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NCT Number: NCT07209215

ctDNA-Informed Management of Early-Stage Rectal Cancer

This is a phase 2 pragmatic study to examine the utility of ctDNA-informed treatment management for participants with early-stage rectal cancer using the Signatera Genome assay. The primary aims are to 1) assess pathologic complete response (path CR) in the ctDNA informed management arm; 2) assess pathologic complete response (path CR) in the post total neoadjuvant therapy (TNT) standard of care (SOC) surgery arm; and 3) assess disease free survival (DFS) in the ctDNA informed management arm.

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Key information

Conditions

Rectal Adenocarcinoma Colorectal Neoplasms Digestive System Diseases Digestive System Neoplasms Early-stage Rectal Cancer Gastrointestinal Diseases Gastrointestinal Neoplasms Intestinal Diseases Intestinal Neoplasms Locally Advanced Rectal Adenocarcinoma Neoplasms Neoplasms by Site Rectal Cancer Rectal Diseases Rectal Neoplasms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2

Primary location

University of California Davis Comprehensive Cancer Center

Sacramento, California, 95817, United States

Location contact

Ankit Sarin, MD

CONTACT

[email protected]

916-734-3772

About this study

Two cohorts of participants will be enrolled: Cohort A (participants appropriate for receiving TNT) and Cohort B (TNT already performed at UC Davis Health or externally). At Time A after TNT is completed and based on ctDNA assay results, the clinical decision will be made to put participants into one of two arms: the ctDNA informed management arm (Watchful Waiting [WW] surveillance) or the post TNT SOC surgery arm; participants will be monitored for ctDNA positivity for up to 5 years.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Tumor tissue histologically confirming rectal adenocarcinoma that is available for Natera ctDNA assay.
  • Cohort A only: Patients appropriate for receiving TNT including chemotherapy and chemoradiation.
  • Cohort B only: TNT must have included at least 4 cycles of CAPEOX or 6 cycles of FOLFOX and at least 45 Gy in 25 fractions to the pelvis during chemoradiation.
  • Patients ≥18 years of age at time of consent.
  • Ability to understand and willingness to sign the informed consent form (ICF).
  • Ability and stated willingness to adhere to the study visit schedule and protocol procedures/requirements.

Exclusion criteria

  • Prior treatment for rectal cancer, except for cohort B.
  • Evidence of distant metastatic disease on staging imaging (CT chest with abdominopelvic imaging by CT or MRI) within 8 weeks of enrollment.
  • Patients on hemodialysis.
  • Any condition that in the opinion of the investigator would interfere with the participant's safety or compliance while on trial

Treatment and study plan

Signatera Genome ultra-sensitive ctDNA blood test + total neoadjuvant therapy (TNT)

Drug

Use of Signatera Genome ultra-sensitive ctDNA blood test post-total neoadjuvant therapy (TNT) for ctDNA-informed treatment management of early-stage rectal cancer.

Primary outcomes

  1. Pathologic complete response (pathCR) rate (ctDNA Informed Management Arm)

    Time frame: Up to 2 years after TNT

    Percent of participants with local regrowth within 2 years of total neoadjuvant therapy (TNT)

  2. Pathologic complete response (pathCR) rate (Post TNT SOC Surgery Arm)

    Time frame: Up to 2 years after TNT

    Percent of participants with local regrowth within 2 years of TNT

  3. Disease-free survival (DFS) rate (ctDNA Informed Management Arm)

    Time frame: Up to 2 years after TNT

    Median interval from first date of TNT to the first occurrence of locoregional failure, distant recurrence, a new invasive colorectal primary cancer.

Secondary outcomes

  1. Frequency of local regrowth (ctDNA Informed Management Arm)

    Time frame: Up to 2 years after TNT

    Percentage of participants with local regrowth within 2 years of TNT

Study contacts

Contact information is provided by the study sponsor or research team.

Ankit Sarin, MD

CONTACT

[email protected]

(916) 734-3772

Sponsors and collaborators

Lead sponsor

University of California, Davis

Other

Collaborators

  • National Cancer Institute (NCI)

Registry information

Official study title

ULtra sensiTive ctDNA-Informed Management eArly-stage recTal cancEr (ULTIMATE)

Acronym: ULTIMATE

Important dates

Study start
2026
Primary completion
2027
Study completion
2028
First posted
Oct 6, 2025
Registry last updated
Jan 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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