Alzheimer's patients received great news in January when the FDA granted accelerated approval to lecanemab, a new treatment for the fatal dementia.

The FDA's accelerated approval program expedites the release of new drugs to treat serious conditions. Over the years, these have included another Alzheimer's drug, aducanumab, as well as treatments for HIV/AIDS, leukemia, and a host of rare diseases.

Unfortunately, several recent federal policy changes have added uncertainty to the accelerated approval program. Without more consistency from the FDA and Medicare, progress toward treating many deadly illnesses could grind to a halt.

Approval on an "accelerated" basis doesn't mean the FDA rushed the review or that drug companies were allowed to cut corners. The FDA's accelerated approval pathway, just like the agency's traditional approval pathway, requires companies to demonstrate that the drug is safe and that there is abundant evidence of its effectiveness.

The pathways differ in just one notable regard. In the traditional pathway, companies must demonstrate directly that a drug delivers a clinical benefit. In the accelerated pathway, companies can instead demonstrate that the drug has an effect on a "surrogate endpoint" -- a measurable outcome reasonably believed to predict a clinical benefit, even if that benefit will take more time to demonstrate directly.

To use a football analogy, accelerated approval is like predicting that a team up by four touchdowns at half-time will win the game, rather than waiting for the final score. Occasionally, such predictions will be wrong. But most of the time, they're right.

Of course, the stakes are much higher than a mere football game. Gaining earlier access to new treatments can make the difference between life and death for patients, who often have no other treatment options.

In addition to saving lives, the accelerated approval pathway also has a major impact across the whole ecosystem of drug development.

Many innovative treatments begin at small biotech start-ups. These companies rely on venture investment to finance their work. Because the accelerated approval pathway offers an opportunity to get a new treatment to patients sooner, investors are often drawn to companies that are pursuing these approvals.

This arrangement has worked extraordinarily well since the accelerated approval program began more than three decades ago. As of 2021, the FDA had granted accelerated approval to 269 medicines. Of those that received such approvals between 1992 and 2016, more than 76% went on to earn traditional FDA approval after their release.

Given that strong track record, it's troubling that federal agencies have introduced so much unpredictability into a program that has been such a success for patients worldwide.

The FDA seems to be shifting the goalposts, now indicating that more and more companies will be required to launch post-approval confirmatory trials before receiving accelerated approval. This is particularly troubling for smaller companies.

Meanwhile, the Centers for Medicare & Medicaid Services has added more ambiguity to the accelerated approval process by severely restricting seniors' access to newly-approved Alzheimer's drugs. Last year, CMS made an unprecedented decision that will prevent the vast majority of Medicare beneficiaries from accessing an entire class of FDA-approved Alzheimer's treatments. Under CMS's new rule, the drugs will only be available to seniors who can enroll in restrictive clinical trials or pay for the treatments out-of-pocket.

In February, CMS officials muddied the waters even more by announcing a Medicare pilot program that would test paying less for medicines granted accelerated approval. In addition to these federal policies, we are also seeing states try to limit Medicaid patients' access to drugs approved on an accelerated basis.

In short, even if a drug secures accelerated approval, it's no longer clear that the government will cover it.

This puts drug developers in an impossible position. Investing billions of dollars in a state-of-the-art medicine is a risky endeavor under the best of circumstances. To have any chance of success, companies need consistent FDA standards and patients need predictable coverage policies.

Federal officials have failed to provide either -- threatening not just a few companies, but the wider search for new treatments and cures that patients desperately need.

Rachel King is the interim CEO of the Biotechnology Innovation Organization. The co-founder and former CEO of GlycoMimetics, she also serves on the board of Novavax.

Signage is seen outside of FDA headquarters in White Oak, Maryland