A Study of DES-1357 in People With Deficient Mismatch Repair (dMMR)/Microsatellite Instability-High (MSI-H) Metastatic Colorectal Cancer (mCRC)

A Phase 1/2 Adaptive Study of DES-1357 in Participants With Deficient Mismatch Repair (dMMR) and/or Microsatellite Instability-High (MSI-H) Metastatic Colorectal Cancer (mCRC)

This study is conducted sequentially in 3 parts. The primary objective for Part 1 is to determine the maximum tolerated dose of DES-1357 in participants with confirmed dMMR/MSI-H colorectal cancer (CRC). The primary objective for Part 2 is to assess the chronic tolerability and to identify the recommended Phase 2 dose (RP2D), to evaluate preliminary antitumor activity of the selected dose level of DES-1357, and to assess the pharmacokinetics (PK) and pharmacodynamics of DES-1357. The primary objective for Part 3 is to evaluate antitumor activity of the selected dose level of DES-1357.

Study Overview

• Status: Not yet recruiting
• Conditions: Metastatic Colorectal Cancer (CRC)
• Intervention / Treatment: Drug: DES-1357

• Study Type: Interventional
• Enrollment (Estimated): 88
• Phase: Phase 2; Phase 1

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

Individuals must meet all of the following criteria to be included in the study:

1. Have read, understood, and signed the Informed Consent Form (ICF).
2. Male or female aged greater than or equal to (>=) 18 years at the time of signing the ICF.
3. Histologically or cytologically confirmed carcinoma of the colon and/or rectum deemed unresectable and/or with evidence of metastases, that has been cytologically or genetically confirmed as dMMR, and/or MSI-H.
4. Demonstrated disease progression and/or intolerability to prior treatment with any of the following: pembrolizumab, nivolumab (±ipilimumab), dostarlimab, chemotherapy (ie, FOLFOX, FOLFIRI, CAPEOX, or FOLFOXIRI [±bevacizumab]), encorafenib/cetuximab, trastuzumab-based combinations, KRAS inhibitor/EGFR inhibitor, regorafenib, or TAS-102 (±bevacizumab)
5. Measurable disease according to RECIST version 1.1.

6. Adequate organ function:

   1. Absolute neutrophil count >=1,500 cells per/μL
   2. Platelets >=100,000 cells/μL
   3. Hemoglobin >=9 grams per deciliter (g/dL)
   4. Total bilirubin less than or equal to (<=) 1.5*the Upper Limit of Normal (ULN) (<=3*ULN if attributable to known Gilbert's syndrome)
   5. Aspartate Aminotransferase (AST)/Alanine Aminotransferase (ALT) <=5*ULN if liver metastasis present; if liver metastasis is not present, then AST/ALT <=3*ULN.
7. Measured creatinine clearance >=60 milliliter per minute (mL/min) per Cockcroft-Gault formula.
8. Prothrombin time (PT) or international normalized ratio and Partial Thromboplastin Time (PTT) <=1.5*ULN, unless receiving anti-coagulant therapy; Note: activated PTT can be used instead of PTT if it is the site's standard practice.
9. Have agreed to tissue sampling (biopsy [if available], baseline archival tissue, and/or fresh frozen tissue [if available]).
10. Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1.
11. An estimated life expectancy of at least 3 months based on investigator judgment.
12. Women of childbearing potential (WOCBP) and men must agree to use 2 highly effective methods of contraception or practice abstinence from 4 weeks before the first dose of DES-1357, throughout the study, and for 6 months after the last dose of DES-1357; men must refrain from donating or banking sperm during the same period.
13. Negative serum pregnancy test result at screening and on Cycle 1 Day 1 for WOCBP.
14. Female participants who are not WOCBP should meet at least 1 of the following criteria:

have undergone a documented hysterectomy, bilateral oophorectomy and/or bilateral salpingectomy; have medically confirmed ovarian failure, or achieved postmenopausal status (defined as follows: cessation of regular menses for at least 12 consecutive months with no alternative pathological or physiological cause, or have a serum follicle-stimulating hormone level within the laboratory's reference range for postmenopausal women).

Exclusion Criteria:

Individuals meeting any of the following criteria at screening or baseline are ineligible to participate in this study:

1. Cytologically and/or genetically confirmed proficient mismatch repair (pMMR) and/or MSS.
2. Evidence of severe gastrointestinal malabsorption as determined by the investigator.
3. History or presence of dysphagia.
4. Symptomatic or clinically significant bowel obstruction, perforation, or high risk for obstruction as determined by the investigator.
5. Hypersensitivity to any component of DES-1357.
6. Mean QT interval corrected for heart rate using Fridericia's formula (QTcF) greater than (>) 470 milliseconds (msec) based on triplicate 12-lead ECGs obtained at screening.
7. Has an active infection.
8. Has known Human Immunodeficiency Virus (HIV) infection that is not under control. All of these criteria are required: undetectable viral RNA, CD4+ counts/levels >=350, no history of Acquired Immune Deficiency Syndrome (AIDS)-defining opportunistic infection within the past 12 months, and clinically stable for at least 3 months on the same anti-HIV medications.

9. Has active or uncontrolled hepatitis B or C infection. Participants are eligible if they:

   1. Have been curatively treated for hepatitis C virus infection as demonstrated clinically and by viral serologies
   2. For hepatitis B, if the participant has a positive hepatitis B surface antigen result, viral load must be below 2000 international units per milliliter (IU/mL) in the absence of antiviral therapy for the last 12 weeks, and AST/ALT <=3*ULN
10. Uncontrolled diabetes as determined by the investigator.
11. Cardiovascular and/or cerebrovascular event in the prior 6 months before screening.
12. Has received prior treatment with a Werner Syndrome Helicase (WRN) inhibitor.
13. Has been diagnosed with Werner Syndrome.
14. Primary Central Nervous System (CNS) tumor/CNS metastasis.
15. Ongoing toxicities from prior anti-cancer therapy that have not resolved to baseline or grade <=1 (according to NCI-CTCAE version 6.0), except for alopecia and endocrinopathies that are stable under medication.
16. Is pregnant or breastfeeding, is planning to become pregnant during the study.
17. Is planning to donate/bank or retrieve eggs (ova, oocytes) or donate sperm during the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Sequential Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Part 1: Dose Escalation; Participants will receive DES-1357 orally once daily (QD) in 21-day treatment cycles with a starting dose of 150 milligrams (mg). The planned escalation dose levels are 300 and 600 mg to identify the maximum tolerated dose (MTD) for DES-1357.	Drug: DES-1357; DES-1357 oral capsules.
Experimental: Part 2: Dose Optimization - Dosing Schedule A; Participants will receive DES-1357 orally QD in Dosing Schedule A. The dosing schedules will be selected based on the escalation ranges of Part 1, to determine the RP2D for expansion in Part 3.	Drug: DES-1357; DES-1357 oral capsules.
Experimental: Part 2: Dose Optimization - Dosing Schedule B; Participants will receive DES-1357 orally QD in Dosing Schedule B. The dosing schedules will be selected based on the escalation ranges of Part 1, to determine the RP2D for expansion in Part 3.	Drug: DES-1357; DES-1357 oral capsules.
Experimental: Part 3: Dose Expansion; Participants will receive DES-1357 orally QD at the RP2D determined in Part 2 to further assess its efficacy and safety.	Drug: DES-1357; DES-1357 oral capsules.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1: Number of Participants With Dose-Limiting Toxicities (DLTs)	A DLT is a toxicity that occurs during cycle 1 that meets the protocol-defined DLT criteria and is graded according to National Cancer Institute - Common Terminology Criteria for Adverse Events (NCI-CTCAE) version 6.0	Part 1: Cycle 1 (Cycle length=21 days)
Part 2: Incidence and Severity of Treatment- related Treatment Emergent Adverse Events (TEAEs) Through at least 3 Cycles of DES-1357	A TEAE is defined as an AE with onset dates on or after the start of the study treatment or AEs that started prior to the start of the study treatment but worsened in severity after start of the study treatment.	Part 2: From the first dose of DES-1357 through at least 3 treatment cycles (Cycle length=21days)
Part 2: Best Overall Response (BOR)	Best overall response is defined as the single best patient level response category (Complete Response [CR], Partial Response [PR], Stable Disease [SD], Progressive disease [PD], or Not Evaluable [NE]) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1.	Part 2: From baseline through disease progression or end of treatment (EOT); tumor assessments every 8 weeks and at the EOT visit; assessed up to approximately 11 months
Part 2: Maximum Observed Concentration (Cmax) of DES-1357		Part 2: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 2: Time to Maximum Concentration (Tmax) of DES-1357		Part 2: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 2: Area Under the Curve (AUC) of DES-1357		Part 2: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 2: Half Life (t1/2) of DES-1357		Part 2: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 2: Clearance (CL) of DES-1357		Part 2: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 2: Volume of Distribution (Vd) of DES-1357		Part 2: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 2: Change in Pharmacodynamic Markers Levels Following Treatment With DES-1357	Blood and tumor tissue samples will be collected for pharmacodynamic assessments. Biomarker evaluations may include circulating tumor Deoxyribonucleic Acid (ctDNA), carcinoembryonic antigen (CEA), Werner Syndrome Helicase (WRN) expression, phospho-H2AX expression, and other exploratory molecular analyses performed using immunohistochemistry and Ribonucleic Acid (RNA) sequencing methods.	Part 2: Blood Samples: At Day 1 (pre-dose) of Cycles 1, 2, 3, 5, 7, and 9; Tumor tissue: At Screening and Cycle 1 Day 15 (±3 days, pre-dose) (Cycle length=21days)
Part 3: Objective Response Rate (ORR) by Independent Review Committee (IRC)	ORR is defined as the percentage of participants with a confirmed objective response (CR or PR) as determined per RECIST Version 1.1.	Part 3: From baseline through EOT; tumor assessments every 8 weeks and at the EOT visit; assessed up to approximately 8 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Part 1: Number of Participants With Treatment-related Adverse Events (AEs) Including TEAEs and Serious AEs	Participants with treatment related AEs, TEAEs and SAEs will be reported, plus treatment-related delays, dose reductions, and/or treatment discontinuations.	Part 1: From the first dose of DES-1357 through 30 days after the last dose (Cycle length=21 days)]
Part 2: ORR According to RECIST Version 1.1	ORR is defined as the percentage of participants with a confirmed objective response (CR or PR) as determined per RECIST Version 1.1.	Part 2: From baseline through EOT; tumor assessments every 8 weeks and at the EOT visit; assessed up to approximately 11 months
Part 2 and Part 3: Disease Control Rate (DCR) According to RECIST Version 1.1	DCR is defined as the percentage of participants who achieve best response of CR, PR, or SD per RECIST version 1.1.	Part 2 and Part 3: From baseline through EOT; tumor assessments every 8 weeks and at the EOT visit; assessed up to approximately 11 months
Part 3: Duration of Response (DOR) According to RECIST Version 1.1	DOR is defined as the time from the first objective response (CR or PR) to the first documented PD per RECIST version 1.1 or death.	Part 3: From first documented objective response until first documented PD or death; assessed up to approximately 8 months
Part 1 and Part 3: Maximum Observed Concentration (Cmax) of DES-1357		Part 1 and Part 3: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 1 and Part 3: Time to Maximum Concentration (Tmax) of DES-1357		Part 1 and Part 3: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 1 and Part 3: Area Under the Curve (AUC) of DES-1357		Part 1 and Part 3: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 1 and Part 3: Half Life (t1/2) of DES-1357		Part 1 and Part 3: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 1 and Part 3: Clearance (CL) of DES-1357		Part 1 and Part 3: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 1 and Part 3: Volume of Distribution (Vd) of DES-1357		Part 1 and Part 3: Cycle 1 Day 1: predose, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours postdose; Cycle 1 Day 15: predose, 1, 2, 4, 8, 12 and 24 hours postdose; Cycle 1 Days 3, 5, and 21: at predose (Cycle length=21 days)
Part 1 and Part 3: Change in Pharmacodynamic Markers Level of DES-1357	Blood and tumor tissue samples will be collected for pharmacodynamic assessments. Biomarker evaluations may include ctDNA, CEA, WRN expression, phospho-H2AX expression, and other exploratory molecular analyses performed using immunohistochemistry and RNA sequencing methods.	Part 1 and Part 3: Blood Samples: At Day 1 (pre-dose) of Cycles 1, 2, 3, 5, 7, and 9; Tumor tissue: At Screening and Cycle 1 Day 15 (±3 days, pre-dose) (Cycle length=21days)
Part 2: ORR by an IRC According to RECIST Version 1.1	Part 2: ORR is defined as the percentage of participants with a confirmed objective response (CR or PR) as determined per RECIST Version 1.1.	Part 2: From baseline through EOT; tumor assessments every 8 weeks and at the EOT visit; assessed up to approximately 11 months
Part 2: DCR by an IRC According to RECIST Version 1.1	Part 2: DCR is defined as the percentage of participants who achieve best response of CR, PR, or SD per RECIST version 1.1.	Part 2: From baseline through EOT; tumor assessments every 8 weeks and at the EOT; assessed up to approximately 11 months
Part 2 and Part 3: Characterization of Biomarker Profiles Following Treatment With DES-1357	Blood and tumor tissue samples will be collected for biomarker analyses. Biomarker assessments may include Deoxyribonucleic Acid (DNA) damage/replication stress markers, ctDNA, WRN expression, and other relevant molecular biomarkers.	Part 2 and Part 3: Blood Samples: At Day 1 (pre-dose) of Cycles 1, 2, 3, 5, 7, and 9; Tumor tissue: At Screening and Cycle 1 Day 15 (±3 days, pre-dose) (Cycle length=21days)
Part 3: European Organisation for Research and Treatment of Cancer Quality of Life Core Questionnaire 30 (EORTC QLQ C30) Questionnaire	Quality-of-life will be assessed through a participant-reported outcome using EORTC QLQ C30	Part 3: Screening, and at Cycle 1 Days 1, 8, 15, 21 and at Day 21 for subsequent cycles up to 37 days after last dose of DES-1357 (Cycle length=21days)
Part 3: Progression-Free Survival (PFS)	PFS is defined as the time from the first dose of DES-1357 to the earlier of the date of the first documented disease progression (per RECIST version 1.1) or death due to any cause.	Part 3: From first dose of DES-1357 up to first documented disease progression or death; assessed for up to approximately 8 months
Part 3: Overall Survival (OS)	OS is defined as the time from the date of the first dose of study treatment to the date of death due to any cause.	Part 3: From first dose of DES-1357 to date of death due to any cause; assessed for up to approximately 8 months

Collaborators and Investigators

• Sponsor: D. E. Shaw Research, LLC

Study record dates

Study Major Dates

• Study Start (Estimated): December 3, 2026
• Primary Completion (Estimated): July 2, 2028
• Study Completion (Estimated): July 2, 2028

Study Registration Dates

• First Submitted: September 2, 2026
• First Submitted That Met QC Criteria: September 2, 2026
• First Posted (Actual): September 8, 2026

Study Record Updates

• Last Update Posted (Actual): September 8, 2026
• Last Update Submitted That Met QC Criteria: September 2, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Keywords: Colorectal cancer; Microsatellite Instability High; Colorectal Neoplasms; Mismatch Repair Deficiency
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Intestinal Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Intestinal Neoplasms; Rectal Diseases; Colonic Diseases; Colorectal Neoplasms; Turcot syndrome
• Other Study ID Numbers: DES-1357-101; 2026-527769-30-00 (Ctis)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No