content: <PAGE>   1
  
              As filed with the Securities and Exchange Commission on
                                   July 10, 1996
  
  
                                                  Registration No. 333-___________
  
  
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
  
                                      FORM S-8
                               REGISTRATION STATEMENT
                                       UNDER
                             THE SECURITIES ACT OF 1933
  
                           NEXSTAR PHARMACEUTICALS, INC.
                 --------------------------------------------------
                 (Exact name of issuer as specified in its charter)
  
  
     DELAWARE                                            84-1173453        
  - ---------------------------------                  ----------------------
  (State or other jurisdiction                       (I.R.S. Employer
  of incorporation or organization)                  Identification Number)
  
  
  2860 Wilderness Place
  Boulder, CO                                                80301   
  - ----------------------------------------                 ----------
  (Address of principal executive offices)                 (zip code)
  
  
                  NEXAGEN, INC. 1994 EMPLOYEE STOCK PURCHASE PLAN
                  -----------------------------------------------
                              (Full title of the plan)
  
  
                                 PATRICK J. MAHAFFY
                              Chief Executive Officer
                           NeXstar Pharmaceuticals, Inc.
                               2860 Wilderness Place
                                 Boulder, CO  80301
                                   (303) 444-5893  
                                 ------------------
            (Name and address, including zip code, of agent for service)
           (Telephone number, including area code, of agent for service)
  
                                 ------------------
  
                                      COPY TO:
                                Peter H. Jakes, Esq.
                              Willkie Farr & Gallagher
                                One Citicorp Center
                                153 East 53rd Street
                                 New York, NY 10022
                                   (212) 821-8000
  <PAGE>   2
  
  
  
                          CALCULATION OF REGISTRATION FEE
  
  <TABLE>
  <CAPTION>
  - ----------------------------------------------------------------------------------------------------
                                               Proposed               Proposed
  Title of              Amount                 maximum                maximum               Amount
  securities            to be                  offering               aggregate             of reg-
  to be                 regis-                 price per              offering              istration
  registered            tered(1)               share (2)              price (2)             fee
  - ----------------------------------------------------------------------------------------------------
  <S>                   <C>                    <C>                    <C>                   <C>
  Common 
  Stock,
  $0.01 par
  value per
  share                 300,000(3)             $20,625                $6,187,500            $2,134
  </TABLE>
  
  - ---------------------
  
  (1)    This Registration Statement covers the additional 300,000 shares of
         Common Stock, $0.01 par value per share, of NeXstar Pharmaceuticals,
         Inc., a Delaware corporation ("NeXstar" or the "Registrant"), authorized
         to be issued under the NeXagen, Inc. 1994 Employee Stock Purchase Plan.
         On February 21, 1995, NeXagen, Inc. changed its name to NeXstar
         Pharmaceuticals, Inc. in connection with the merger of its wholly-owned
         subsidiary Neptune Merger-Sub Corp., a Delaware corporation, with and
         into Vestar, Inc., a Delaware corporation.
  
  (2)    Reflects the average of the high and low prices of NeXstar Common Stock
         on July 8, 1996 on the Nasdaq National Market pursuant to Rule 457(h)
         and (c) under the Securities Act of 1933, as amended (the "Securities
         Act").
  
  (3)    Represents shares which have not yet been issued.
  
  
  
  
  
                                       -2-
  <PAGE>   3
  
  
                                       PART I
                              INFORMATION NOT REQUIRED
                           IN THE REGISTRATION STATEMENT
  
                                      PART II
                            INFORMATION REQUIRED IN THE
                               REGISTRATION STATEMENT
  
  Item 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
  
                   The following documents, filed with the Securities and
  Exchange Commission (the "Commission") by NeXstar, a Delaware corporation, are
  incorporated herein by reference:
  
                            (a)  The Registrant's Registration Statement on Form
                   S-8 (Registration No. 33-88074), dated December 30, 1994,
                   filed pursuant to the Securities Act.
  
                            (b)  The Registrant's annual report on Form 10-K for
                   the fiscal year ended December 31, 1995, filed pursuant to the
                   Securities Exchange Act of 1934 (the "Exchange Act").
  
                            (c)  All other reports filed by the Registrant
                   pursuant to Section 13(a) or 15(d) of the Exchange Act since
                   the end of the fiscal year covered by the Form 10-K referred
                   to in (b) above, including, without limitation, the reports
                   referred to in items (d) and (e) below.
  
                            (d)  The Registrant's quarterly report on Form 10-Q
                   for the quarter ended March 31, 1996, filed pursuant to the
                   Exchange Act.
  
                            (e)  The Registrant's current reports on Form 8-K,
                   filed with the Commission on April 10, 1996, June 21,
                   1996, and July 8, 1996, respectively.
  
                            (f)  The description of NeXstar's common stock, $0.01
                   par value per share (the "Common Stock"), which is contained
                   in NeXagen's Registration Statement filed under the Exchange
                   Act, on Form 8-A (File No. 0-23012) on December 6, 1993, as
                   amended on Form 8-A/A filed on January 25, 1994.
  
                   In addition, all documents filed by NeXstar with the
  Commission pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act
  subsequent to the date of this Registration Statement and prior to the filing
  of a post-effective amendment which indicates that all the securities offered
  hereby have been sold or which deregisters all securities then remaining unsold
  shall be
  
  
  
  
  
                                        -3-
  <PAGE>   4
  
  
  deemed to be incorporated herein by reference and to be a part hereof from the
  date of the filing of such documents with the Commission.  Any statement
  contained in a document incorporated by reference herein shall be deemed to be
  modified or superseded for purposes hereof to the extent that a statement
  contained herein (or in any other subsequently filed document which also is
  incorporated by reference herein) modifies or supersedes such statement.  Any
  statement so modified or superseded shall not be deemed to constitute a part
  hereof except as so modified or superseded.
  
  Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL
  
                 Certain legal matters with respect to the shares of Common Stock
  registered hereunder will be passed upon for the Registrant by Willkie Farr &
  Gallagher, New York, New York.  A member of the firm of Willkie Farr &
  Gallagher owns 2,440 shares of the Registrant's Common Stock.
  
  Item 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS
  
                 The Registrant's By-Laws require the Registrant to indemnify any
  and all of its directors or officers, or directors or officers who serve at the
  request of the corporation as a director or officer of another corporation, to
  the full extent permitted by the Delaware General Corporation Law (the "DGCL").
  
                 The Registrant's Second Amended and Restated Certificate of
  Incorporation (the "Certificate of Incorporation") also provides that:
  
                 The Registrant shall indemnify to the fullest extent permitted
           under and in accordance with the laws of the State of Delaware any
           person who was or is a party or is threatened to be made a party to
           any threatened, pending or completed action, suit or proceeding,
           whether civil, criminal, administrative or investigative by reason of
           the fact that he is or was a director, officer, employee or agent of
           the Registrant, or is or was serving at the request of the Registrant
           as a director, officer, trustee, employee or agent of or in any other
           capacity with another corporation, partnership, joint venture, trust
           or other enterprise, against expenses (including attorneys' fees),
           judgments, fines and amounts paid in settlement actually and
           reasonably incurred by him in connection with such action, suit or
           proceeding if he acted in good faith and in a manner he reasonably
           believed to be in or not opposed to the best interests of the
           Registrant, and, with respect to any criminal action or proceeding,
           had no reasonable cause to believe his conduct was unlawful.
  
                 Expenses incurred in defending a civil or criminal action, suit
           or proceeding shall (in the case of any action, suit or proceeding
           against a director of the Registrant) or may (in the case of any
           action, suit or proceeding against an officer, trustee, employee or
           agent) be paid by the Registrant in advance of the final disposition
           of such action, suit or proceeding as authorized by the Registrant's
           Board of Directors upon receipt of an undertaking by or on behalf of
           the indemnified person to repay such amount if it shall ultimately be
           determined that he is not entitled to be indemnified by the Registrant
           as authorized in the Registrant's Certificate of Incorporation.
  
  
  
  
  
                                        -4-
  <PAGE>   5
  
  
                 The indemnification and other rights set forth in the
           Certificate of Incorporation shall not be exclusive of any provisions
           with respect thereto in the By-Laws or any other contract or agreement
           between the Registrant and any officer, director, employee or agent of
           the Registrant.
  
                 Neither the amendment nor repeal of the provisions (described
           above) in the Certificate of Incorporation regarding indemnification,
           nor the adoption of any provision of the Certificate of Incorporation
           inconsistent with such provisions, shall eliminate or reduce the
           effect of such provisions, in respect of any matter occurring prior to
           such amendment, repeal or adoption of an inconsistent provision or in
           respect of any cause of action, suit or claim relating to any such
           matter which would have given rise to a right of indemnification or
           right to receive expenses pursuant to such provisions, if such
           provision had not been so amended or repealed or if a provision
           inconsistent therewith had not been so adopted.
  
                 No director shall be personally liable to the Registrant or any
           stockholder for monetary damages for breach of fiduciary duty as a
           director, except for any matter in respect of which such director (A)
           shall be liable under Section 174 of the DGCL or any amendment thereto
           or successor provision thereto, or (B) shall be liable by reason that,
           in addition to any and all other requirements for liability he:
  
                   (i)      shall have breached his duty of loyalty to the
           Registrant or its stockholders;
  
                   (ii)     shall not have acted in good faith or, in failing to
           act, shall not have acted in good faith;
  
                   (iii)    shall have acted in a manner involving intentional
           misconduct or a knowing violation of law or, in failing to act, shall
           have acted in a manner involving intentional misconduct or a knowing
           violation of law; or
  
                   (iv)     shall have derived an improper personal benefit.
  
                 If the DGCL is amended after the date upon which a document is
           filed in the State of Delaware to authorize corporate action further
           eliminating or limiting the personal liability of directors, then the
           liability of a director of the Registrant shall be eliminated or
           limited to the fullest extent permitted by the DGCL, as so amended.
  
                 Section 145 of the DGCL empowers a Delaware corporation to
  indemnify any persons who are, or are threatened to be made, parties to any
  threatened, pending or completed legal action, suit or proceeding, whether
  civil, criminal, administrative or investigative (other than an action by or in
  the right of such corporation), by reason of the fact that such person is or
  was an
  
  
  
  
  
                                        -5-
  <PAGE>   6
  
  
  officer or director of such corporation, or is or was serving at the request of
  such corporation as a director, officer, employee or agent of another
  corporation or enterprise.  The indemnity may include expenses (including
  attorneys' fees), judgments, fines and amounts paid in settlement actually and
  reasonably incurred by such person in connection with such action, suit or
  proceeding, provided that such officer or director acted in good faith and in a
  manner reasonably believed to be in or not opposed to the corporation's best
  interests, and, for criminal proceedings, had no reasonable cause to believe
  his conduct was illegal.  A Delaware corporation may indemnify officers and
  directors in an action by or in the right of the corporation under the same
  conditions, except that no indemnification is permitted without judicial
  approval if the officer or director is adjudged to be liable to the corporation
  in the performance of his duty.  Where an officer or director is successful on
  the merits or otherwise in the defense of any action referred to above, the
  corporation must indemnify him against the expenses which such officer or
  director actually and reasonably incurred.
  
  Item 8.  EXHIBITS
  
  <TABLE>
  <CAPTION>
  Exhibit No.
  - -----------
  <S>              <C>
  4.1              Second Amended and Restated Certificate of Incorporation of the Registrant (Previously filed as an exhibit to the
                   Registrant's Registration Statement on Form S-3 (File No. 333-04653), declared effective by the Commission on June
                   19, 1996, and incorporated herein by reference.)
  
  4.2              Form of Common Stock Certificate of the Registrant (Previously filed as an exhibit to the Registrant's Annual
                   Report on Form 10-K for the fiscal year ended December 31, 1994, and incorporated herein by reference.)
  
  5.1              Opinion of Willkie Farr & Gallagher, counsel to NeXstar, as to the legality of the shares being registered.
  
  23.1             Consent of Ernst & Young LLP.
  
  23.2             Consent of Willkie Farr & Gallagher (contained in exhibit 5.1).
  
  24.1             Power of Attorney (reference is made to the signature page).
  
  99.1             Registrant's 1994 Employee Stock Purchase Plan (Previously filed as an exhibit to the Registrant's Annual Report on
                   Form 10-K for the fiscal year ended December 31, 1994, and incorporated herein by reference.)
  
  99.2             Amendment No. 1 to Registrant's 1994 Employees Stock Purchase Plan (Previously filed as an exhibit to the 
                   Registrant's Registration Statement on Form S-3 (File No. 333-04653), declared effective by the Commission on 
                   June 19, 1996, and incorporated herein by reference.)
  
  </TABLE>
  
  
  
  
  
                                        -6-
  <PAGE>   7
  
  
  
                                     SIGNATURES
  
  
             Pursuant to the requirements of the Securities Act of 1933, as
  amended, the registrant certifies that it has reasonable grounds to believe
  that it meets all of the requirements for filing on Form S-8 and has duly
  caused this Registration Statement to be signed on its behalf by the
  undersigned, thereunto duly authorized, in Boulder, Colorado on the 10th day of
  July 1996.
  
                                       NEXSTAR PHARMACEUTICALS, INC.
  
  
                                       By:  /s/ Patrick J. Mahaffy  
                                            ------------------------
                                            Patrick J. Mahaffy
                                            President and
                                            Chief Executive Officer
  
  
  
  
  
                                        -7-
  <PAGE>   8
  
  
                                 POWER OF ATTORNEY
  
                   KNOW ALL MEN BY THESE PRESENTS, that each person whose
  signature appears below constitutes and appoints Patrick J.  Mahaffy, Michael
  E. Hart and Adam Cochran and each of them singly, with full power to act
  without the other, his true and lawful attorney-in-fact and agent, with full
  power of substitution and resubstitution, for him and in his name, place and
  stead, in any and all capacities, to sign any and all amendments to this
  Registration Statement, and to file the same, with all exhibits thereto, and
  other documents in connection therewith, with the Securities and Exchange
  Commission, granting unto said attorneys-in-fact and agents, and each of them,
  full power and authority to do and perform each and every act and thing
  requisite and necessary fully to all intents and purposes as he might or could
  do in person thereby ratifying and confirming all that said attorneys-in-fact
  and agents or any of them, or their or his substitutes or substitute, may
  lawfully do or cause to be done by virtue hereof.
  
                   Pursuant to the requirements of the Securities Act of 1933, as
  amended, this Registration Statement has been signed by the following persons
  in the capacities and on the dates indicated.
  
  <TABLE>
  <CAPTION>
  Signature                               Title                             Date
  - ---------                               -----                             ----
  <S>                                     <C>                               <C>
  /s/ Lawrence M. Gold                    Chairman of the Board             July 10, 1996
  - --------------------------------------  and Chief Scientific Offer                                                
  Lawrence M. Gold                        
  
  /s/ Patrick J. Mahaffy                  Director, President and           July 10, 1996
  - --------------------------------------  Chief Executive Officer                                                
  Patrick J. Mahaffy                      (Principal Executive Officer) 
                                         
  
  /s/ Michael E. Hart                     Vice President and                July 10, 1996
  - --------------------------------------  Chief Financial Officer                                                 
  Michael E. Hart                         (Principal Financial Officer
                                          and Principal Accounting
                                          Officer)
  
  /s/ John D. Baldeschwieler              Director                          July 10, 1996
  - --------------------------------------                                                  
  John D. Baldeschwieler
  
  /s/ James A. Eskridge                   Director                          July 10, 1996
  - --------------------------------------                                                  
  James A. Eskridge
  
  /s/ David I. Hirsh                      Director                          July 10, 1996
  - --------------------------------------                                                  
  David I. Hirsh
  
  /s/ Rodman W. Moorhead, III             Director                          July 10, 1996
  - --------------------------------------                                                  
  Rodman W. Moorhead, III
  
  /s/ Carl F. Pollard                     Director                          July 10, 1996
  - --------------------------------------                                                  
  Carl F. Pollard
  </TABLE>
  
  
  
  
  
                                        -8-
  <PAGE>   9
  
  
  
  
  
                                 INDEX TO EXHIBITS
  
  
  <TABLE>
  <CAPTION>
                                                                                              Sequentially
                                                                                                Numbered
  Exhibit No.                                      Exhibit                                        Page
  - -----------                                      -------                                    ------------
  <S>                   <C>                                                                   <C>
      4.1               Second Amended and Restated Certificate of Incorporation of
                        the Registrant (Previously filed as an exhibit to the
                        Registrant's Registration Statement on Form S-3 (File No.
                        333-04653), declared effective by the Commission on June 19,
                        1996, and incorporated herein by reference.)
  
      4.2               Form of Common Stock Certificate of the Registrant
                        (Previously filed as an exhibit to the Registrant's Annual
                        Report on Form 10-K for the fiscal year ended December 31,
                        1994, and incorporated herein by reference.)
  
      5.1               Opinion of Willkie Farr & Gallagher, counsel to NeXstar, as
                        to the legality of the shares being registered.
  
     23.1               Consent of Ernst & Young LLP.
  
     23.2               Consent of Willkie Farr & Gallagher (contained in exhibit
                        5.1).
  
     24.1               Power of Attorney (reference is made to the signature page).
  
     99.1               Registrant's 1994 Employee Stock Purchase Plan (Previously
                        filed as an exhibit to the Registrant's Annual Report on
                        Form 10-K for the fiscal year ended December 31, 1994, and
                        incorporated herein by reference.)
  
     99.2               Amendment No. 1 to Registrant's 1994 Employee Stock Purchase
                        Plan (Previously filed as an exhibit to the Registrant's 
                        Registration Statement on Form S-3 (File No. 333-04653),
                        declared effective by the Commission on June 19, 1996, and
                        incorporated herein by reference.)
  
  </TABLE>
metadata_documents: [{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 23029}]
metadata_filer: {"company-data": {"conformed-name": "NEXSTAR PHARMACEUTICALS INC", "cik": "0000915359", "assigned-sic": "2834", "irs-number": "841173453", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-07887", "film-number": "96593067"}, "business-address": {"street1": "2860 WILDERNESS PLACE", "city": "BOULDER", "state": "CO", "zip": "80301", "phone": "3034445893"}, "mail-address": {"street1": "2860 WILDERNESS PL", "city": "BOULDER", "state": "CO", "zip": "80301"}}
text: 1
  
              As filed with the Securities and Exchange Commission on
                                   July 10, 1996
  
                                                  Registration No. 333-___________
  
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
                                      FORM S-8
                               REGISTRATION STATEMENT
                                       UNDER
                             THE SECURITIES ACT OF 1933
  
                           NEXSTAR PHARMACEUTICALS, INC.
                 --------------------------------------------------
                 (Exact name of issuer as specified in its charter)
  
     DELAWARE                                            84-1173453        
  - ---------------------------------                  ----------------------
  (State or other jurisdiction                       (I.R.S. Employer
  of incorporation or organization)                  Identification Number)
  
  2860 Wilderness Place
  Boulder, CO                                                80301   
  - ----------------------------------------                 ----------
  (Address of principal executive offices)                 (zip code)
  
                  NEXAGEN, INC. 1994 EMPLOYEE STOCK PURCHASE PLAN
                  -----------------------------------------------
                              (Full title of the plan)
  
                                 PATRICK J. MAHAFFY
                              Chief Executive Officer
                           NeXstar Pharmaceuticals, Inc.
                               2860 Wilderness Place
                                 Boulder, CO  80301
                                   (303) 444-5893  
                                 ------------------
            (Name and address, including zip code, of agent for service)
           (Telephone number, including area code, of agent for service)
  
                                 ------------------
  
                                      COPY TO:
                                Peter H. Jakes, Esq.
                              Willkie Farr & Gallagher
                                One Citicorp Center
                                153 East 53rd Street
                                 New York, NY 10022
                                   (212) 821-8000
  2
  
                          CALCULATION OF REGISTRATION FEE
  - ----------------------------------------------------------------------------------------------------
                                               Proposed               Proposed
  Title of              Amount                 maximum                maximum               Amount
  securities            to be                  offering               aggregate             of reg-
  to be                 regis-                 price per              offering              istration
  registered            tered(1)               share (2)              price (2)             fee
  - ----------------------------------------------------------------------------------------------------
  Common 
  Stock,
  $0.01 par
  value per
  share                 300,000(3)             $20,625                $6,187,500            $2,134
  - ---------------------
  
  (1)    This Registration Statement covers the additional 300,000 shares of
         Common Stock, $0.01 par value per share, of NeXstar Pharmaceuticals,
         Inc., a Delaware corporation ("NeXstar" or the "Registrant"), authorized
         to be issued under the NeXagen, Inc. 1994 Employee Stock Purchase Plan.
         On February 21, 1995, NeXagen, Inc. changed its name to NeXstar
         Pharmaceuticals, Inc. in connection with the merger of its wholly-owned
         subsidiary Neptune Merger-Sub Corp., a Delaware corporation, with and
         into Vestar, Inc., a Delaware corporation.
  
  (2)    Reflects the average of the high and low prices of NeXstar Common Stock
         on July 8, 1996 on the Nasdaq National Market pursuant to Rule 457(h)
         and (c) under the Securities Act of 1933, as amended (the "Securities
         Act").
  
  (3)    Represents shares which have not yet been issued.
  
                                       -2-
  3
  
                                       PART I
                              INFORMATION NOT REQUIRED
                           IN THE REGISTRATION STATEMENT
  
                                      PART II
                            INFORMATION REQUIRED IN THE
                               REGISTRATION STATEMENT
  
  Item 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE
  
                   The following documents, filed with the Securities and
  Exchange Commission (the "Commission") by NeXstar, a Delaware corporation, are
  incorporated herein by reference:
  
                            (a)  The Registrant's Registration Statement on Form
                   S-8 (Registration No. 33-88074), dated December 30, 1994,
                   filed pursuant to the Securities Act.
  
                            (b)  The Registrant's annual report on Form 10-K for
                   the fiscal year ended December 31, 1995, filed pursuant to the
                   Securities Exchange Act of 1934 (the "Exchange Act").
  
                            (c)  All other reports filed by the Registrant
                   pursuant to Section 13(a) or 15(d) of the Exchange Act since
                   the end of the fiscal year covered by the Form 10-K referred
                   to in (b) above, including, without limitation, the reports
                   referred to in items (d) and (e) below.
  
                            (d)  The Registrant's quarterly report on Form 10-Q
                   for the quarter ended March 31, 1996, filed pursuant to the
                   Exchange Act.
  
                            (e)  The Registrant's current reports on Form 8-K,
                   filed with the Commission on April 10, 1996, June 21,
                   1996, and July 8, 1996, respectively.
  
                            (f)  The description of NeXstar's common stock, $0.01
                   par value per share (the "Common Stock"), which is contained
                   in NeXagen's Registration Statement filed under the Exchange
                   Act, on Form 8-A (File No. 0-23012) on December 6, 1993, as
                   amended on Form 8-A/A filed on January 25, 1994.
  
                   In addition, all documents filed by NeXstar with the
  Commission pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act
  subsequent to the date of this Registration Statement and prior to the filing
  of a post-effective amendment which indicates that all the securities offered
  hereby have been sold or which deregisters all securities then remaining unsold
  shall be
  
                                        -3-
  4
  
  deemed to be incorporated herein by reference and to be a part hereof from the
  date of the filing of such documents with the Commission.  Any statement
  contained in a document incorporated by reference herein shall be deemed to be
  modified or superseded for purposes hereof to the extent that a statement
  contained herein (or in any other subsequently filed document which also is
  incorporated by reference herein) modifies or supersedes such statement.  Any
  statement so modified or superseded shall not be deemed to constitute a part
  hereof except as so modified or superseded.
  
  Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL
  
                 Certain legal matters with respect to the shares of Common Stock
  registered hereunder will be passed upon for the Registrant by Willkie Farr &
  Gallagher, New York, New York.  A member of the firm of Willkie Farr &
  Gallagher owns 2,440 shares of the Registrant's Common Stock.
  
  Item 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS
  
                 The Registrant's By-Laws require the Registrant to indemnify any
  and all of its directors or officers, or directors or officers who serve at the
  request of the corporation as a director or officer of another corporation, to
  the full extent permitted by the Delaware General Corporation Law (the "DGCL").
  
                 The Registrant's Second Amended and Restated Certificate of
  Incorporation (the "Certificate of Incorporation") also provides that:
  
                 The Registrant shall indemnify to the fullest extent permitted
           under and in accordance with the laws of the State of Delaware any
           person who was or is a party or is threatened to be made a party to
           any threatened, pending or completed action, suit or proceeding,
           whether civil, criminal, administrative or investigative by reason of
           the fact that he is or was a director, officer, employee or agent of
           the Registrant, or is or was serving at the request of the Registrant
           as a director, officer, trustee, employee or agent of or in any other
           capacity with another corporation, partnership, joint venture, trust
           or other enterprise, against expenses (including attorneys' fees),
           judgments, fines and amounts paid in settlement actually and
           reasonably incurred by him in connection with such action, suit or
           proceeding if he acted in good faith and in a manner he reasonably
           believed to be in or not opposed to the best interests of the
           Registrant, and, with respect to any criminal action or proceeding,
           had no reasonable cause to believe his conduct was unlawful.
  
                 Expenses incurred in defending a civil or criminal action, suit
           or proceeding shall (in the case of any action, suit or proceeding
           against a director of the Registrant) or may (in the case of any
           action, suit or proceeding against an officer, trustee, employee or
           agent) be paid by the Registrant in advance of the final disposition
           of such action, suit or proceeding as authorized by the Registrant's
           Board of Directors upon receipt of an undertaking by or on behalf of
           the indemnified person to repay such amount if it shall ultimately be
           determined that he is not entitled to be indemnified by the Registrant
           as authorized in the Registrant's Certificate of Incorporation.
  
                                        -4-
  5
  
                 The indemnification and other rights set forth in the
           Certificate of Incorporation shall not be exclusive of any provisions
           with respect thereto in the By-Laws or any other contract or agreement
           between the Registrant and any officer, director, employee or agent of
           the Registrant.
  
                 Neither the amendment nor repeal of the provisions (described
           above) in the Certificate of Incorporation regarding indemnification,
           nor the adoption of any provision of the Certificate of Incorporation
           inconsistent with such provisions, shall eliminate or reduce the
           effect of such provisions, in respect of any matter occurring prior to
           such amendment, repeal or adoption of an inconsistent provision or in
           respect of any cause of action, suit or claim relating to any such
           matter which would have given rise to a right of indemnification or
           right to receive expenses pursuant to such provisions, if such
           provision had not been so amended or repealed or if a provision
           inconsistent therewith had not been so adopted.
  
                 No director shall be personally liable to the Registrant or any
           stockholder for monetary damages for breach of fiduciary duty as a
           director, except for any matter in respect of which such director (A)
           shall be liable under Section 174 of the DGCL or any amendment thereto
           or successor provision thereto, or (B) shall be liable by reason that,
           in addition to any and all other requirements for liability he:
  
                   (i)      shall have breached his duty of loyalty to the
           Registrant or its stockholders;
  
                   (ii)     shall not have acted in good faith or, in failing to
           act, shall not have acted in good faith;
  
                   (iii)    shall have acted in a manner involving intentional
           misconduct or a knowing violation of law or, in failing to act, shall
           have acted in a manner involving intentional misconduct or a knowing
           violation of law; or
  
                   (iv)     shall have derived an improper personal benefit.
  
                 If the DGCL is amended after the date upon which a document is
           filed in the State of Delaware to authorize corporate action further
           eliminating or limiting the personal liability of directors, then the
           liability of a director of the Registrant shall be eliminated or
           limited to the fullest extent permitted by the DGCL, as so amended.
  
                 Section 145 of the DGCL empowers a Delaware corporation to
  indemnify any persons who are, or are threatened to be made, parties to any
  threatened, pending or completed legal action, suit or proceeding, whether
  civil, criminal, administrative or investigative (other than an action by or in
  the right of such corporation), by reason of the fact that such person is or
  was an
  
                                        -5-
  6
  
  officer or director of such corporation, or is or was serving at the request of
  such corporation as a director, officer, employee or agent of another
  corporation or enterprise.  The indemnity may include expenses (including
  attorneys' fees), judgments, fines and amounts paid in settlement actually and
  reasonably incurred by such person in connection with such action, suit or
  proceeding, provided that such officer or director acted in good faith and in a
  manner reasonably believed to be in or not opposed to the corporation's best
  interests, and, for criminal proceedings, had no reasonable cause to believe
  his conduct was illegal.  A Delaware corporation may indemnify officers and
  directors in an action by or in the right of the corporation under the same
  conditions, except that no indemnification is permitted without judicial
  approval if the officer or director is adjudged to be liable to the corporation
  in the performance of his duty.  Where an officer or director is successful on
  the merits or otherwise in the defense of any action referred to above, the
  corporation must indemnify him against the expenses which such officer or
  director actually and reasonably incurred.
  
  Item 8.  EXHIBITS
  Exhibit No.
  - -----------
  4.1              Second Amended and Restated Certificate of Incorporation of the Registrant (Previously filed as an exhibit to the
                   Registrant's Registration Statement on Form S-3 (File No. 333-04653), declared effective by the Commission on June
                   19, 1996, and incorporated herein by reference.)
  
  4.2              Form of Common Stock Certificate of the Registrant (Previously filed as an exhibit to the Registrant's Annual
                   Report on Form 10-K for the fiscal year ended December 31, 1994, and incorporated herein by reference.)
  
  5.1              Opinion of Willkie Farr & Gallagher, counsel to NeXstar, as to the legality of the shares being registered.
  
  23.1             Consent of Ernst & Young LLP.
  
  23.2             Consent of Willkie Farr & Gallagher (contained in exhibit 5.1).
  
  24.1             Power of Attorney (reference is made to the signature page).
  
  99.1             Registrant's 1994 Employee Stock Purchase Plan (Previously filed as an exhibit to the Registrant's Annual Report on
                   Form 10-K for the fiscal year ended December 31, 1994, and incorporated herein by reference.)
  
  99.2             Amendment No. 1 to Registrant's 1994 Employees Stock Purchase Plan (Previously filed as an exhibit to the 
                   Registrant's Registration Statement on Form S-3 (File No. 333-04653), declared effective by the Commission on 
                   June 19, 1996, and incorporated herein by reference.)
  -6-
  7
  
                                     SIGNATURES
  
             Pursuant to the requirements of the Securities Act of 1933, as
  amended, the registrant certifies that it has reasonable grounds to believe
  that it meets all of the requirements for filing on Form S-8 and has duly
  caused this Registration Statement to be signed on its behalf by the
  undersigned, thereunto duly authorized, in Boulder, Colorado on the 10th day of
  July 1996.
  
                                       NEXSTAR PHARMACEUTICALS, INC.
  
                                       By:  /s/ Patrick J. Mahaffy  
                                            ------------------------
                                            Patrick J. Mahaffy
                                            President and
                                            Chief Executive Officer
  
                                        -7-
  8
  
                                 POWER OF ATTORNEY
  
                   KNOW ALL MEN BY THESE PRESENTS, that each person whose
  signature appears below constitutes and appoints Patrick J.  Mahaffy, Michael
  E. Hart and Adam Cochran and each of them singly, with full power to act
  without the other, his true and lawful attorney-in-fact and agent, with full
  power of substitution and resubstitution, for him and in his name, place and
  stead, in any and all capacities, to sign any and all amendments to this
  Registration Statement, and to file the same, with all exhibits thereto, and
  other documents in connection therewith, with the Securities and Exchange
  Commission, granting unto said attorneys-in-fact and agents, and each of them,
  full power and authority to do and perform each and every act and thing
  requisite and necessary fully to all intents and purposes as he might or could
  do in person thereby ratifying and confirming all that said attorneys-in-fact
  and agents or any of them, or their or his substitutes or substitute, may
  lawfully do or cause to be done by virtue hereof.
  
                   Pursuant to the requirements of the Securities Act of 1933, as
  amended, this Registration Statement has been signed by the following persons
  in the capacities and on the dates indicated.
  Signature                               Title                             Date
  - ---------                               -----                             ----
  /s/ Lawrence M. Gold                    Chairman of the Board             July 10, 1996
  - --------------------------------------  and Chief Scientific Offer                                                
  Lawrence M. Gold                        
  
  /s/ Patrick J. Mahaffy                  Director, President and           July 10, 1996
  - --------------------------------------  Chief Executive Officer                                                
  Patrick J. Mahaffy                      (Principal Executive Officer) 
                                         
  
  /s/ Michael E. Hart                     Vice President and                July 10, 1996
  - --------------------------------------  Chief Financial Officer                                                 
  Michael E. Hart                         (Principal Financial Officer
                                          and Principal Accounting
                                          Officer)
  
  /s/ John D. Baldeschwieler              Director                          July 10, 1996
  - --------------------------------------                                                  
  John D. Baldeschwieler
  
  /s/ James A. Eskridge                   Director                          July 10, 1996
  - --------------------------------------                                                  
  James A. Eskridge
  
  /s/ David I. Hirsh                      Director                          July 10, 1996
  - --------------------------------------                                                  
  David I. Hirsh
  
  /s/ Rodman W. Moorhead, III             Director                          July 10, 1996
  - --------------------------------------                                                  
  Rodman W. Moorhead, III
  
  /s/ Carl F. Pollard                     Director                          July 10, 1996
  - --------------------------------------                                                  
  Carl F. Pollard
  -8-
  9
  
                                 INDEX TO EXHIBITS
  Sequentially
                                                                                                Numbered
  Exhibit No.                                      Exhibit                                        Page
  - -----------                                      -------                                    ------------
  4.1               Second Amended and Restated Certificate of Incorporation of
                        the Registrant (Previously filed as an exhibit to the
                        Registrant's Registration Statement on Form S-3 (File No.
                        333-04653), declared effective by the Commission on June 19,
                        1996, and incorporated herein by reference.)
  
      4.2               Form of Common Stock Certificate of the Registrant
                        (Previously filed as an exhibit to the Registrant's Annual
                        Report on Form 10-K for the fiscal year ended December 31,
                        1994, and incorporated herein by reference.)
  
      5.1               Opinion of Willkie Farr & Gallagher, counsel to NeXstar, as
                        to the legality of the shares being registered.
  
     23.1               Consent of Ernst & Young LLP.
  
     23.2               Consent of Willkie Farr & Gallagher (contained in exhibit
                        5.1).
  
     24.1               Power of Attorney (reference is made to the signature page).
  
     99.1               Registrant's 1994 Employee Stock Purchase Plan (Previously
                        filed as an exhibit to the Registrant's Annual Report on
                        Form 10-K for the fiscal year ended December 31, 1994, and
                        incorporated herein by reference.)
  
     99.2               Amendment No. 1 to Registrant's 1994 Employee Stock Purchase
                        Plan (Previously filed as an exhibit to the Registrant's 
                        Registration Statement on Form S-3 (File No. 333-04653),
                        declared effective by the Commission on June 19, 1996, and
                        incorporated herein by reference.)