A blood glucose control system is configured to modify therapy provided to a subject. The system can cause first therapy to be delivered by the blood glucose control system to a subject during a first therapy period. The first therapy can be delivered based at least in part on a first value of a control parameter used by a control algorithm to generate a dose control signal. The system can determine a first effect corresponding at least in part to the first therapy and autonomously generate a second value of the control parameter. The system can cause second therapy to be delivered by the blood glucose control system to the subject during a second therapy period, wherein the second therapy is delivered based at least in part on the second value of the control parameter.