KDC-MN-225 – Kodiac biolabs

Plain-language summaryIntrigue 66 / 100

Rasagiline (Azilect) is a second-generation MAO-B inhibitor from Teva, approved by the FDA in 2006 for Parkinson disease. It is structurally distinct from selegiline (built around an indane scaffold rather than a phenethylamine) and the key practical advantage is that the body does not break it down into amphetamine derivatives. That eliminates one of the more annoying features of selegiline and makes drug screening cleaner. Like selegiline it binds MAO-B irreversibly, so a single daily dose keeps the enzyme suppressed for weeks. The ADAGIO trial controversially suggested it might also slow disease progression rather than just treat symptoms, although that finding has not been universally accepted. Used as monotherapy in early Parkinson and as an add-on in advanced disease. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Our opinion on this compoundEstablished workhorse

47/100

Mature MAO-B reference standard with solid clinical evidence but limited frontier research appeal

Rasagiline is the second-generation irreversible MAO-B inhibitor that largely displaced selegiline’s role in Parkinson pharmacology by doing one thing better: it doesn’t metabolize to amphetamines. That’s a meaningful difference in practice. No methamphetamine or l-amphetamine metabolites means cleaner drug-screen profiles, no cardiovascular overstimulation at clinical doses, and no tyramine restriction at the approved 1 mg daily dose. Teva’s development team got this right, and the FDA agreed in 2006. The PRESTO, TEMPO, and LARGO trials gave it solid regulatory legs across both monotherapy and levodopa-adjunct settings.

The more interesting research angle isnt the MAO-B inhibition itself, which is textbook at this point, but the propargylamine-mediated neuroprotection signal that sits underneath it. The propargyl group appears to influence Bcl-2 family expression, APP processing, and mitochondrial membrane stability through mechanisms that are partly independent of MAO-B. The ADAGIO delayed-start trial tried to pin this down. At 1 mg, it showed a weak disease-modification signal; at 2 mg, it didn’t, which muddied the interpretation. The FDA reviewed this carefully and declined a neuroprotection label claim, but the biological question isnt fully closed, and several groups have continued probing propargylamine biology in cell and rodent models. Thats where the remaining bench interest lives.

Here’s the thing though: rasagiline isnt on the frontier anymore. Safinamide arrived as a reversible, selective MAO-B inhibitor with an additional sodium-channel and glutamate-release angle that gives it a more interesting pharmacological story for combination PD research. The longevity-oriented MAO-B work has largely migrated toward broader monoamine biology in the context of aging rather than Parkinson’s specifically, and rasagiline doesn’t have the novel positioning to anchor that conversation the way a mitochondrial-targeted peptide or an mTOR-adjacent compound might. Its 14:1 MAO-B selectivity is good; it’s just not surprising anymore.

We think rasagiline earns its place in a research library as a reference standard rather than a frontier target. If your program involves dopamine metabolism, MAO-B selectivity profiling, or the propargylamine neuroprotection hypothesis, it’s a clean, well-sourced, thoroughly characterized tool. The irreversible kinetics are well-documented; the approximately 14-day recovery period is practically useful for experimental design. It’s just not a compound where bench work is likely to surface surprising findings in 2026. The primary questions have been asked, the big trials are done, and the remaining uncertainty around neuroprotection is real but not easily resolved at bench scale. Solid compound. Not an exciting one.

Novelty: 22
Mechanism promise: 38
In-category differentiation: 42
Evidence quality: 72
Translational signal: 68
Research bench value: 52

Rationale Rasagiline scores well on evidence and translational signal as an FDA-approved Phase 3-validated drug, but nearly 20 years of market presence and a fully characterized mechanism drag novelty and differentiation down sharply; safinamide’s reversible inhibition plus glutamate-modulation angle has moved the field forward, leaving rasagiline as a clean reference compound rather than a compelling new research target.

Selective irreversible MAO-B inhibitor (second-generation)

A second-generation propargyl MAO-B inhibitor lacking the amphetamine metabolites of selegiline.

Abstract

Rasagiline ((R)-N-(prop-2-yn-1-yl)-2,3-dihydro-1H-inden-1-amine; CAS 136236-51-6; molecular formula C12H13N; molecular weight 171.24) is a second-generation irreversible MAO-B inhibitor developed at Teva and approved by the FDA in 2006 under the trade name Azilect. Structurally distinct from selegiline by the indane scaffold replacing the phenethylamine, rasagiline does not yield amphetamine-class metabolites, simplifying its drug screening profile and avoiding the subjective stimulation associated with selegiline. MAO-B selectivity is approximately 14:1 over MAO-A at clinical dose (1 mg daily); the inhibition is irreversible and recovery requires de novo enzyme synthesis (approximately 14-day washout). Approved as monotherapy in early Parkinson disease and as adjunct to levodopa in advanced disease. The ADAGIO trial suggested possible disease-modifying effect for the 1 mg dose, though this remains debated. Tyramine restriction is not required at 1 mg daily; at higher experimental doses (2 mg) the cheese-effect risk emerges. Plasma half-life is approximately 3 hours, but the irreversible binding produces effective enzyme inhibition for weeks. Used as a reference second-generation MAO-B inhibitor in Parkinson research.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

Tag: KDC-MN-225

Rasagiline

Abstract

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