Let's take a look a four stocks -- MannKind (MNKD -0.24%), GlaxoSmithKline (GSK 0.12%), Myriad Genetics (MYGN -3.49%), and Alnylam Pharmaceuticals (ALNY -0.06%) -- all of which could loom large in health care headlines this Wednesday morning.

FDA advisory panel recommends the approval of MannKind's Afrezza
MannKind has nearly doubled in pre-market trading today, after an FDA advisory panel voted to recommend its market approval for glycemic control in type 1 and 2 diabetes. The panel voted 13 to 1 in favor of the type 1 indication, and 14 to 0 in favor of the type 2 indication.

Although the FDA is not bound by the advisory panel's recommendation, it's a strong hint that it may be approved for both indications. The Prescription Drug User Fee Act (PDUFA) review date for Afrezza is on April 15, when the FDA will reach a final decision regarding the drug. Afrezza, MannKind's main drug candidate, has been rejected twice in the past.

If approved, Afrezza will be the second inhalable insulin approved after Pfizer's Exubera. Exubera, which was approved in 2006, was discontinued only a year later due to low demand. Afrezza, however, has a much smaller inhaler and uses a faster-acting mealtime insulin. Peak sales for Afrezza are difficult to estimate, since it's unclear if patients and doctors would choose to switch from injected insulin analogs like Novo Nordisk's Novolog.

GlaxoSmithKline's bad news drags down Agenus
GlaxoSmithKline has just stopped a clinical trial for a novel vaccine to fight lung cancer. The MAGE-A3 vaccine failed to benefit patients with non-small cell lung cancer (NSCLC) during its phase 3 study less than two weeks ago. Despite that setback, GSK originally planned to continue the trial by finding patients with a particular genetic profile on which the vaccine might work. GSK announced today that it could not find patients with that profile.

The immunotherapeutic also failed to help patients as a vaccine for melanoma. However, GSK is still investigating the vaccine's potential benefits in sub-populations for that indication. The therapeutic vaccine is intended to help patients who already have the disease, and attempts to prevent the return of the disease after surgery.

The drug's peak sales were only estimated at $233 million in 2018 by Citigroup analyst Andrew Baum after the melanoma trial failure. However, the news is dragging down shares of Agenus (AGEN 11.86%), which develops the adjuvant (booster) for the vaccine. Agenus' QS-21 Stimulon adjuvant is currently a key component in 21 vaccine candidates in clinical development, with GSK being one of its principal clients. Agenus only generated a little over $3 million in revenue last year and is dependent on programs like its QS-21 Stimulon adjuvant to generate future income -- income which depends on approval of vaccines like GSK's -- so this setback is certainly disappointing for Agenus investors.

Myriad Genetics rallies on a bullish upgrade
Meanwhile, Myriad Genetics is getting a positive lift this morning after being upgraded by analysts at Jefferies, who raised their price target from $30 to $33 on the stock. Analysts at Credit Suisse were also slightly more bullish on the stock, upgrading it from "underperform" to "neutral" with a $29 price target on the stock. Analysts at JPMorgan Chase currently have an "underweight" rating on the stock with a less optimistic $25 price target.

Myriad's most well-known products are its BRCA1 and BRCA2 diagnostic tests, which can identify genes which have been implicated in breast and ovarian cancers. Myriad has been under pressure due to the invalidation of several key patents by the U.S. Supreme Court, which has allowed competitors such as Ambry Genetics and Quest Diagnostics to produce similar tests. To decrease its dependence on its BRACAnalysis tests, which account for 69% of its top line, Myriad acquired blood test maker Crescendo Bioscience for $270 million in February.

Alnylam's ALN-TTRsc gets a positive opinion in Europe
Last but not least, Alnylam, a company specializing in RNAi therapeutics, announced that the European Medicines Agency (EMA) Committee for Orphan Medicinal Products has  recommended ALN-TTRsc for designation as an orphan drug for the treatment of TTR-mediated amyloidosis. Alnylam initiated a phase 2 trial for ALN-TTRsc for the indication last December.

Alnylam does not have any marketed products, but it has an extensive pipeline for RNAi treatments for amyloidosis, hemophilia, hypercholesterolemia, hyperlipidemia, and other indications. ALN-TTRsc is the company's second most advanced pipeline candidate after ALN-TTR02, another treatment for TTR-mediated amyloidosis which is currently in phase 3 trials.

Analysts expect Alnylam's TTR treatments to generate $1.3 billion to $2.6 billion in annual peak sales if approved -- which would be a huge boost for a company which only reported $47.2 million in collaborative revenues in fiscal 2013.