Investing.com - Barclays (LON:BARC) became the latest firm to upgrade Merck (NYSE:MRK) because of its blockbuster cancer drug Keytruda. The firm gave Merck an overweight rating and raised its stock price target from $62 to 64. Morgan Stanley (NYSE:MS) recently upped its price target from $60 to $63 while Leerick Partners upgraded Merck to outperform. Keytruda is expected to gain a larger share of the market treating non-small cell lung cancers as it competes with Bristol-Myers Squibb. Sales of Keytruda more than doubled in 2017 to $3.8 billion and are expected to reach $8.2 billion by their peak in 2020. The drug is already approved for lung, skin and several other cancers types and is being tested for still others.Merck shares, however, are down 13% in the past 12 months.