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.

Let's take a look at four stocks -- Roche (RHHBY -0.50%), Regeneron (REGN 0.79%), Cell Therapeutics (CTIC), and AstraZeneca (AZN 0.39%) -- which could all loom large in health-care headlines this morning.

Roche's MetMab fails to help lung cancer patients
First and foremost, Swiss pharmaceutical giant Roche (RHHBY -0.50%) announced that it had halted a study of its experimental lung cancer drug, MetMab. The recommendation to halt the study was made by an independent data monitoring committee on grounds that MetMab wasn't shown to work in treating non-small cell lung cancer (NSCLC) when taken with Roche's (RHHBY -0.50%) Tarceva.

Although MetMab had been considered a potential blockbuster drug by several analysts, the drug's failure shouldn't have any long-term effect on Roche's (RHHBY -0.50%) stock, according to analysts at J. Safra Sarasin, since it isn't considered a major catalyst for the company in 2014. However, this is the second recent setback for Roche (RHHBY -0.50%), following the late-stage failure of its schizophrenia drug bitopertin in January.

Regeneron and Bayer's Eylea inches closer to a market approval for DME
Regeneron (REGN 0.79%) and Bayer (BAYR.Y 1.22%) just announced that Bayer's (BAYR.Y 1.22%) Japanese subsidiary Bayer Yakuhin has submitted an application for the marketing authorization of its eye drug Eylea as a treatment for diabetic macular edema (DME) to the Japanese government.

Eylea is currently approved in the U.S. for the treatment of wet age-related macular degeneration (AMD) and macular edema following central retinal vein occlusion (CRVO). The drug is approved in the EU and other countries for the same two indications.

Eylea's primary competitor, Novartis' Lucentis, is approved for the same indications along with three others (the first two indications in the U.S. and Europe, and the third in Europe) -- macular edema following branch retinal vein occlusion (BRVO), DME, and chronic neovascularization (CNV) secondary to pathologic myopia.

Regeneron (REGN 0.79%) and Bayer (BAYR.Y 1.22%) are eager to match Lucentis' indications, and have already made regulatory submissions in the U.S. and Europe for Eylea as a DME treatment, and a submission in the U.S. for Eylea as a treatment of macular edema following BRVO.

Regeneron (REGN 0.79%) maintains exclusive rights to Eylea within the United States. Bayer (BAYR.Y 1.22%) holds exclusive marketing rights to the drug in overseas markets except for Japan, where Regeneron (REGN 0.79%) receives a percentage of net sales.

Regeneron (REGN 0.79%)recently reported that U.S. sales of Eylea, which account for more than two-thirds of its revenue, rose 68% year over year to $1.41 billion in fiscal 2013. Overseas sales of Eylea, mainly contributing to Bayer's (BAYR.Y 1.22%) top line, came in at $472 million for a total of $1.88 billion in Eylea sales for the year. Some analysts believe that Eylea still has room to run, with peak sales estimates falling between $3.5 billion to $4.0 billion by 2020.

Cell Therapeutics initiates a phase 3 trial for pacritinib
Meanwhile, Cell Therapeutics (CTIC) just announced the initiation of a phase 3 trial to test pacritinib, an investigational JAK2/FLT3 inhibitor, in patients with myelofibrosis, a bone marrow disorder that affects blood cell production.

The new trial, known as PERSIST-2, will enroll up to 300 patients in Australia, Europe, New Zealand, and North America within the next 12 to 14 months. PERSIST-2 is the second phase 3 trial testing pacritinib as a myelofibrosis treatment.

Cell (CTIC) also has two other drugs in phase 3 trials or on the market -- Pixuvri, a treatment for non-Hodgkin's lymphoma (NHL), and Opaxio, an experimental treatment for brain and ovarian cancers. Pixuvri, which is conditionally approved in the EU, is Cell's only marketed product, and generated sales of $1.8 million in the first three quarters of fiscal 2013.

Cell (CTIC) expects Pixuvri to eventually generate peak sales of $240 million based on the EU approval alone. Sales of pacritinib are expected to achieve peak sales of $750 million, according to Roth Capital Partners analyst Bert Hazlett, if the drug is approved for myelofibrosis along with other blood disorders. If approved, pacritinib will be jointly commercialized with Baxter International.

Investors should note that Cell (CTIC) is scheduled to report earnings tomorrow after the market close.

AstraZeneca's Bydureon Pen is approved by the FDA
Last but not least, AstraZeneca (AZN 0.39%) announced that the FDA has approved the Bydureon Pen, a prefilled, single-use pen injector filled with the company's GLP-1 drug Bydureon. Bydureon, also known in a different dosage as Byetta, improves glycemic control in adults with type 2 diabetes by "tricking" the pancreas into producing more insulin naturally.

The self-injecting pen eliminates the need for patients to transfer the drug between a vial and syringe prior to self-injection. U.S. Sales of Bydureon are expected to hit $730 million by 2018, according to a report from Bank of America. The approval of the self injector could cause analysts to rethink those estimates, considering that Bydureon/Byetta's biggest competitor, Novo Nordisk's Victoza, can also be injected via a self injecting pen.

AstraZeneca (AZN 0.39%) reported $25.7 billion in revenue in fiscal 2013, so Bydureon still only plays a minor part in the company's overall growth. AstraZeneca (AZN 0.39%) previously shared commercial rights to Bydureon, Byetta, and other diabetes drugs with Bristol-Myers Squibb, but AstraZeneca (AZN 0.39%) bought out Bristol's share for $4.3 billion last December -- indicating that it still sees considerable growth potential in the diabetes market.