1 EXHIBIT 2.1 FIRST AMENDMENT TO STOCK EXCHANGE AGREEMENT This FIRST AMENDMENT TO STOCK EXCHANGE AGREEMENT (the "Amendment"), is made as of the _______ day of April, 1997, by and among PEREGRINE PHARMACEUTICALS, INC., a Delaware corporation (The "Company"), those Stockholders of the Company who have executed that certain Stock Exchange Agreement dated January 15, 1997 (the "Agreement") and this Amendment, TECHNICLONE CORPORATION, a Delaware corporation ("Techniclone") the successor in interest to TECHNICLONE INTERNATIONAL CORPORATION, a California corporation which was merged into and with Techniclone on March __, 1997, PHILIP E. THORPE, Ph.D. ("Thorpe"), SANDERLING VENTURE PARTNERS III, L.P., SANDERLING III LIMITED PARTNERSHIP, SANDERLING III BIOMEDICAL, L.P. and SANDERLING VENTURE MANAGEMENT (collectively, "Sanderling"), S.K. PARTNERS, L.P. ("Saunders"), JENNIFER H. LOBO ("Jennifer") and BIOTECHNOLOGY FINANCIAL CORP. PROFIT SHARING PLAN ("BFC"). Jennifer and BFC are collectively referred to in this Amendment as "Lobo" and Lobo, Thorpe, Sanderling and Saunders are sometimes collectively referred to herein as the "Major Stockholders." Any other Stockholder of the Company that entered into the Agreement and enters into this Amendment shall be referred to herein individually as a "Minor Stockholder" and collectively as the "Minor Stockholders." The Major Stockholders and the Minor Stockholders shall sometimes be referred to herein collectively or jointly as the "Stockholders." Except as otherwise defined herein, capitalized terms used herein shall have the meanings ascribed to them in the Agreement. R E C I T A L S A. Pursuant to the terms of the Agreement, Techniclone has agreed to issue shares of its Common Stock (the "Techniclone Shares") to the Stockholders in exchange for shares of capital stock of the Company held by the Stockholders. B. Subsequent to the date of the Agreement, disputes have arisen among Techniclone, certain of the Major Stockholders and the Company, which disputes relate to the interpretation of the terms of the Agreement by such parties. C. The parties hereto desire to resolve their disputes and to amend certain of the terms of the Agreement as such provisions apply to them and to the other Stockholders. D. The Company's Board of Directors agreed to permit the conversion of the Seven Hundred Fifty Thousand Dollar ($750,000) Note at Five Dollars Forty Cents ($5.40) per share and the Stockholders by executing this Amendment will approve such conversion 25 2 A G R E E M E N T NOW, THEREFORE, in consideration of the mutual promises of the parties contained herein, and with the intent to be legally bound hereby, the parties hereto agree as follows: 1. CONVERSION OF NOTE. The Stockholders agree that the Seven Hundred Fifty Thousand Dollar ($750,000) Note shall be converted into One Hundred Thirty Eight Thousand Eight Hundred Eighty-Nine (138,889) shares of the Company's Common Stock. 2. AMENDMENT OF AGREEMENT. The parties hereto agree that Section 1.2 of the Agreement is hereby amended to provide that, in connection with the consummation of the transactions contemplated in the Agreement, Techniclone shall increase the aggregate number of Techniclone Shares that it will issue to the Stockholders, in the amounts and to the Stockholders set forth on EXHIBIT A hereto. Except as expressly set forth herein and on EXHIBIT A hereto, the Agreement shall continue to be in full force and effect as otherwise existing. 3. LIMITATION ON SANDERLING LIABILITY. Sanderling makes no representation or warranty as to the following: 1. "Section 2.3 Licenses and Permits." to the extent that such section can be read to imply that Peregrine has received any governmental approvals to develop, market or commercialize its products, such as any required approvals from the United States Federal Food and Drug Administration; 2. "Section 2.11 Intangible Personal Property." and Section 2.13 Title to and Adequacy of Assets." to the extent that such sections involve any representation that the Peregrine technology may be commercialized by Techniclone without infringement or license of patent rights held by or obtained by third parties; 3. "Section 2.27 Disclosure." to the extent that the Schedules attached to the Agreement do not contain any statement of a material fact that was untrue when made or omit any material fact necessary to make the information contained therein not misleading. 4. Restriction on Sale. Section 5.10 of the Agreement shall be amended to read as follows: 5.10 Restriction on Sale of Techniclone Shares. Except as provided below in this Section, for a period of (i) one year following the closing date if the Techniclone Shares become freely tradable as a result of being issued under an exemption from registration under the Securities Act, or (ii) if the Techniclone Shares are not freely tradable as a result of (i) above, then 120 days from the date on which a registration statement covering the Techniclone Shares is filed with the Securities and Exchange Commission, no Major Stockholder may sell any Techniclone Shares. 26 3 4. INDEMNIFICATION. 4.1 Limitation. Techniclone hereby confirms that Section 9.1.3 is in full force and effect that no indemnification within the scope of Sections 9.1.1 and 9.1.2 in the Agreement shall be due unless and to the extent that such indemnification shall individually or in the aggregate exceed the sum of $100,000. In no event, however, shall any Major Stockholder be obligated to indemnify Techniclone for the amount of any Loss or expense suffered or incurred by Techniclone, net of any reimbursements by insurance (net of the premiums, if any, paid by Techniclone or Company attributable to a period after the Closing for the insurance policy under which the claim is paid), which exceed the lesser of (i) fair market value of the Techniclone Shares issued to such Major Stockholder hereunder, at the time such indemnification is sought; or (ii) the fair market value of the Techniclone Shares issued to such Major Stockholder as determined by calculating the average of the last reported sales price of the Techniclone Common Stock over the ten (10) trading days immediately prior to that date that the transaction is publicly announced. The Major Stockholders shall be entitled, at their option, to satisfy any claim through the delivery of the Techniclone Shares valued at their applicable fair market value at any time that such shares can not be readily sold by the Major Stockholders in the public market. 4.2 Pro Rata Claims. Techniclone agrees that to the extent it asserts any claim for indemnification under the Agreement that it will assert and diligently pursue against all of the Major Shareholders its claim for indemnification. For purposes of this amendment the pro rata portion of any Major Stockholder indemnification shall be calculated as follows: the amount to be indemnified shall be the product of the total amount to be indemnified multiplied by a fraction, the numerator of which that number of Techniclone Shares delivered to such indemnifying Stockholder pursuant to the Exchange Agreement and denominator of which is the total number of all Techniclone Shares delivered to all Peregrine Stockholders pursuant to the Exchange Agreement. 4.3 Time Limitation. Section 9.4 of the Agreement shall be amended to read as follows: 9.4 Time Limitations on Assertion of Claims. Techniclone shall give notice to the Major Stockholders of any claim for indemnification pursuant to Section 9.1 within twelve (12) months after the Closing Date, except that notices of claims (i) relating to tax deficiencies pursuant to Section 9.1.4 may be given within the applicable periods of the statues of limitations for the assertion of such claims against Company or Techniclone, (ii) relating to Sections 2.1, 2.4, 2.5 and 2.8 may be given at any time, (iii) relating to Section 2.11, any time within the ten (10) year period commencing on the Closing Date and (iv) relating to Sections 2.16 and 2.18, may be given as long as the applicable statute of limitations for the assertion of such claims against Company or Techniclone. 27 4 5. UNPROVEN TECHNOLOGY. Techniclone acknowledges that the Peregrine technology is as yet unproven and recognizes that the Major Stockholders make no representations that such technology can be developed, marketed or commercialized by Techniclone in a timely or cost-effective matter or at all. Techniclone acknowledges that it has conducted substantial due diligence into Peregrine's product development and had been afforded an opportunity to review the status of Peregrine's technology. Techniclone assumes the risks of further technology development. 6. LOCK-UP PROVISIONS. The Major Stockholders agree they will not offer, sell, contract to sell, grant any option to purchase, make any short sale or otherwise dispose of or make a distribution of any Common Stock of the Company (including, without limitation, Common Stock of the Company which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations of the Securities and Exchange Commission) for a period of one year after the Closing Date of the transactions contemplated by the Agreement (the "Lock-Up Period"). Notwithstanding anything to the contrary in the foregoing, during the Lock-Up Period each of the Major Stockholders may sell or otherwise transfer that number of Shares of the Company's Common Stock which is set forth next to their name below: NUMBER OF SHARES WHICH ---------------------- MAY BE SOLD DURING THE ---------------------- MAJOR STOCKHOLDER LOCK-UP PERIOD ----------------- -------------- Sanderling 275,000 Saunders 275,000 Lobo 90,000 Thorpe 50,000 The Major Stockholders agree that this provision is irrevocable and shall be binding upon each of them and their heirs, legal representatives, successors and assigns. The Major Stockholders agree and consent to the entry of stop transfer instructions with the Company's transfer agent against the transfer of securities held by the Major Stockholders, except in compliance with this Amendment. 7. MUTUAL RELEASE. In consideration for Techniclone agreeing to increase the number of Techniclone Shares to be issued to the Stockholders, as provided in Section 2 above, each of the Stockholders and Company agree to, and do hereby, waive, release and discharge each of the other Stockholders, the officers, directors and agents of the Company, and the Company, as well as their respective officers, directors, shareholders and agents, from any and all claims including, without limitation, any claims to additional shares of Company or Techniclone Stock by reason of exercise of warrants, conversion of notes or otherwise, demands, costs, contracts, liabilities, objections, rights, damages, expenses, compensation and actions and causes of action of every nature, whether in law or in equity, known or unknown, or suspected or unsuspected, which such Stockholders ever had or now have against each other, the Company, or the Company's Officers, Directors or Agents, which relate to (i) their positions or actions at the Company, (ii) the negotiation, execution and performance of the terms of the Agreement, this Amendment or (iii) their investment in the Company. 28 5 8. WAIVER OF CIVIL CODE SECTION 1542. The Major Stockholders hereto each expressly waive and relinquish any and all rights that they may have under the provisions of Section 1542 of the California Civil Code, which reads as follows: A GENERAL RELEASE DOES NOT EXTEND TO CLAIMS WHICH THE CREDITOR DOES NOT KNOW OR SUSPECT TO EXIST IN HIS FAVOR AT THE TIME OF EXECUTING THE RELEASE, WHICH IF KNOWN BY HIM MUST HAVE MATERIALLY AFFECTED HIS SETTLEMENT WITH THE DEBTOR. 9. SALE OF ADDITIONAL SHARES TO SANDERLING. Techniclone agrees to sell to Sanderling $550,000 of its Common Stock on the Closing Date of the transactions contemplated by the Agreement (the "Closing Date") at a purchase price equal to eighty percent (80%) of the average of the Closing Price, as that term is defined below, of Techniclone's Common Stock for the five (5) trading days immediately preceding the Closing Date. For purposes hereof the "Closing Price" shall be the Closing Price on the NASDAQ Small Cap Market or if the Company's Common Stock is then traded on a national securities exchange or NASDAQ National Market System the Closing Price shall be the Closing Price of the Company's Common Stock on the principal national securities exchange. Sanderling (i) agrees to enter into a Purchaser Representation and Subscription Agreement with respect to the purchase of the shares of Common Stock pursuant to this Section 9 and (ii) understands and agrees that the shares of Common Stock to be issued pursuant to this Section 9 will be "restricted shares" as that term is defined in Rule 144 promulgated under the Securities Act of 1933. 10. EFFECTIVE DATE. The parties to this Amendment agree that this Amendment and the release contained herein shall only be effective upon the closing of the Agreement. 11. COMPREHENSION OF DOCUMENTS. In entering into this Amendment, the parties represent that they relied upon the legal advice of their respective attorneys, who are the attorneys of their own choice, and that the terms of this Amendment are fully understood and voluntarily accepted by the parties without duress or coercion, economic or otherwise. 12. MUTUAL DRAFTING. Each party hereto has cooperated in the negotiation, drafting and preparation of this Amendment. Therefore, this Amendment shall not be construed against any party, but shall be construed to have been drafted jointly by each of the parties. 13. AUTHORITY TO EXECUTE AMENDMENT. Each party or responsible officer thereof has read this Amendment and understands the contents hereof. Each party or responsible officer thereof executing this Amendment is empowered to do so and thereby binds himself, herself or the party for whom he or she signs. 14. COUNTERPART EXECUTION. This Amendment may be executed simultaneously in two or more counterparts, each of which shall be deemed an original, but all of which together shall constitute but one and the same original. 29 6 IN WITNESS WHEREOF, the undersigned have executed this Amendment as of the day and year first above written. TECHNICLONE CORPORATION PEREGRINE PHARMACEUTICALS, INC. By: _________________________________ By: _____________________________ Lon H. Stone, Chairman and Jennifer H. Lobo, President CEO __________________________________ Jennifer H. Lobo __________________________________ Philip E. Thorpe, Ph.D. SANDERLING VENTURES MANAGEMENT By: _____________________________ Its: _____________________________ 30 7 SANDERLING VENTURE PARTNERS III, L.P. By: _____________________________ Its: _____________________________ SANDERLING III LIMITED PARTNERSHIP By: _____________________________ Its: _____________________________ SANDERLING III BIOMEDICAL, L.P. By: _____________________________ Its: _____________________________ BIOTECHNOLOGY FINANCIAL CORP. PROFIT SHARING PLAN By: _____________________________ Jennifer Lobo Its: _____________________________ S.K. PARTNERS, L.P. By: _____________________________ Its: _____________________________ __________________________________ Marc E. Lippman, M.D. __________________________________ Phyllis Rand __________________________________ Thomas Maciag, Ph.D. __________________________________ Stuart A. Aaronson, M.D. 31 8 __________________________________ Merton Bernfield, M.D. __________________________________ Harold F. Dvorak, M.D. __________________________________ Rakesh K. Jain, Ph.D. __________________________________ Michael Klagsbrun, Ph.D. __________________________________ Christina L. Schumacher __________________________________ Steven King BETH ISRAEL HOSPITAL By: _____________________________ Its: _____________________________ 32 9 AMENDED TERMS FOR THE ISSUANCE OF TECHNICLONE SHARES SANDERLING SAUNDERS/ THORPE LOBO OTHERS TOTAL KARP ---------- -------- ------ ---- ------ ----- Existing Stock 279,630 350,000 80,000 270,000 96,332 1,075,962 Add: Conversion of $550,000 Note 16,215 16,215 16,215 12,466 61,111 at $9.00 per share Conversion of $326,700 Note at 12,100 12,100 12,100 36,300 $9.00 per share Conversion of $750,000 Note at 92,592 37,037 9,260 138,889 $5.40 per share Thorpe Adjustment 56,918 52,885 400,537 415,352 136,918 307,575 108,798 1,369,180 Conversion Factor 3.6518207 3.6518207 3.6518207 3.6518207 3.6518207 3.6518207 Techniclone 1,462,689 1,516,791 500,000 1,123,209 397,311 5,000,000 Shares Techniclone 50,000 13,000 17,000 80,000 Contribution 1,512,689 Total Shares 1,512,689(A) 1,516,791 500,000 1,136,209 414,311 5,080,000 Conversion Factor: 5,000,000 = 3.6518207 --------- 1,369,180 (A) Techniclone will enter into a side agreement to sell, and will sell to, Sanderling $550,000 of Techniclone Common Stock at 80% of the average of the Closing Price of the Techniclone Common Stock on the NASDAQ Small Cap Market for the fine trading days preceding the Closing Date of the Agreement per share at the closing.