Granulocyte-Macrophage Stimulating Factor (GM-CSF) in Peripheral Arterial Disease

Participants walk up and down a 100-foot hallway for 6 minutes to cover the maximum distance possible. The distance, measured in meters, completed after 6 minutes will be recorded. The primary outcome examines walking distance following two consecutive 3-monthly administrations of the study treatments.

Graded treadmill exercise testing is performed using the Gardner protocol where the treadmill speed is kept at 2 mph and the grade starts at 0 and inclines by 2% every two minutes. The peak walking time (PWT) is the time (measured in seconds) until exercise is terminated because of severe claudication (pain in legs). Exercise testing is performed twice and longest time is used as the PWT for that study visit.

To investigate whether there is further improvement with GM-CSF administered twice compared to a single administration, PWT at Month 6 compared to Month 3 is examined. Graded treadmill exercise testing is performed using the Gardner protocol where the treadmill speed is kept at 2 mph and the grade starts at 0 and inclines by 2% every two minutes. The peak walking time (PWT) is the time (in seconds) until exercise is terminated because of severe claudication (pain in legs). Exercise testing is performed twice and longest time is used as the PWT for that study visit.

To investigate whether there is improvement following a single treatment of GM-CSF, PWT at Month 3 compared to Baseline is examined. Graded treadmill exercise testing is performed using the Gardner protocol where the treadmill speed is kept at 2 mph and the grade starts at 0 and inclines by 2% every two minutes. The peak walking time (PWT) is the time (in seconds) until exercise is terminated because of severe claudication (pain in legs). Exercise testing is performed twice and longest time is used as the PWT for that study visit.

To investigate whether there is further improvement with GM-CSF administered twice compared to a single administration, the examine walking distance at Month 6 compared to Month 3 is examined. Participants walk up and down a 100-foot hallway for 6 minutes to cover the maximum distance possible. The distance, measured in meters, completed after 6 minutes is recorded.

To investigate whether there is improvement following a single treatment of GM-CSF, the walking distance at Month 3 compared to Baseline is examined. Participants walk up and down a 100-foot hallway for 6 minutes to cover the maximum distance possible. The distance, measured in meters, completed after 6 minutes is recorded.

The Walking Impairment Questionnaire (WIQ) domain of walking distance asks respondents to rate how difficult it is to walk around home, as well as distances of 50, 150, 300, 600, 900 and 1500 feet. Possible responses are: not hard (4), slightly difficult (3), somewhat difficult (2), very difficult (1), and unable to do (0). Total raw scores range from 0 to 28 with higher scores indicating increased ability to walk further distances.

The Walking Impairment Questionnaire (WIQ) domain of walking speed asks respondents to rate how difficult it is to walk the distance of one block slowly, at an average speed, quickly, and running/jogging. Possible responses are: not hard (4), slightly difficult (3), somewhat difficult (2), very difficult (1), and unable to do (0). Total raw scores range from 0 to 16 with higher scores indicating increased ability to walk fast.

The Walking Impairment Questionnaire (WIQ) domain of stair climbing asks respondents to rate how difficult it is to climb 1, 2, and 3 flights of stairs. Possible responses are: not hard (4), slightly difficult (3), somewhat difficult (2), very difficult (1), and unable to do (0). Total raw scores range from 0 to 12 with higher scores indicating better ability to climb stairs.

36-item Short-Form Health Survey (SF-36) consists of eight scaled scores for the domains of: vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning, and mental health. The domains can be summarized to represent two distinct concepts for a Physical Component Summary (PCS) and a Mental Component Summary (MCS). Study participants respond to questions relating to their health and activity level by selecting from a variety of Likert scale and yes/no response options. Each scale is directly transformed into a 0-100 scale and lower scores indicate more disability (a score of 0 equates to maximum disability while a score of 100 indicates no disability). This study examines the Physical Component Summary (PCS) score as well as all domains.

Claudication onset time (COT) during the treadmill exercise will be recorded along with the peak walking time (PWT). The claudication onset time (COT) is the duration of exercise until onset of the participant's typical claudication. This is differentiated from the peak walking time (PWT) which is the time until exercise is terminated because of severe claudication. Graded treadmill exercise testing will be performed using the Gardner protocol where the treadmill speed is kept at 2 mph and the grade starts at 0 and inclines by 2% every two minutes.

To obtain the ankle-brachial index (ABI), bilateral upper and lower extremity blood pressure cuffs are inflated about 30 millimeters of mercury (mmHg) above the systolic pressure. Doppler flow signals are used to detect the reappearing perfusion while reducing the cuff pressure. The results is expressed as a segmental/arm pressure ratio (ABI index). The highest pressure of the two arms will be used for calculating the ABI. The average ratio is about 1.0+/-0.10; an index of 0.90 or lower is considered abnormal. In patients with calcific, non-compressible arteries (certain diabetics) where ABI measurements are unreliable, a toe/ arm pressure index ratio will be performed, with a 2.5 cm cuff used on the great or second toes. A toe/arm index less than 0.65 is considered abnormal.

Foot transcutaneous oxygen tension (TcPO2) is a noninvasive way to measure peripheral arterial disease. TcPO2 is obtained with a monitor before exercise after the patients have been standing for three minutes and is monitored throughout exercise. Values are recorded at initial claudication distance, absolute claudication distance, and after recovery from exercise. A commonly used cut point is 60 millimeters of mercury (mmHg), with values below this indicating the presence of peripheral arterial disease.

The number of circulating mononuclear cells expressing the PC specific epitopes CD34 is counted using fluorescent activated sorting (FACS).

The number of circulating mononuclear cells expressing the PC specific epitopes CD133 is counted using fluorescent activated sorting (FACS).

The number of circulating mononuclear cells expressing the PC specific epitopes VEGF2R (KDR) is counted using fluorescent activated sorting (FACS).

The number of circulating mononuclear cells expressing the PC specific epitopes CXCR4 is counted using fluorescent activated sorting (FACS).