Primetime Life Sciences is developing mutual prodrugs of currently approved small molecule drugs that have synergetic and/or additive therapeutically beneficial effects on efficacy, distribution, metabolism, excretion, and toxicity. This approach, called drug repurposing, builds on the available clinical safety and pharmacologic data to reduce both the cost and the time expended in introducing a new drug. Primetime has identified several proprietary linkers that facilitate two drugs that are stable in gastric and intestinal fluids but are cleaved in plasma to the parent drugs in a time-dependent manner. Thus, these mutual drugs improve pharmacokinetic characteristics, pharmacodynamic response, and the safety profile of the constituent drugs. The company is currently targeting two widely used drugs that have shown synergetic effects in preclinical and clinical studies for several cancers including ovarian, head, neck, prostate, and breast cancers.