Is A + B = AB when combining multiple drugs?

Drug combinations has shown great promise in many diseases including cancer, HIV etc. Despite its empirical success, drug combination therapy is far from being theoretically understood. This is because very often efforts to discover synergistic drug combos by high throughput screening are not followed with an in depth investigation of how synergistic combinations work at a molecular level. In our recent paper, we study and try understand in depth how the molecular response of cells to each of two drugs combine when the two drugs are given in combination. Check it out here.