After many months of shortages affecting attention-deficit/hyperactivity disorder (ADHD) drugs, it was hoped that new generics to Takeda’s Vyvanse would ease the supply situation.
But according to a letter from the Association for Accessible Medicines (AAM), production limits on the drug’s active ingredient—set by the government—are at least partly to blame for the shortage that has spread to the generics.
Generic drugmakers haven’t been able to obtain enough raw material to “launch their products at full commercial scale,” AAM wrote to the Drug Enforcement Administration (DEA), according to Bloomberg.
The DEA sets specific restrictions on production to avoid an excess of supply that could spread to the black market due to Vyvanse’s status as a controlled substance. The agency sets its limits based on past production levels and future sales commitments, which poses a problem given that some companies are cleared to launch the generics but haven’t sold any so far, AAM wrote, according to the news service.
The trade group did not immediately reply to Fierce Pharma's request for comment.
The American Society of Health-System Pharmacists (ASHP) reported a shortage of several Vyvanse generics in October. According to ASHP, three of the manufacturers that produce the generics cited “an issue with the active ingredient,” lisdexamfetamine dimesylate, as the reason for low supply.
Takeda’s Vyvanse shortage followed in the footsteps of similar shortfalls faced by popular ADHD drug Adderall and its generics last summer.
Meanwhile, shortages of several key medicines across therapeutic areas have prompted U.S. lawmakers to probe the FDA and its mitigation strategies, plus work on legislation to tackle the issue.
Across the pond, the U.K. is feeling the effects of the shortages as well.
A national patient safety alert issued by the U.K.’s Department of Health and Social Care (DHSC) earlier this fall listed supply disruptions to active ingredients that are used in several ADHD drugs, including Vyvanse and Concerta. Doctors in England were warned not to prescribe the meds to new patients due to supply constraints, the Guardian reported.