A Randomized Study of Trabectedin With Low‑Dose Radiotherapy Versus Trabectedin Alone in Adults With Advanced Soft Tissue Sarcoma, Osteosarcoma, or Ewing Sarcoma

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What is this study about?

The study focuses on patients with advanced Soft tissue sarcoma, osteosarcoma or Ewing’s sarcoma, which are cancers that arise in the muscles, bones or surrounding tissues. The medication being tested is trabectedin, given by an intravenous infusion, and it is being compared to the same medication combined with low-dose radiotherapy, a type of treatment that uses small amounts of radiation to try to shrink tumors.

The purpose of the study is to evaluate how well the treatments work by measuring the Objective Response Rate, which looks at the proportion of patients whose tumors shrink enough to be called a complete response (tumor disappears) or a partial response (tumor shrinks but does not disappear). Tumor changes are assessed using a set of rules called RECIST v1.1, which provides a standardized way to measure tumor size on scans. Participants are randomly assigned to receive either trabectedin alone or the combination with low-dose radiotherapy, and they will undergo regular clinic visits and imaging studies over several treatment cycles to monitor safety and tumor response.

1 randomization

after joining the study, you will be assigned to one of two treatment groups: one that receives trabectedin alone, or one that receives trabectedin together with low‑dose radiotherapy.

2 receive trabectedin infusion

trabectedin is given by intravenous infusion at a dose of 0.07 mg per square meter of body surface area.

the infusion is administered according to the schedule defined by the study protocol.

3 receive low‑dose radiotherapy (if assigned to combination arm)

if you are in the combination group, low‑dose radiotherapy will be given at the same time as the trabectedin infusion.

details of the radiotherapy dose and schedule are defined by the study protocol.

4 response assessment

your tumor will be measured using recist v1.1 criteria, which compare the size of target lesions to determine if there is a complete or partial response.

these assessments are performed by the local investigator and later reviewed centrally.

5 continue treatment or end of study

treatment cycles will continue until the study ends, disease progression, or an unacceptable side effect occurs, as determined by the investigators.

the study will collect data on the overall response rate and other outcomes.

Who Can Join the Study?

Give written permission to join the study and agree to follow the treatment plan and follow‑up visits; this permission is called informed consent.
Have healthy enough bone marrow, which means blood tests must show: hemoglobin (the protein that carries oxygen) at least 9 g/dL, white blood cells at least 3,000 per mm³, neutrophils (a type of white blood cell) at least 1,500 per mm³, and platelets (cells that help blood clot) at least 100,000 per mm³.
Have kidney function that clears at least 30 mL per minute (measured by a test called creatinine clearance), and blood protein (albumin) at least 25 g/dL.
Have liver tests that are not too high: ALT and AST enzymes no more than 2.5 times the normal upper limit, total bilirubin (a waste product) at normal level, creatine phosphokinase (CPK) no more than 2.5 times normal, and alkaline phosphatase no more than 2.5 times normal (if alkaline phosphatase is higher, the liver‑specific part of it or GGT must be normal).
Use an effective birth‑control method before joining the study, during treatment, and for 6 months after the last dose; women who could become pregnant must also have a negative urine pregnancy test.
Have normal heart function, measured by an echocardiogram or MUGA scan showing a left‑ventricular ejection fraction (LVEF) of 50 % or higher.
Have blood tests for hepatitis B and C done before enrollment; if hepatitis B surface antigen (HBsAg) is positive, the doctor must be sure the infection is not active, and if hepatitis C antibodies are positive, a special test (PCR) must show no active virus. If these tests cannot be done, the person cannot join.
Have a central venous catheter (a tube placed in a large vein), preferably a port‑a‑cath rather than a PICC line, which is needed to give the study medicines.
Be between 16 and 75 years old.
Have a confirmed diagnosis of soft‑tissue sarcoma (excluding certain rare types) that is metastatic or locally advanced and not suitable for surgery; a tumor sample must be sent to a central lab for confirmation.
Have disease locations that allow safe radiation treatment, with radiation doses of 45 Gy for arms or legs and 30 Gy for other areas, as approved by a radiation oncologist.
Have shown disease progression (the cancer getting worse) within the last 6 months before entering the study.
Be eligible for chemotherapy and have received at least one prior line of systemic therapy (usually an anthracycline drug) but no more than three prior lines for advanced disease, and must not have previously received trabectedin or lurbinectedin.
Have measurable cancer lesions that can be measured according to the RECIST v1.1 criteria (a standard way to size tumors).
Have a good overall health status, with a performance score of 0 or 1 on the ECOG scale (meaning fully active or restricted in physically strenuous activity but ambulatory).
If the lungs are involved, have adequate breathing function: forced expiratory volume in 1 second (FEV1) greater than 1 L and diffusing capacity of the lung for carbon monoxide (DLCO) greater than 40 % of normal.

Who Cannot Join the Study?

Having already received the chemotherapy medicines trabectedin or lurbinectedin, or having had radiotherapy (treatment that uses radiation to kill cancer cells) that would prevent safe use of radiation in this study.
Being a woman who is pregnant (carrying a baby) or breast‑feeding (feeding a baby with breast milk).
Being a woman who does not plan to follow the study’s contraceptive guidelines (rules about using birth control to prevent pregnancy).
Having mental, family, social, or travel problems that would make it difficult to follow the study rules or give informed consent.
If the liver would need to be included in the radiation area, unless the amount of radiation to the liver can be kept within strict safety limits (dose constraints).
Having a performance status of 2 or higher on the ECOG scale (a measure of how well a person can carry out daily activities; a score of 2 means limited activity).
Having a blood level of bilirubin (a substance made when red blood cells break down) that is higher than the normal upper limit.
Having a kidney function test showing creatinine clearance (how well the kidneys filter waste) less than 30 ml/min.
Having a history of other cancers (neoplastic diseases) except for basal cell carcinoma (a common, usually low‑risk skin cancer) or early‑stage in situ cervical cancer that was treated well and has not returned for at least five years.
Having severe lung (pulmonary), heart (cardiovascular) or other serious illnesses that are grade 3 or higher on the NCI‑CTCAE scale (a system doctors use to grade side effects), or that could make treatment unsafe, including shortness of breath worse than NYHA class 2 (moderate to severe breathlessness).
Having an ongoing uncontrolled bacterial, fungal (mycotic) or viral infection.
Having a known positive test for HIV infection (the virus that can cause AIDS).

Where you can join this trial?

Verified and Recommended Sites

No sites found in this category

Verified Sites

Site Name	City	Country	Status
Hospital Universitario Y Politecnico La Fe	Valencia	Spain

Other Sites

Site Name	City	Country
Hospital Universitario De Canarias	La Laguna	Spain
Hospital General Universitario Gregorio Maranon	Madrid	Spain
Huiehhmr Vvmc dnlxddnj	Barcelona	Spain
Vgumaz dkx Rjndv Ulpkevvjkl Hzpdtnzw	Sevilla	Spain
Hnxgpbyp Uvqkpchauowpj Fjnbpawrz Jxomalk Dhdg	Madrid	Spain
Hjiikhpt Cnxvqma Soo Cqzqws	Madrid	Spain
Hyspzlsh Dh Lw Soiev Ccqh I Sbns Ptt	Barcelona	Spain
Htccpbel Uamkfwzafvypm 1e Db Oaxfymv	Madrid	Spain
Hzkxjayl Udjsszbodxsbg Bootkcy	Bilbao	Spain

Trial status

Country	Status	Recruitment Start
Spain	Not yet recruiting	01.09.2026

Trial locations

Investigated Drugs:

Trabectedin

trabectedin is a chemotherapy drug given through an intravenous infusion. In this study it is used to try to shrink or stop the growth of advanced sarcoma tumors. The drug works by interfering with the cancer cells’ DNA, which can prevent them from multiplying and cause them to die.

Low‑dose radiotherapy is a treatment that uses small amounts of radiation aimed at the tumor area. In the trial it is given at the same time as trabectedin to see if the combination helps control the cancer better than the chemotherapy alone. The radiation damages the cancer cells’ DNA, making them more vulnerable to the effects of the chemotherapy.

Investigated Diseases:

Soft tissue sarcoma – A cancer that starts in the body’s connective tissues such as muscle, fat, nerves, or blood vessels. It often appears as a painless lump that can enlarge over time. The tumor may grow locally and can invade surrounding structures. In some cases it spreads to distant organs, most commonly the lungs. The disease course varies depending on the specific type and size of the tumor.

Osteosarcoma – A malignant bone tumor that most often develops in the long bones near the knee or shoulder. It typically causes pain and swelling in the affected area. The cancer can break through the bone surface and extend into nearby tissues. It may also spread through the bloodstream to other parts of the body. The pattern of growth is usually rapid, especially in adolescents and young adults.

Ewing sarcoma – A fast‑growing tumor that usually arises in the bones or soft tissue of children and teenagers. It often presents with pain, fever, and a lump that can enlarge quickly. The tumor can invade surrounding muscles and spread through the blood to the lungs and other organs. Its progression is characterized by rapid expansion and potential metastasis. Early signs can be mistaken for infection, leading to delayed diagnosis.

Trial ID:

2026-525703-27-00

Protocol code:

SYNERGOS

Trial Phase:

Therapeutic confirmatory (Phase III)

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A Randomized Study of Trabectedin With Low‑Dose Radiotherapy Versus Trabectedin Alone in Adults With Advanced Soft Tissue Sarcoma, Osteosarcoma, or Ewing Sarcoma

What is this study about?

Who Can Join the Study?

Who Cannot Join the Study?