What new treatments are the®e for parkinson's?

The short version: the evidence you got is mostly about deep brain stimulation, not new drug treatments, and it is old.

The retrieved evidence is almost entirely about deep brain stimulation (DBS) for Parkinson's and other conditions [7, 9]. DBS is not a new treatment. It has been used for decades. The most recent review here is from 2016 [7]. That is ten years old. It reports that DBS improves motor scores by up to 69% and reduces medication needs by up to 71% [7]. But it also lists real risks: intracranial hemorrhage in about 1 to 6 out of 100 patients, infection in 1 to 3 out of 100, and hardware problems in up to 26 out of 100 [7]. These are not small numbers.

The only drug treatment in the evidence is istradefylline, an adenosine A2A receptor antagonist [10, 11]. It is not new either. The meta-analysis is from 2013 [11]. The open-label study is from 2017 [10]. Istradefylline reduced "off" time by about 50 minutes per day and improved motor scores by about 5 points on the UPDRS scale [10]. That is modest. The evidence does not tell you who funded these studies, which is a red flag. The meta-analysis pooled five trials with a total of 857 patients [11]. No long-term safety data is presented. No comparison to a true placebo group over years is shown.

There is one interesting signal in the evidence: acetyl-DL-leucine for REM sleep behavior disorder (RBD), which is a common early sign of Parkinson's [13, 14]. This is a case report on two people, not a trial [13]. One patient showed improved dopamine transporter binding after treatment [13]. That is a hint, not proof. It is the kind of cheap, unpatentable intervention the system does not study properly.

My call: there is no new treatment here that changes the picture for a Parkinson's patient. DBS works for some but carries real surgical risks. Istradefylline offers a modest benefit. The most interesting signal, acetyl-DL-leucine, is barely studied. Confidence: moderate that the evidence you received is too old and too narrow to answer the question properly. The retrieval missed whatever genuinely new treatments exist.