The purpose of this study is to test whether a drug called PRA023/MK7240 (the study drug) is a good treatment for patients with Systemic Sclerosis associated with Interstitial Lung Disease (SSc-ILD). The study drug PRA023/7240 is an investigational drug that is given by infusion every 4 weeks. An investigational drug is not approved by The US Food and Drug Administration. It can only be used in a research study like this one. In this study, PRA023/MK7240 will be compared with a placebo (dummy drug). The placebo will be a saline solution that does not have any study drug in it. The comparison with the placebo helps to determine whether the effects seen in your body is because of the PRA023/MK7240 or not. This is a randomized study meaning that you will be assigned by chance (like flipping a coin) to receive either the study drug or placebo. This will be done with the help of a computer-based program and you will have 50% chance of receiving either the study drug or placebo. The study is double-blinded study and 50 weeks long, meaning you and your study doctor will not know what you are receiving, the study drug or placebo.

The study is sponsored by Prometheus Biosciences, Inc., a subsidiary of Merck & Co., Inc. The study is being done at approximately 25 sites across the United States. The main portion of the study will require 15 visits to the MUSC main campus and will have the following procedures completed over the course of your participation: blood draw, physician-led assessments of your disease (for example physical exam and skin thickness testing), tests to assess your pulmonary function and health (Pulmonary Function Test (PFT) and High Resolution Computed Tomography (HRCT)), electrocardiogram, as well as asked to complete surveys. If you complete the initial blinded treatment period of 50 weeks, the study doctor will discuss whether you are eligible to enter the open label period of the study, meaning no placebo. If you are eligible and agree, you will receive 500 mg of study drug once every 4 weeks for an additional 52 weeks. Compensation is available for participation.

The purpose of this study is to test whether a drug called HZN-825 (the study drug) is an appropriate treatment for patients with Systemic Sclerosis (SSc). HZN-825 is an investigational drug that taken by mouth as a pill. An investigational drug is not approved by The US Food and Drug Administration and can only be used in a research study, like this one.

In this study, HZN-825 will be compared with a placebo (a pill that looks like the study pill but does not have any study drug in it). The comparison with the placebo helps to determine whether the effects seen in your body is because of HZN-825 or not. This is a randomized study meaning that you will be assigned by chance (like flipping a coin) to receive either the study drug or placebo. This will be done with the help of a computer-based program, and you will have 67% chance of receiving HZN-825. The study is double-blinded, meaning you and your study doctor will not know what you are receiving, the study drug or placebo. Should an emergency arise, and it is determined necessary, your study doctor will be able to find out what medication group you have been assigned.

The study is sponsored by Horizon Therapeutics Ireland DAC. The study is being done at approximately 135 sites across the world. The study is 60 weeks long will require 12 visits to the MUSC main campus. During study participation, the following procedures will be completed: blood draw, physician-led assessments of your disease (for example physical exam and skin thickness testing), tests to assess your pulmonary function and health (Pulmonary Function Test (PFT) and High-Resolution Computed Tomography (HRCT)), electrocardiogram, as well as being asked to complete surveys about your overall health and wellbeing.