<PAGE>
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
----------------------------------------------------------
FORM 8-K
CURRENT REPORT
PURSUANT TO SECTION 13 OR 15(d) OF
THE SECURITIES EXCHANGE ACT OF 1934
Date of Report (Date of earliest event reported): August 14, 2000
(August 13, 2000)
Chiron Corporation
--------------------------------------------------------------------------------
(Exact name of registrant as specified in its charter)
Delaware 0-12798 94-2754624
--------------------------------------------------------------------------------
(State or other (Commission (IRS Employer
jurisdiction of File Number) Identification No.)
incorporation)
4560 Horton Street, Emeryville, CA 94608
--------------------------------------------------------------------------------
(Address of principal executive offices) (Zip Code)
Registrant's telephone number, including area code (510) 655-8730
--------------
N/A
--------------------------------------------------------------------------------
(Former name or former address, if changed since last report)
ITEM 5. OTHER EVENTS.
On August 14, 2000, Chiron Corporation ("Chiron") and PathoGenesis
Corporation, a Delaware corporation ("PathoGenesis"), issued a joint press
release announcing that Chiron, PathoGenesis and Picard Acquisition Corp., a
Delaware corporation and a wholly owned subsidiary of Chiron ("Merger Sub"),
have entered into an Agreement and Plan of Merger (the "Merger Agreement"),
dated as of August 13, 2000, under which Chiron has agreed, subject to
customary conditions, to make a tender offer (the "Offer") to purchase any or
all of the outstanding shares of common stock, par value $0.001 per share
(the "Common Stock"), of PathoGenesis at a purchase price equal to $38.50 per
share in cash. The Merger Agreement provides for the Offer to be followed by
a subsequent merger (the "Merger") of Merger Sub with and into PathoGenesis,
after which PathoGenesis will be a wholly owned subsidiary of Chiron. Chiron
issued a separate press release on August 14, 2000 announcing the Merger
Agreement. Both the press releases issued August 14, 2000 appear as exhibits
to this report.
<PAGE>
ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS.
(c) Exhibits.
EXHIBIT NUMBER
99.1 Joint Press Release by Chiron Corporation and PathoGenesis
Corporation dated August 14, 2000 referred to in Item 5
above.
99.2 Press Release by Chiron Corporation dated August 14, 2000
referred to in Item 5 above.
2
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned hereunto duly authorized.
CHIRON CORPORATION
Date: August 14, 2000 By: /s/ William G. Green
------------------------
William G. Green
Senior Vice President,
General Counsel and
Secretary
3
