Patent Law Could Also Limit Mifepristone Access

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Existing patents deter the marketing of more affordable generic drugs that could be used off-label for abortions.

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Recent efforts to make abortion pills unavailable have brought public attention to the ways in which Food and Drug Administration (FDA) regulations—and courts—control how patients access medicine. But another type of government regulation has been flying under the radar: patents.

A recent federal lawsuit in Texas challenged FDA approval of two mifepristone abortion pills: Mifeprex tablets and their generic version. In that case, Judge Kacsmaryk issued an order that could enjoin the effective date of both approval decisions. The U.S. Supreme Court placed that order on hold while the appeal of the order proceeds.

Depending on how this litigation is resolved, patents could become the next major barrier to mifepristone access.

How? The reason depends on the distinction between Mifeprex tablets and the chemical compound mifepristone.

Beyond Mifeprex, FDA has approved another pill that contains mifepristone as an active ingredient. In 2012, FDA approved a new drug application for mifepristone tablets—called Korlym—to treat Cushing’s syndrome, a condition that causes high levels of cortisol in the body. The Korlym application and Mifeprex application were filed by different companies and each relied on independent clinical data.

The Texas lawsuit does not challenge FDA’s approval of Korlym. The lawsuit therefore will not impact FDA’s separate approval of mifepristone tablets for Cushing’s syndrome, no matter how the case is ultimately resolved.

The lawsuit will also not prohibit health care providers from prescribing Korlym pills to patients seeking abortions. As long as mifepristone tablets remain approved for Cushing’s syndrome, health care providers could prescribe them for unapproved uses—including abortions.

So-called off-label prescriptions happen regularly. FDA does not prohibit medical professionals from prescribing pills for off-label use if they conclude it would be medically appropriate based on scientific evidence. Accordingly, health care providers could prescribe Korlym pills off-label for patients seeking abortions, even if that use became unapproved.

In practice, off-label Korlym prescriptions may not be accessible to many patients. State laws penalizing abortion services could deter off-label prescription. State laws could also restrict access to mifepristone and even prohibit off-label prescriptions. Providers may conclude that Korlym pills, which contain higher doses of mifepristone than Mifeprex, are not appropriate for abortions. Korlym is also only available through a specialty pharmacy.

Another significant barrier could be the price. The price for Korlym is much higher than Mifeprex. And patents play a major role in explaining that price difference.

Although Mifeprex and Korlym tablets have the same active ingredient, their patent portfolios are very different. No patents remain on Mifeprex, which was originally approved in 2000 and currently faces competition from a generic version. Korlym, in contrast, claims protection from 16 patents in the Orange Book, a publication that lists drug products approved by FDA.

The compound mifepristone was developed in the 1980s, and patents on the compound have since expired. But, as is common practice in the pharmaceutical industry, Corcept Therapeutics, the company that owns Korlym, obtained patents on methods of using mifepristone to treat diseases.

With those patents, Corcept has been able to keep generic tablets off the market. In 2017, Teva Pharmaceuticals submitted an application to market a generic version of Korlym. FDA approved that application in 2020. In the interim, however, Corcept sued Teva for patent infringement. That patent litigation is still pending, so it remains unclear whether Teva’s generic would infringe any of Corcept’s patents. But under the threat of potential patent infringement liability, Teva has not yet marketed its generic mifepristone tablets.

Strikingly, Corcept did not even apply for any of its patents currently listed in the Orange Book until after Korlym was approved. After approving Korlym, FDA granted Corcept a seven-year market exclusivity because Korlym provided a new treatment for a rare disease. As the expiration date for that exclusivity approached, Corcept obtained a thicket of patents to extend its exclusivity period over Korlym tablets. The latest-expiring listed patent will expire in August 2038—26 years after Korlym was approved and over 50 years after mifepristone was first discovered.

The status of Teva’s mifepristone tablets means the abortion pill litigation could have unintended consequences for Cushing’s syndrome patients. Although Teva is not yet marketing its generic version of Korlym, lower-cost mifepristone is available through Mifeprex and its generic. These alternative pills might provide an option for Cushing’s syndrome patients who cannot afford Korlym. Just as doctors could theoretically prescribe Korlym off-label for abortions, health care providers could prescribe Mifeprex or its generic off-label for Cushing’s syndrome.

As with off-label Korlym prescription, off-label Mifeprex prescription may face obstacles in practice, such as federal and state restrictions on its distribution. Yet Judge Kacsmaryk’s order could totally remove off-label prescription as an option for Cushing’s syndrome patients. If it takes effect, his order would enjoin approval of both Mifeprex and its generic version.

Currently, overlapping regulations create a precarious balance that allows patients seeking mifepristone for both abortions and Cushing’s syndrome to potentially obtain generic mifepristone. But the Texas litigation has thrown uncertainty into this intricate regulatory maze. Suspension of FDA approval of mifepristone abortion tablets could create serious obstacles for patients who need mifepristone to treat Cushing’s syndrome and even other conditions.

A major obstacle would be patents that were filed years after FDA approved Korlym tablets—and decades after mifepristone was first developed. These patents may not even be infringed by Teva’s generic tablets. But the mere threat of patent infringement liability is deterring Teva from marketing tablets that FDA has concluded are safe and effective.

Depending on how the Texas litigation is ultimately resolved, Mifeprex pills may remain on the market uninterrupted. But either way, the Korlym patents are currently restricting access to generic pills for Cushing’s syndrome patients. These patents raise the question: Is this really the best system for regulating how Americans access medicine?

Laura Dolbow is a Sharswood Fellow at the University of Pennsylvania Carey Law School.