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Rapastinel. A novel NMDA pharma drug for depression

Hexagon Sun

Bluelighter
Joined
Mar 29, 2010
Messages
737
The light at the end of the tunnel, or just another over-hyped disappointment?

From wikipedia

https://en.wikipedia.org/wiki/Rapastinel

Rapastinel (INN) (former developmental code names GLYX-13, BV-102) is a novel antidepressant that is under development by Allergan (previously Naurex) as an adjunctive therapy for the treatment of treatment-resistant major depressive disorder.[1][2] It is a centrally active, intravenously administered (non-orally active) amidated tetrapeptide (Thr-Pro-Pro-Thr-NH2) that acts as a selective, weak partial agonist (mixed antagonist/agonist) of an allosteric site at the glycine site of the NMDA receptor complex (Emax ≈ 25%).[1][2] The drug is a rapid-acting and long-lasting antidepressant as well as robust cognitive enhancer by virtue of its ability to both inhibit and enhance NMDA receptor-mediated signal transduction.[1][2]

On March 3, 2014, the U.S. FDA granted Fast Track designation to the development of rapastinel as an adjunctive therapy in treatment-resistant major depressive disorder.[3] As of 2015, the drug has completed phase II clinical development for this indication.[4] Phase III clinical trials were expected to be starting in 2015.[4] On January 29, 2016, Allergan (who acquired Naurex in July 2015) announced that rapastinel had received Breakthrough Therapy designation from the U.S. FDA for adjunctive treatment of major depressive disorder.

Rapastinel belongs to a group of compounds, referred to as glyxins (hence the original developmental code name of rapastinel, GLYX-13),[5] that were derived via structural modification of B6B21, a monoclonal antibody that similarly binds to and modulates the NMDA receptor.[2][6][7] The glyxins were invented by Joseph Moskal, the co-founder of Naurex.[5] Glyxins and B6B21 do not bind to the glycine site of the NMDA receptor but rather to a different regulatory site on the NMDA receptor complex that serves to allosterically modulate the glycine site.[8] As such, rapastinel is technically an allosteric modulator of the glycine site of the NMDA receptor, and hence is more accurately described as a functional glycine site weak partial agonist.[8]

In addition to its antidepressant effects, rapastinel has been shown to enhance memory and learning in both young adult and learning-impaired, aging rat models.[9] It has been shown to increase Schaffer collateral-CA1 long-term potentiation in vitro. In concert with a learning task, rapastinel has also been shown to elevate gene expression of hippocampal NR1, a subunit of the NMDA receptor, in three-month-old rats.[10] Neuroprotective effects have also been demonstrated in Mongolian Gerbils by delaying the death of CA1, CA3, and dentate gyrus pyramidal neurons under glucose and oxygen-deprived conditions.[11] Additionally, rapastinel has demonstrated antinociceptive activity, which is of particular interest, as both competitive and noncompetitive NMDA receptor antagonists are ataxic at analgesic doses, while rapastinel and other glycine subunit ligands are able to elicit analgesia at non-ataxic doses.[12]

Mods, feel free to move to another section if more indicated
 
Well I didn't see what the dosing schedule would be for this but the fact that it is non orally active and requires injections (I hope not daily) would be a bit of a problem. Also I hope it has no abuse potential or it will never make it mainstream. Mabey for clinical drug resistant major depression. I mean they probably would have to market it like a insulin pen. With pre dosed amounts.
 
They're just trying to kill Ketamine before it can get off the starting line for depression treatment I bet >.>

In all seriousness, it's about time they came up with an effective NMDA anti-depressant drug, as MXE has been one of the only drugs that has given me consistent relief, and I assume that comes down to the NMDA receptors.
 
I totally advocate for pharma trying to milk the MXE/K antidepressors. And that try is lame as needles are needed. Would love to try it for curiosity, tho
 
Anyone care to comment on how this drug would interact with a traditional NMDA antagonist if co administered? Is this the tolerance reset hardened disso users have been waiting for?
 
damn yo, this sounds like K but good for you
 
Anyone care to comment on how this drug would interact with a traditional NMDA antagonist if co administered? Is this the tolerance reset hardened disso users have been waiting for?

I suspect tolerance will be shared with glycine antagonists and NMDA antagonists because a lot of tolerance is compensation by downstream brain cells. But I imagine glycine antagonists could possibly be worse as far as tolerance and withdrawal go.
 
Im curious to know this "clinical phases"

But really... I think they want to make even more money with depression.

Call me loco, but I think they are more into money than into health.
 
They're just trying to kill Ketamine before it can get off the starting line for depression treatment I bet >.>

In all seriousness, it's about time they came up with an effective NMDA anti-depressant drug, as MXE has been one of the only drugs that has given me consistent relief, and I assume that comes down to the NMDA receptors.

Ya, 1st thing I thought of was Ketamine, joke or no...which is just getting a good looking at/studies & I am a bit gun shy of anti-ds as they caused me more problems than they ever came close to fixing. Yet it doesn't mean it's not a break-thru but MAPS MDMA & other research has been very successful. Good to know regardless...
 
The cognitive enhancement doesn't suggest dissociative effect, and that is not what they are looking for in an AD drug anyway, on the contrary..

So no I bet it's not any fun, but it is a smart and interesting approach to treatment for depression. Discuss it in NSP imo, leave PD for the actual swirly drugs :) not even the tentative ones either. (my 0.02)

But chemically speaking: sweet rumpelstiltskin peptide, as long as it doesn't adversely target random shit in the brain, the metabolic toxicology should be real clean :) use the amino acids for your workout even.
 
I agree, I'll move this to NSP where people will have more informed opinions/speculation. :)

PD -> NSP
 
Anyone care to comment on how this drug would interact with a traditional NMDA antagonist if co administered? Is this the tolerance reset hardened disso users have been waiting for?

If it is a weak glycine partial agonist then it would tend to reduce the response to arylcyclohexylamines (ACAs) and other PCP site ligands. ACA binding is use dependent (the channel has to be open in order for their binding site to be accessible), so manipulations that reduce NMDA receptor channel opening will diminish the ability of ACAs to bind to the PCP site.

So the interactions really comes down to how they are co-administered. If you take the ACA first, then rapastinel would not block its effects. But if rapastenil was on board first, then it would reduce the ability of the ACA to interact with the NMDA receptor.
 
The subjective effects depend on if the drug is low-catching or high-catching of NMDA antagonists so it's pretty unlikely to have psychoactive effects.
 
speaking of NMDA related drugs for depression, i found this article on nature http://www.nature.com/articles/natu...h2C7HvpLAY4zOne65hU3v1CK0szqnJbkk2V_M1aA2GA== where they say that 2R,6R 6 hidroxy norketamine, a metabolite of R ketamine is responsible for most of ketamine antidepressant action since it causes an antidepressant effect similar to that of k when administered, and this effect is mediated via AMPA receptor activation being blocked by an AMPA antagonist. This explains also the higher antidepressant activity of R ketamine vs S ketamine and the higher antidepressant effect of ketamine in female vs male is in accord with higher concentration of the metabolite recorded in female rat's blood. Also they say that the increase in AMPA-mediated excitatory post synaptic potential is suistained after washout of the drug, and that 2R 6R 6 hidroxy norketamine showed no affinity for the NMDA receptor.
 
Do mice get depressed? do they actually also jump off a brigde? I never quite get it: the rat or mice model of major depression used to trial new drugs!
 
Do mice get depressed? do they actually also jump off a brigde? I never quite get it: the rat or mice model of major depression used to trial new drugs!

The point of using animal models is that they are useful ways to study human illnesses and can help guide choices made during drug development; models are not necessarily supposed to have "face validity". In fact, if mice do get depressed, one might argue that they probably would express the illness very differently than humans.

https://www.acnp.org/g4/GN401000076/CH.html
 
This is why drugs should ultimately be tested on people rather than animals.
Your not going to find a better human model than an actual human!
 
of course animal models have limitations but you know this is how it works drugs get tested first in animal models and then they start clinical trial...by the way they notice that published human data also reveal a positive correlation between ketamine antidepressant effect and 2R,6R 6hidroxy norketamine concentration
 
dotchem has a good point. what kind of a model is a depressed mouse anyway. i doubt mice can really be depressed tho unless you poke em with needles while prohibiting them having sex or eating food for extensive periods of time and even then its more like stress than what can be compared to human depression. how the hell do people test antidepressants on animals someone explain how this works? but then again, even depression in humans is hard to understand before it is possible to threat it so that is a very complex issue here...
 
A chronic stress model of depression might have some relevance to cortisol induced reductions of neurogenesis in humans, though there might be different causes of depression in humans. Most antidepressant therapies have some element of increasing neurogenesis. I bet you medications that are effective for animal models of learned helplessness are effective in humans with learned helplessness to a degree as well.
 
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