ClinicalTrials.gg
RecruitingNCT07633756Updated Jul 31, 2026

A Phase 1b, Open-Label Study Of REC-617, A Selective CDK7 Inhibitor, In Patients With Metastatic Or Unresectable RB1-Negative Leiomyosarcoma After Prior Systemic Therapy

A Phase 1 interventional study of REC617 in Phase 1b, Open Label and REC-617, sponsored by M.D. Anderson Cancer Center. Recruiting at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-31.

Sponsored by M.D. Anderson Cancer Center · Phase 1, Interventional, and Treatment

Phase
Phase 1
Study type
Interventional
Enrollment
15
Allocation
Not applicable
Ages
18 Years and older
Sex
All
01

Study summary

To learn if the study drug REC-617 can help to control LMS. The safety of REC-617 will also be studied.

Read the detailed description

Primary Objectives The primary objective of this trial is to assess ORR to REC-617 in RB1-negative leiomyosarcoma, as defined by RECIST v1.1.

Secondary objectives

  • To estimate clinical benefit rate, duration of response, duration of complete response, duration of stable disease per best response by RECIST 1.1
  • To estimate median PFS and PFS rate at 12 - 24 weeks
  • To estimate median OS and OS rate at 12 months
  • To assess toxicity per CTCAE v6
02

Conditions studied

  • Phase 1b
  • Open Label
  • REC-617
  • RB1-Negative
  • Leiomyosarcoma

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03

In context

Leiomyosarcoma

177 studies on the registry are indexed under Leiomyosarcoma; 35 are open to participants now.

This study's planned enrollment of 15 is below the median of 54 across 151 interventional studies indexed under Leiomyosarcoma.

Browse Leiomyosarcoma studies →

Lead sponsor

M.D. Anderson Cancer Center is the lead sponsor of 3,047 studies on the registry; 578 are open to participants now.

Of its 612 completed or terminated interventional studies of FDA-regulated products, 409 (67%) have results posted.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years and older
Sexes eligible
All
Accepts healthy volunteers
No

Eligibility criteria

Eligibility Criteria A. Disease Characteristics

  • confirmed leiomyosarcoma (any site of origin).
  • RB1-negative tumor, as assessed by immunohistochemistry (IHC) with a cutoff of 0% versus any expression Participants will have measurable diseases by 1.1. Previously ablated/ radiated/treated areas can only be counted towards if there is unequivocal progression after directed therapy.
  • Participant will have tumor lesion(s) or amenable to , excluding bone metastases, as confirmed by a radiologist, if appropriate, and as deemed safe by the Investigator. If there is only one target lesion per RECIST 1.1 which is accessible to biopsy, this lesion should be at least 2cm.

B. Prior and Current Therapy Requirements

  • At least one . C. Participants Characteristics
  • Age ≥18 years. Because no dosing or adverse event data are currently available on the use of REC-617 in Participants \<18 years of age, children are excluded from this study.
  • performance status ≤ 2 ( ≥60%,).
  • of >3 months, as determined by the investigator.
  • Ability to swallow and retain oral medication.
  • Ability to understand and the willingness to sign a written document and comply with study procedures.

D. Organ and Marrow Function Requirements

Participants will have adequate organ and marrow functions as defined below:

≥8.5 g/dL. ≥1,000/mcL ≥150,000/mcL, no platelet transfusion within 7 days prior to screening visit Total ≤ institutional (ULN) (except Participants with Gilbert's syndrome, who must have total bilirubin \< 3.0 mg/dL) (SGOT)/ALT(SGPT) ≤3 × institutional ULN ≤1.5 except for Participants on oral anticoagulants ≥60 mL/min based on the Cockcroft-Gault equation or method standard to institution E. Viral and Infectious Disease Requirements

  • Participants may not have active or chronic infections with virus (HBV), virus (HCV), and (HIV) F. CNS and Cardiac Requirements
  • Participants with asymptomatic treated CNS lesions who have completed treatment ≥30 days prior with documented stability on imaging and are on a stable dose are eligible.
  • Participants with known history or current symptoms of cardiac disease, or history of treatment with cardiotoxic agents, should have a clinical risk assessment of cardiac function using the Functional Classification. To be eligible for this trial, Participants should be class 2B or better.
  • Participants should not have a >470 msec or history of torsades de pointes or history of congenital long QT syndrome.

G. Reproductive/ Requirements

The effects of REC-617 on the developing human fetus are unknown. For this reason and because CDK7 inhibitor agents as well as other therapeutic agents used in this trial are known to be teratogenic, women of and men will agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. (Refer to Pregnancy Assessment Policy MD Anderson Institutional Policy # CLN1114). This includes all female Participants, between the onset of menses (as early as 8 years of age) and 55 years unless the Participant presents with an applicable exclusionary factor which may be one of the following:

  • (no menses in greater than or equal to 12 consecutive months).
  • History of hysterectomy or bilateral salpingo-oophorectomy.
  • Ovarian failure (Follicle Stimulating Hormone and Estradiol in menopausal range, who have received Whole Pelvic Radiation Therapy).
  • History of bilateral tubal ligation or another surgical sterilization procedure.

    • Participants are eligible to participate if they agree to use 2 methods of contraception, approved methods of birth control are as follows: Hormonal contraception (i.e. birth control pills, injection, implant, transdermal patch, vaginal ring), Intrauterine device (IUD), Tubal Ligation or hysterectomy, Subject/Partner post vasectomy, Implantable or injectable contraceptives, and condoms plus spermicide. Not engaging in sexual activity for the total duration of the trial and the drug is an acceptable practice; however periodic abstinence, the rhythm method, and the withdrawal method are not acceptable methods of birth control. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately.

Men and women treated or enrolled on this protocol will also agree to use adequate contraception prior to the study, for the duration of study participation, and 6 months after completion of REC-617 administration.

Exclusion Criteria A. Concurrent Treatments and Agents

  • Participants who are receiving any other investigational agents or have received any other investigational agent within 3 weeks prior to enrollment.
  • Current enrollment in another clinical study unless it is non-interventional or the follow-up period of an interventional study.
  • Prior treatment with radiotherapy (including radio-labeled spheres and/or cyberknife, hepatic arterial embolization (with or without chemotherapy) or cryotherapy/ablation) is allowed if these therapies did not affect the areas of measurable disease being used for this protocol.
  • Received medications known to prolong QTc within 5 half-lives before the first dose of the study treatment. List of medications that prolong QTc can be obtained from crediblemeds.org.
  • Administration of a within 28 days of starting study treatment and for up to 1 month after the final dose of study treatment or anticipation that such vaccine will be required during the study. Note: mRNA-based vaccines for COVID-19 are allowed as well as inactivated flu vaccines.
  • Has had or is scheduled to have major surgery \<28 days prior to the first dose of study treatment.

B. Disease or Cancer-Related Exclusions

  • Active concurrent second within 2 years of trial enrollment. Note: Participants with a prior or concurrent malignancy whose natural history or treatment does not have the potential to interfere with the safety or efficacy assessment of the investigational regimen are eligible for this trial. Examples include non-melanomatous skin cancer, in situ carcinoma, or low-risk prostate cancer.
  • Unresolved or unstable toxic side-effects of prior anticancer therapy, except fatigue, alopecia, infertility, peripheral neuropathy, or those relating to palliative radiotherapy within 6 weeks prior to first dose of study treatment will have resolved to Grade 1 or less.

C. Other comorbidities affecting participation

  • Active gastrointestinal bleeding.
  • Evidence of severe or uncontrolled systemic disease or psychiatric illness that, in the investigator's judgment, would limit safety or compliance.
  • Impaired gastrointestinal absorption
  • History of allergic reactions to compounds like REC-617. D. Transplant History
  • Prior organ or stem-cell transplantation
Terms in these criteria, in plain language(32)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Histologically or cytologically confirmed

The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).

Your pathology report is the document that shows this.

RECIST

The standard rules for measuring tumours on CT or MRI scans, to tell whether a cancer is shrinking, stable or growing during treatment.

“Measurable disease per RECIST 1.1” usually means at least one tumour 10 mm or more at its longest on a CT scan, or a lymph node 15 mm or more across its short axis.

Measurable disease

The amount of disease can be tracked with a defined measurement, so the study can see whether it shrinks or grows. It might be a tumour measured on a scan or, in some blood cancers such as myeloma, a marker measured in blood or urine.

The criteria or the study team say which measurement counts — having no tumour visible on a scan does not by itself rule you out.

Metastases

Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.

Biopsy and archival tissue

A biopsy takes a small piece of tissue to examine. “Archival tissue” is a sample already taken, for example at diagnosis, and kept by the hospital.

Whether a stored sample will do depends on when it was taken, how much there is and what the study needs. Ask whether the study accepts your stored sample or needs a new biopsy.

Line of therapy

A line of therapy is one course of treatment, which may combine several drugs. First-line is the first course given; second-line follows when that stops working or is not tolerated.

“Two prior lines” means two courses that count separately under the study’s rules — not simply two drugs. Ask the study team if you are unsure how yours are counted.

ECOG performance status

A scale of how much an illness limits everyday activity. For people being assessed to join a study, scores run from 0 (fully active) to 4; lower is more active.

0
Fully active, no restrictions.
1
Limited in strenuous activity, but walking and able to do light work, such as housework or office work.
2
Walking and able to look after yourself, but unable to work; up and about more than half of waking hours.
3
Able to look after yourself only in part; in bed or a chair more than half of waking hours.
4
Unable to look after yourself at all; in bed or a chair all day.

Studies most often ask for 0–1 or 0–2. Your doctor gives the score; the WHO scale uses the same steps. The full scale also has 5, which records death.

Karnofsky performance status (KPS)

A 0–100 scale of how well someone can carry out everyday activities. 100 is no complaints and no signs of illness; 70 is able to look after yourself but not to work or keep up normal activity; 50 is needing considerable help and frequent medical care.

Studies often ask for 60 or 70 and above. Your doctor gives the score.

Life expectancy

The study doctor’s estimate of how long someone is likely to live. Criteria use it so that people can stay in the study long enough for it to answer its question.

Informed consent

Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.

You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).

Absolute neutrophil count (ANC)

The number of neutrophils, white blood cells that help fight infection, in a given amount of blood. Too few raises the risk of infection.

It is a count, not a percentage of the white cells. Limits are written in units that mean the same: ≥ 1.5 × 10⁹/L is ≥ 1,500 per mm³ (µL). Each lab has its own reference range.

Platelets

Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.

Bilirubin

A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.

Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.

ULN (upper limit of normal)

The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.

“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.

ALT and AST (liver enzymes)

Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.

Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.

INR, PT and aPTT (clotting tests)

Blood tests of how long blood takes to clot. The INR is the prothrombin time (PT) put on a common scale; about 1 is usual for someone not taking a blood thinner.

Criteria often make an exception for people on a blood thinner such as warfarin, whose INR is raised on purpose.

Creatinine clearance (CrCl)

How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.

Hepatitis B tests

Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.

Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.

Hepatitis C tests

Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.

After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.

HIV

The human immunodeficiency virus, which weakens the immune system.

Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

NYHA class (heart failure)

The New York Heart Association’s four classes of how much heart failure limits physical activity.

I
No limits: ordinary activity causes no undue tiredness or breathlessness.
II
Slight limits: comfortable at rest, ordinary activity causes symptoms.
III
Marked limits: comfortable at rest, less than ordinary activity causes symptoms.
IV
Symptoms even at rest; any activity makes them worse.

Studies set their own limit — many outside heart failure leave out class III–IV, while heart failure studies may ask for a particular class. Check the class this study names.

QT and QTc

On an ECG, the QT interval is the time the heart’s lower chambers take to activate electrically and recover in each beat. QTc is that time adjusted for heart rate (QTcF by Fridericia’s formula, QTcB by Bazett’s). Some medicines lengthen it, and a long QTc can raise the risk of a dangerous heart rhythm.

The study may name a correction formula and a limit in milliseconds, often around 450–480.

Contraception

Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.

Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.

Childbearing potential

Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).

Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.

Postmenopausal

Periods have stopped for good: usually no period for 12 months in a row without another medical reason, sometimes confirmed by a blood test (FSH).

Washout period

A planned gap after a treatment, so that its effects can lessen before the study treatment or a study assessment. Ask the study team and the doctor who prescribed it before changing any medicine.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Live vaccines

Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.

Cancer (malignancy)

Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.

Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.

Allogeneic and autologous transplant

Stem cell (bone marrow) transplants. Allogeneic uses cells from a donor; autologous uses your own cells, collected earlier and given back.

05

Study design

Phase
Phase 1
Primary purpose
Treatment
Allocation
Not applicable
Intervention model
Single group
Masking
None (open label)
Enrollment
15 participants (estimated)

Study arms

  • Experimental
    Treatment with REC617

    Participants will receive REC-617 orally at a dose of 10 mg once daily

    Drug: REC617

Interventions

  • DrugREC617

    Given by PO

06

What researchers measure

Primary outcomes

  1. Safety and adverse events (AEs).

    Incidence of Adverse Events, Graded According to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) Version (v) 5.0

    Time frame: Through study completion; an average of 1 year

07

Study locations

1 of 1 sites recruiting
08

References and documents

09

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Jul 31, 2026, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT07633756
Responsible party
Sponsor
First posted
Jun 8, 2026
Start date
Oct 19, 2026 (estimated)
Primary completion
Dec 26, 2029 (estimated)
Completion
Dec 26, 2031 (estimated)
Last update
Jul 31, 2026

Study contacts

Elise Nassif, MD
Contact
efnassif@mdanderson.org
281-460-0607
Elise Nassif, MD
principal investigator · M.D. Anderson Cancer Center

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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