Outcome after Discontinuing Long-Term Benzimidazole Treatment in 11 Patients with Non-resectable Alveolar Echinococcosis with Negative FDG-PET/CT and Anti-EmII/3-10 Serology

• Published in: PLoS neglected tropical diseases Vol. 9; no. 9; p. e0003964
• Main Authors: Ammann, Rudolf W, Stumpe, Katrin D M, Grimm, Felix, Deplazes, Peter, Huber, Sabine, Bertogg, Kaja, Fischer, Dorothee R, Müllhaupt, Beat
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-09-2015; Public Library of Science (PLoS)
• Subjects: Adult; Aged; Anthelmintics - administration & dosage; Antibodies, Helminth - blood; Antigens; Benzimidazoles; Benzimidazoles - administration & dosage; CAT scans; Chemotherapy; Drug Monitoring; Drug therapy; Echinococcosis; Echinococcosis, Hepatic - diagnosis; Echinococcosis, Hepatic - drug therapy; Echinococcosis, Hepatic - pathology; Experiments; Female; Humans; Liver - diagnostic imaging; Liver - pathology; Male; Methods; Middle Aged; Parasites; Parasitic diseases; Patient outcomes; Positron emission tomography; Prospective Studies; R&D; Research & development; Studies; Tomography, X-Ray Computed; Treatment Outcome
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0003964

Benzimidazoles are efficacious for treating non-resectable alveolar echinococcosis (AE), but their long-term parasitocidal (curative) effect is disputed. In this study, we prospectively analyzed the potential parasitocidal effect of benzimidazoles and whether normalization of FDG-PET/CT scans and anti-Emll/3-10-antibody levels could act as reliable "in vivo" parameters of AE-inactivation permitting to abrogate chemotherapy with a low risk for AE-recurrence.
This prospective study included 34 patients with non-resectable AE subdivided into group A (n = 11), followed-up after diagnosis and begin of chemotherapy at months 6, 12 and 24, and group B (n = 23) with a medium duration of chemotherapy of 10 (range 2-25) years. All patients were assessed by FDG-PET/CT examinations and anti-EmII/3-10 serology. Chemotherapy was abrogated in patients with normalization of FDG-PET/CT and serum anti-EmII/3-10 levels. These patients were closely followed-up for AE recurrence. Endpoint (parasitocidal efficacy) was defined by the absence of AE-recurrence >24 months after stopping treatment.
Normalization of FDG-PET/CT scan and anti-EmII/3-10 levels occurred in 11 of 34 patients (32%). After abrogation of chemotherapy in these 11 patients, there was no evidence of AE-recurrence within a median of 70.5 (range 16-82) months. However, the patients' immunocompetence appears pivotal for the described long-term parasitocidal effect of benzimidazoles.
The combination of negative FDG-PET/CT-scans and anti-EmII/3-10 antibody levels seem to be reliable parameters for assessing in vivo AE-larval inactivity after long-term benzimidazole chemotherapy.
clinicaltrials.gov: NCT00658294.