This is a seamless, Phase 1b/2 Multiple Ascending Dose (MAD)/Proof of Concept (POC) Study (hereafter referred to as Phase 2 Program) of XTMAB-16 in participants with pulmonary sarcoidosis with or without extrapulmonary involvement. The study is comprised of two parts: Part A is a randomized double-blind placebo-controlled multiple dose-escalating study, and Part B is a randomized double-blind placebo-controlled POC study.
The objective of Part A is to evaluate the safety and tolerability of MADs of XTMAB-16, and to determine the recommended Phase 2 dose and frequency for Part B for XTMAB-16 administration in participants with pulmonary sarcoidosis with or without extrapulmonary manifestations.
The objective of Part B is to confirm preliminary efficacy of XTMAB-16 as measured by the ability to reduce background oral corticosteroid use in participants with pulmonary sarcoidosis with or without extrapulmonary manifestations.

The study will test OATD-01, an experimental medicine, for the first time in patients with pulmonary sarcoidosis (swollen tissue in the lungs). The study goal is to evaluate OATD-01 in the reduction of inflammation and assessing OATD-01 safety.

Everyone who participates in this study will receive OATD-01 or matching placebo (inactive mock tablet). Subjects will be randomly assigned to receive either OATD-01 or placebo for 12 weeks.

The study will run in several hospitals or outpatient clinics, in different countries in Europe and in the USA. In this study, there will be about 98 study subjects in total.

For all patients whether taking OATD-01 or matching placebo, there will be a screening period, a treatment period which will commence after randomization has taken place and will last for 12 weeks and then a follow up visit approximately 4 weeks post last dose of OATD-01.

The total duration of the study is 18 weeks.

The purpose of this study is to measure clinical safety and efficacy of oral brepocitinib in adult participants with cutaneous sarcoidosis.