The human brain contains roughly one hundred billion neurons arranged in extremely intricate networks that generate every thought, memory, emotion, and dream, and coordinate our ability to perceive, respond to, and interact with the world. These remarkable capabilities are only possible if neurons can efficiently coordinate with other cells in the network, using specialized junctions known as synapses.
At these contact points, electrical and chemical signals flow between cells to form the basis of cognition, movement, and behavior. Given their central role in neurophysiology, it is no surprise that disruption of synaptic integrity is an early and common feature of many devastating central nervous system (CNS) disorders, including Alzheimer’s disease, amyotrophic lateral sclerosis (ALS), schizophrenia, Huntington’s and Parkinson’s disease, multiple sclerosis, and others.
Now, a small biotechnology company believes it may have found a way to address that shared vulnerability directly. Spinogenix has developed tazbentetol, a first-in-class oral therapy aimed at restoring glutamatergic synapse structure and function. Early Phase 2a data across ALS, Alzheimer’s disease, and schizophrenia suggest the approach may work — raising the provocative possibility of a generalizable synaptic therapy across multiple conditions.
From symptom control to synaptic repair
Tazbentetol is what Spinogenix calls a Transient Activator of Glutamatergic Synaptogenesis, or TAGS. The compound has a short half-life and does not require continuous dosing to exert its effects. Instead, brief exposure appears sufficient to activate intracellular signaling pathways that drive the formation of new glutamatergic synapses.
“You don't need chronic exposure to the target,” Peter Vanderklish, Chief Science Officer at Spinogenix, told DDN. “It's also highly potent, producing regenerative effects at low doses. Importantly, those effects appear durable — the new synapses that form persist over time and are functionally active.”
This places it outside the dominant pharmacological strategies used in CNS disorders and differentiates it from rapid-acting synaptogenic compounds such as psychedelics, which typically act through serotonin (5-HT) receptors and carry hallucinogenic risks.
“We’re not targeting 5-HT2A or any of the usual suspects,” Vanderklish said. “We’re operating in a completely different mechanistic neighborhood — one that appears to be both physiologically relevant and inherently self-limiting.”
There's something about the mechanism of action that has its own built-in safety mechanism. You don’t get supernumerary synapses. We weren't blowing the doors off the circuit.
—Peter Vanderklish, Spinogenix
That self-limiting behavior has been a key safety consideration. In preclinical studies, synapse formation plateaued within a normal physiological range, rather than producing excessive or aberrant connectivity. Even at doses far exceeding those needed for synaptic regeneration, the company observed no seizure activity or signs of excitotoxicity.
“There's something about the mechanism of action that has its own built-in safety mechanism,” Vanderklish said. “You don’t get supernumerary synapses. We weren't blowing the doors off the circuit.”
Why test three diseases at once?
Spinogenix’s decision to advance tazbentetol simultaneously into ALS, Alzheimer’s disease, and schizophrenia runs counter to conventional development wisdom, which typically emphasizes de-risking one indication before expanding. The confidence, according to the company, came from both clean early safety data and the nature of the mechanism itself.
What we saw in toxicology and preclinical models carried straight through into the clinic. I sometimes jokingly call it a ‘well-behaved molecule,’ but the data really were that clear, and that gave us tremendous confidence.
—Sharron Gargosky, Spinogenix
“We did all the appropriate preclinical and toxicology studies to evaluate safety, and Peter had done — and continues to do — the mechanistic work on the science,” Sharron Gargosky, Chief Development Officer at Spinogenix, told DDN. “What we saw in toxicology and preclinical models carried straight through into the clinic. I sometimes jokingly call it a ‘well-behaved molecule,’ but the data really were that clear, and that gave us tremendous confidence.”
Strategically, ALS provided a logical starting point. Synapse loss is one of the earliest detectable features of ALS, often preceding overt neuron death and clinical symptoms. It is also an orphan indication with accelerated regulatory pathways and profound unmet need.
“When we started, there was essentially nothing that meaningfully altered disease progression for most ALS patients,” said Vanderklish. “That made it both a scientific and an ethical place to begin.”
With early signals in ALS supporting both safety and biological activity, the company then looked at other, larger indications where cognitive changes are central. “In diseases like Alzheimer’s and schizophrenia, there are standard-of-care treatments, but they’re often not optimal. Our goal was to see how we could add to those treatments — either as adjunctive or supportive therapies — and improve outcomes for patients,” said Gargosky.
Signals across ALS, Alzheimer’s, and schizophrenia
Across all three trials, Spinogenix used quantitative electroencephalography (EEG) as a pharmacodynamic biomarker. Unlike subjective cognitive or behavioral assessments, EEG provides an objective measure of cortical synaptic activity and network synchronization.
“What’s particularly powerful about EEG is that it’s largely independent of placebo effects,” Gargosky explained. “You can’t consciously influence those signals in the way you might with subjective measures. So, it provides a clean, objective readout of brain activity that we can then correlate with clinically meaningful outcomes.”
At its simplest, EEG measures large-scale synchronous synaptic firing in the cortex, making it sensitive to both synaptic function and synaptic density. “Unique EEG signatures of abnormal brain activity have been defined in each of the indications we are in. We’ve seen a drug effect on these EEG signatures in terms of normalization of brain activity, which in some cases has correlated with the degree of improvement seen in behavioral measures in those indications,” said Vanderklish. “So, it’s been a really nice one-two punch, combining an objective physiological signal with functional clinical measures, as evidence of drug activity.”
That combined signal — physiological and behavioral — has been observed across ALS, Alzheimer’s disease, and schizophrenia studies, alongside a consistent safety and tolerability profile for tazbentetol. In all three indications, the compound was well tolerated, with no unexpected safety signals as trials progressed from healthy volunteer studies into patient populations.
In ALS, patients showed EEG changes consistent with improved cortical function alongside clinical outcomes suggesting slowed functional decline. At the end of treatment, 82 percent of patients treated with tazbentetol showed a stable or improved rate of decline as measured by the ALS Functional Rating Scale–Revised (ALSFRS-R). When benchmarked against historical controls from the PRO-ACT database, this subset of patients in the treated cohort (19 of 23) showed an average 76 percent reduction in the rate of decline over six months.
“In ALS, it looks like the most important impact may come from intervening early,” said Vanderklish. “Once that cascade of pathogenic events begins and the dominoes start to fall, it becomes something of an avalanche of pathology, and our goal is really to try to nip that in the bud.”
These findings have contributed to the FDA granting Fast Track Designation to tazbentetol for the treatment of ALS.
In Alzheimer’s disease, patients with mild to moderate disease experienced rapid cognitive improvements within weeks, followed by sustained benefits over six months of treatment. Many participants have remained on therapy for more than a year through compassionate use programs, with continued tolerability and perceived benefit.
In schizophrenia, where synaptic and dendritic dysfunction rather than widespread neuron loss is thought to underlie much of the disease, early indications show that tazbentetol was associated with improvements across positive, negative, and cognitive domains. This is notable given that existing antipsychotics are largely effective against positive symptoms but have limited impact on negative and cognitive symptoms. These clinical signals were accompanied by EEG changes consistent with normalization of schizophrenia-related abnormalities in cortical network activity across multiple brain regions.
A shift in how CNS diseases are treated
Rather than a series of disconnected diseases, the data point to a shared vulnerability across CNS disorders — and a potential opportunity for a single regenerative approach to address it. As an oral tablet that can be readily combined with existing standard-of-care therapies, tazbentetol is also designed to integrate easily into current treatment pathways.
This does not negate the need for pathology-targeted therapies. Instead, Vanderklish suggested that synaptic regeneration could function both as a standalone strategy and as a complementary layer of treatment — providing a regenerative component that could work in tandem with agents targeting any number of underlying pathogenic mechanisms.
“Even if future Alzheimer’s therapies were able to perfectly address the underlying molecular pathology — whether that’s amyloid, microglial activity, mitochondrial dysfunction, autophagy, all of it — that still doesn’t guarantee you’ll restore the synapses that have already been lost,” Vanderklish explained. “And in the aging Alzheimer’s brain, regenerative capacity is already significantly reduced.”
If those lost connections can be rebuilt, synaptic regeneration could become the missing piece that turns disease-modifying control into functional recovery — shifting CNS therapy from slowing decline to actively restoring brain function.
