Albendazole and albendazole placebo are not available in our local suppliers or in the international market. Consequently, it is no possible to re-initiate the enrollment to complete the original sample size.

Taenia solium neurocysticercosis (NCC) is a parasitic infection causing much neurological disease in most of the world. When parasites locate in the cavities around the brain (subarachnoid NCC, SANCC), it becomes an aggressive, progressive and frequently lethal presentation. Current treatment regimens for SANCC have quite limited efficacy. The investigators propose to compare the current standard of care (a single antiparasitic drug, albendazole) with a combined regimen using two antiparasitic drugs simultaneously by adding praziquantel. The trial will enrol 164 patients in four centers, two in Peru, one in Ecuador, and one in Brasil.

Double-blind, randomized, placebo-controlled study in patients with subarachnoid cysticercosis of the basal cisterns or the Sylvian fissure, comparing in two parallel arms the efficacy of the standard of care anti-parasitic regime (30 days of ABZ at 15 mg/k/d, up to 1200 mg/k/d) with a combined regime using similar doses of ABZ and adding PZQ at 50 mg/k/d for the initial 15 days of anti-parasitic treatment. The study and interim analysis plan are designed to allow direct, concrete efficacy comparison in this deadly type of NCC while minimizing the risks of disease progression in the standard of care arm.

In short, this is a parallel group study with a dichotomous primary outcome variable. The main analysis will compare the proportions of patients obtaining the primary outcome at 6 months, using a Chi-square test in a bivariate analysis. A similar analysis will be used for the proportions of patients with a good clinical outcome, and the proportions of patients in whom lesion resolution sustains when assessed at month 12. A Student T test analysis will be used to compare for reduction in parasite volume and non-parametric Mann-Whitney test will be alternatively applied for non-normally distributed data. A non-parametric Spearman's Rho test will be used to assess the correlation between the proportions of cyst mass reduction with the decrease in antigen levels in each study group. A Chi-square test in a bivariate analysis will evaluate the association between negative antigen levels at 6 months versus the complete disappearance of cyst mass.

Inclusion Criteria:

• - Male or female adult individuals (18 to 65 y.o.) with a diagnosis of basal subarachnoid cysticercosis (including locations in the Sylvian fissure or lower interhemispheric spaces) by neuroimaging and confirmed by serology.
• Baseline laboratory results along acceptable ranges (specifically defined in the study protocol).
• Willingness to accomplish the two-week minimum hospitalization required.

Exclusion Criteria:

• Previous therapy with ABZ or PZQ in the preceding 3 years (except for patients who received single-dose ABZ for intestinal parasites, or patients who received antiparasitic treatment between one and three years before enrollment but demonstrated lesion persistence or progression during the past 12 months).
• A type of NCC which can expose the patient to increased risk during the study, specifically: a) intraventricular cysts; b) cysts in brainstem; c) concomitant intraparenchymal lesions greater than 3 cm of diameter in addition to their SANCC lesions; d) more than 20 intraparenchymal cysts in addition to their SANCC lesions; or d) untreated ocular cysticercosis. Patients with a lateral ventricle cyst, less than 2 cm in diameter, without hydrocephalus or intracranial hypertension, can be included. The presence of concomitant intraparenchymal cysts of less than 3 cm in diameter will not exclude the patient unless there are more than 20 of them.
• Active pulmonary tuberculosis evidenced by positive chest X-ray and positive sputum smears, or symptoms compatible with tuberculosis (fever+sweats or fever+cough) not otherwise explained.
• Individuals with positive markers for active hepatitis.
• Systemic disease that may affect therapy or short-term prognosis, including but not limited to chronic renal failure, hepatic insufficiency, cardiac failure, and steroid-dependent immune diseases.
• Patients in unstable condition or with symptomatic intracranial hypertension (ICH). Definition of symptomatic ICH for this study is the presence of headaches, nausea, and vomiting, with papilledema at fundoscopic examination. Patients in this category can be considered for entrance into the study only after resolution of ICH by ventricular-peritoneal shunting or neuroendoscopic procedures involving CSF flow derivation. These procedures would be done as part of their standard medical care and are not part of the trial intervention.
• Pregnancy during anti-parasitic treatment. If a patient becomes pregnant after treatment, she will continue in the study but will have radiological exams delayed until after delivery.
• History of hypersensitivity to ABZ or PZQ
• Chronic or drug abuse as defined in the study protocol.
• Unwilling or unable to undergo MRI exams (like patients with ferromagnetic implants)
• Inability or unwillingness of subject or legal representative to give written informed consent.

Anonymized patient data will be shared upon request and review by the project leaders.

Available: December 2021, until December 2023

The information will be shared upon requested by interested researchers

Tablets containing placebo for PZQ and placebo for ABZ will be purchased from the same commercial sources than those containing active drug if possible. As much as possible, they should have the same size, appearance, excipient, smell, and taste as those containing active drug. A preliminary evaluation of the potential for distinction of active drug and placebo by patients will be performed by the investigators before randomization of the drugs and placebos to their individual coded packages. If distinguishable, a new lot will be ordered.