A Clinical Study to Evaluate DNTH103 in Adults With Multifocal Motor Neuropathy

Inclusion Criteria:

1. Must have given written informed consent before any study-related activities arecarried out

2. Adult males and females, 18 to 75 years of age (inclusive).

3. Weight range between 40 to 120 kilograms (kg).

4. Confirmed diagnosis of definite or probable MMN.

5. Evidence of:

6. Responsiveness to Ig treatment; and

7. Receiving a stable Ig regimen

8. Documented vaccinations against encapsulated bacteria in accordance with localrequirements and vaccine availability.

9. Female participants must be of nonchildbearing potential or if of childbearingpotential, must agree not to donate ova, not to attempt to become pregnant and, ifengaging in sexual intercourse with a male partner, must agree to use a highlyeffective method of contraception.

10. Male participants must be surgically sterile for at least 90 days prior to Screeningor agree not to donate sperm and, if engaging in sexual intercourse with a femalepartner who could become pregnant, must agree to use an acceptable method ofcontraception.

Exclusion Criteria:

1. History or presence of significant medical/surgical condition including any acuteillness or major surgery considered to be clinically significant or that couldimpact efficacy assessments.

2. Any coexisting conditions which may interfere with outcome assessments (eg, severediabetic neuropathy).

3. Concurrent or previous use of rituximab, cyclophosphamide, mycophenolate mofetil,azathioprine, or cyclosporine. If a participant has previously used thesemedications, the last dose must be at least 6 months prior to randomization.

4. Currently or previously on complement inhibitors including in a clinical trialsetting.

5. Prior history (at any time) of N. meningitidis infection.

6. Diagnosis of an autoimmune disorder other than MMN.

7. Positive test results for active human immunodeficiency virus (HIV-1 or HIV-2),hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibodies duringScreening.

8. History of active malignancy within 5 years prior to Screening, except basal cellcarcinoma of the skin, curatively resected squamous cell carcinoma of the skin,cervical carcinoma in situ curatively treated or low-grade prostate adenocarcinomafor which appropriate management is observation alone.

9. Participation in another clinical study of an investigational drug within 90 days or 5 half-lives of the investigational agent (whichever is longer) prior torandomization (Day 1).

10. Any other overlapping condition for which the condition or treatment of thecondition may affect the study assessments or outcomes.

11. Any other condition, including mental illness or prior therapy, that in the opinionof the Investigator would make the participant unsuitable for this study, includinginability to cooperate fully with the requirements of the study protocol orlikelihood of noncompliance with any study requirements.