text: Combination therapy has gained momentum in oncology in recent years, with various studies demonstrating higher response rates with combinations of drugs compared to monotherapies, and the FDA recently approving therapeutic combination regimens that demonstrated superior safety and efficacy to monotherapies. In a recent study about solid cancers, Martin Nowak, Bert Vogelstein, and colleagues showed that in most clinical cases, combination therapies are needed to avoid the evolution of resistance to targeted drugs. Furthermore, they find that the simultaneous administration of multiple targeted drugs minimizes the chance of relapse when no single mutation confers cross-resistance to both drugs.
  Various systems biology methods must be used to discover combination therapies to overcome drug resistance in select cancer types. Recent precision medicine approaches have focused on targeting multiple biomarkers found in individual tumors by using combinations of drugs. However, with 300 FDA-approved cancer drugs on the market, there almost 45,000 possible two-drug combinations and almost 4.5 million three-drug combinations for to choose from. That level of complexity is one of the primary impediments to the growth of combination therapy in oncology.
  The National Cancer Institute has recently highlighted combination therapy as a top research priority in oncology.