Safety and Tolerability of ISX (Isoxsuprine HCL) in MS Relapses

This is a proof of concept, randomized, double-blind, placebo-controlled, 2-arm, parallel
group study of Isoxsuprine in MS subjects experiencing a typical relapse.

All subjects will have a documented diagnosis of relapsing MS or a clinically isolated
syndrome by international criteria. The relapse will be of sufficient severity that their
physician recommends treatment with a high dose corticosteroid pulse. All subjects will have
a physical examination and history with questions on drug sensitivities. Subjects
experiencing the onset of objective neurological deficits consistent with relapse within 7
days of randomization are eligible for screening for this study. Those currently on MS
disease modifying therapy will have received a stable regimen of the medications for at least
30 days prior to screening and will continue the same doses and regimens for the duration of
their study participation.

Consented subjects will be assessed for relapse criteria and those who meet study eligibility
criteria and agree to be treated with a standard 3 to 5 day pulse of high dose
corticosteroids, will be randomized with equal probability to 1 of 2 treatment groups:
placebo capsule or active Isoxsuprine (ISX).

The Screening Visit will take place within 7 days of relapse onset and within 48 hours of
initiating high dose steroids. Subjects may start corticosteroids anytime during this 7 day
window. During the screening period, subjects will be assessed with the Expanded Disability
Status Scale (EDSS), Multiple Sclerosis Functional Composite (MSFC), and cognitive testing
prior to treatment with ISX or placebo (1:1 ratio). Safety Assessments during screening will
include a physical exam, electrocardiogram, vital signs, weight and a urine pregnancy test
for females of child bearing potential. At 7 (± 1) days following the completion of the 5-day
ISX dosing, subjects will be re-assessed with the EDSS.

Subjects will be evaluated for treatment response using the EDSS and other standard measures.

Study drug will be administered as one (1) 10 mg capsule, 3 times daily for 5 days in
conjunction with concomitant dosing with high dose corticosteroids. This can be any accepted
regimen, including daily iv methylprednisolone 1000 mg/day or 600mg oral prednisone two times
a day at approximately 8AM and noon, with food, as typically provided by UNM MS Specialty
Clinic.

Inclusion Criteria:

- 1. Subjects must be adequately informed and understand the nature and risks of the
study and must be able to provide a signature and date on the ICF; 2. Male or female
subjects between 18 and 50 years of age, inclusive; 3. Confirmed diagnosis of Multiple
Sclerosis or Clinically Isolated Syndrome (CIS) suggestive of MS, according to the
2010 Revised McDonald criteria.

4. On a stable regimen of medications taken specifically to treat MS for at least 30
days prior to screening, and willing to continue the same doses and regimens for the
duration of study participation; 5. New neurological disability consistent with MS
relapse no longer than 7 days prior to screening; 6. Screen visit and randomization
must occur within 48 hours of subject initiating steroid treatment.

7. Maximum EDSS score during screening of 6.5; 8. Sufficient ambulatory ability
(ambulatory aids acceptable if used consistently) to complete two trials of the Timed
25 Foot Walk (T25FW) at the screening visit with the two trials completed within 5
minutes of each other in accordance with the specific instructions provided by the
National MS Society Functional Composite Manual.

9. Subject must be willing to take a high dose steroid (600mg oral prednisone two
times a day (bid).

10. Subjects must have a mean systolic blood pressure ≤ 160 and greater than 100 mm Hg
and a mean diastolic blood pressure of ≤ 100 and greater than 50 mm Hg determined by
the average of 3 seated readings taken at least 5 minutes apart at the Screening
Visit.

11. Subjects must be able to communicate effectively with study personnel. For this
reason only English speaking subjects will be eligible for the study.

12. Subjects must be able and willing to follow all protocol requirements and study
restrictions.

13. Subjects must be able and willing to return for all study visits.

Exclusion Criteria:

- 1. Subject is from a vulnerable population, as defined by the US CFR Title 45, Part
46, Section 46.111(b) and other local and national regulations, including but not
limited to, employees (temporary, part-time, full time, etc) or a family member of the
research staff conducting the study, or of the sponsor, or of the IRB.

2. Subject has only sensory, bowel/bladder, and/or cognitive symptoms of MS associated
with the most recent relapse.

3. Subject has cognitive or behavioral impairment that in the opinion of the
investigator would impair the ability of the subject to comply with study procedures.

4. Subject has any known contraindication(s) to the use of corticosteroids or
isoxsuprine hydrochloride (ISX), including, but not limited to:

- any current uncontrolled hypertension, primary adrenocortical insufficiency

- Any current psychoses, infectious disease, or Cushing's syndrome.

- Any current congestive heart failure (defined as New York Heart Association
(Functional Class III to IV).

- Peptic ulcer (within 24 weeks prior to the Screening Visit).

- Recent major surgery (within 24 weeks prior to the Screening Visit).

- Use of tizanidine any time in the past 30 days. 5. Subject has a clinically
significant infection requiring intravenous administration of antibiotics and
hospitalization prior to the Screening Visit.

6. Subject has poorly controlled type 1 or type 2 diabetes mellitus (prior
diagnosis of gestational diabetes mellitus is not exclusionary 7. Received
systemic steroids for a problem unrelated to the MS relapse within 30 days prior
to screening.

8. History of other neurological disease that, 'in the opinion of the
Investigator, would affect motor function or cognition; 9. For patients with a
history of Major Depressive Disorder, at risk for worsening depression due to
steroids or the presence of active depressive symptoms sufficient, in the opinion
of the investigator, to affect the subject's ability to complete study
assessments, or which would not be in the subject's best Interest to participate
in the study; 10. Presence of cognitive impairment sufficient, in the opinion of
the investigator, to affect the subject's ability to complete study assessments,
or which would not be In the subject's best interest to participate in the study
11. History of sensory impairments (e.g., hearing, vision) that, In the opinion
of the investigator, would impair the subject's ability to complete study
assessments; 12. History of current alcohol or substance abuse or dependence; 13.
History of myocardial infarction, or NYHA Functional Classification of Heart
Failure Class 3 or 4 within 2 years prior to screening, or history of coronary
artery disease and/or active angina pectoris; 14. Any clinically significant ECG
abnormalities;; 15. Inability to swallow oral capsules, or a history of
gastrointestinal malabsorption that would preclude the use of oral medication;
16. If female, is pregnant or lactating; 17. History of hypersensitivity or
allergic reaction to any of the study drugs. 18. History of heavy use of
tobacco/smoking