Objective: We evaluate the long-term efficacy and safety of incobotulinumtoxinA injections in Parkinson’s disease (PD) patients suffering from sialorrhea (10 injection cycles (IC)).

Background: Sialorrhea is frequently a bothersome problem in patients with advanced Parkinson’s disease. The SIAXI trial demonstrated the efficacy and safety up to 4 IC over 64 weeks.

Method: Patients with idiopathic Parkinson’s disease suffering from sialorrhea were injected with a total of up to 100 U incobotulinumtoxinA (3:2 ratio parotid vs. submandibular gland bilaterally) based on anatomical landmarks every 3 months, unless prolonged effect allowed for a longer interinjection interval (up to 6 months).

Efficacy was determined using the 7-point Likert Global Impression of Change Scale (GICS) 6 weeks after each injection, and the Drooling Severity and Frequency Scale (DSFS) at baseline and 6 weeks after every injection.

We actively explored and recorded (if any) the treatment-related adverse events.

Results: Seven years into the study now we have included 35 advanced PD patients (average age of 77.7 +/- 2.5 years). 

GICS consistently scored improvement (value below 4 (=no improvement) on a 7-point Likert scale) with a mean score of 2.5+/-0.2 at 6 weeks after injection 10 (p<0.001).

The total DSFS decreased from 7.5+/-0.2 at baseline to 5.4+/-0.5 at 6 weeks after injection 10 (p<0.001).

13 patients (38%) could stop their injections earlier (on average after 5 cycles; range after 2-9 cycles) because of a sustained benefit. These patients typically go through a phase of longer (6 month) interinjection intervals.

In 45/208 treatment cycles (22 % of overall cycles) did side-effects occur. Swallowing difficulties occurred in 24 cycles (12%). These side-effects spontaneously resolved. In 12 patients a dose reduction to 75 U incobotulinum toxin (or even lower) was warranted because of moderate swallowing difficulties. Treatment interruption was never warranted.

Conclusion: Our interim results confirm the efficacy and safety of repeated incobotulinumtoxinA injections for sialorrhea in PD patients in a real-world setting.

13 patients (38%) could stop their injections after 2-9 cycles because of a sustained benefit. We hypothesize that salivary gland atrophy could explain this unexpected result.

We recommend starting with 60 U incobotulinum toxin only in the parotid glands in patients with pre-existing swallowing difficulties.

References: SIAXI Wolfgang H. Jost, Andrzej Friedman, Olaf Michel, Christian Oehlwein, Jaroslaw Slawek, Andrzej Bogucki,Stanislaw Ochudlo, Marta Banach, Fernando Pagan, Birgit Flatau-Baqué, János Csikós, Claire J. Cairney, Andrew Blitzer; Neurology Apr 2019, 92 (17) e1982-e1991

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MDS Abstracts - https://www.mdsabstracts.org/abstract/incobotulinumtoxina-to-treat-sialorrhea-in-parkinsons-disease-a-real-life-study-7-year-interim-results/