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 four stocks which could make health care headlines this morning -- Onconova Therapeutics (ONTX 0.15%), Enzymotec (NASDAQ: ENZY), DepoMed (ASRT 11.94%), and Omeros (OMER 0.98%).

Onconova plunges after discontinuing a phase 3 study of rigosertib
Onconova Therapeutics is set to plunge this morning, after the company discontinued its phase 3 ONTRAC study of intravenous rigosertib with gemcitabine for the treatment of front-line metastatic pancreatic cancer yesterday.

Rigosertib is a small molecule inhibitor, and the combination treatment with the chemotherapy drug gemcitabine (Eli Lilly's Gemzar) was one of the company's most advanced drug candidates. Analysts had forecast annual peak sales of $625 million for the intravenous version of the drug and $1.04 billion for an oral version. The phase 3 trial was canceled since rigosertib showed no statistically significant improvement in overall survival.

However, rigosertib isn't down for the count yet -- it is still in phase 3 trials as a second-line treatment for higher risk MDS (myelodysplastic syndromes), phase 1 trials as a first-line treatment for lower-risk MDS, and in early phase 2 trials as an oral treatment for head and neck cancer.

This is still a huge setback for Onconova, since it only has two other products in its pipeline -- ON 013105 for lymphoma and Recilisib for acute radiation syndrome, which are both still in phase 1 trials. The company has no marketed products, and reported cash and equivalents of $117 million and no debt last quarter.

Enzymotec could be forced to make peace with Neptune Technologies
Shares of Enzymotec, a manufacturer of nutritional and medical foods, could be volatile today, since a recent settlement between Neptune Technologies and Aker BioMarine could force Enzymotec to enter a similar agreement. Both Aker BioMarine and Enzymotec were sued by Neptune in 2011 over patent issues regarding oils derived from Antarctic krill.

In the recently announced agreement, Neptune granted Aker Biomarine a global, non-exclusive, royalty-bearing license which allows Aker Biomarine to sell Neptune's nutraceutical products in licensed countries. The belief is that Enzymotec, which is also under pressure from Neptune, will also sign a similar deal, reducing the margins in its nutrition segment, which accounts for approximately 70% of its top line.

Wells Fargo analyst John Baumgartner estimates that if Enzymotec signs a licensing deal with Neptune at a 5% annual royalty rate, Enzymotec's annual EPS could be reduced by as much as $0.11 per share in 2014.

While I would take that exact estimate with a grain of salt, the pressure for Enzymotec to settle is definitely higher with Aker throwing in the towel. Prior to recent developments, Enzymotec had a spectacular year -- last quarter, its revenue soared 66.3% year-over-year, its earnings jumped 87.5%, and its shares climbed over 70% since the beginning of the year.

DepoMed purchases Cambia from Nautilus Neurosciences
Meanwhile, DepoMed just purchased the U.S. rights to Cambia from Nautilus Neurosciences for $48.7 million. DepoMed will also pay Nautilus up to $5 million in net sales milestone payments, and a maximum of $10 million in third party milestone payments. This is DepoMed's third product acquisition in 18 months.

Cambia is an NSAID, or non-steroidal anti-inflammatory drug, that is used to treat migraine attacks in adults. The acquisition will substantially boost DepoMed's pain and neurology offerings, since it is the only approved NSAID in the U.S. specifically indicated as a migraine treatment.

DepoMed also expects the acquisition to create synergies with Gralise, its treatment for seizures, restless legs syndrome, and pain caused by shingles. In addition to Gralise, DepoMed sells two other commercialized products -- Zipsor for mild to moderate acute pain, and Lazanda for breakthrough cancer pain.

Last quarter, Gralise sales, at $9.8 million, accounted for 60% of its top line. Zipsor accounted for another 37%, with the remaining 3% coming from Lazanda. The company notably sold its royalty portfolio to PDL BioPharma in October for $240.5 million to streamline its business toward pain management drugs.

Omeros' OMS721 granted an orphan drug status by the FDA
Last but not least, Omeros could climb higher this morning since the company announced that its lead human monoclonal antibody OMS721 was granted an orphan drug designation by the FDA for the prevention of complement-mediated thrombotic microangiopathies -- a rare debilitating disorder that causes multiple clots in the body's organs, most commonly in the kidney and the brain. An orphan drug designation will protect OMS721 for seven years without a patent if approved.

Omeros' OMS721 targets MASP-2 (mannan-binding lectin-associated serine protease-2), which plays a role in maintaining the lectin pathway, a pathway implicated in the development of TMAs. Omeros is the only company focusing on MASP-2 drugs at the moment. OMS721 is currently in phase 1 trials.

Omeros does not have any marketed products yet, but its two most advanced products, OMS302 (ophthalmology) and OMS103HP (arthroscopy, meniscectomy), have completed phase 3 trials. The stock is already up more than 70% since the beginning of the year.