Intervention: Cilostazol
Trial phase: Phase 4
ATC code: B01AC23
SMILES: O=C1CCc2cc(OCCCCc3nnnn3C3CCCCC3)ccc2N1
Sex: All
Age groups: Adult | Older Adult
Healthy volunteers: No
Participants at risk: 83
Group description: cilostazol : Background therapy beginning at 50mg (1 pill) taken by mouth two times per day for two to three weeks. Then 100 mg (1 pill) to be taken by mouth two times per day (morning and evening) for one to two weeks.

Randomized therapy will consist of 100 mg (1 pill) to be taken by mouth two times per day (morning and evening) for approximately 180 days.
Eligibility criteria:
Inclusion Criteria:

The subject is >40 years old.
The subject has a diagnosis of Intermittent Claudication (IC) due to Peripheral Artery Disease (PAD).
Ankle brachial index (ABI) < 0.90 in at least one extremity, or if Ankle brachial index (ABI)is ≥ 0.90 to ≤ 1.0, a reduction of at least 20% in Ankle brachial index (ABI), in at least one extremity, when measured within 1 minute after claudication-limiting treadmill testing. If the subject has non-compressible arteries then a toe brachial index (TBI) < 0.70 is required in at least one extremity.
Symptoms of Intermittent Claudication (IC)must be stable for at least 3 months prior to Screening 1.
Peak Walking Time (PWT) of ≥ 1 to ≤ 12 minutes on a Gardner protocol at Screening 2.
If the subject is currently on statin therapy, they need to have been on statin therapy for at least 3 months prior to Screening 1. Subjects who have recently discontinued statin therapy must "wash-out" for at least one month prior to Screening 1.
Tolerance to background therapy of cilostazol (approximately 2 weeks of 50 mg by mouth (PO) twice daily (BID), approximately 1 week of 100 mg PO BID) between Screening 2 and Baseline Visit.
Subjects must be either male or females that are post-menopausal, surgically incapable of bearing children or if they are of childbearing potential must have a negative serum pregnancy test at Screening 1 and a negative urine pregnancy test at Day 0 and must agree to use double-barrier contraceptive methods until the end of investigational therapy (Day 180 Visit).
The subject is able to comply with scheduled visits, treatment plan and laboratory tests.
The subject is willing to participate in this study as documented by written informed consent.
During the tolerance phase of the Screening period, the subject demonstrates at least 70% compliance with cilostazol and is willing to continue treatment.

Exclusion Criteria:

Evidence of critical limb ischemia (CLI) (e.g., ischemic rest pain or ischemic ulceration).
The subject has had a major amputation of the leg or any other amputation that limits walking ability.
The subject has diabetes mellitus type 1 or poorly controlled diabetes mellitus type 2 (hemoglobin A1c (HbA1c) > 10).
The subject has had a transient ischemic attack (TIA) or deep vein thrombosis in the last 3 months.
The subject has had a stroke within the last 6 months.
The subject has participated in an angiogenic gene therapy study, unless known to be given placebo.

The subject has any of the following laboratory parameters at Screening 1:

Alanine aminotransferase (ALT), aspartate aminotransferase (AST) or total bilirubin >3 times the upper limit of normal (ULN)
Serum creatinine >2.5 mg/dL
Hemoglobin (Hb) <10 g/dL
White blood cell (WBC) count <3.0 x 103/µL; or > 15 x 103/µL
Platelet count <100 x 103/µL
The subject walks less than 1 minute at 2 miles per hour (mph), 0% grade as determined during the Screening 1 treadmill familiarization.
The subject has clinically significant electrocardiogram (ECG) abnormalities at rest or changes during exercise or post-exercise at Screening 2 or Day 0.
The subject has any history or clinical evidence of congestive heart failure (CHF), with which the clinician-investigator concurs.
The subject has uncontrolled hypertension (resting blood pressure (BP) > 180/100 mmHg) or uncontrolled arrhythmic disorders at Screening 1.
History of coronary or peripheral revascularization within 6 months prior to Screening 1.
The subject plans to undergo coronary or peripheral revascularization during the course of the study.
The subject is currently taking L-carnitine or medication for claudication (including pentoxifylline or cilostazol). In this situation, the subject would become eligible for Screening 1 after a 6 week washout of the medication.
Subjects currently taking or those who anticipate taking ketoconazole, itraconazole, or erythromycin. The subject would become eligible for Screening 1 immediately after completion of therapy or discontinuation of the drug(s).
The subject has a known, active malignancy that requires active anti-neoplastic therapy. (stable basal cell skin cancer allowed. Cancer being treated soley with hormonal therapy is allowed.)
The subject has a severe co-morbidity with an expected survival of less than 2 years.
The subject's Peak Walking Time (PWT) is limited by symptoms other than claudication (e.g., shortness of breath (SOB), fatigue, angina, arthritis, etc.). If, in the opinion of the investigator, the subject were to improve their Peak Walking Time (PWT) from study therapy to the extent that his or her walking would then be limited by a symptom other than claudication, the subject should not be enrolled.
The subject has a history of alcohol or other substance abuse within 6 months of Screening 1.
The subject has an inability to tolerate oral medication administration.
The subject has a known or suspected allergy to the study medication(s) or class of study medication(s) (cilostazol or L-carnitine) to be administered.
The subject has initiated an exercise training program within 3 months of Screening 1, has the inability to maintain his or her current level of physical activity throughout the study, or the subject plans on enrolling in an exercise training program during the study.
The subject plans to change his/her smoking status during the planned duration of this study (subjects will be advised that stopping smoking is best for his/her health).
The subject is currently pregnant or breastfeeding.
The subject has received an investigational drug or biological agent within 30 days prior to Screening 1.
The subject is currently participating in or plans to enroll in another clinical trial during this study.
The subject has any other clinically significant medical or psychiatric condition that in the opinion of the Investigator could impact the subject's ability to successfully complete this trial.
In the Investigator's opinion, the subject experienced any Adverse Events (AEs) during the tolerance phase of the Screening period that present a potential ongoing safety concern.