I think it's on or off, but little chance of being able to make it 25%, 50% or 75% on. That's a level of control that will be very difficult to achieve.
Above my pay grade to quibble, however I would point out the following from BLCM's website:
In addition to using our CaspaCIDe technology for the substantial elimination of cellular therapy, like an “off” switch, we are studying partial elimination of a cellular therapy, like a “dimmer” switch, by delivering reduced doses of rimiducid. We observed the dose response to rimiducid by measuring the viability of BPX-501 cells in culture following the addition of increasing amounts of rimiducid to the culture medium, as well as by measuring the survival of BPX-501 cells in vivo in immune-deficient mice following injection of increasing doses of rimiducid. In these preclinical studies, rimiducid rapidly and consistently reduced or eliminated CaspaCIDe-containing cells in a dose-dependent manner.