Randomized Controlled Trial of Chemotherapy Regimens Including Gemcitabine, Lenvatinib, and Temozolomide for Recurrent and Primary Refractory Ewing Sarcoma

The primary objective of the study is to compare various systemic anti-cancer therapy regimens in patients with **recurrent and primary refractory Ewing Sarcoma**. The aim is to identify the most effective regimen in terms of imaging response and survival, while also evaluating the toxicity and acceptability to patients. This is clinically relevant as it seeks to optimize treatment strategies for a challenging and aggressive form of cancer, potentially improving patient outcomes and quality of life.

The clinical trial involves a total of **276 participants** diagnosed with **Recurrent and Primary Refractory Ewing Sarcoma**. The study population includes both male and female subjects, with an age range starting from 2 years and no upper age limit specified, although trial sites in Austria will only recruit patients aged between 2 and 30 years. Participants are required to have a histologically confirmed diagnosis of Ewing or Ewing-like sarcoma of the bone or soft tissues, either at initial diagnosis or upon disease progression. The trial population was selected based on their eligibility for randomization between at least two open study arms, and they must demonstrate adequate renal and liver function, as well as controlled blood pressure. Participants are expected to be medically fit to receive trial treatment and must provide written informed consent. The study also includes vulnerable populations, and lifestyle considerations such as the use of effective contraception during therapy and for 12 months after the last trial treatment are mandated. The trial does not specify any particular dietary or physical activity requirements for participants.

The clinical trial is designed as an **international randomized controlled trial** to evaluate the efficacy, toxicity, and acceptability of various systemic anti-cancer therapy regimens for the treatment of recurrent and primary refractory **Ewing sarcoma**. The trial employs a double-blind methodology to ensure unbiased results and includes multiple study arms to compare different treatment regimens. The trial is expected to run until September 2031, with recruitment having commenced in July 2015.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as histological confirmation of Ewing or Ewing-like sarcoma, adequate organ function, and agreement to use effective contraception. Following randomization, participants will attend regular follow-up visits to monitor treatment response and adverse events. Imaging assessments will be conducted after 2, 4, and 6 cycles for certain regimens, and at the end of trial treatment for all arms. The end-of-study visit will evaluate the primary endpoint of event-free survival time, along with secondary endpoints such as objective imaging response, progression-free survival, overall survival, and quality of life.

The expected length of participant involvement varies depending on the treatment arm, with a maximum treatment period of 104 weeks for some regimens. Conditions that may lead to early termination from the study include significant adverse events, disease progression, or withdrawal of consent. The trial aims to identify the most effective treatment regimen for recurrent and primary refractory Ewing sarcoma, contributing valuable data to the field of oncology.

The clinical trial involves the administration of several experimental medications, each with specific pharmaceutical forms, dosages, and routes of administration. **Gemcitabine** is provided as a solution for infusion, administered intravenously. The maximum daily dose is 900 mg/m², with a total maximum dose of 10,800 mg/m² over a treatment period of 18 weeks. This medication is of chemical origin and is not a paediatric formulation.

**Lenvima** is available in two dosages: 4 mg and 10 mg hard capsules, containing the active substance **lenvatinib**. These capsules are administered orally, with a maximum daily dose of 24 mg and a total maximum dose of 17,520 mg over a treatment period of 104 weeks. The capsules have been modified for clinical use, with different markings and indications, and are not within the current licensed indication for Ewing Sarcoma.

**Temozolomide** is provided in hard capsule form for oral use. The maximum daily dose is 100 mg/m², with a total maximum dose of 3,000 mg/m² over 18 weeks. This medication is also of chemical origin and is not formulated for paediatric use.

**Ifosfamide** is administered as a solution for infusion intravenously. The maximum daily dose is 3 g/m², with a total maximum dose of 60 g/m² over a 12-week treatment period. It is of chemical origin and not a paediatric formulation.

**Anhydrous Docetaxel** and **Docetaxel** are both provided as solutions for infusion, administered intravenously. The maximum daily dose for both is 80 mg/m², with a total maximum dose of 480 mg/m² over 18 weeks. These medications are of chemical origin and not formulated for paediatric use.

**Carboplatin** is administered as a solution for infusion intravenously, with a maximum daily dose of 400 mg/m² and a total maximum dose of 2,400 mg/m² over 18 weeks. It is of chemical origin and not a paediatric formulation.

**Etoposide Phosphate** is provided as a powder for solution for injection, administered intravenously. The maximum daily dose is 136.32 mg/m², with a total maximum dose of 2,453.76 mg/m² over 18 weeks. This medication is of chemical origin and not formulated for paediatric use.

**Irinotecan** is administered as a solution for infusion intravenously, with a maximum daily dose of 50 mg/m² and a total maximum dose of 1,500 mg/m² over 18 weeks. It is of chemical origin and not a paediatric formulation.

**Cyclophosphamide** is provided as a powder for solution for injection, administered intravenously. The maximum daily dose is 250 mg/m², with a total maximum dose of 7,500 mg/m² over 18 weeks. This medication is of chemical origin and not formulated for paediatric use.

**Topotecan** is administered as a concentrate for solution for infusion intravenously, with a maximum daily dose of 0.75 mg/m² and a total maximum dose of 22.5 mg/m² over 18 weeks. It is of chemical origin and not a paediatric formulation.

**Etoposide** is provided as a solution for infusion, administered intravenously. The maximum daily dose is 120 mg/m², with a total maximum dose of 2,160 mg/m² over 18 weeks. This medication is of chemical origin and not formulated for paediatric use.

Participant compliance with the dosing schedule is monitored throughout the trial to ensure adherence to the prescribed treatment regimens. No non-experimental treatments, such as standard-of-care therapy or placebo, are mentioned in the trial data provided.

The efficacy of the clinical trial will be assessed using several primary and secondary endpoints. The primary endpoint is **Event-free survival time (EFS)**, which will be measured to evaluate the effectiveness of the treatment regimens in patients with recurrent or refractory Ewing Sarcoma. Secondary endpoints include Objective Imaging Response (OR) according to RECIST 1.1 criteria, which will be assessed after 2, 4, and 6 cycles for certain treatment arms and at the end of trial treatment for all arms. Progression-free survival time (PFS) and Overall survival time (OS) will also be evaluated as secondary endpoints.

Additional secondary endpoints include toxicity, which will be defined by the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE) v4.0, PET-CT response after 4 cycles, Quality of Life (QoL), and the number of days spent in the hospital. These parameters will be measured at specified intervals throughout the trial to provide a comprehensive assessment of the treatment's efficacy and impact on patients' well-being.