Study for patients with Primary Hyperoxaluria to evaluate the Long-Term Safety and Efficacy of DCR-PHXC Solution for Injection

You may be able to join if

• Participants starting at birth are eligible for this study
• Documented diagnosis of PH, confirmed by genotyping (historically available genotype information is acceptable for study eligibility)
• Participant successfully completed a Dicerna Pharmaceuticals, Inc. study of DCR PHXC, or is the sibling of a participant who either successfully completed a Dicerna Pharmaceuticals, Inc. study of DCR PHXC or completed 24 weeks of participation in Study DCR-PHXC-204. a. For participants rolling over from a multidose study of DCR-PHXC, enrollment should occur within a window of 25 to 75 days from the last dose of study intervention. In order to minimize any gap in administration of DCR-PHXC, every effort should be made to enroll participants as soon as all assessments from the previous study have been completed. It should be noted if the participant was required to repeat the end-of-study (EOS) 24-hour Uox collection for violation of completeness criteria. b. Siblings must i. be younger than 18 years of age ii. meet all other eligibility criteria (including genotyping) iii. have two 24-hour Uox values ≥ 0.7 mmol (adjusted per 1.73 m2 BSA) at Screening OR for siblings aged 0 to 5 years old, average spot Uox-to-creatinine ratio at Screening above 2 times the 95th percentile for age based on Matos et al, 1999: 1. 0.44 mol/mol in participants < 6 months 2. 0.34 mol/mol in participants from 6 months to <12 months 3. 0.26 mol/mol in participants 12 months to < 2 years 4. 0.20 mol/mol in participants from 2 to < 3 years and 5. 0.16 mol/mol in participants from 3 to 5 years iv. Participants who perform 24-hour collections must have less than 20% variation between the two 24-hour urinary creatinine excretion values obtained in the screening period. Individuals who do not achieve < 20% variation between the 2 screening values may undergo a second round of urine collection. An extra 7 calendar days may be added to the screening window for participants to complete a second round of urine collection. Should potential participants again fail to achieve the within- 20% variation, they will be excluded from participation
• Estimated GFR at screening ≥ 30 mL/min normalized to 1.73 m2 BSA, calculated using the equations found in Section 8.2.4.1. For infants aged less than 12 months, serum creatinine below the 97.5th percentile of a healthy population (Boer et al., 2010). Note: For participants rolling over from a 6-month multidose study of DCR-PHXC, the eGFR/serum creatinine value from either the Day 150 or Day 180 (EOS) visit may be used for screening.
• Body weight ≥ 12.75 kg for pediatric siblings
• Male participants: A male participant with a female partner of childbearing potential must agree to use contraception, as detailed in Section 10.4.2, during the treatment period and for at least 12 weeks after the last dose of study intervention and refrain from donating sperm during this period. Female participants: A female participant is eligible to participate if she is not pregnant (see Section 10.4.1), not breastfeeding, and at least one of the following conditions applies: Not a woman of childbearing potential (WOCBP) as defined in Section 10.4.1 OR A WOCBP who agrees to follow the contraceptive guidance in Section 10.4.2 during the treatment period and for at least 12 weeks after the last dose of study intervention. Contraceptive use by men or women should be consistent with local regulations regarding the methods of contraception for those participating in clinical studies.