Several Republican senators in tough re-election races haven’t been playing up the upper chamber’s accomplishments on drug-pricing over lawmakers’ August recess, analysts say, though the most impactful bill would save taxpayers more than $100 billion. Some think the silence could be a vulnerability for GOP incumbents, while others see it as a warning sign of intra-party discord that could cause problems for the legislation going forward. Voters of both parties consistently say that high drug prices are a top issue,...