Evaluation of Pasireotide as Maintenance Therapy in SSTR2/3/5-Expressing Synovial Sarcoma and Desmoplastic Small Round Cell Tumor

The primary objective of this study is to evaluate the clinical efficacy of **pasireotide** as a maintenance therapy in prolonging progression-free survival (PFS) in patients with SSTR2/3/5-expressing synovial sarcoma (SySa) and desmoplastic small round cell tumor (DSRCT). Prolonging PFS is clinically significant as it may delay disease progression and improve the quality of life for patients with these aggressive tumors.

Secondary objectives include assessing the clinical efficacy of pasireotide maintenance therapy in prolonging overall survival (OS) in the same patient population. Evaluating OS is crucial as it provides insights into the potential of pasireotide to extend the lifespan of patients with these challenging malignancies.

The clinical trial involves a study population comprising both **male** and **female** participants, aged between 13 and 50 years, who are diagnosed with locally advanced or metastatic **synovial sarcoma** or desmoplastic small round cell tumor. The trial does not specify the total number of participants, as this information was not provided by the sponsor. Participants were selected based on specific criteria, including a reference pathological diagnosis of the aforementioned conditions, stable disease status, and high SSTR2/3/5 mRNA expression. The trial population includes individuals with adequate bone marrow, renal, and hepatic function, and a body weight of at least 30 kg. Participants must have a Lansky-Index of 80% or higher if under 16 years of age, or a Karnofsky-Index of 80% or higher if 16 years or older. Lifestyle considerations such as the use of contraception are required for participants of childbearing potential. The trial includes a vulnerable population, and participants must have no curative treatment options available. The time from the last chemotherapy to enrollment must be less than 8 weeks.

The clinical trial is designed to evaluate the efficacy of **pasireotide** as a maintenance therapy for patients with locally advanced or metastatic synovial sarcoma and desmoplastic small round cell tumor. This is a Phase II, randomized, double-blind, controlled trial. The trial aims to assess the prolongation of progression-free survival (PFS) in patients expressing SSTR2/3/5. The study is expected to commence on October 15, 2024, and conclude by October 15, 2028, with a maximum treatment period of 36 months.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as age, body weight, and specific health indices. Following successful screening, participants will receive monthly deep intramuscular injections of pasireotide. Follow-up visits will be scheduled regularly to monitor the patient's response to treatment and any adverse effects. The end-of-study visit will occur at the conclusion of the treatment period or upon early termination.

The expected length of participant involvement is up to 36 months, contingent upon the absence of disease progression or unacceptable toxicity. Conditions that may lead to early termination from the study include significant adverse reactions, withdrawal of consent, or any condition that, in the investigator's opinion, warrants discontinuation for the participant's safety. The primary endpoint is progression-free survival, while secondary endpoints include overall survival, measured from study registration to death from any cause.

The clinical trial involves the use of **PASIREOTIDE** as the experimental medication. **PASIREOTIDE** is administered in the form of a **suspension for injection**. The active substance, **pasireotide**, is delivered via the **intramuscular** route. The dosing regimen specifies a maximum daily dose of 60 mg, with a total maximum dose of 2160 mg over the course of the treatment. The treatment period is set to a maximum of 36 months. The formulation is not specifically designed for pediatric use, and the substance is classified as a chemical compound. The trial aims to evaluate the efficacy of **pasireotide** as a maintenance therapy in patients with SSTR2/3/5-expressing synovial sarcoma and desmoplastic small round cell tumor.

In this study, **PASIREOTIDE** is utilized as an orphan drug, designated under the number EU/3/09/670. The pharmaceutical form remains consistent as a **suspension for injection**, and the administration is conducted through deep intramuscular injections on a monthly basis. The trial does not include any non-experimental treatments such as standard-of-care therapy, placebo, or comparator treatments. Participant compliance with the dosing schedule is monitored throughout the trial to ensure adherence to the prescribed regimen. The study does not involve any additional devices or formulations beyond the specified **PASIREOTIDE** suspension.

The clinical trial aims to assess the efficacy of **pasireotide** as a maintenance treatment for prolonging progression-free survival (PFS) in patients with SSTR2/3/5-expressing synovial sarcoma (SySa) and desmoplastic small round cell tumor (DSRCT). The primary endpoint for evaluating efficacy is progression-free survival, measured from study registration to radiologically confirmed disease progression according to the Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1, or death from any cause, whichever occurs first. Patients without an event will be censored at the date of the last follow-up.

Secondary endpoints include overall survival (OS), measured from study registration to death from any cause, with censoring of patients without an event at the date of the last follow-up. The efficacy parameters will be collected and analyzed using validated scales and criteria, ensuring accurate and reliable assessment of the treatment's impact on disease progression and survival outcomes. The trial is designed to provide comprehensive data on the clinical benefits of pasireotide in this patient population.