A Study of the Efficacy and Safety of DMX-200 in Patients With FSGS Who Are Receiving an ARB

DOUBLE BLIND PERIOD

Inclusion Criteria:

1. Patients must be 12 to 80 years old

2. A diagnosis of primary FSGS, genetic FSGS, or FSGS of undetermined cause. Confirmedby kidney biopsy within 7 years of screening

3. Must be either receiving an ARB at the maximal tolerated dose or willing totransition

4. If taking corticosteroids, the dosage must be stable for ≥4 weeks prior to Screeningand during Stabilization

5. If taking aldosterone inhibitors, mineralocorticoid receptor antagonists, directrenin inhibitors, sodium-glucose co-transporter-2 (SGLT2) inhibitors, or endothelinreceptor antagonists (ERAs, including dual antagonists), the dose and regimen mustbe stable for ≥12 weeks prior to Screening and during Stabilization

6. Urine PCR >1.5 g/g (>169.5 mg/mmol) or 24-hour total protein >1.5 g/day based on 24-hour urine collection during Screening.

7. Estimated eGFR ≥25 and ≤120 mL/min/1.73 m2 at Screening for adults & eGFR ≥25mL/min/1.73 m2 for adolescent patients (<18 years)

8. Seated blood pressure ≤160/100 mm Hg (mean of 3 values) (patients ≥18 years of age)or between the 5th and 95th percentile for age, sex, and height (patients <18 yearsof age) at Screening

9. Body weight ≥35 kg (all patients) AND a body mass index (BMI) ≤40 kg/m2 (patients ≥18 years of age) or between the 5th and 98th percentile for age and sex (patients <18 years of age) at Screening.

10. A female patient is eligible to participate if she is not pregnant or planning tobecome pregnant during the study, not breastfeeding, and at least one of thefollowing conditions applies:

11. Is not of childbearing potential

12. If of childbearing potential and beginning at menarche, agrees to use a highlyeffective method of contraception consistently during the treatment period.

13. A male patient with a female partner of childbearing potential is eligible toparticipate if he agrees to use acceptable contraception

14. A patient or parent/legal guardian (as appropriate) who is capable of giving signedinformed consent, and where required, the patient is capable of providing assent.

Exclusion Criteria:

1. Has FSGS secondary to another condition.

2. Patients with nephrotic syndrome (>3.5 g/day proteinuria and serum albumin <30 g/L)who have not previously been treated with standard of care FSGS-directed therapies (including steroids).

3. History of type 1 diabetes mellitus, or uncontrolled type 2 diabetes mellitus (defined as glycated hemoglobin [HbA1c] >8% at Screening)

4. History of lymphoma, leukemia, or any active malignancy within the past 2 years (except for basal cell or squamous cell carcinomas of the skin or cervical carcinomain situ that have been resected and with no evidence of metastatic disease).

5. Active clinically significant hepatobiliary disease.

6. Documented history of heart failure (New York Heart Association Class III/IV) or amajor adverse cardiac event within 12 weeks prior to Screening.

7. Has a physical, medical, or psychological condition, that in the opinion of theInvestigator, may interfere with the evaluation the study.

8. The patient has a history of alcohol or illicit drug use disorder within 1 yearprior to Screening.

9. Had a prior organ transplant or stem cell transplant, with the exception of cornealtransplant.

10. Positive screening assessment for viral hepatitis B surface antigen, oranti-hepatitis C virus (HCV) antibody AND positive HCV RNA, or humanimmunodeficiency virus 1 and 2.

11. Serum potassium levels >5.5 mmol/L at Screening.

12. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) >2 × upper limitof normal (ULN) at Screening.

13. Treatment with non-steroid immunosuppressant agents including biological drugs (e.g.rituximab), calcineurin inhibitors, cyclophosphamide, azathioprine, or mycophenolatemofetil within 12 weeks prior to Screening.

14. History of serious side effects or allergic response to an angiotensin II antagonistor has a known sensitivity to any components in the IP.

15. Unable to swallow oral medication.

16. Prior participation in any Dimerix-sponsored DMX-200 clinical study.

17. Participation in a clinical study with an investigational product (IP) within 28days or 5 half-lives (whichever is longer) prior to Screening or plans toparticipate in another study during the course of this study.

18. Are study site personnel directly affiliated with this study and their immediatefamilies

OLE PERIOD

Inclusion Criteria:

1. A patient or parent/legal guardian (as appropriate) who is capable of giving signedinformed consent, and where required, the patient is capable of providing assent.

2. Patients who have completed participation in the double-blind period, including theWeek 104 visit, and who may derive benefit from (continued) treatment with DMX-200,and/or continued follow-up

3. The patient received blinded Investigational Product throughout the duration of thedouble-blind period up to the Week 104 visit

4. The patient continues to meet the contraceptive requirements

Exclusion Criteria:

1. The patient has met the criteria for permanent IP discontinuation or studydiscontinuation

2. Any safety concerns identified during the double-blind period which, in theInvestigator's opinion, may interfere with the patient's continued participationduring the OLE period.