Efficacy

Xadago (Safinamide) Efficacy in Parkinson's Disease

Xadago (safinamide) is a medication that has been approved as an add-on treatment to levodopa/carbidopa in adults with Parkinson's disease (PD) who are experiencing "off" episodes. An "off" episode is a time when a patient’s medications are not working well, causing an increase in PD symptoms, such as tremor and difficulty moving. Clinical trials have demonstrated that safinamide helps to reduce these "off" times. Studies have shown that patients taking safinamide experience an improvement in motor function compared to those taking a placebo. This is measured by the Unified Parkinson's Disease Rating Scale (UPDRS), which is a widely used scale to assess the severity and progression of Parkinson's disease symptoms.

Moreover, safinamide has been shown to have a dual mechanism of action. It works by enhancing dopaminergic function through the reversible inhibition of monoamine oxidase B (MAO-B) and by blocking voltage-dependent sodium channels, which may help to reduce the abnormal release of glutamate. This dual action may contribute to the efficacy of safinamide in improving motor symptoms and reducing "off" times in PD patients. However, it is important to note that safinamide does not cure Parkinson's disease and its long-term effects on the disease progression have not been established.

Nuplazid (Pimavanserin) Efficacy in Parkinson's Disease

Nuplazid (pimavanserin) is an atypical antipsychotic medication approved by the FDA specifically for the treatment of hallucinations and delusions associated with Parkinson’s disease psychosis. Unlike traditional antipsychotics, pimavanserin does not block dopamine receptors, which is an important consideration in Parkinson's disease, where dopaminergic pathways are already compromised. Instead, pimavanserin acts as an inverse agonist and antagonist at serotonin 5-HT2A receptors, which are thought to play a role in psychosis.

Clinical trials have shown that pimavanserin significantly reduces the frequency and severity of hallucinations and delusions without worsening the primary motor symptoms of Parkinson’s disease. This is a critical aspect of its efficacy, as many antipsychotic drugs can exacerbate motor symptoms in PD patients. The improvement in psychosis symptoms with pimavanserin treatment has been measured using the Parkinson's disease-adapted Scale for the Assessment of Positive Symptoms (SAPS-PD). Patients treated with pimavanserin have shown a meaningful reduction in SAPS-PD scores compared to placebo, indicating a decrease in psychosis symptoms. It is important to note that while Nuplazid can significantly improve quality of life by addressing hallucinations and delusions, it is not a treatment for the motor symptoms of Parkinson's disease.