Experience with the quality control testing of C. parvum suspension for clinical trial.

The control of C. parvum suspension presents special problems. The intended application of this preparation is in a therapeutic area where clinicians are accustomed to using defined chemical entities the biological activity of which are usually predictable according to weight of active principle administered, the route and number of doses. But the essential character of C. parvum is that of a vaccine in which the character of the active principle or principles is not clearly identified and can vary according to certain conditions. The control of the preparation therefore depends on the nature and relevance of tests for biological activity. These problems are exacerbated by uncertainty as to which of several possible mechanisms of antitumour activity might prove relevant in clinical practice. Experience with these problems as they have affected the quality control of large numbers of batches of C. parvum suspension prepared for clinical trial, will be discussed.