EX-99.A5 6 ex-99_a5.txt EXHIBIT 99-A5 OFFER TO PURCHASE FOR CASH ALL OUTSTANDING SHARES OF COMMON STOCK (INCLUDING THE ASSOCIATED RIGHTS TO PURCHASE SERIES A JUNIOR PREFERRED STOCK) OF PATHOGENESIS CORPORATION AT $38.50 NET PER SHARE BY PICARD ACQUISITION CORP. A WHOLLY OWNED SUBSIDIARY OF CHIRON CORPORATION ------------------------------------------------------------ THE OFFER AND WITHDRAWAL RIGHTS WILL EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON MONDAY, SEPTEMBER 18, 2000, UNLESS THE OFFER IS EXTENDED. -------------------------------------------------------------------------------- August 21, 2000 To Brokers, Dealers, Commercial Banks, Trust Companies And Other Nominees: We have been appointed by Picard Acquisition Corp., a Delaware corporation ("Merger Sub") and a wholly owned subsidiary of Chiron Corporation, a Delaware corporation ("Parent"), to act as Dealer Manager in connection with Purchaser's offer to purchase all outstanding shares of common stock, par value $0.001 per share (the "Common Stock"), of PathoGenesis Corporation, a Delaware corporation (the "Company"), together with the associated rights to purchase Series A Junior Preferred Stock (the "Rights") issued pursuant to the Rights Agreement, dated as of June 26, 1997, as amended (the "Rights Agreement"), between the Company and Harris Trust and Savings Bank (the Common Stock and the Rights together being referred to herein as the "Shares"), at a purchase price of $38.50 per Share, net to the seller in cash, without interest (the "Offer Price"), upon the terms and subject to the conditions set forth in the Offer to Purchase dated August 21, 2000, and in the related Letter of Transmittal (which, together with any amendments or supplements hereto or thereto, collectively constitute the "Offer"). Please furnish copies of the enclosed materials to those of your clients for whose accounts you hold Shares registered in your name or in the name of your nominee. THE OFFER IS CONDITIONED UPON, AMONG OTHER THINGS, (I) THERE BEING VALIDLY TENDERED AND NOT WITHDRAWN PRIOR TO THE EXPIRATION OF THE OFFER THAT NUMBER OF SHARES WHICH, WHEN ADDED TOGETHER WITH ALL OTHER SHARES OWNED BY CHIRON CORPORATION AND ITS SUBSIDIARIES, WOULD REPRESENT AT LEAST A MAJORITY OF THE OUTSTANDING SHARES (DETERMINED ON A FULLY DILUTED BASIS FOR ALL OUTSTANDING STOCK OPTIONS AND OTHER RIGHTS (OTHER THAN THE RIGHTS, 1 IF SUCH RIGHTS ARE NOT AT THAT TIME EXERCISABLE) TO ACQUIRE SHARES OUTSTANDING ON THE DATE OF PURCHASE), (II) ANY REQUISITE WAITING PERIOD UNDER THE HART-SCOTT-RODINO ANTITRUST IMPROVEMENTS ACT OF 1976, AS AMENDED, APPLICABLE TO THE PURCHASE OF SHARES PURSUANT TO THE OFFER OR THE MERGER DESCRIBED HEREIN HAVING BEEN TERMINATED OR HAVING EXPIRED, AND (III) THE APPLICABLE WAITING PERIODS UNDER CERTAIN FOREIGN ANTITRUST AND COMPETITION LAWS HAVING BEEN TERMINATED OR HAVING EXPIRED, EXCEPT FOR SUCH WAITING PERIODS THE FAILURE OF WHICH TO TERMINATE OR EXPIRE IS NOT REASONABLY LIKELY TO HAVE A PARENT MATERIAL ADVERSE EFFECT OR A COMPANY MATERIAL ADVERSE EFFECT (AS SUCH TERMS ARE DEFINED IN THE OFFER TO PURCHASE) OR TO PROVIDE A REASONABLE BASIS TO CONCLUDE THAT PARENT, MERGER SUB OR THE COMPANY OR ANY OF ITS DIRECTORS, OFFICERS, AGENTS, ADVISORS OR OTHER REPRESENTATIVES WOULD BE SUBJECT TO THE RISK OF CRIMINAL LIABILITY. THE OFFER IS BEING MADE PURSUANT TO AN AGREEMENT AND PLAN OF MERGER, DATED AS OF AUGUST 13, 2000 (THE "MERGER AGREEMENT"), AMONG PARENT, MERGER SUB, AND THE COMPANY. THE BOARD OF DIRECTORS OF THE COMPANY HAS DETERMINED THAT THE OFFER AND THE MERGER ARE ADVISABLE AND IN THE BEST INTERESTS OF THE COMPANY'S STOCKHOLDERS AND UNANIMOUSLY RECOMMENDS THAT THE COMPANY'S STOCKHOLDERS ACCEPT THE OFFER AND TENDER THEIR SHARES PURSUANT TO THE OFFER. For your information and for forwarding to your clients for whom you hold Shares registered in your name or in the name of your nominee, we are enclosing the following documents: 1. Offer to Purchase dated August 21, 2000; 2. Letter of Transmittal for your use in accepting the Offer and tendering Shares and for the information of your clients; 3. Notice of Guaranteed Delivery to be used to accept the Offer if certificates for the Shares and all other required documents cannot be delivered to Harris Trust Company of New York (the "Depositary"), or if the procedures for book-entry transfer cannot be completed, by the Expiration Date; 4. A printed form of letter which may be sent to your clients for whose accounts you hold Shares registered in your name or in the name of your nominee, with space provided for obtaining such clients' instructions with regard to the Offer; 5. A letter to stockholders of the Company from Sean P. Lance, President and Chief Executive Officer of the Company, together with a Solicitation/Recommendation Statement on Schedule 14D-9 dated August 21, 2000, which has been filed by the Company with the Securities and Exchange Commission which includes the recommendation of the Board of Directors of the Company that stockholders accept the Offer and tender their Shares to Purchaser pursuant to the Offer; 6. Guidelines of the Internal Revenue Service for Certification of Taxpayer Identification Number on Substitute Form W-9; and 7. A return envelope addressed to the Depositary. Upon the terms and subject to the conditions of the Offer (including, if the Offer is extended or amended, the terms and conditions of any such extension or amendment), Merger Sub will accept for payment and pay for any Shares which are validly tendered on or prior to the Expiration Date, or any Subsequent Offering Period, and not theretofore properly withdrawn, when permitted, when, as and if Merger Sub gives oral or written notice to the Depositary of Purchaser's acceptance of such Shares for payment pursuant to the Offer. Payment for any Shares purchased pursuant to the Offer will in all 2 cases be made only after timely receipt by the Depositary of (i) certificates for the Shares, or timely confirmation of a book-entry transfer of such Shares into the Depositary's account at The Depository Trust Company, pursuant to the procedures described in Section 3 of the Offer to Purchase, (ii) a properly completed and duly executed Letter of Transmittal (or a properly completed and manually signed facsimile thereof) or an Agent's Message (as defined in the Offer to Purchase) in connection with a book-entry transfer and (iii) all other documents required by the Letter of Transmittal. Merger Sub will not pay any fees or commissions to any broker or dealer or other person (other than the Depositary, the Information Agent and the Dealer Manager as described in the Offer to Purchase) in connection with the Offer. Merger Sub will, however, upon request, reimburse brokers, dealers, commercial banks and trust companies for customary mailing and handling costs incurred by them in forwarding the enclosed materials to their customers. Purchaser will pay or cause to be paid all stock transfer taxes applicable to its purchase of the Shares pursuant to the Offer, except as otherwise provided in Instruction 6 of the Letter of Transmittal. WE REQUEST THAT YOU CONTACT YOUR CLIENTS PROMPTLY. PLEASE NOTE THAT THE OFFER AND WITHDRAWAL RIGHTS EXPIRE AT 12:00 MIDNIGHT, NEW YORK CITY TIME, ON MONDAY, SEPTEMBER 18, 2000 UNLESS THE OFFER IS EXTENDED. In order to accept the Offer, a duly executed and properly completed Letter of Transmittal (or a manually signed facsimile thereof), with any required signature guarantees, or an Agent's Message in connection with a book-entry transfer of the Shares, and any other required documents, should be sent to the Depositary, and certificates representing the tendered Shares should be delivered or tendered by book-entry transfer, all in accordance with the Instructions set forth in the Letter of Transmittal and in the Offer to Purchase. If holders of the Shares wish to tender, but it is impracticable for them to forward their certificates or other required documents or to comply with the procedures for delivery by book-entry transfer prior to the expiration of the Offer, a tender may be effected by following the guaranteed delivery procedures specified in Section 3 of the Offer to Purchase. Any inquiries you may have with respect to the Offer should be addressed to, and additional copies of the enclosed materials may be obtained from, the Information Agent or the undersigned at the addresses and telephone numbers set forth on the back cover of the Offer to Purchase. Very truly yours, DONALDSON, LUFKIN & JENRETTE SECURITIES CORPORATION NOTHING CONTAINED HEREIN OR IN THE ENCLOSED DOCUMENTS SHALL CONSTITUTE YOU THE AGENT OF PARENT, MERGER SUB, THE COMPANY, THE DEALER MANAGER, THE INFORMATION AGENT, THE DEPOSITARY, OR ANY AFFILIATE OF ANY OF THE FOREGOING, OR AUTHORIZE YOU OR ANY OTHER PERSON TO USE ANY DOCUMENT OR MAKE ANY STATEMENT ON BEHALF OF ANY OF THEM IN CONNECTION WITH THE OFFER OTHER THAN THE DOCUMENTS ENCLOSED HEREWITH AND THE STATEMENTS CONTAINED THEREIN. 3