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Stocks are surging today as earnings season powers on, and the Dow Jones Industrial Average's (DJINDICES:^DJI) push higher has it within 100 points of its all-time high. As of 2:15 p.m. EDT, the Dow has ridden strong momentum all day to gains of more than 90 points. Most blue-chip stocks are up on the index, and Pfizer's (NYSE:PFE) strong earnings report has sent this big pharma stock soaring with the Dow's leaders today.

That's a relief to health care investors disappointed with Merck's (NYSE:MRK) lackluster earnings release yesterday, although the stock has rebounded slightly today. Here's what you need to know.

Pfizer hits the right marks
Pfizer's stock has risen by 1.7% after the company announced before the opening bell today that its third-quarter diluted earnings came in at $0.58 per share. That pushed the company to raise the lower end of its full-year guidance, impressing investors who have worried about the ongoing sales dive of former best-seller Lipitor and the slow pace of two recently approved drugs, Xeljanz and Eliquis.

Sales still fell 2.5% for the quarter, an expected drop that managed to beat estimates. While Lipitor's been taking a pounding, Pfizer's cancer-fighting drug portfolio is shining for investors. Oncology drug sales jumped by 26% for the quarter, highlighter by the 92% year-over-year revenue gain of small but surging drug Xalkori. If this division can keep up its momentum, it'll help investors to quickly get over the pain of the patent cliff.

Even better for Pfizer investors, the company announced separately today that it will continue its push to get osteoarthritis drug tanezumab to the market. The drug seemed dead a few years ago following the finding that it was linked to the possibility of joint destruction in patients. Fellow Big Pharma giant Eli Lilly (NYSE:LLY) has signed on to share the costs of kicking up another late-stage trial of the drug, although Pfizer and Eli Lilly have now agreed to share any profits should they get it to the market.

An FDA panel gave the go-ahead last year for trials to start back up using more carefully chosen patients, although it's still a long shot that tanezumab will overcome its risky image. If it does, it's competition for Merck's bone-treating drug hopeful odanacatib, one of the company's best hopes for a future blockbuster from its lackluster pipeline. Merck disappointed investors earlier this year by delaying odanacatib's FDA filing until 2014, although analysts still peg the drug's peak sales near or above $1 billion.

Merck's stock has still risen 0.5% today, but it will need odanacatib -- and any other hopeful that can succeed in phase 3 trials -- to make a big impact on the market as soon as possible. With diabetes drugs Januvia and Janumet slowing down and the patent cliff still taking a big bite out of sales and earnings, Merck's in dire need of a booster shot to its finances.

Fool contributor Dan Carroll has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.