VECTORS Trial - BMJ Open Gastro Feb. 26

The VECTORS trial, a landmark phase 4 randomized controlled trial (RCT), was recently published in *BMJ Open Gastroenterology* on February 26. This trial represents a significant step forward in the treatment of Crohn’s disease (CD) by evaluating transmural healing (TMH) as a novel treatment target. The trial explores the potential benefits of targeting deeper levels of disease control beyond the traditional focus on mucosal healing.

### Key Highlights of the VECTORS Trial:

#### Purpose and Rationale:

• **Transmural Disease in Crohn's**: CD is a transmural inflammatory disease, meaning it affects the entire bowel wall, not just the mucosal lining. Historically, treatment targets have focused on symptom relief or mucosal healing seen through colonoscopy. However, these targets may not address the deeper, transmural nature of the disease.
• **Transmural Healing (TMH)**: The trial aims to evaluate TMH as a treatment goal, hypothesising that it could offer more comprehensive disease control, reduce complications, and improve long-term outcomes.

#### Trial Design:

• **Phase**: Phase 4, multicenter RCT.
• **Participants**: 304 patients with moderately to severely active Crohn’s disease.
• **Sites and Countries**: Conducted across 66 sites in 13 countries.
• **Novel Monitoring Tool**: The trial uses intestinal ultrasound (IUS), a non-invasive, radiation-free, and repeatable imaging tool to monitor TMH. IUS offers real-time insights into bowel wall inflammation, making it a game-changer for tight disease monitoring.

#### Treatment Comparison:

The trial compares two treatment strategies:

1. **Corticosteroid-free TMH Remission Group**:

• TMH assessed via serial IUS.
• Combined with clinical and biomarker remission.

2. **Corticosteroid-free Clinical and Biomarker Remission Group**:

• Focuses only on clinical and biomarker remission without TMH as a target.

#### Endpoints:

• **Primary Endpoint**: Corticosteroid-free endoscopic remission at week 48.
• **Key Secondary Endpoint**: CD-related complications through week 96, such as strictures, fistulae, and surgeries.

### Why the VECTORS Trial Matters:

1. **Pushes the Boundaries of Treatment**: By moving beyond mucosal healing to target the entire bowel wall, the trial addresses the full scope of Crohn’s disease pathology.

2. **Validates IUS**: Demonstrates the utility of intestinal ultrasound as a safe, accessible, and radiation-free tool for real-time disease monitoring.

3. **Potential to Reduce Complications**: TMH could help prevent long-term complications like strictures, fistulae, and surgeries, which are common in Crohn's disease.

4. **Influences Clinical Guidelines**: If successful, the trial could lead to updated clinical guidelines emphasising TMH as a formal treatment target.

5. **Builds on Previous Successes**: Builds on the "treat-to-target" approach established by prior trials like CALM, but takes it a step further by targeting deeper disease control.

### Summary of Implications:

1. Current treatment targets, such as mucosal healing, may be insufficient to address the transmural nature of Crohn’s disease.

2. TMH could offer a more comprehensive approach to disease management, potentially improving long-term outcomes for patients.

3. The use of IUS as a monitoring tool is a significant advancement, offering a fast, cost-effective, and non-invasive alternative to traditional imaging methods.

4. The VECTORS trial is the first RCT to rigorously test TMH as a treatment target, and its findings could have substantial real-world implications for both patients and clinicians.

In conclusion, the VECTORS trial is a groundbreaking study that could redefine treatment strategies for Crohn’s disease, emphasizing the importance of transmural healing and the role of innovative tools like intestinal ultrasound in achieving better patient outcomes.