In US alone, patents of biologics worth US$ 67 Billion will expire before 2020. These biologics majorly include the blockbuster drugs of the pharma giants. As these drugs approach their patent expiry, pharma giants are looking for ways to protect their heavily invested upon innovations. One such strategy is patent fencing or patent blocking. Following the same strategy, Roche, has already released Kadcyla, an ADC, based on its blockbuster drug Herceptin for breast cancer. Big pharma players are therefore, using ADCs as an opportunity to fence the patents protecting their blockbuster drugs.