A Study of Darvadstrocel for Treating Complex Perianal Fistulas in Children and Teenagers With Crohn's Disease

A Phase 3, Open-Label, Multicenter Study to Evaluate the Efficacy and Safety of Darvadstrocel in the Treatment of Complex Perianal Fistula in Pediatric Subjects With Crohn's Disease Over a Period of 24 Weeks and an Extended Follow-up Period for a Total of up to 52 Weeks

Status

Terminated

Phases

Phase 3

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT04701411

Enrollment

Registered

2021-01-08

Start date

2021-06-30

Completion date

2025-05-07

Last updated

2025-11-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Complex Perianal Fistula, Crohn's Disease

Keywords

Drug therapy.

Brief summary

A perianal fistula is an abnormal passageway that develops between the rectum and the skin near the anus. The fistula is considered complex if it branches into several openings or an abscess is also present. The main aim of this study is to learn if complex perianal fistulas in children and teenagers close after treatment with darvadstrocel. 2 to 3 weeks before treatment with darvadstrocel, each participant will have surgery to clean the fistula and to drain any abscesses. On the day of treatment, each participant will have the fistula cleaned and will receive an injection of darvadstrocel near the fistula, under anesthetic. For up to 1 year after treatment, participants will regularly visit the clinic for follow-up. The fistula will be examined and any side effects from the treatment will be recorded. Participants will have an MRI at one clinic visit (about 24 weeks after treatment).

Detailed description

The drug being tested in this study is called darvadstrocel (Cx601, cell suspension containing 120 million cells of allogeneic expanded adipose-derived mesenchymal stem cells \[eASCs\]). Darvadstrocel is being tested to treat complex perianal fistula in pediatric participants who have Crohn's disease (CD). This study will look at the safety and efficacy of darvadstrocel in the treatment of complex perianal fistula in CD. The study will enroll at least 20 patients who will receive a single dose of darvadstrocel. This multi-center trial will be conducted worldwide. The overall time to participate in this study is 52 weeks. Participants will make multiple visits to the clinic. In unavoidable circumstances, such as the coronavirus disease 2019 pandemic, exceptions may be granted for alternative methods for conducting participant visits with approval by the medical monitor and/or sponsor.

Interventions

BIOLOGICALDarvadstrocel

Darvadstrocel perilesional injection.

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

ALL

Age

4 Years to 17 Years

Healthy volunteers

Inclusion criteria

1. Has a CD diagnosis based on accepted clinical, endoscopic, histological and/or radiologic criteria at least 6 months before the screening visit. 2. Has complex perianal fistula refractory to at least one of the following treatments: immunosuppressants or biologics (anti-TNFs, anti-integrin, anti-interleukin \[IL\] 12/23). Fistula(s) refractory to therapy is defined in this study as follows: Immunosuppressants: Inadequate response after 3 months, based on clinical assessment, or more treatment with azathioprine, 6-mercaptopurine or methotrexate. Biologics: Inadequate response after 14 weeks (16 weeks for anti-IL 12/23), based on clinical assessment, or more standard treatment for induction and maintenance. 3. A complex perianal fistula(s) that meets one or more of the following criteria, modified from the American Gastroenterological Association (AGA) technical review: High intersphincteric, transsphincteric, extrasphincteric, or suprasphincteric as assessed by MRI. Presence of 2 or 3 external openings (tracts) as assessed by clinical examination. Associated fluid (abscess) collections as determined by MRI. This study requires that the participant has complex perianal fistulas with a maximum of 2 internal openings and a maximum of 3 external openings, based on clinical assessment. Darvadstrocel treatment is targeted for fistulas that connect between internal and external openings. A central reading of a locally performed pelvic MRI will be performed to confirm the location of the fistula and potential associated perianal abscess(es). Fistulas must have been draining for at least 6 weeks before the screening visit. Participants with actively draining simple subcutaneous fistulas, at the time of the screening visit, are not allowed in this study. 4. Has inactive or mildly active luminal CD defined by meeting all of the following criteria: 1. Colonoscopy, flexible sigmoidoscopy or rectoscopy performed either at screening or within the 6 months before screening, demonstrating no rectal ulcers larger than 0.5 cm. A participant who has documented rectal ulcers larger than 0.5 cm within the 6 months before screening but has undergone subsequent treatment may be eligible if there are no rectal ulcers larger than 0.5 cm on a sigmoidoscopy or rectoscopy performed after treatment or at the time of screening. 2. The improvement of, or no worsening in stool frequency, sustained for 1 week or more, in the interval between the colonoscopy, flexible sigmoidoscopy or rectoscopy in inclusion criteria 4(a) and the screening visit. 3. No initiation or intensification of treatment with corticosteroids, immunosuppressants, or monoclonal antibody dose regimen between the colonoscopy, flexible sigmoidoscopy or rectoscopy in inclusion criteria 4(a) and the screening visit.

Exclusion criteria

1. Has received any investigational compound within 12 weeks/84 days before screening. 2. Has received darvadstrocel/eASC in a previous clinical study or as a therapeutic agent. 3. The participant weighs \<10 kg at screening. 4. Has concomitant perianal fistula(s) with only internal or external opening(s). 5. Has concomitant internal fistula(s) such as ileo-vesical, rectovaginal or ileo-colonic fistula(s). 6. Has an abscess \>2 cm, unless resolved in the preparation procedure. 7. Has rectal and/or anal stenosis, and/or active proctitis, which would restrict the surgical procedure. 8. The participant underwent surgery for the fistula other than drainage or seton placement. 9. Has diverting stomas. 10. Has ongoing systemic corticosteroid treatment or has been treated with systemic corticosteroids within 4 weeks before screening. 11. The participant requires new treatment with immunosuppressants/anti-TNF agents during the screening period. 12. The participant has known or suspected COVID-19 by the investigator within the past 2 months (additional testing may be performed at the discretion of the investigator). Positive antibody testing for COVID without other evidence of current or recent active infection does not exclude participation. Participants who were in screening at the time that COVID-19-related factors resulted in discontinuation may also be rescreened with approval of the sponsor or designee. 13. The participant requires surgery in the perianal region for reasons other than fistulas at the time of screening or foreseen either during the study and/or during the 24 weeks after treatment administration. 14. Has malignant tumor or a prior history of any malignant tumor, including any type of fistula carcinoma. 15. Has current or recent (within 3 months before the screening) history of abnormal, severe, progressive, uncontrolled hepatic, hematologic, gastrointestinal (except CD), endocrine, pulmonary, cardiac, neurological, psychiatric, or cerebral disease. 16. Has either congenital or acquired immunodeficiencies, including participants known to be HIV carriers or participants with, in the judgment of the investigator, are suspected to have monogenic inflammatory bowel disease. 17. Has previously received a bone marrow transplant. 18. Has a contraindication to MRI scan or other planned study procedures. 19. Has a contraindication to the anesthetic procedure. 20. Had major surgery or severe trauma within 6 months before the screening visit.

Design outcomes

Primary

Measure	Time frame	Description
Percentage of Participants Who Achieved Combined Remission	Week 24	Combined remission was defined as the closure of all treated external openings that were draining at baseline despite gentle finger compression, and absence of abscess(es) \>2 centimeters (cm) (in at least 2 dimensions) of the treated perianal fistula(s) confirmed by central magnetic resonance imaging (MRI) assessment.

Secondary

Measure	Time frame	Description
Percentage of Participants Who Achieved Clinical Response	Weeks 24 and 52	Clinical response was defined as closure of at least 50% of all treated external openings that were draining at baseline despite gentle finger compression.
Time to Clinical Remission	Up to Week 52	Time to Clinical Remission was defined as the time in weeks from treatment start to first visit at which clinical remission was observed before Week 52; where clinical remission is said to have occurred if a clinical assessment showed closure of all treated external openings that were draining at baseline despite gentle finger compression. Participants without documented time to clinical remission by the end of study (Week 52), were censored at the date of last assessment along with the participants who discontinued without clinical remission before Week 52 at the date of last visit.
Time to Clinical Response	Up to Week 52	Time to clinical response defined as the time in weeks from treatment start to first visit at which clinical response was observed before Week 52; where clinical response is said to have occurred if a clinical assessment showed closure of at least 50% of all treated external openings that were draining at baseline despite gentle finger compression. Participants without documented time to clinical response by the end of study (Week 52), were censored at the date of last assessment along with the participants who discontinued without clinical response before Week 52 at the date of last visit.
Percentage of Participants With Relapse in Participants With Combined Remission at Week 24	From Week 24 to Week 52	Relapse was defined as reopening of any of the treated fistula(s) external openings with active drainage as clinically assessed in participants who were in combined remission at Week 24.
Percentage of Participants Who Achieved Clinical Remission	Weeks 24 and 52	Clinical remission was defined as the closure of all treated external openings that were draining at baseline despite gentle finger compression.
Percentage of Participants With At Least One Treatment-Emergent Serious Adverse Event (SAE)	Up to Week 52	An SAE is defined as an untoward medical occurrence, significant hazard, contraindication, side effect or precaution that at any dose: results in death, is life-threatening, requires in-patient hospitalization or prolongation of existing hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect or is medically significant. A treatment-emergent SAE is an SAE which occurs after exposure to study treatment.
Percentage of Participants With At Least One Treatment-Emergent Adverse Event of Special Interest (AESI)	Up to Week 52	AESIs include immunogenicity/alloimmune reactions, hypersensitivity reactions, ectopic tissue formation, medication errors, tumorigenicity, and transmission of infectious agents. A treatment-emergent AESI is an AESI which occurs after exposure to study treatment.
Percentage of Participants With Potentially Clinically Significant Vital Sign Values	Up to Week 52	Vital signs include body temperature (oral measurement), blood pressure (systolic and diastolic, resting more than 5 minutes), and heart rate (beats per minute).
Percentage of Participants With Potentially Clinically Significant Laboratory Values	Up to Week 52	Laboratory parameters include hematology, biochemistry, and urinalysis.
Percentage of Participants With At Least One Treatment-Emergent Adverse Event (AE)	Up to Week 52	An AE is defined as any untoward medical occurrence in a clinical investigation participant administered a drug; it does not necessarily have to have a causal relationship with this treatment. A treatment-emergent AE is an AE which occurs after exposure to study treatment.

Countries

Israel, Japan, Netherlands, Poland, Spain

Participant flow

Recruitment details

Participants took part in the study at various investigative sites globally from 30 June 2021 to 07 May 2025.

Pre-assignment details

Participants with complex perianal fistula due to Crohn's Disease (CD) participated in this study to receive darvadstrocel (Cx601). The study was terminated early based on the sponsor's decision and did not meet the planned enrollment number. All enrolled participants completed all the study assessments.

Participants by arm

Arm	Count
Darvadstrocel Participants were administered darvadstrocel (Cx601), 24 mL suspension of 120 million cells as a perilesional injection, once on Day 0.	7
Total	7

Baseline characteristics

Characteristic	Darvadstrocel
Age, Continuous	15.7 years STANDARD_DEVIATION 1.38
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants
Ethnicity (NIH/OMB) Not Hispanic or Latino	7 Participants
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants
Race (NIH/OMB) Asian	0 Participants
Race (NIH/OMB) Black or African American	0 Participants
Race (NIH/OMB) More than one race	0 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants
Race (NIH/OMB) White	7 Participants
Sex: Female, Male Female	2 Participants
Sex: Female, Male Male	5 Participants

Adverse events

Event type	EG000 affected / at risk
deaths Total, all-cause mortality	0 / 7
other Total, other adverse events	6 / 7
serious Total, serious adverse events	2 / 7

Outcome results

Primary

Percentage of Participants Who Achieved Combined Remission

Combined remission was defined as the closure of all treated external openings that were draining at baseline despite gentle finger compression, and absence of abscess(es) \>2 centimeters (cm) (in at least 2 dimensions) of the treated perianal fistula(s) confirmed by central magnetic resonance imaging (MRI) assessment.

Time frame: Week 24

Population: Intent-to-treat (ITT) analysis set included all participants who underwent the fistula preparation procedure regardless of being treated or not.

Arm	Measure	Value (NUMBER)
Darvadstrocel	Percentage of Participants Who Achieved Combined Remission	42.9 percentage of participants

Secondary

Percentage of Participants Who Achieved Clinical Remission

Clinical remission was defined as the closure of all treated external openings that were draining at baseline despite gentle finger compression.

Time frame: Weeks 24 and 52

Population: ITT analysis set included all participants who underwent the fistula preparation procedure regardless of being treated or not.

Arm	Measure	Group	Value (NUMBER)
Darvadstrocel	Percentage of Participants Who Achieved Clinical Remission	Week 24	42.9 percentage of participants
Darvadstrocel	Percentage of Participants Who Achieved Clinical Remission	Week 52	28.6 percentage of participants

Secondary

Percentage of Participants Who Achieved Clinical Response

Clinical response was defined as closure of at least 50% of all treated external openings that were draining at baseline despite gentle finger compression.

Time frame: Weeks 24 and 52

Population: ITT analysis set included all participants who underwent the fistula preparation procedure regardless of being treated or not.

Arm	Measure	Group	Value (NUMBER)
Darvadstrocel	Percentage of Participants Who Achieved Clinical Response	Week 24	71.4 percentage of participants
Darvadstrocel	Percentage of Participants Who Achieved Clinical Response	Week 52	28.6 percentage of participants

Secondary

Percentage of Participants With At Least One Treatment-Emergent Adverse Event (AE)

An AE is defined as any untoward medical occurrence in a clinical investigation participant administered a drug; it does not necessarily have to have a causal relationship with this treatment. A treatment-emergent AE is an AE which occurs after exposure to study treatment.

Time frame: Up to Week 52