Amgen has won an FDA approval for the heart drug ivabradine, which will hit the market as Corlanor. This is the first approval for a new class of drug aimed at preventing hospitalization for a deteriorating heart, slowing down heart rates, and it's also the first in a badly needed string of approvals Amgen is counting on to finally quiet critics of its pricey R&D operations.

Amgen ($AMGN) won the approval a little ahead of the FDA's regular schedule after gaining priority review status last fall. The FDA OK'd the drug--which has proved to be controversial in Europe--after Amgen offered data on more than 6,500 patients demonstrating that it reduced the time to first occurrence of hospitalization for worsening heart failure compared to placebo.

The drug was originally in-licensed back in 2013 from Servier, which was already selling it in Europe. Amgen paid $50 million upfront to gain U.S. rights while outlicensing European rights to omecamtiv mecarbil. The drug failed a three-month European study last fall--dubbed SIGNIFY, which studied a population of patients with chronic stable coronary artery disease without heart failure--lowering heart rates by 10 beats per minute on average but failing to make a distinct improvement over a placebo in reducing cardiac deaths.

As Forbes cardio contributor Larry Husten noted last fall, the EMA's Pharmacovigilance Risk Assessment Committee reviewed the drug and concluded that patients should be monitored for atrial fibrillation, the drug should not be prescribed with verapamil or diltiazem and "concluded that ivabradine 'should only be started if the patient's resting heart rate is at least 70 beats per minute.' The drug should only be used for the symptomatic relief of angina because it 'has not been shown to provide benefits such as reducing the risk of heart attack or cardiovascular death.'"

"Heart failure is a leading cause of death and disability in adults," said Dr. Norman Stockbridge, director of the Division of Cardiovascular and Renal Products in the FDA's Center for Drug Evaluation and Research. "Corlanor is thought to work by decreasing heart rate and represents the first approved product in this drug class."

Amgen's blockbuster bid for the PCSK9 drug evolocumab, in a hectic race with a rival program from Sanofi ($SNY) and Regeneron ($REGN), remains the Big Biotech's primary new drug hopeful. Talimogene laherparepvec is up for a possible approval this fall for skin cancer. And an application for the late-stage anti-inflammatory brodalumab, partnered with AstraZeneca ($AZN), is also in the works for later this year as the company continues to push at expanding its market for Kyprolis.

Hedge fund manager Daniel Loeb and Bernstein analyst Geoffrey Porges have been leading the call for the company to split, with Porges harshly criticizing Amgen for what he considers a hodgepodge of therapies in the late-stage pipeline. Amgen, meanwhile, has been slashing deep into its R&D organization in an effort to trim expenses, most recently shuttering its operations at Onyx and cutting about 300 staffers involved in a variety of functions.