To the Editor: In their article about neuroprotection in Parkinson disease (PD), Drs Schapira and Olanow1 briefly discussed our phase 2 study of coenzyme Q10 in early PD.2 We believe that in their statement that "activity of daily living scores improved significantly following introduction of the drug, raising the possibility that an unanticipated symptomatic effect might also have confounded interpretation," the authors have overstated the significance of one item in the results.
The prespecified, primary response variable for our study was the change in the total score on the Unified Parkinson Disease Rating Scale (UPDRS) from the baseline visit to last visit. Our primary analysis showed a positive but nonsignificant trend (P = .09) for coenzyme Q10 to attenuate the worsening on the UPDRS, and in a prespecified secondary analysis, the highest dosage (1200 mg/d) was the most effective compared with placebo (P = .04, uncorrected for multiple comparisons). Because we were concerned that an early effect of coenzyme Q10, which could be due to a symptomatic effect, as has been reported with selegiline in the Deprenyl and Tocopheral Antioxidative Therapy of Parkinsonism (DATATOP) study,3 we performed a prespecified, secondary analysis of the change in the total score on the UPDRS between the baseline and month 1 visits, which showed no significant effect (P = .99). The UPDRS includes 3 parts, of which the second assesses activities of daily living. As we noted in our article, there was a nonsignificant trend (P = .07, uncorrected for multiple comparisons) for coenzyme Q10 to reduce worsening on these items at the 1-month visit.
When the total UPDRS score was plotted over time, the separation between the treatment groups emerged gradually over the first 8 months of follow-up. This pattern of change in total UPDRS score was very different from that reported for selegiline in the DATATOP study,3 in which there was significant improvement in the total UPDRS score at month 1.
In our phase 2 study, both the prespecified analysis of change in total UPDRS score (our primary response variable) at month 1 and the pattern of change in the total UPDRS score did not indicate a symptomatic effect of coenzyme Q10, as asserted by Schapira and Olanow. However, the short- and long-term effects of coenzyme Q10 in PD will only be fully elucidated by a larger phase 3 trial.
Financial Disclosures: Dr Shults is listed as coinventor in a pending patent application for the use of coenzyme Q10 in neurodegenerative diseases. The application is jointly owned by Enzymatic Therapy Inc and The Regents of the University of California. Our published study was supported by grant R01 NS36714 from the National Institutes of Health (Dr Shults). The coenzyme Q10 and placebo used in the study were formulated into wafers and packaged without charge by Vitaline Corp/Enzymatic Therapy. Enzymatic Therapy has provided unrestricted funds to the University of California, San Diego (Dr Shults), University of Rochester (Drs Kieburtz, Oakes, Shoulson, and Ms Plumb), and Weill Medical College of Cornell University (Dr Beal) for studies of coenzyme Q10 in Parkinson disease, which followed our published study, and preparation of a proposal for a phase 3 study. Dr Beal serves as a consultant to Enzymatic Therapy.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
Instructions
Comments are moderated and will appear on the site at the discretion of the Journal of American Medical Association editors. Comments should not exceed 500 words of text and 10 references.
Do not submit personal medical questions or information that could identify a specific patient, questions about a particular case, or general inquiries to an author. Only content that has not been published, posted, or submitted elsewhere should be submitted. By submitting this Comment, you and any coauthors transfer copyright to the journal if your Comment is posted.
* = Required Field
Disclosure of Any Conflicts of Interest* Indicate all relevant conflicts of interest of each author below, including all relevant financial interests, activities, and relationships within the past 3 years including, but not limited to, employment, affiliation, grants or funding, consultancies, honoraria or payment, speakers’ bureaus, stock ownership or options, expert testimony, royalties, donation of medical equipment, or patents planned, pending, or issued. If all authors have none, check "No potential conflicts or relevant financial interests" in the box below. Please also indicate any funding received in support of this work. The information will be posted with your response.
Register and get free email Table of Contents alerts, saved searches, PowerPoint downloads, CME quizzes, and more
Subscribe for full-text access to content from 1998 forward and a host of useful features
Activate your current subscription (AMA members and current subscribers)
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Customize your page view by dragging & repositioning the boxes below.
and access these and other features:
Register Now
Enter your username and email address. We'll send you a reminder to the email address on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.