Brain tissue transplantation or Neurotransplantation for the treatment of Parkinson’s disease is considered experimental, investigational and unproven when performed by any method, including but not limited to:
- Adrenal-to-brain transplantation with autograft or fetal allograft; or
- Human or xenogeneic fetal mesencephalic transplantation.
Xenotransplantation and/or heterotransplantation (between different species) such as fetal porcine and/or swine brain cells is considered experimental, investigational and unproven for the treatment of Parkinson's disease.
This policy is based on a 2001 Blue Cross Blue Shield Technology Evaluation Center (TEC) Assessment, which updated a prior 1995 TEC Assessment The 2001 TEC Assessment offered the following observations and conclusions:
Most of the studies published since the 1995 TEC Assessment consist of uncontrolled open trials, examining clinical outcomes in small groups of patients. As such, they lack the strength conferred by study designs with control groups, randomization, and double-blinding protocol. However, these studies report minor to moderate improvement in motor function in at least some patients in each study. Magnitude of the treatment effect, however, is variable.
There has been one randomized controlled trial, reporting clinical outcomes for 33 patients. Clinical outcomes among these patients were variable, moderate in magnitude, and were in part affected by age. The primary outcome variable, a patient-scored global rating, showed no significant difference at 12 months after surgery between patients treated with transplantation and those undergoing sham surgery.
A 2005 updated search of the literature found publications on two randomized controlled trials (RCT) addressing health outcomes for Parkinson’s disease patients receiving embryonic mesencephalic transplantation. The publications identified included results from the National Institute of Health (NIH) RCT and an RCT sponsored by the National Institute of Neurological Disorders and Stroke (NINDS).
In the NIH study, Olanow and colleagues reported on a double-blind, placebo-controlled trial of fetal-nigral (the layer of gray substance separating the tegmentum of the midbrain from the crus cerebri) transplantation in 34 patients with advanced Parkinson’s disease followed prospectively for 24 months. Patients were randomized to one of four donor bilateral transplantation or a placebo procedure. The authors reported no significant difference in overall effect (p=0.244) and persistent dyskinesia in 56% of patients in the transplant group. While a treatment effect was seen in milder patients (p=0.006), the authors concluded the results did not support fetal nigral transplantation as a recommended therapy for Parkinson’s disease.
In the NINDS double-blind, placebo-controlled RCT, 40 patients with Parkinson’s disease were randomized to receive bilateral 4-donor implantation of embryonic mesencephalic cells or a placebo procedure and followed for one year. Gordon and colleagues reported that patients in the NINDS trial improved significantly on reaction and movement times twelve months post transplantation (p=0.005) while patients in the placebo group deteriorated. The authors concluded reaction time analyses can be useful in identifying subtle motor performance changes over time.
McRae and colleagues reported on a portion of the NINDS RCT that evaluated quality of life (QOL) of 30 of the 40 study patients at baseline, four, eight, and twelve months post procedure. The authors reported a strong placebo effect, since all patients reported better scores if they believed they had received the transplant.
Trott and colleagues reported on cognition one year post-procedure in the NINDS study. The authors reported no significant differences in cognitive performance at follow-up for the transplant or placebo group as performance for most measures remained the same.
A search of peer reviewed literature through July 2011 identified no new clinical trial publications or any additional information that would change the coverage position of this medical policy.
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