An Extension Study to Evaluate the Long-Term Efficacy, Safety and Tolerability of Minzasolmin (UCB0599) in Study Participants With Parkinson's Disease

An Extension Study to Evaluate the Long-Term Efficacy, Safety and Tolerability of Minzasolmin (UCB0599) in Study Participants With Parkinson's Disease

A Dose-Blinded Extension Study to Evaluate the Long-Term Efficacy, Safety, and Tolerability of UCB0599 in Study Participants With Parkinson's Disease

The purpose of the study is to estimate the pharmacodynamic effects of minzasolmin (UCB0599) on brain pathophysiology in Early-start versus Delayed-start participants originally diagnosed with new onset Parkinson's disease.

Participants will receive a predefined high dosage of minzasolmin (UCB0599) during the Treatment Period.

Participants will receive a predefined low dosage of minzasolmin (UCB0599) during the Treatment Period.

Minzasolmin (UCB0599) Pharmaceutical form: Granules in capsules Route of administration: Oral use Participants will receive minzasolmin (UCB0599) in a pre-specified sequence during the Treatment Period.

Baseline adjusted Dopamine Transporter Imaging with Single Photon Emission Computed Tomography (DaT-SPECT) whole striatum SBR at PD0055 Month 18

The change from baseline (screening) in mean striatum specific binding ratios (SBR) will be assessed by Dopamine Transporter Imaging with Single Photon Emission Computed Tomography using 123I-Ioflupane as radiopharmaceutical. Baseline will refer to PD0053 (NCT04658186) Screening Visit date.

The Cumulative Levodopa Equivalent Daily Dose (LEDD) will be calculated for each participant at each visit and at the end of study. This is the sum of all the LEDDs taken up to that visit. Any changes in medication (type, dose, or dosing regimen) should be accounted for when calculating cumulative doses.

Any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related.

Any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related. Serious criteria of death, a life-threatening adverse event, inpatient hospitalization or prolongation of existing hospitalization, a persistent or significant incapacity or substantial disruption of the ability to conduct normal life functions, or a congenital anomaly/birth defect . Important medical events that may not result in death, be life-threatening, or require hospitalization may be considered serious when, based upon appropriate medical judgment, they may jeopardize the patient or subject and may require medical or surgical intervention to prevent one of the outcomes listed in this definition.

Any untoward medical occurrence associated with the use of a drug in humans, whether or not considered drug related.

Inclusion Criteria Participant completed the Treatment Period of PD0053 (NCT04658186). The Baseline Visit for PD0055 (Visit 2) should be no later than 4 weeks following the end of treatment (EOT) Visit in PD0053 (NCT04658186). Any delay needs to be justified by the Investigator and approved by the Sponsor A male study participant must agree to use contraception during the Treatment Period and for at least 90 days after the last dose of the IMP and refrain from donating sperm during this period. A female study participant is eligible to participate if she is not pregnant, not breastfeeding, and at least 1 of the following conditions applies: ◦ Not a woman of childbearing potential (WOCBP) OR A WOCBP who agrees to follow the contraceptive guidance during the Treatment Period and for at least 1 month after the last dose of investigational medicinal product (IMP). The study participant must have a negative urine pregnancy test at Screening (Visit 1), which is to be confirmed negative by urine testing prior to the first dose of IMP at PD0055 Baseline Visit. If oral contraception is used, an additional barrier method will be required during the study as an IMP-related gastrointestinal upset or a drug interaction by cytochrome P450 3A4 (CYP3A4) induction could interfere with efficacy Capable of giving signed informed consent which includes compliance with the requirements and restrictions listed in the Informed Consent form (ICF) and in this protocol. Exclusion Criteria: Study participant has any medical or psychiatric condition that, in the opinion of the Investigator, could jeopardize or would compromise the study participant's ability to participate in this study A female study participant who tests positive for pregnancy, plans to get pregnant during the participation in the study, or who is breastfeeding Study participant had previously participated in PD0055 Study participant meets any withdrawal criteria in PD0053 (NCT04658186) Study participants wearing any kind of implantable active device, including cardiac pacemakers, pumps, and implantable cardioverters, will be excluded from using Digital Health Technology, but may participate in the main study Study participant does not agree to refrain from donating blood or blood products or other body fluids

Data from this trial may be requested by qualified researchers six months after product approval in the US and/or Europe, or global development is discontinued, and 18 months after trial completion. Investigators may request access to anonymized individual patient-level data and redacted trial documents which may include: analysis-ready datasets, study protocol, annotated case report form, statistical analysis plan, dataset specifications, and clinical study report. Prior to use of the data, proposals need to be approved by an independent review panel at www.Vivli.org and a signed data sharing agreement will need to be executed. All documents are available in English only, for a prespecified time, typically 12 months, on a password protected portal. This plan may change if the risk of re-identifying trial participants is determined to be too high after the trial is completed; in this case and to protect participants, individual patient-level data would not be made available.

Data from this trial may be requested by qualified researchers six months after product approval in the US and/or Europe or global development is discontinued, and 18 months after trial completion.

Qualified researchers may request access to anonymized IPD and redacted study documents which may include: raw datasets, analysis-ready datasets, study protocol, blank case report form, annotated case report form, statistical analysis plan, dataset specifications, and clinical study report. Prior to use of the data, proposals need to be approved by an independent review panel at www.Vivli.org and a signed data sharing agreement will need to be executed. All documents are available in English only, for a pre-specified time, typically 12 months, on a password protected portal.