Let's take a look at four stocks -- Pfizer (PFE -0.19%), AstraZeneca (AZN 0.49%), MediWound (MDWD 7.19%), and Gilead Sciences (GILD 0.07%) -- which could loom large in health care headlines this Wednesday morning.

Pfizer could still raise its bid for AstraZeneca
Pfizer might not be done with AstraZeneca yet, despite claiming that its previous £69 billion ($117 billion) cash and stock bid was its "final offer". AstraZeneca rejected that offer -- the third from Pfizer -- stating that the bid undervalued the company's portfolio and pipeline.

Although U.K. takeover law states that Pfizer must make another bid for AstraZeneca before May 26 to keep the deal alive, Pfizer could still push the deal through if it convinces AstraZeneca's board of directors to recommend its higher proposal, which values the company at £55 per share. AstraZeneca had previously stated that only a bid above £58.85 per share would convince it to take the proposal to shareholders.

AstraZeneca's major shareholders are currently at odds with each other regarding Pfizer's offer. Neil Woodford, a major shareholder, has argued that AstraZeneca will earn better returns by remaining independent. Other major stakeholders, including Axa Investment Managers and Schroder Investment Management, have stated that AstraZeneca should have at least negotiated with Pfizer before rejecting its prior offers.

Pfizer wants to acquire AstraZeneca to lower its corporate tax rate and boost its oncology pipeline. The U.K. government has expressed concerns that the acquisition would result in job losses in the U.K. and the disruption of promising drugs in AstraZeneca's pipeline.

MediWound initiates a phase 2 trial for EscharEx
MediWound just initiated a phase 2 clinical trial to evaluate the safety and efficacy of EscharEx, its gel treatment for hard-to-heal wounds such as diabetic foot ulcers and post-surgical wounds. The study will consist of 72 patients and be conducted in 10 locations. If approved, EscharEx could compete against another treatment, Santyl, which generates $270 million in annual sales.

MediWound's most advanced product is NexoBrid, a similar treatment which has been approved to treat severe burns in Europe. NexoBrid is currently in phase 3 trials in the U.S. for the same indication and in a phase 2 trial for chronic wounds. According to the company, an estimated 14 million people in U.S. and Europe suffer from chronic wounds, comprising a potential market of $25 billion.

NexoBrid is still in the early phases of its European launch, but analysts at BMO believe the drug has peak sales potential of $275 million. Shares of MediWound, which went public in March, are down 16% from its IPO price of $14 per share, and down 32% from its first day of trading.

Gilead's RSV drug achieves positive results, but Sovaldi faces new criticism
Gilead Sciences is also worth watching this morning due to two new developments -- one positive and the other negative.

First of all, Gilead reported that its investigational oral antiviral fusion inhibitor, GS-5806, achieved its primary and secondary endpoints in a mid-stage trial evaluating its efficacy in treating intranasally infected respiratory syncytial virus (RSV) in healthy adults. The treatment achieved the endpoints of a lower viral load, improvement in total mucus weight, and symptom diary score versus a placebo. There are currently no effective antiviral treatments for RSV which occurs annually -- in the U.S., outbreaks generally last for 4 to 5 months during the fall, winter, or spring, depending on geographic location.

Meanwhile, Gilead's closely watched hepatitis C treatment Sovaldi faces a fresh round of criticism regarding its controversial price of $84,000 per regimen. Health insurance trade group AHIP (America's Health Insurance Plans) stated that despite the drug's major benefits, the price is not sustainable for patients. Sovaldi is an oral drug which does not require an additional dose of interferon for certain genotypes of hepatitis C. In its first full quarter on the market, Sovaldi generated over $2 billion in sales, topping all analyst expectations.