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

Good morning, fellow Foolish investors! Let's take a look at three stocks -- Biogen Idec (BIIB -1.68%), Amgen (AMGN 0.10%), and Omeros (OMER 1.82%) -- which could loom large in health care headlines this morning.

Biogen's revenue climbs by 26% in 2013 on strong MS franchise sales
First and foremost, Biogen just reported its fourth quarter and full year earnings this morning. For fiscal 2013, Biogen's revenue rose 26% year-over-year to $6.9 billion, while its GAAP adjusted diluted earnings per share rose 36% to $7.81 per share. Both its fourth quarter and full year earnings exceeded Wall Street estimates.

Sales of Avonex, Biogen's top selling multiple sclerosis (MS) treatment, rose 3% year-over-year to $3.0 billion in 2013. Sales of Tysabri, its MS and Crohn's disease treatment, surged 34% to $1.5 billion thanks to the acquisition of its complete rights from Elan (now part of Perrigo) during the second quarter of 2013.

Biogen's oral MS drug Tecfidera, pegged as a future blockbuster with peak sales estimates of $3.3 billion, finished its first year on the market with sales of $876 million.

Although Biogen's main products were firing on all cylinders, its earnings outlook for the coming year was a bit light. Biogen expects to earn $11.00 to $11.20 per share for fiscal 2014, missing the consensus estimate of $11.63. Revenue is expected to rise 22% to 25%.

Investors are reacting that conservative outlook -- shares of Biogen are down more than 2% in pre-market trading at the time of this writing.

Amgen's evolocumab meets its co-primary endpoints during a phase 3 trial
Yesterday, Amgen announced that a Phase 3 trial of evolocumab (also known as AMG-145) in combination with a statin therapy for high cholesterol had met its co-primary endpoints.

The study, known as LAPLACE-2, tested the safety, tolerability, and efficacy of evolocumab combined with a statin therapy compared to a placebo and ezetimibe in 1,896 patients with high cholesterol levels. The positive results indicate that evolocumab shows considerable promise as a treatment for patients who do not respond to high doses of statins alone.

Evolocumab belongs to a new class of drugs known as PCSK9 inhibitors, which are believed to be the next generation of cholesterol drugs. PCSK9 inhibitors work differently from statins, which inhibit the production of a liver enzyme known as HMG-CoA.

While statins inhibit the production of "bad" LDL cholesterol by inhibiting that enzyme, it inadvertently stimulates the production of another enzyme, PCSK9, which degrades the performance of the LDL receptors responsible for maintaining LDL levels. Evolocumab directly inhibits the production of PCSK9 instead.

To date, no PCSK9 inhibitors have been approved, but alirocumab, a similar product from Sanofi and Regeneron, is racing against evolocumab to reach the market first.

If approved, analysts expect evolocumab to generate peak sales of $4 billion -- which would go a long way toward diversifying Amgen's portfolio away from its top drug Enbrel, which generated $4.2 billion in sales last year.

Omeros poised to surge on positive phase 2a results for OMS824
Last but not last, Omeros just reported positive results from a phase 2a clinical trial of OMS824, an inhibitor of PDE10, an enzyme implicated in brain diseases such as Huntington's disease and schizophrenia. Shares of Omeros are surging by the double-digits in pre-market trading as a result.

The OMS824 trial consisted of 33 patients, and the results showed that the drug was well tolerated with limited adverse effects. The company has stated the trial results indicate that OMS824 has a bright future as both a monotherapy and as an adjunctive therapy in combination with approved antipsychotics. Full efficacy data could not be drawn yet, due to the small size of the trial, but Omeros stated that the data suggests the continuing development of the drug for schizophrenia and other neuropsychiatric conditions.

Analysts believe that OMS824 has peak sales potential of $1 billion -- which would be a huge boost for Omeros, which has no marketed products and only reported $6 million in revenue in 2012.

Investors should remember that OMS824 isn't the company's most advanced drug candidate. Omeros has already sent in a new drug application and a market authorization application for OMS302, a treatment for ophthalmological procedures. It has also completed a phase 3 trial for OMS103HP, a treatment for arthroscopy and menisectomy procedures.

However, neither OMS302 nor OMS103HP matches the blockbuster potential of OMS824 -- the two drugs combined have peak sales potential of just over $1 billion.