KW-6356 (Sipagladenant) 1mg – 60 tablets (preorder)

KW-6356 / Sipagladenant 1 mg — 60 oral research tablets. Sipagladenant (KW-6356) is the world’s most pharmacologically refined adenosine A2A receptor antagonist / inverse agonist — and the leading next-generation successor to istradefylline (Nourianz®), the FDA-approved A2A antagonist for adjunctive Parkinson’s disease therapy. Developed by Kyowa Kirin (the same group that brought istradefylline to market), KW-6356 was designed to combine A2A antagonism with inverse-agonist activity at the constitutively active receptor — a pharmacological refinement that produces substantially greater motor-symptom efficacy in Parkinson’s models with sub-milligram dose tiers. The 1 mg per-tablet potency reflects the dose range explored in published Phase II clinical pharmacology.

Research Overview

The adenosine A2A receptor is densely expressed in the striatum, where it sits in functional opposition to the dopamine D2 receptor on indirect-pathway striatopallidal neurons — the same cell population that becomes dysregulated in Parkinson’s disease [1]. A2A antagonism enhances dopaminergic signaling without itself increasing dopamine release, providing a clean pharmacological strategy for reducing motor fluctuations and “off time” in advanced Parkinson’s disease — a mechanism validated by the FDA approval of istradefylline (Nourianz®) in 2019 as the first A2A-class drug for any indication [1,2]. KW-6356 (sipagladenant) is the next-generation Kyowa Kirin successor to istradefylline, developed with two key pharmacological refinements: substantially higher A2A receptor affinity (sub-nanomolar Kᵢ) and inverse-agonist activity at the constitutively active receptor — meaning it not only blocks adenosine binding but actively reduces basal A2A signaling tone [2,3]. In Phase II clinical trials in Parkinson’s disease, KW-6356 produced significant reductions in motor-fluctuation “off time” at sub-milligram daily doses, and is currently in pivotal Phase III development [3]. The compound is also being investigated in cognitive-enhancement and cancer-immunotherapy contexts, where A2A antagonism reverses adenosine-mediated immunosuppression of tumor-infiltrating T cells.

Primary Research Areas

• Adenosine A2A receptor pharmacology — the most pharmacologically refined A2A antagonist / inverse agonist in clinical development; the cleanest research probe for sub-nanomolar A2A pharmacology [1,2].
• Parkinson’s disease and motor-fluctuation research — Phase II evidence of significant reduction in “off time”; Phase III development ongoing as a successor to istradefylline [2,3].
• Inverse-agonist pharmacology — active reduction of constitutive A2A signaling tone, distinguishing KW-6356 from neutral antagonists [2].
• Cognitive enhancement research — A2A antagonism enhances striatal dopaminergic and prefrontal cholinergic signaling; investigated for cognitive-symptom modulation [1].
• Cancer immunotherapy applications — A2A antagonism reverses adenosine-mediated immunosuppression of tumor-infiltrating T cells, a parallel oncology-research direction [1].

References

1. Pinna A. Adenosine A2A receptor antagonists in Parkinson’s disease: progress in clinical trials from the newly approved istradefylline to drugs in early development and those already discontinued. CNS Drugs. 2014;28(5):455–474.
2. Sako W, Murakami N, Motohashi N, Izumi Y, Kaji R. The effect of istradefylline for Parkinson’s disease: a meta-analysis. Sci Rep. 2017;7(1):18018.
3. Kanda T, Uchida S. Clinical/pharmacological aspect of adenosine A2A receptor antagonist for dyskinesia. Int Rev Neurobiol. 2014;119:127–150.