Moxidectin is not approved to treat scabies in humans. The effective dose of moxidectin to treat scabies is not known. This study aims to assess the efficacy of a single administration of 8 mg, 16 mg, or 32 mg moxidectin per oral in achieving Scabies Complete Cure at Day 28. This study also aims to assess the safety of three strengths of single moxidectin doses in adults with scabies.

Inclusion Criteria:

1. Aged 18 years or older.
2. Provided written informed consent.
3. Diagnosis of active scabies infestation confirmed by the presence of clinical signs and symptoms (evidence of burrows or typical inflammatory/noninflammatory lesions and pruritus) and either microscopic confirmation of scabies mite(s), ova or scybala by skin scraping or dermoscopy.
4. All female subjects of childbearing potential must agree to the use of a highly effective method of birth control until 16 weeks after administration of Investigational Product (IP).

Exclusion Criteria:

1. Diagnosis of crusted/Norwegian scabies or scabies presentation that, in the opinion of the Investigator, would require treatment with more than one standard of care treatment for scabies (e.g., scabies requiring concurrent topical and oral treatment).
2. History of chronic or recurrent dermatologic disease or skin conditions other than scabies that could interfere with the diagnosis of scabies and evaluation of cure.
3. Received any treatment with one or more scabicides within the 28 days prior to Screening, or between Screening and Baseline, including but not limited to permethrin, ivermectin, benzyl benzoate, sulfur, lindane, crotamiton, malathion, tea tree oil or spinosad.
4. Body mass index > 35 kg/m2.
5. Creatinine clearance < 30 mL/min (using Cockcroft-Gault equation).
6. Both total bilirubin >1.5 x upper limit of normal (ULN) and AST > ULN.
7. Abnormal and clinically relevant findings in hematology or biochemistry assessments at Screening, or in vital signs, 12-lead ECG, or physical examination at Screening and/or Baseline, that in the opinion of the Investigator would put the subjects at increased risk from participating in the study, confound study evaluations, or may interfere with study conduct.
8. Presence of any other clinically relevant condition, including infection, immunological disorder, malignant disease, and/or other underlying condition or circumstance at Screening or Baseline that in the opinion of the Investigator would put the subjects at increased risk from participating in the study, confound study evaluations, or interfere with the study conduct.
9. Use of topical steroids, systemic or high-dose inhaled corticosteroids (>500 µg per day of fluticasone propionate or equivalent for adults), or other immunomodulators within 14 days of Baseline.
10. Requiring ongoing treatment with, or received within 5 half-lives before Screening, any of the following medications that are clinical BCRP inhibitors: curcurmin (turmeric) supplements, cyclosporine A, darolutamide, eltrombopag, febuxostat, fostamatinib, rolapitant and teriflunomide.
11. Received an investigational agent within 28 days of Screening (or 5 half-lives of the investigational agent, whichever is longer).
12. Known or suspected hypersensitivity to macrocyclic lactones or excipients used in the formulation of moxidectin or ivermectin.
13. Known or suspected hypersensitivity to any of the components in permethrin 5% cream, to any synthetic pyrethroid or pyrethrin, or to the components of spinosad 0.9% topical suspension.
14. Known, suspected or at risk of Loa loa coinfection.
15. Difficulty swallowing tablets or capsules.
16. Pregnant or breastfeeding or planning to become pregnant from Screening until 16 weeks after treatment with IP.
17. Known or suspected alcohol or illicit substance abuse.
18. Unwilling, unlikely or unable to comply with all protocol specified assessments.
19. Previous enrolment in this study.
20. Previous moxidectin exposure within 6 months (5 half-lives) from Baseline.
21. Has household members who refuse or are unable to receive permethrin 5% cream treatment for scabies.

Deidentified individual participant data in the form of data listings and datasets may be available for sharing on application to the Sponsor.

Data will become available 12 months after publication, ending 36 months following publication.

Provision of a methodologically sound and relevant proposal detailing the intended use of the data and relevant ethics approval for the proposed analysis, as applicable.

Double blinded. Subjects will be randomized to one of the treatment arm by Interactive Response Technology at 1:1:1:1