<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)   May 21, 1998
                                                           ----------------
                                          
                               NEOTHERAPEUTICS, INC.
               (Exact name of registrant as specified in its charter)



            Delaware                 0-28782               93-0979187
 ----------------------------      ------------        -------------------
 (State or other jurisdiction      (Commission           (IRS Employer
       of incorporation)           File Number)        Identification No.)


    157 Technology Drive, Irvine, California                   92618        
    ------------------------------------------------------------------
    (Address of principal executive offices)                (Zip Code)
                                          

         Registrant's telephone number, including area code: (949) 788-6700
                                                             --------------

                                  Not Applicable
                      ------------------------------------
          (Former name or former address, if changed since last report)
               (Telephone area code changed from (714) to (949)


<PAGE>


ITEM 5.   OTHER EVENTS

     Reference is made to the press releases issued to the public by the 
Registrant on May 21, 1998, the text of which are attached hereto as Exhibits 
99.1 and 99.2, for a description of the events reported pursuant to this Form 
8-K.


ITEM 7.   EXHIBITS

          EXHIBIT:
          --------
            99.1           PRESS RELEASE DATED MAY 21, 1998.

            99.2           PRESS RELEASE DATED MAY 21, 1998.

            99.3           PRESS RELEASE DATED MAY 21, 1998.
     




                                      SIGNATURE

     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 thereunto duly authorized.

                                   NEOTHERAPEUTICS, INC.



Date:  May 21, 1998                By:  /s/ Samuel Gulko          
                                        --------------------------
                                        Samuel Gulko
                                        Chief Financial Officer


                                        2


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                                    EXHIBIT INDEX




     EXHIBITS                             DESCRIPTION
     --------                             -----------
       99.1                     Press Release dated May 21, 1998
  
       99.2                     Press Release dated May 21, 1998
     
       99.3                     Press Release dated May 21, 1998




                                        3





<PAGE>
                                                                   EXHIBIT 99.1





FOR IMMEDIATE RELEASE

Contact:  NeoTherapeutics, Inc.                        Ruder Finn, Inc.
          Carol M. Hess, Investor Relations            Robert D. Ferris
          Tel: (949) 788-6700                          Tel: (212) 715-1573
          Fax: (949) 788-6706                          Fax: (212) 715-1660


                NEOTROFIN-TM- REPORTED TO STIMULATE NERVE REGENERATION


IRVINE, Calif., May 21, 1998 -- NeoTherapeutics, Inc. (Nasdaq:  NEOT; NEOTW) 
announced today that researchers from North Carolina and Canada reported that 
the Company's lead product candidate, AIT-082 (NEOTROFIN-TM-), has been shown 
to stimulate nerve regeneration in tissue culture and in animals.

At the 6th International Symposium on Adenosine and Adenine Nucleotides, held 
in Ferrara, Italy, Dr. Bernhard H.J. Juurlink of the Department of Anatomy 
and Cell Biology at the University of Saskatchewan, Saskatoon, Saskatchewan, 
Canada, reported that treatment of hippocampal neurons with AIT-082 caused 
nerve outgrowth and enhanced branching of the nerve processes.  Hippocampal 
neurons have been reported to be involved in memory function.

"AIT-082 is potentially therapeutic in a number of neurodegenerative 
disorders. We have demonstrated in hippocampal neurons grown in culture that 
AIT-082 not only promotes neurite formation in developing hippocampal 
neurons,
 but it prevents much of the neurite degeneration following exposure 
to excessive amounts of the neurotransmitter glutamate.  Glutamate 
excitotoxicity is implicated in a number of neurodegenerative diseases," Dr. 
Juurlink stated.

Dr. Julio J. Ramirez, the R. Stuart Dickson Professor of Psychology, Davidson 
College, Davidson, North Carolina, demonstrated in animals that after 
destruction of a discreet area of the brain involved in memory, treatment 
with AIT-082 caused re-growth of neurons into the damaged area.  These 
effects were seen after only four days of treatment with AIT-082.
     
"Since the reorganization of brain circuitry has been shown to contribute to 
recovery of memory function after injury or degeneration in areas crucial to 
learning and memory," Dr. Ramirez stated, "the possibility that AIT-082 might 
enhance this reorganization opens up marvelous opportunities to promote 
recovery of function in injured and diseased brains." 

                                      -- more --


                                        4

<PAGE>

NEOTROFIN-TM- Reported to Stimulate Nerve Regeneration
May 21, 1998
Page 2


NeoTherapeutics is engaged in the discovery and development of drugs that act on
the central nervous system to repair nerve cells and treat neurodegenerative
diseases such as Alzheimer's disease, spinal cord injury, Parkinson's disease
and stroke, as well as other neurological conditions such as migraine. 
NeoTherapeutics' products are orally administered and based upon patented
technologies.  AIT-082 (NEOTROFIN-TM-) is currently in human clinical trials for
the treatment of Alzheimer's disease.  For additional company information, visit
the NeoTherapeutics website at www.neotherapeutics.com.

This press release contains forward-looking statements regarding future events
and the future performance of NeoTherapeutics that involve risks and
uncertainties that could cause actual results to differ materially.  These risks
include, but are not limited to, the biological activity, side effect profile
and efficacy of AIT-082, the early stage of product development, the potential
need for additional funding, the initiation and completion of clinical trials
and dependence on third parties for clinical testing, manufacturing and
marketing.  These risks are described in further detail in the Company's annual
and quarterly reports filed with the Securities and Exchange Commission.

                                        ###




                                        5



<PAGE>
                                                                   EXHIBIT 99.2




FOR IMMEDIATE RELEASE

Contact:  NeoTherapeutics, Inc.                   Ruder Finn, Inc.
          Carol M. Hess, Investor Relations       Robert D. Ferris
          Tel: (949) 788-6700 Tel:                (212) 715-1573
          Fax: (949) 788-6706 Fax:                (212) 715-1660

                     EXPERIMENTS SHOW AIT-082 IS ABLE TO PREVENT

                      DETRIMENTAL EFFECTS OF SEVERE BRAIN DAMAGE


IRVINE, Calif., May 21, 1998 -- NeoTherapeutics, Inc. (Nasdaq:  NEOT; NEOTW)
announced that new and important findings demonstrate that its lead compound,
AIT-082 (NEOTROFIN-TM-), has been able to prevent the subsequent detrimental
effects of severe brain damage.

These findings, which may open a novel therapeutic approach to the treatment of
brain and spinal cord injuries, were presented today by Drs. R. Ciccarelli and
P. Di Iorio of the Department of Biomedical Sciences, University of Chieti,
Italy, at the 6th International Symposium on Adenosine and Adenine Nucleotides,
held in Ferrara, Italy.
     
They reported that a type of supporting cell in the brain - astrocytes - could
produce factors that protect the brain against both acute damage following
injuries or stroke and against chronic damage as well. These protective factors
include nerve growth factor (NGF) as well as two other proteins, S100B and
transforming growth factor beta (TGF beta).
 When the brain or spinal cord are 
damaged, guanosine, which is present normally in every cell, can be released 
in high concentrations to stimulate astrocytes to produce these protective 
factors.

Though guanosine cannot be used as a therapeutic because it is broken down
before it can be absorbed, AIT-082 has been shown to activate the production of
these neuroprotective proteins from astrocytes, just like guanosine.  In
experimental models, Drs. Ciccarelli and Di Iorio have been able to prevent the
subsequent detrimental effects of severe brain damage by using AIT-082.  This
compound is under development by NeoTherapeutics as a therapeutic for
neurodegenerative diseases such as Alzheimer's disease.

Professor Francesco Caciagli, Chairman of the Department of Biomedical Sciences
at the University of Chieti, who was a co-author of this study with Drs.
Ciccarelli and Di Iorio, stated that "AIT-082 is a very potent drug.  It does
not have any important side effects and also enters the brain and spinal cord
after being taken by mouth," said Professor Caciagli.  "I think that it can
therefore be a very good candidate for the treatment of a number of acute
injuries of brain and spinal cord including trauma, stroke, transient ischemia
and other disorders."

                                     -- more --


                                          6

<PAGE>

AIT-082 IS ABLE TO PREVENT DETRIMENTAL EFFECTS OF SEVERE BRAIN DAMAGE
May 21, 1998
Page 2


Professor Caciagli added, "As far as our Department is concerned, this
development is very exciting.  The Department is playing a major role in
developing entirely new strategies in the treatment of neurological disorders. 
Ongoing collaborations with other groups, particularly NeoTherapeutics, is very
productive for our Department in these endeavors."

NeoTherapeutics is engaged in the discovery and development of drugs that act on
the central nervous system to repair nerve cells and treat neurodegenerative
diseases such as Alzheimer's disease, spinal cord injury, Parkinson's disease
and stroke as well as other neurological conditions such as migraine. 
NeoTherapeutics' products are orally administered and based upon patented
technologies.  AIT-082 (NEOTROFIN-TM-) is currently in human clinical trials for
the treatment of Alzheimer's disease.  For additional company information, visit
the NeoTherapeutics web site at www.neotherapeutics.com.

This press release contains forward-looking statements regarding future events
and the future performance of NeoTherapeutics that involve risks and
uncertainties that could cause actual results to differ materially.  These risks
include, but are not limited to, the biological activity, side effect profile
and efficacy of AIT-082, the early stage of product development, the potential
need for additional funding, the initiation and completion of clinical trials
and dependence on third parties for clinical testing, manufacturing and
marketing.  These risks are described in further detail in the Company's annual
and quarterly reports filed with the Securities and Exchange Commission.

                                      # # #




                                        7



<PAGE>
                                                                   EXHIBIT 99.3




FOR IMMEDIATE RELEASE

Contact:       NeoTherapeutics, Inc.                   Ruder Finn, Inc.
               Carol M. Hess, Investor Relations       Robert D. Ferris
               Tel: (949) 788-6700                     Tel: (212) 715-1573
               Fax: (949) 788-6706                     Fax: (212) 715-1660



            NEOTHERAPEUTICS ISSUES CLARIFICATION OF MAY 20, 1998 NEWS ITEM


IRVINE, Calif., May 21, 1998 - This news release is being issued by
NeoTherapeutics, Inc. (Nasdaq:  NEOT; NEOTW) in order to clarify information
contained in a May 20, 1998 Dow Jones News Service story.  The article was based
on an interview with the Company's CEO, Dr. Alvin J. Glasky, conducted on May
20, 1998.  Comments made by Dr. Glasky during the interview consisted primarily
of information that has been disclosed previously by the Company.  This news
release provides clarification of information contained in the Dow Jones News
Service story which the Company believes is necessary to accurately reflect the
comments made by Dr. Glasky.  Following are the Company's clarifications to the
article:

- -    The first Phase I clinical trial of the Company's lead compound, 
     AIT-082, demonstrated improved memory and behavior in some, but not all, 
     of the 10 Alzheimer's disease patients included in that study.  The 
     trial was designed primarily to determine the safety of the drug. Two
 
     additional Phase I clinical trials of AIT-082 were conducted in healthy 
     elderly volunteers and were also designed to determine the safety 
     profile of AIT-082.  The Phase I trials included a total of 42 
     individuals.  In these, studies doses from 10 to 4,000 milligrams of 
     AIT-082 were used and no significant adverse effects were observed.  
     Because of the small number of people involved in these studies, any 
     conclusions regarding the safety or efficacy following long-term 
     administration of AIT-082 must await the results of future clinical 
     trials involving substantially larger numbers of patients with 
     Alzheimer's disease.

- -    NeoTherapeutics has an agreement with a European company that is limited 
     to manufacturing the AIT-082 drug compound for the Company's development 
     efforts.  This agreement does not involve any licensing rights and the 
     Company presently does not have a license agreement with any 
     pharmaceutical company.

- -    NeoTherapeutics recently announced that it received a commitment from a 
     private investor for a $15 million equity investment in the Company.  
     The Company believes that this amount will be sufficient to complete the 
     Phase II clinical trial which was initiated earlier this month as well 
     as other planned projects.  However, in order to complete the additional 
     trials needed to obtain FDA approval for AIT-082 in Alzheimer's disease, 
     substantial additional financing will be necessary.


                                        8

<PAGE>

NEOTHERAPEUTICS ISSUES CLARIFICATION OF MAY 20, 1998 NEWS ITEM
May 21, 1998
Page 2


NeoTherapeutics is engaged in the discovery and development of drugs that act on
the central nervous system to repair nerve cells and treat neurodegenerative
diseases such as Alzheimer's disease, spinal cord injury, Parkinson's disease
and stroke as well as other neurological conditions such as migraine. 
NeoTherapeutics' compounds are orally administered and based upon patented
technologies.  AIT-082 (NEOTROFIN-TM-) is currently in human clinical trials for
the treatment of Alzheimer's disease.  For additional company information, visit
the NeoTherapeutics web site at www.neotherapeutics.com.

This press release contains forward-looking statements regarding future events
and the future performance of NeoTherapeutics that involve risks and
uncertainties that could cause actual results to differ materially.  These risks
include, but are not limited to, the biological activity, side effect profile
and efficacy of AIT-082, the early stage of product development, the potential
need for additional funding, the initiation and completion of clinical trials
and dependence on third parties for clinical testing, manufacturing and
marketing.  These risks are described in further detail in the Company's annual
and quarterly reports filed with the Securities and Exchange Commission.

                                      # # #


                                        9