My thanks to Iqbal at HU for pointing me at this news.

The FDA "has approved istradefylline (Nourianz, Kyowa Kirin) tablets as add-on treatment to levodopa/carbidopa in adults with Parkinson's disease (PD) experiencing "off" episodes.

Istradefylline is a selective adenosine A2A receptor antagonist." [1]

Istradefylline has been around for years. It was well covered in the early days of the forum, but nothing for the last 5 years.

Efficacy for those concurrently taking L/C was:

"The pooled analysis included 2719 treated patients (placebo, n=992; 20 mg/day, n=848; 40 mg/day, n=879). At week 12, OFF-hours/day with 20 and 40mg istradefylline was reduced (LS mean difference from placebo in reduction from baseline [95%CI], −0.38 [−0.61, −0.15] and −0.45 [−0.68, −0.22], respectively)

long half-life (>60 h)

At steady state, istradefylline exposure increased by 35% in the presence of Cyp3A4 inhibitors" [2]

But, what really interests me is:

"It is estimated that the caffeine intake from a cup of coffee would only lead to 20% occupation of A2A receptors" [3]

So, a cup of coffee gives just a few minutes more "on" time. But, with the long half-life this is good quality time and it may be additive.

References:

[1] FDA OKs Istradefylline for Parkinson's Disease 'Off' Episodes

[2] A Pooled Analysis for Eight Randomized Controlled Trials of Istradefylline, an Adenosine A2A Receptor Antagonist: Efficacy as Adjunct to Levodopa in Parkinson’s Disease (PD) (P3.8-3) | Neurology

[3] Client Request Error

John