Development and Clinical Trials

When I presented this concept and the prototype at the annual meeting of the ASAIO (Chang, 1966), Professor Kolff was most supportive and encouraging. He wrote a letter to the Medical Research Council of Canada giving his strong support. This letter played an important role in my successful application for an MRC special project grant for me to develop and test the concept in my laboratory for clinical trials. At that time this was a very new idea and physicians were not ready to use it on their patients in clinical trials. Professor Kolff again offered his support by writing a letter stating that he would invite me to go to his center to carry out clinical trials on the invention if no one else was prepared to do so. With this strong support, McGill's human ethics committee having reviewed in details all the preclinical safety and efficacy animal studies (Chang, 1969a, 1972a, Chang & Malave, 1970, Chang etal., 1971a) approved the use of the invention in clinical trials at McGill's teaching hospitals. The arrangement was for me to prepare the hemoperfusion device in my laboratory which could then be used at the hospitals for clinical trials. It was agreed that the procedure as described in the next section be followed. The physicians at the

Blood

PATIENT

PATIENT

HEMOPERFUSION USING ADSORBENT ARTIFICIAL CELLS

Thousands of 90 micron diameter artificial cells containing adsorbents are retained inside the container by screens at either end. Blood containing toxins or drug can perfuse through the screens to come in contact with the artificial cells. Toxins or drugs diffusing into the artificial cells are removed by the adsorbents inside artificial cells. This cleanses the blood that returns to the patient.

A typical adsorbent artificial cell

Blood + toxins membrane membrane

PLATELETS RBC, WBC

Artificial cell Hemoperfusion device compared to an artificial kidney machine

Laboratory device prepared and used by Chang in first clinical trials (1970)

Fig. 10.1. Upper: Basic principle of adsorbent artificial cells in hemoperfusion. Lower left : Laboratory and commercial hemoperfusion devices. Lower right: Much smaller and simpler hemoperfusion device compared to an artificial kidney machine.

dialysis units would refer patients to me and I would then make the final decision whether to carry out the procedure and to do the treatment on the patients myself.

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