<PAGE>
--------------------------
UNITED STATES OMB APPROVAL
SECURITIES AND EXCHANGE COMMISSION --------------------------
WASHINGTON, D.C. 20549 OMB Number 3235-0167
Expires: October 31, 2001
Estimated average burden
hours per response....1.50
--------------------------
FORM 15
CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF
THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER
SECTIONS 13 AND 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934.
000-19809
Commission File Number 000-23051
----------------
DURA PHARMACEUTICALS, INC.
SPIROS DEVELOPMENT CORPORATION II, INC.
- -------------------------------------------------------------------------------
(Exact name of registrant as specified in its charter)
ATTN: JOHN R. COOK
7475 LUSK BLVD., SAN DIEGO, CALIFORNIA 92121
- -------------------------------------------------------------------------------
(Address, including zip code, and telephone number, including area code, of
registrant's principal executive offices)
UNITS CONSISTING OF 1 SHARE OF CALLABLE COMMON STOCK OF SPIROS DEVELOPMENT
CORPORATION II, INC., PAR VALUE $.001 PER SHARE, AND 1 WARRANT TO PURCHASE
1/4 SHARE OF COMMON STOCK OF
DURA PHARMACEUTICALS, INC., PAR VALUE $.001 PER SHARE
- -------------------------------------------------------------------------------
(Title of each class of securities covered by this Form)
WARRANT TO PURCHASE 1/4 OF 1 SHARE OF COMMON STOCK, PAR VALUE $.001 PER SHARE,
OF DURA PHARMACEUTICALS, INC.
CALLABLE COMMON STOCK, PAR VALUE $.001 PER SHARE, OF SPIROS DEVELOPMENT
CORPORATION II, INC.
- -------------------------------------------------------------------------------
(Titles of all other classes of securities for which a duty to file
reports under section 13(a) or 15(d) remains)
Please place an X in the box(es) to designate the appropriate rule
provision(s) relied upon to terminate or suspend the duty to file reports:
Rule 12g-4(a)(1)(i) /X/ Rule 12h-3(b)(1)(i) / /
Rule 12g-4(a)(1)(ii) / / Rule 12h-3(b)(1)(ii) / /
Rule 12g-4(a)(2)(i) / / Rule 12h-3(b)(2)(i) / /
Rule 12g-4(a)(2)(ii) / / Rule 12h-3(b)(2)(ii) / /
Rule 15d-6 / /
Approximate number of holders of record as of the certificate or notice
date: 0
------------------
EFFECTIVE AS OF JANUARY 1, 2000, THE UNITS CEASE TO EXIST AND THE CALLABLE
COMMON STOCK AND THE WARRANTS WILL TRADE SEPARATELY.
Pursuant to the requirements of the Securities Exchange Act of 1934 Dura
Pharmaceuticals, Inc. has caused this certification/notice to be signed on its
behalf by the undersigned duly authorized person.
Date: January 1, 2000 By: /s/ John R. Cook
----------------------------------- --------------------------------
John R. Cook, Vice President,
Associate General Counsel and
Secretary
Pursuant to the requirements of the Securities Exchange Act of 1934 Spiros
Development Corporation II, Inc. has caused this certification/notice to be
signed on its behalf by the undersigned duly authorized person.
Date: January 1, 2000 By: /s/ John R. Cook
----------------------------------- --------------------------------
John R. Cook, Secretary
Instruction: This form is required by Rules 12g-4, 12h-3 and 15d-6 of the
General Rules and Regulations under the Securities Exchange Act of 1934. The
registrant shall file with the Commission three copies of Form 15, one of which
shall be manually signed. It may be signed by an officer of the registrant, by
counsel or by any other duly authorized person. The name and title of the person
signing the form shall by typed or printed under the signature.
