Talampanel
glutamatergic · blocks ampa receptor mediated excitatory signaling class / glutamatergicspec sheet6 rows
Talampanel began life at Eli Lilly as LY300164 before the company licensed the compound to Hungary's IVAX Drug Research Institute in February 2001; IVAX, later absorbed into Teva, carried it through more than a decade of trials chasing three very different indications: epilepsy, ALS, and glioblastoma. As an AMPA receptor antagonist rather than a potentiator, it works the opposite direction from ampakines, dialing excitatory glutamate signaling down instead of up, which made it a candidate anywhere excitotoxicity or seizure activity was the problem. Phase II epilepsy trials showed real seizure reduction, and an early ALS trial looked promising enough, about 15 percent less strength decline and 30 percent slower functional decline, to justify a Phase III; that Phase III came back negative in 2010 and effectively ended the program. It also ran through NCI-sponsored glioblastoma trials without ever producing a marketed drug.
- Reduced seizure frequency in refractory partial epilepsy trials
- Slowed early ALS symptom progression in Phase II testing
- Investigated as a radiosensitizing adjunct in glioblastoma treatment
- Clean AMPA-selective antagonism without broad CNS depressant effects
- Never demonstrated large-scale efficacy sufficient for approval
- Discontinued rather than fully characterized for long-term human safety
- Talampanel started out as an Eli Lilly compound (LY300164) before Lilly licensed it away to a Hungarian research institute in 2001.
- In its Phase II ALS trial, patients on talampanel had about 30 percent slower decline on the ALS functional rating scale than those on placebo, before the Phase III trial failed to confirm it.
Mechanism
Selective, orally active noncompetitive at -type receptors, dampening fast excitatory neurotransmission and glutamate-driven rather than potentiating it.
Dosingtypical ranges, not medical advice
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Safetyrisks and cautions, not medical advice
Dizziness and ataxia were the dose-limiting problems and they were common. In a crossover trial in refractory partial seizures dizziness hit 52 percent and ataxia 26 percent, and those were the only significant adverse events recorded; the glioblastoma trial saw fatigue in 27 percent, dizziness in 23 percent and ataxia in 17 percent, mostly mild and reversible. Damping AMPA receptors is what produces that, so balance and driving are the real-world risks. Enzyme-inducing antiepileptics roughly halved talampanel levels while valproate raised them, forcing individual titration. No organ toxicity ever emerged.
History
Discovered at Eli Lilly as LY300164; licensed to IVAX Drug Research Institute (Budapest, Hungary) in February 2001; ran Phase II epilepsy trials, NCI-sponsored Phase II glioblastoma trials, and a Phase II ALS trial with promising signals; a subsequent Phase III ALS trial reported negative results in 2010, after which development effectively stopped; Teva inherited the asset through its 2006 acquisition of IVAX.
Subjective profileweighing the evidence above
A compound that actually worked its way through three separate Phase II programs on real promise, and still couldn't clear the one Phase III trial that mattered.
Resources
This entry is here for reference.
Research
- 1.A phase II trial of talampanel in subjects with amyotrophic lateral sclerosis
- 2.Phase 2 trial of talampanel, a glutamate receptor inhibitor, for adults with recurrent malignant gliomas
2 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
Is talampanel available as a treatment today?
No. It never received regulatory approval for epilepsy, ALS, or glioblastoma. Its Phase III ALS trial came back negative in 2010 and development stopped there.
How is talampanel different from ampakines like CX-717?
Ampakines are positive allosteric modulators that boost AMPA receptor signaling; talampanel does the opposite, blocking AMPA receptors to reduce excessive excitatory signaling, which is why it was tested for seizures and excitotoxic conditions like ALS instead of for cognitive enhancement.
Limitations of the evidence
- Phase III ALS trial failed to confirm the Phase II benefit
Adverse effects
- Never demonstrated large-scale efficacy sufficient for approval
- Discontinued rather than fully characterized for long-term human safety