At the start of the study, your condition will be assessed to establish baseline measurements.

Your ulcerative colitis activity will be evaluated using a modified Mayo score, which is a system that measures the severity of your disease based on stool frequency, rectal bleeding, findings from a colonoscopy, and a physician’s assessment.

A colonoscopy will be performed to examine the inside of your colon and rectum. This procedure will confirm that inflammation extends at least 15 centimeters from the anal opening.

The colonoscopy will also provide an endoscopic subscore, which rates the appearance of inflammation in your intestinal lining.

Your rectal bleeding and stool frequency will be recorded as part of the baseline assessment.

You will be randomly assigned to receive either XmAb942 or placebo.

The placebo is a solution that looks identical to the active drug but contains no active ingredient. It consists of a buffer solution with sucrose and polysorbate.

Neither you nor the study staff will know which treatment you are receiving. This is called a double-blind design and helps ensure accurate results.

You will receive your assigned treatment through intravenous infusion, which means the medication will be delivered directly into a vein through a needle.

Alternative routes of administration may include subcutaneous injection under the skin or intramuscular injection into a muscle, depending on the study protocol.

The specific dosage, frequency, and duration of treatment administration are determined by the study protocol but are not specified in the available information.

You will continue receiving the assigned treatment according to the schedule determined by the study protocol.

Throughout this period, your symptoms and any side effects will be monitored.

Any adverse events, which are unwanted or harmful reactions that occur during treatment, will be recorded.

Your rectal bleeding and stool frequency will be tracked regularly to assess how your condition responds to treatment.

At week 12, a comprehensive evaluation of your condition will be performed.

Another colonoscopy will be conducted to assess the current state of inflammation in your colon and rectum.

Your modified Mayo score will be calculated again to determine if your disease activity has improved.

The study will evaluate whether you have achieved clinical remission, which is defined as having minimal disease activity with a modified Mayo score of 2 or less, minimal or no inflammation seen on colonoscopy, no rectal bleeding, and stool frequency that is normal or nearly normal.

Endoscopic remission will be assessed, which means the inflammation seen during colonoscopy has resolved or is minimal.

Your response to treatment will be determined by comparing your week 12 scores to your baseline measurements.

Tissue samples taken during the colonoscopy will be examined under a microscope to evaluate histologic improvement, which means improvement in the cellular structure of your intestinal lining.

Throughout the entire study period, any treatment-emergent adverse events will be recorded. These are any medical problems that occur after you start receiving treatment.

Serious adverse events, which are severe medical problems that may require hospitalization or are life-threatening, will be closely monitored.

If you experience significant treatment-related side effects, discontinuation of the study treatment may be necessary.