Approval of a Cure for Narcolepsy and 5-Year Cultured Brain Organoids Mark Milestones in Conquering Brain Diseases
Background
The human brain is considered the most complex organ in the universe. Humanity has repeatedly pursued research to unravel this mysterious domain. However, observing live human brain cells in real-time and analyzing the causes of diseases remains a difficult challenge.
Previous research teams have attempted to simulate brain development using brain organoids derived from human induced pluripotent stem cells (iPSCs). However, artificial brains have struggled to survive for extended periods in laboratory settings. The longest survival record reported to date is only 694 days, limiting observations to early fetal developmental stages.
The situation in drug development is no different. Narcolepsy Type 1 (NT1), a representative rare and intractable sleep disorder, is caused by the loss of neurons that secrete orexin, a substance regulating wakefulness. Existing drugs have only provided temporary relief through stimulants, without offering a fundamental solution to restore the damaged neural network. Patients are thus forced to manage symptoms for life.
Key Findings
Recently, the field of neuroscience has reached two significant milestones. Professor Paola Arlotta from Harvard University introduced a new culture medium formulation that supports neuronal activity. This technique enabled the long-term culture of human brain organoids for over five years (approximately 1,800 days), surpassing the previous longest record by more than three times.
The long-cultured artificial brain follows the developmental trajectory of the human brain and exhibits characteristics of postnatal maturation. Researchers found that the gene transcriptome of the organoids records the passage of time. In chimeric organoid experiments using progenitor cells of different ages, aged progenitor cells were observed to skip early developmental stages and produce mature neurons within two weeks.
On another research front, Takeda Pharmaceuticals' orexin receptor 2 (OX2R) agonist, oveporexton (trade name: Ozeipul), received approval from the U.S. Food and Drug Administration (FDA) on August 5. This new drug actively restores the damaged wakefulness neural network by directly implementing the missing orexin signal in the body. According to the results of the Phase 3 clinical trials FirstLight and RadiantLight, the oveporexton-treated group maintained wakefulness for longer periods during the day and showed a significant reduction in cataplexy frequency. The academic community anticipates that this approval for narcolepsy treatment will not only improve sleep disorders but also serve as a valuable tool to advance research on Parkinson's Disease (PD) and Attention Deficit Hyperactivity Disorder (ADHD), both of which are associated with impaired orexin function.
Significance and Outlook
These research achievements are being highlighted as important indicators that could change the paradigm of brain disease modeling and drug development. The brain organoid culture technology, which can survive for over five years, opens an unprecedented opportunity to closely observe the long-term progression of degenerative diseases such as Parkinson's Disease (PD) and Alzheimer's Disease (AD). Additionally, the commercialization of a new drug that stimulates orexin receptors is emerging as a promising alternative for various neurological disorders, going beyond the treatment of narcolepsy.
However, artificial brains lack vascular systems and immune cells, making it difficult to fully represent human physiological responses. The new drug also requires further safety verification for long-term use and regulatory classification procedures. Nevertheless, the intersection of long-term in vitro culture platforms and precision-targeted drug technologies is seen as a breakthrough that could shorten the journey toward overcoming brain diseases.
Nature, Published online: 21 August 2026; doi:10.1038/d41586-026-02626-xNature staff discuss how an FDA-approved drug for narcolepsy could have promise beyond the condition, and the longest-lived human brain organoids yet.
These research achievements significantly enhance the performance of drug screening platforms in the early stages of drug development by improving the evaluation of efficacy and safety. A specific application scenario involves using brain organoids that have matured for over five years as test models for validating candidate drugs in an in vitro environment. By adopting this technology, it becomes possible to accurately predict human adult brain physiological responses and cellular changes due to long-term drug use. As a result, it is expected that human-specific brain toxicity, which is difficult to detect in animal models, can be blocked before clinical trials.
In clinical settings, the mechanism of action of the narcolepsy drug oveporexton will be applied to design personalized treatment pathways for patients with degenerative brain diseases who suffer from sleep disorders. For example, it is anticipated that clinical research will gain momentum in preemptively administering orexin receptor agonists to Parkinson's Disease (PD) patients, where orexin signaling deficits are directly linked to cognitive decline, in order to delay cognitive deterioration.