You may be able to take part in a clinical study that is evaluating the safety and efficacy of an investigational medicine called LAD191 in people with moderate-to-severe HS.

Why are we conducting this study?

HS is a chronic, inflammatory disease that causes painful skin wounds and gradually destroys the skin. Even though approved treatments exist, they are only effective in around 50% of treated people and some show that their benefits lessen over time. Therefore, more effective and lasting treatment options are needed.

LAD191 (study drug) is a protein that targets the process involved in the development of HS and helps stop it from progressing further. LAD191 (study drug) has already been tested in healthy adults and a limited number of HS patients, where it where it did not show any safety concerns. This study will assess how safe and efficacious LAD191 (study drug) is in patients with moderate-to-severe HS and will aim to identify the best dose.

Who can participate in the study?

You may qualify to participate if you:

• Are aged between 18 to 65 years, inclusively
• Have moderate-to-severe HS, with signs and symptoms of HS for at least 6 months
• Have HS skin wounds present in at least 2 distinct areas on your body

Other requirements will be reviewed by the study team with you to determine if you qualify for the study.

What is involved in the study?

The study will enroll up to approximately 200 adults with moderate-to-severe HS. If you choose to take part in the study, you will go through the following stages:

Screening: You will attend a clinic visit where you will provide your consent for participating in the study and have some routine tests and health checks to see if you are eligible to take part. At this visit you will be shown how to use the Study App, which you will use to record daily updates of your skin pain and complete health-related questionnaires.

Treatment: If you are eligible, you will enter the treatment period, which will include 33 clinic visits, where 20 of them could occur optionally at your home (if you wish and if allowed by local regulations).

The first part of the treatment period will last for 16 weeks, where you will be assigned at random (like drawing from a hat) to 1 of 4 groups to receive either:

• LAD191 (study drug) dose A
• LAD191 (study drug) dose B
• LAD191 (study drug) dose C, or
• Placebo (a substance that looks like the study drug but contains no active ingredients)

When a proportion of the planned participants have completed the first part of the treatment period, at least 1 dose of LAD191 (study drug) will be dropped and replaced with adalimumab (already approved treatment).

The second part of the treatment period will last for a further 16 weeks, where all participants will receive LAD191 (study drug). If you were already receiving LAD191 (study drug), you will continue to receive that same dose. If you were receiving placebo, or a dose of LAD191 that was dropped, or adalimumab, you will switch to the highest available LAD191 dose.

All study treatments will be given as a subcutaneous injection, i.e. an injection under the skin.

Follow-up: After treatment, you will have 1 telephone call and 1 clinic visit so the study team can monitor your health.

The total duration of the clinical study, including Screening, Treatment, and Follow-Up periods, is estimated at approximately 48 weeks.

How will my health be monitored?

The health assessments and procedures will vary from visit to visit, but may include:

• Physical examination
• Vital signs check
• Heart scan (electrocardiogram that records electrical signals in the heart)
• Evaluation of the HS lesions
• Pregnancy test (where applicable)
• Blood tests
• Urine test
• Monitoring for side effects
• Health-related quality of life questionnaires
• Skin pain assessments
• Review of past and current medications

Additional Information

LAD191 (study drug) is not available by prescription and can only be obtained through participation in a clinical study like this one.

If you decide to take part in the study and are eligible, all study-related medication and assessments will be provided to you at no cost. Study staff can provide additional details regarding costs and reimbursement for this study. Participation is voluntary and you would be able to leave the study at any point.