The purpose of the study is to assess the long-term safety and tolerability of UCB0107 in study participants with progressive supranuclear palsy (PSP).

Inclusion Criteria:

• Participant meets the criteria for possible or probable progressive supranuclear palsy (PSP) Richardson's Syndrome according to the Movement Disorder Society-PSP criteria (Hoeglinger et al, 2017)

• Participant completed the Treatment Period (regardless of the total number of infusions) in PSP003 (NCT04185415)

• Participant can be male or female

  a) A male participant must agree to use contraception as detailed in the protocol during the Treatment Period and for at least 6 months after the last dose of study treatment and refrain from donating sperm during this period b) A female participant is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: I. Not a woman of childbearing potential (WOCBP) OR II. A WOCBP who agrees to follow the contraceptive guidance in the protocol during the Treatment Period and for at least 6 months after the last dose of study treatment.

• Participant (or legal representative, as applicable and acceptable by local regulations) is giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICF and in this protocol. Informed consent must be obtained before initiating any study procedures

Exclusion Criteria:

• Participant has met a mandatory withdrawal and/or stopping criterion in PSP003 (NCT04185415)
• Participant made a suicide attempt (including an actual attempt, interrupted attempt, or aborted attempt) during PSP003 (NCT04185415), or has current suicidal ideation with at least some intent to act as indicated by a positive response ("Yes") to either Question 4 or Question 5 of the "Since Last Visit" version of the Columbia Suicide Severity Rating Scale (CSSRS) at the Day 1 Visit. However, participants will not be excluded if, based upon a mental healthcare professional assessment, and the investigator's judgment of benefit/risk, the participant is deemed suitable for receiving study medication

Due to the small sample size in this trial, Individual Patient Data cannot be adequately anonymized and there is a reasonable likelihood that individual participants could be re-identified. For this reason, data from this trial cannot be shared.