EXHIBIT 2.1 AGREEMENT AND PLAN OF MERGER THIS AGREEMENT AND PLAN OF MERGER (hereinafter called the "Merger Agreement") is made as of June 4, 1998, by and between INHALE THERAPEUTIC SYSTEMS, a California corporation ("Inhale California"), and INHALE THERAPEUTIC SYSTEMS (DELAWARE), INC., a Delaware corporation ("Inhale Delaware"). Inhale California and Inhale Delaware are sometimes referred to as the "Constituent Corporations." The authorized capital stock of Inhale California consists of thirty-million (30,000,000) shares of Common Stock, no par value, and ten million (10,000,000) shares of Preferred Stock, no par value. The authorized capital stock of Inhale Delaware, upon effectuation of the transactions set forth in this Merger Agreement, will consist of fifty million (50,000,000) shares of Common Stock, each having a par value of one-hundredth of one cent (.0001), and ten million (10,000,000) shares of Preferred Stock, each having a par value of one-hundredth of one cent (.0001). The directors of the Constituent Corporations deem it advisable and to the advantage of the Constituent Corporations that Inhale California merge into Inhale Delaware upon the terms and conditions herein provided. NOW, THEREFORE, the parties do hereby adopt the plan of reorganization encompassed by this Merger Agreement and do hereby agree that Inhale California shall merge into Inhale Delaware on the following terms, conditions and other provisions: 1. TERMS AND CONDITIONS. 1.1 MERGER. Inhale California shall be merged with and into Inhale Delaware (the "Merger"), and Inhale Delaware shall be the surviving corporation (the "Surviving Corporation") effective upon the date when this Merger Agreement is filed with the Secretary of State of Delaware (the "Effective Date"). 1.2 NAME CHANGE. On the Effective Date, the name of Inhale Delaware shall be Inhale Therapeutic Systems, Inc. 1.3 SUCCESSION. On the Effective Date, Inhale Delaware shall continue its corporate existence under the laws of the State of Delaware, and the separate existence and corporate organization of Inhale California, except insofar as it may be continued by operation of law, shall be terminated and cease. 1.4 TRANSFER OF ASSETS AND LIABILITIES. On the Effective Date, the rights, privileges, powers and franchises, both of a public as well as of a private nature, of each of the Constituent Corporations shall be vested in and possessed by the Surviving Corporation, subject to all of the disabilities, duties and restrictions of or upon each of the Constituent Corporations; and all and singular rights, privileges, powers and franchises of each of the Constituent Corporations, and all property, real, personal and mixed, of each of the Constituent Corporations, and all debts due to each of the Constituent Corporations on whatever account, and all things in action or belonging to each of the Constituent Corporations shall be transferred to and vested in the Surviving Corporation; and all property, rights, privileges, powers and franchises, and all and every other interest, shall be thereafter the property of the Surviving Corporation as they were of the Constituent Corporations, and the title to any real estate vested by deed or otherwise in either of the Constituent Corporations shall not revert or be in any way impaired by reason of the Merger; provided, however, that the liabilities of the Constituent Corporations and of their shareholders, directors and officers shall not be affected and all rights of creditors and all liens upon any property of either of the Constituent Corporations shall be preserved unimpaired, and any claim existing or action or proceeding pending by or against either of the Constituent Corporations may be prosecuted to judgment as if the Merger had not taken place except as they may be modified with the consent of such creditors and all debts, liabilities and duties of or upon each of the Constituent Corporations shall attach to the Surviving 1 Corporation, and may be enforced against it to the same extent as if such debts, liabilities and duties had been incurred or contracted by it. 1.5 COMMON STOCK OF INHALE CALIFORNIA AND INHALE DELAWARE. On the Effective Date, by virtue of the Merger and without any further action on the part of the Constituent Corporations or their shareholders, each share of Common Stock of Inhale California issued and outstanding immediately prior thereto shall be converted into one (1) fully paid and nonassessable share of the Common Stock of Inhale Delaware and each share of Common Stock of Inhale Delaware issued and outstanding immediately prior thereto shall be canceled and returned to the status of authorized but unissued shares. 1.6 STOCK CERTIFICATES. On and after the Effective Date, all of the outstanding certificates which prior to that time represented shares of the Common Stock or of the Preferred Stock of Inhale California shall be deemed for all purposes to evidence ownership of and to represent the shares of Inhale Delaware into which the shares of Inhale California represented by such certificates have been converted as herein provided and shall be so registered on the books and records of the Surviving Corporation or its transfer agents. The registered owner of any such outstanding stock certificate shall, until such certificate shall have been surrendered for transfer or conversion or otherwise accounted for to the Surviving Corporation or its transfer agent, have and be entitled to exercise any voting and other rights with respect to and to receive any dividend and other distributions upon the shares of Inhale Delaware evidenced by such outstanding certificate as above provided. 1.7 OPTIONS. On the Effective Date, the Surviving Corporation will assume and continue Inhale California's 1994 Non-Employee Directors' Stock Option Plan, Employee Stock Purchase Plan, and 1994 Equity Incentive Plan and any and all other stock option plans of Inhale California and the outstanding and unexercised portions of all options to purchase Common Stock of Inhale California, including without limitation all options outstanding under such stock plans and any other outstanding options, shall be converted into options of Inhale Delaware, such that an option for one (1) share of Inhale California shall be converted into an option for one (1) share of Inhale Delaware, with no change in the exercise price of the Inhale Delaware option. No other changes in the terms and conditions of such options will occur. Effective on the Effective Date, Inhale Delaware hereby assumes the outstanding and unexercised portions of such options and the obligations of Inhale California with respect thereto. 1.8 EMPLOYEE BENEFIT PLANS. On the Effective Date, the Surviving Corporation shall assume all obligations of Inhale California under any and all of Inhale California's employee benefit plans, including the Employee Stock Purchase Plan, in effect as of such date. On the Effective Date, the Surviving Corporation shall adopt and continue in effect all such employee benefit plans upon the same terms and conditions as were in effect immediately prior to the Merger and shall reserve that number of shares of Inhale Delaware Common Stock with respect to each such employee benefit plan as is proportional to the number of shares of Inhale California Common Stock (if any) so reserved on the Effective Date. 2. CHARTER DOCUMENTS, DIRECTORS AND OFFICERS. 2.1 CERTIFICATE OF INCORPORATION AND BYLAWS. The Certificate of Incorporation and Bylaws of Inhale Delaware in effect on the Effective Date shall continue to be the Certificate of Incorporation and Bylaws of the Surviving Corporation, except that Article I of the Certificate of Incorporation and Bylaws of the Surviving Corporation shall, effective upon the filing of this Merger Agreement with the Secretary of State of the State of Delaware, be amended to read in its entirety as follows: "The name of this corporation is Inhale Therapeutic Systems, Inc." 2.2 DIRECTORS. The directors of Inhale California immediately preceding the Effective Date shall become the directors of the Surviving Corporation on and after the Effective Date to serve until the expiration of their terms and until their successors are elected and qualified. 2 2.3 OFFICERS. The officers of Inhale California immediately preceding the Effective Date shall become the officers of the Surviving Corporation on and after the Effective Date to serve at the pleasure of its Board of Directors. 3. MISCELLANEOUS. 3.1 FURTHER ASSURANCES. From time to time, and when required by the Surviving Corporation or by its successors and assigns, there shall be executed and delivered on behalf of Inhale California such deeds and other instruments, and there shall be taken or caused to be taken by it such further and other action, as shall be appropriate or necessary in order to vest or perfect in or to conform of record or otherwise, in the Surviving Corporation the title to and possession of all the property, interests, assets, rights, privileges, immunities, powers, franchises and authority of Inhale California and otherwise to carry out the purposes of this Merger Agreement, and the officers and directors of the Surviving Corporation are fully authorized in the name and on behalf of Inhale California or otherwise to take any and all such action and to execute and deliver any and all such deeds and other instruments. 3.2 AMENDMENT. At any time before or after approval by the shareholders of Inhale California, this Merger Agreement may be amended in any manner (except that, after the approval of the Merger Agreement by the shareholders of Inhale California, the principal terms may not be amended without the further approval of the shareholders of Inhale California) as may be determined in the judgment of the respective Board of Directors of Inhale Delaware and Inhale California to be necessary, desirable, or expedient in order to clarify the intention of the parties hereto or to effect or facilitate the purpose and intent of this Merger Agreement. 3.3 CONDITIONS TO MERGER. The obligations of the Constituent Corporations to effect the transactions contemplated hereby is subject to satisfaction of the following conditions (any or all of which may be waived by either of the Constituent Corporations in its sole discretion to the extent permitted by law): (a) the Merger shall have been approved by the shareholders of Inhale California in accordance with applicable provisions of the General Corporation Law of the State of California; and (b) Inhale California, as sole stockholder of Inhale Delaware, shall have approved the Merger in accordance with the General Corporation Law of the State of Delaware; and (c) any and all consents, permits, authorizations, approvals, and orders deemed in the sole discretion of Inhale California to be material to consummation of the Merger shall have been obtained. 3.4 ABANDONMENT OR DEFERRAL. At any time before the Effective Date, this Merger Agreement may be terminated and the Merger may be abandoned by the Board of Directors of either Inhale California or Inhale Delaware or both, notwithstanding the approval of this Merger Agreement by the shareholders of Inhale California or Inhale Delaware, or the consummation of the Merger may be deferred for a reasonable period of time if, in the opinion of the Boards of Directors of Inhale California and Inhale Delaware, such action would be in the best interest of such corporations. In the event of termination of this Merger Agreement, this Merger Agreement shall become void and of no effect and there shall be no liability on the part of either Constituent Corporation or its Board of Directors or shareholders with respect thereto, except that Inhale California shall pay all expenses incurred in connection with the Merger or in respect of this Merger Agreement or relating thereto. 3.5 COUNTERPARTS. In order to facilitate the filing and recording of this Merger Agreement, the same may be executed in any number of counterparts, each of which shall be deemed to be an original. 3 IN WITNESS WHEREOF, this Merger Agreement, having first been duly approved by the Board of Directors of Inhale California and Inhale Delaware, is hereby executed on behalf of each said corporation and attested by their respective officers thereunto duly authorized. INHALE THERAPEUTIC SYSTEMS a California corporation By /s/ Robert B. Chess -------------------------------- Robert B. Chess PRESIDENT AND CHIEF EXECUTIVE OFFICER ATTEST: /s/ Mark P. Tanoury - ----------------------------------- Mark P. Tanoury SECRETARY INHALE THERAPEUTIC SYSTEMS (DELAWARE), INC. a Delaware corporation By /s/ Robert B. Chess -------------------------------- Robert B. Chess PRESIDENT AND CHIEF EXECUTIVE OFFICER ATTEST: /s/ Mark P. Tanoury - ----------------------------------- Mark P. Tanoury SECRETARY 4