Primary Objective: To determine the efficacy of MYOBLOC (administered via intraglandular as a single total dose of 2,500 Units or 3,500 Units) versus placebo in the treatment of troublesome sialorrhea in adult subjects via the assessment of unstimulated salivary flow rate and clinical global impression of sialorrhea severity and improvement at Week 4 post-injection (Part A). It is hypothesized that both MYOBLOC doses will achieve greater efficacy than placebo in relieving sialorrhea at 4 weeks post-injection.
To compare the safety and tolerability of MYOBLOC versus placebo over a 13 week post-injection period (Part A).
Secondary Objective: To assess the onset and duration of therapeutic response of MYOBLOC using efficacy assessments performed at Weeks 1, 2, 4, 8, and 13 after the first treatment (Part A).
To assess the duration of therapeutic response of MYOBLOC (administered via intraglandular as a single total dose of 3,500 Units) using efficacy assessments performed at intervals after treatments every 13 weeks over a maximum possible duration of 65 weeks (Part B).
To determine the long-term safety and tolerability of MYOBLOC treatments every 13 weeks over a maximum possible duration of 65 weeks (Part B).
