Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

It's been almost nothing but green on the markets today as the Dow Jones Industrial Average (^DJI -0.17%) hit a stride at the opening bell and hasn't looked back. The blue-chip index had jumped more than 180 points as of 2 p.m. EST, with every stock but struggling Cisco taking in gains so far.

The markets might be celebrating congressional testimony in which new Federal Reserve Chairwoman Janet Yellen expressed her intent to continue stimulus tapering while furthering many of predecessor Ben Bernanke's strategies. It's been a particularly great day for health care stocks as Merck (MRK -0.33%) has gained 1.1% and Johnson & Johnson (JNJ 0.84%) has picked up 1.6%. Let's catch up on what you need to know.

Merck takes on diabetes
Merck announced yesterday that it's looking to develop a biosimilar version of rival Sanofi's (SNY 1.45%) star diabetes-fighting drug Lantus. Merck's developmental therapy, known under the drug's generic term of glargine, is headed to late-stage trials soon, according to the company.

Merck is hardly alone in its ambitions, however. Sanofi's Lantus ranks among Big Pharma's best-selling drugs and racked up more than $7 billion in sales last year. Lantus' patent expires in 2015, and the temptation of biting into the therapy's astronomical sales already has tempted Merck competitor Eli Lilly to push for a generic version of the treatment. However, Sanofi successfully sued for a 30-month delay of the generic competition, and it's not unlikely that a similar suit could be headed Merck's way. Regardless, the sales potential of a generic glargine is a hopeful sign for Merck, which has struggled with its pipeline as of late and looks to jump-start drug development for the future.

Johnson & Johnson's stock is climbing today despite no market-shaking news out from the company. The diversified health care stock's jumped more than 20% over the past six months even with the market's downturn to open 2014, but it's in pharmaceuticals that Johnson & Johnson investors hope to see even greater growth over the next few years. The company's oncology and immunology drug divisions have been among its fastest-growing businesses as of late, with each pulling in double-digit percentage growth year over year in 2013. Top-selling drug Remicade, one of the strongest names in Big Pharma, isn't facing the patent cliff in the immediate future, so investors can feel confident that Johnson & Johnson's best division isn't going to hit a big slump anytime soon.

Outside of the Dow, it's been a huge day for Regeneron (REGN -0.12%) investors. The biotech stock's jumped to among the best performers on the S&P 500 today with a 6.6% gain after it announced quarterly earnings. Regeneron's revenue jumped by 47% and its adjusted earnings exploded by 51% in the fourth quarter, but it was the company's optimistic forecast for the coming year that has Wall Street excited. Regeneron projects between $1.7 billion and $1.8 billion in U.S. sales of its successful eye treatment Eylea, a mark that would indicate great year-over-year growth over the $1.4 billion in U.S. sales it posted for the full 2013. Eylea's performed exceptionally since it roared onto the scene in 2011, and 2014 looks bright for Regeneron investors as the stock rallies behind this new blockbuster.