees who are neither directors nor
            officers.

                                       2
<PAGE>

            (ii) Administration with respect to Directors and Officers. With
            respect to grants of Options to Employees or Consultants who are
            also officers or directors of the Company, the Plan shall be
            administered by (A) the Board, if the Board may administer the Plan
            in compliance with Rule 16b-3 as it applies to a plan intended to
            qualify thereunder as a discretionary plan, or (B) a Committee
            designated by the Board to administer the Plan, which Committee
            shall be constituted in such a manner as to (I) permit the Plan to
            comply with Rule 16b-3 as it applies to a plan intended to qualify
            thereunder as a discretionary plan, (II) satisfy the Applicable
            Laws and (III) satisfy the requirements for employee compensation
            deductibility under Section 162(m) of the Code and any applicable
            rules and regulations related thereto.

            (iii) Administration with respect to Other Persons. With respect to
            grants of Options to Employees or Consultants who are neither
            directors nor officers of the Company, the Plan shall be
            administered by (A) the Board or (B) a Committee designated by the
            Board, which Committee shall be constituted in such a manner as to
            satisfy (I) the Applicable Laws and (II) the requirements for
            employee compensation deductibility under Section 162(m) of the
            Code and any applicable rules and regulations related thereto. 

            (iv) General. Once a Committee has been appointed pursuant to
            subsection (ii) or (iii) of this Section 4(a), such Committee shall
            continue to serve in its designated capacity until otherwise
            directed by the Board. From time to time the Board may increase the
            size of any Committee and appoint additional members thereof, remove
            members (with or without cause) and appoint new members in
            substitution therefor, fill vacancies (however caused) and remove
            all members of a Committee and thereafter directly administer the
            Plan, all to the extent permitted by the Applicable Laws and, in the
            case of a Committee appointed under subsection (ii), to the extent
            permitted by Rule 16b-3 as it applies to a plan intended to qualify
            thereunder as a discretionary plan.

       (b) Powers of the Administrator. Subject to the provisions of the Plan
       and in the case of a Committee, the specific duties delegated by the
       Board to such Committee, the Administrator shall have the authority, in
       its discretion

            (i) to determine the Fair Market Value of the Common Stock, in
            accordance with Section 2(k) of the Plan;

            (ii) to select the officers, Consultants and Employees to whom
            Options may from time to time be granted under the Plan;

            (iii) to determine whether and to what extent Options are granted
            under the Plan;

            (iv) to determine the number of shares of Common Stock to be covered
            by each such award granted under the Plan;

            (v) to approve forms of agreement for use under the Plan;

            (vi) to determine the terms and conditions, not inconsistent with
            the terms of the Plan, of any award granted hereunder (including,
            but not limited to, the share price and any restriction or
            limitation, or any waiver or forfeiture restrictions regarding any
            Option and/or the shares of Common Stock relating thereto, based in
            each case on such factors as the Administrator shall determine, in
            its sole discretion); and

            (vii) to reduce the exercise price of any Option to the then current
            Fair Market Value if the Fair Market Value of the Common Stock
            covered by such Option shall have declined since the date the Option
            was granted.

       (c) Effect of Administrator's Decision. All decisions, determinations and
       interpretations of the Administrator shall be final and binding on all
       Optionees and any other holders of any Options.

5. Eligibility

       (a) Options may be granted only to Employees and Consultants. Incentive
       Stock Options may be granted only to Employees. An Employee or Consultant
       who has been granted an Option may, if he or she is otherwise eligible,
       be granted an additional Option or Options.

                                       3
<PAGE>

       (b) Each Option shall be designated in the written option agreement as
       either an Incentive Stock Option or a Nonstatutory Stock Option. However,
       notwithstanding such designations, to the extent that the aggregate Fair
       Market Value of stock for which Options are exercisable for the first 
       time by an Optionee during any calendar year (under all plans of the 
       Company or any Parent or Subsidiary) exceeds $100,000, such excess 
       Options shall be treated as Nonstatutory Stock Options.

       (c) For purposes of Section 5(b), Incentive Stock Options shall be taken
       into account in the order in which they were granted, and the Fair Market
       Value of the Shares shall be determined as of the time the Option with
       respect to such Shares is granted.

       (d) The maximum number of shares with respect to which Options or rights
       may be granted to any Employee during the course of one year is
       1,000,000.

       (e) The Plan shall not confer upon any Optionee any right with respect to
       continuation of employment or consulting relationship with the Company,
       nor shall it interfere in any way with his or her right or the Company's
       right to terminate his or her employment or consulting relationship at
       any time, with or without cause,

6. Term of Plan. The Plan shall become effective upon the earlier to occur of
its adoption by the Board of Directors or its approval by the stockholders of
the Company as described in Section 18 below. It shall continue in effect for a
term of ten (10) years unless sooner terminated under Section 13 below.

7. Term of Option. The term of each Option shall be ten (10) years from the date
of grant thereof or such shorter term as may be provided in the Stock Option
Agreement. However, in the case of an Option granted to an Optionee who, at the
time the Option is granted, owns stock representing more than ten percent (10%)
of the voting power of all classes of stock of the Company or any Parent or
Subsidiary, the term of the Option shall be five (5) years from the date of
grant thereof or such shorter time as may be provided in the Stock Option
Agreement.

8. Exercise Price and Consideration.

       (a) The per Share exercise price for the Shares to be issued pursuant to
       exercise of an Option shall be such price as is determined by the
       Administrator, but shall be subject to the following:

             (i) In the case of an Incentive Stock Option

                  (A) granted to an Employee who, at the time of the grant of
                  such Incentive Stock Option, owns stock representing more than
                  ten percent (10%) of the voting power of all classes of stock
                  of the Company or any Parent or Subsidiary, the per Share
                  exercise price shall be no less than one hundred ten percent
                  (110%) of the Fair Market Value per Share on the date of
                  grant.

                  (B) granted to any other Employee, the per Share exercise
                  price shall be no less than one hundred percent (100%) of the
                  Fair Market Value per Share on the date of grant.

            (ii) In the case of any Option, the per Share exercise price shall
            be no less than eighty-five percent (85%) of the Fair Market Value
            per Share on the date of grant.

       (b) The Administrator shall determine the acceptable form of
       consideration for exercising an Option, including the method of payment.
       In the case of an Incentive Stock Option, the Administrator shall
       determine the acceptable form of consideration at the time of grant. Such
       consideration may consist entirely of:

             (i) cash;

             (ii) check;

            (iii) other Shares which (a) in the case of Shares acquired upon
            exercise of an option, have been owned by the Optionee for more than
            six months on the date of surrender, and (b) have a Fair Market
            Value on the date of surrender equal to the aggregate exercise price
            of the Shares as to which said Option shall be exercised;

                                       4
<PAGE>

            (iv) delivery of an irrevocable subscription agreement for the
            Shares to be issued which irrevocably obligates the holder to take
            and pay for the shares not more than twelve (12) months after the
            date of delivery of the subscription agreement;

            (v) any combination of such methods of payment; or

            (vi) such other consideration and method of payment for the issuance
            of Shares to the extent permitted under Section 157 of the Delaware
            General Corporation Law.

9. Exercise of Option.

       (a) Procedure for Exercise; Rights as a Stockholder. Any Option granted
       under this Plan shall be exercisable at such times and under such
       conditions as determined by the Administrator, including performance
       criteria with respect to the Company and/or the Optionee, and shall be
       permissible under the terms of the Plan.

       An Option may not be exercised for a fraction of a Share.

       An Option shall be deemed to be exercised when written notice of such
       exercise has been given to the Company in accordance with the terms of
       the Option by the person entitled to exercise the Option and full payment
       for the Shares with respect to which the Option is exercised has been
       received by the Company. Full payment may, as authorized by the
       Administrator, consist of any consideration and method of payment
       allowable under Section 8(b) above. Until the issuance (as evidenced by
       the appropriate entry on the books of the Company or of a duly authorized
       transfer agent of the Company) of the stock certificate evidencing such
       Shares, no right to vote or receive dividends or any other rights as a
       stockholder shall exist with respect to the Optioned Stock,
       notwithstanding the exercise of the Option. No adjustment shall be made
       for a dividend or other right for which the record date is prior to the
       date the stock certificate is issued, except as provided in Section 11
       below.

       Exercise of an Option in any manner shall result in a decrease in the
       number of Shares which thereafter may be available, both for purposes of
       the Plan and for sale under the Option, by the number of Shares as to
       which the Option is exercised.

       (b) Termination of Status as an Employee or Consultant. If an Employee or
       Consultant ceases to serve as an Employee or Consultant, then he or she
       may, but only within three (3) months (twelve (12) months in the case of
       a Nonstatutory Stock Option) or such other shorter period as is specified
       by the Administrator after the date he or she ceases to be an Employee or
       Consultant of the Company (but in no event later than the date of
       expiration of the term of such Option as set forth in the Option
       Agreement), exercise his or her Option to the extent that he or she was
       entitled to exercise it at the date of such termination. To the extent
       that he or she was not entitled to exercise the Option at the date of
       such termination, or if he or she does not exercise such Option (which he
       or she was entitled to exercise) within the time specified herein, the
       Option shall terminate.

       (c) Disability of Optionee. Notwithstanding the provisions of Section
       9(b) above, if an Employee or Consultant is unable to continue his or her
       employment or consulting relationship with the Company as a result of his
       or her total and permanent disability (as defined in Section 22(e)(3) of
       the Code), then he or she may, but only within twelve (12) months from
       the date of termination or such other shorter period as is specified by
       the Administrator (but in no event later than the date of expiration of
       the term of such Option as set forth in the Option Agreement), exercise
       his or her Option to the extent he or she was entitled to exercise it at
       the date of termination of employment or consulting. To the extent that
       he or she was not entitled to exercise the Option at the date of
       termination, or if he or she does not exercise such Option (which he or
       she was entitled to exercise) within the time specified herein, the
       Option shall terminate.

       (d) Death of Optionee. In the event of the death of an Optionee:

            (i) during the term of the Option who is at the time of his or her
            death an Employee or Consultant of the Company and who shall have
            been in Continuous Status as an Employee or Consultant since the
            date of grant of the Option, the Option may be exercised, at any
            time within twelve (12) months following the date of death or such
            other shorter period as is specified by the Administrator (but in no
            event later than the date of expiration of the term of such Option
            as set forth in the Option Agreement), by the Optionee's estate or
            by a person who acquired the right to exercise the Option by bequest
            or inheritance, but only to the extent of the right to exercise that
            would have accrued had the Optionee continued living and remained in
            Continuous Status as an Employee or Consultant three (3) months
            after the date of death; or

                                       5
<PAGE>

            (ii) within three (3) months after the termination of Continuous
            Status as an Employee or Consultant, the Option may be exercised, at
            any time within three (3) months following the date of death or such
            other shorter period as is specified by the Administrator (but in no
            event later than the date of expiration of the term of such Option
            as set forth in the Option Agreement), by the Optionee's estate or
            by a person who acquired the right to exercise the Option by bequest
            or inheritance, but only to the extent of the right to exercise that
            had accrued at the date of termination.

       (e) Rule 16b-3. Options granted to persons subject to Section 16(b) of
       the Exchange Act must comply with Rule 16b-3 and shall contain such
       additional conditions or restrictions as may be required thereunder to
       qualify for the maximum exemption from Section 16 of the Exchange Act
       with respect to Plan transactions.

10. Non-Transferability of Options. The Option may not be sold, pledged,
assigned, hypothecated, transferred or disposed of in any manner other than by
will or by the laws of descent or distribution. The designation of a beneficiary
by an Optionee shall not constitute a transfer. An Option may be exercised,
during the lifetime of the Optionee, only by the Optionee.

11. Adjustments Upon Changes in Capitalization or Merger. Subject to any
required action by the stockholders of the Company, the number of shares of
Common Stock covered by each outstanding Option, and the number of shares of
Common Stock which have been authorized for issuance under the Plan but as to
which no Options have yet been granted or which have been returned to the Plan
upon cancellation or expiration of an Option, as well as the price per share of
Common Stock covered by each such outstanding Option, shall be proportionately
adjusted for any increase or decrease in the number of issued shares of Common
Stock resulting from a stock split, reverse stock split, stock dividend,
combination or reclassification of the Common Stock, or any other increase or
decrease in the number of issued shares of Common Stock effected without receipt
of consideration by the Company; provided, however, that conversion of any
convertible securities of the Company shall not be deemed to have been "effected
without receipt of consideration." Such adjustment shall be made by the
Administrator, whose determination in that respect shall be final, binding, and
conclusive. Except as expressly provided herein, no issuance by the Company of
shares of stock of any class, or securities convertible into shares of stock of
any class, shall affect, and no adjustment by reason thereof shall be made with
respect to, the number or price of shares of Common Stock subject to an Option.

In the event of the proposed dissolution or liquidation of the Company, the
Administrator shall notify the Optionee at least fifteen (15) days prior to such
proposed action. To the extent it has not been previously exercised, the Option
shall terminate immediately prior to the consummation of such proposed action.
In the event of a proposed sale of all or substantially all of the assets of the
Company, or the merger of the Company with or into another corporation, the
Option shall be assumed or an equivalent option shall be substituted by such
successor corporation or a parent or subsidiary of such successor corporation,
unless such successor corporation does not agree to assume the Option or to
substitute an equivalent option, in which case such Option shall terminate upon
the consummation of the merger.

12. Time of Granting Options. The date of grant of an Option shall, for all
purposes, be the date on which the Administrator makes the determination
granting such Option or such other date as is determined by the Administrator.
Notice of the determination shall be given to each Employee or Consultant to
whom an Option is so granted within a reasonable time after the date of such
grant.

13. Amendment and Termination of the Plan.

       (a) Amendment and Termination. The Board may amend or terminate the Plan
       from time to time in such respects as the Board may deem advisable;
       provided, however, that the following revisions or amendments shall
       require approval of the stockholders of the Company in the manner
       described in Section 18 of the Plan:

            (i) any increase in the number of Shares subject to the Plan, other
            than in connection with an adjustment under Section 11 above;

                                       6
<PAGE>

            (ii) any change in the designation of the class of persons eligible
            to be granted Options; or

            (iii) if the Company has a class of equity security registered under
            Section 12 of the Exchange Act at the time of such revision or
            amendment, any material increase in the benefits accruing to
            participants under the Plan.

       (b) Stockholder Approval. If any amendment requiring stockholder approval
       under Section 13(a) above is made subsequent to the first registration of
       any class of equity security by the Company under Section 12 of the
       Exchange Act, then such stockholder approval shall be solicited as
       described in Section 18 below.

       (c) Effect of Amendment or Termination. Any such amendment or termination
       of the Plan shall not affect Options already granted and such Options
       shall remain in full force and effect as if this Plan had not been
       amended or terminated, unless mutually agreed otherwise between the
       Optionee and the Board, which agreement must be in writing and signed by
       the Optionee and the Company.

14. Conditions Upon Issuance of Shares. Shares shall not be issued pursuant to
the exercise of an Option unless the exercise of such Option and the issuance
and delivery of such Shares pursuant thereto complies with all relevant
provisions of law, including, without limitation, the Securities Act of 1933, as
amended, the Exchange Act, the rules and regulations promulgated thereunder, and
the requirements of any stock exchange upon which the Shares may then be listed.
The exercise of such Option and the issuance and delivery of such Shares
pursuant thereto shall be further subject to the approval of counsel for the
Company with respect to such compliance.

As a condition to the exercise of an Option, the Company may require the person
exercising such Option to represent and warrant at the time of any such exercise
that the Shares are being purchased only for investment and without any present
intention to sell or distribute such Shares if, in the opinion of counsel for
the Company, such a representation is required by any of the aforementioned
relevant provisions of law.

15. Reservation of Shares. The Company, during the term of this Plan, will at
all times reserve and keep available such number of Shares as shall be
sufficient to satisfy the requirements of the Plan.

Inability of the Company to obtain authority from any regulatory body having
jurisdiction, which authority is deemed by the Company's counsel to be necessary
to the lawful issuance and sale of any Shares under this Plan, shall relieve the
Company of any liability in respect of the failure to issue or sell such Shares
as to which such requisite authority shall not have been obtained.

16. Option Agreement. Options shall be evidenced by written option agreements in
such form as the Administrator shall approve.

17. Annual Report to Optionees. The Board of Directors shall cause an annual
report to be sent to the Optionees not later than one hundred twenty (120) days
after the close of the fiscal year adopted by the corporation. Such report shall
be sent at least fifteen (15) days (or, if sent by third-class mail, thirty-five
(35) days) before the annual meeting of stockholders to be held during the next
fiscal year. The annual report shall contain (i) a balance sheet as of the end
of the fiscal year, (ii) an income statement for the fiscal year, (iii) a
statement of cash flow for the fiscal year, and (iv) any report of independent
accountants or, if there is not such report, the certificate of an authorized
officer of the corporation that the statements were prepared without audit from
the books and records of the corporation.

The foregoing requirement of an annual report shall be waived so long as the
shares of the Company are held by fewer than one hundred (100) holders of
record.

18. Stockholder Approval.

       (a) Continuance of the Plan shall be subject to approval by the
       stockholders of the Company within twelve (12) months before or after the
       date the Plan is adopted.

       (b) If and in the event that the Company registers any class of equity
       securities pursuant to Section 12 of the Exchange Act, any required
       approval of the stockholders of the Company obtained after such
       registration shall be solicited substantially in accordance with Section
       14(a) of the Exchange Act and the rules and regulations promulgated
       thereunder.

                                       7
<PAGE>

       (c) If any required approval by the stockholders of the Plan itself or of
       any amendment thereto is solicited at any time otherwise than in the
       manner described in Section 18(b) hereof, then the Company shall, at or
       prior to the first annual meeting of stockholders held subsequent to the
       later of (1) the first registration of any class of equity securities of
       the Company under Section 12 of the Exchange Act or (2) the granting of
       an Option hereunder to an officer or director after such registration, do
       the following:

            (i) furnish in writing to the holders entitled to vote for the Plan
            substantially the same information which would be required (if
            proxies to be voted with respect to approval or disapproval of the
            Plan or amendment were then being solicited) by the rules and
            regulations in effect under Section 14(a) of the Exchange Act at the
            time such information is furnished; and

            (ii) file with, or mail for filing to, the Securities and Exchange
            Commission four copies of the written information referred to in
            subsection (i) hereof not later than the date on which such
            information is first sent or given to stockholders,


                                       8