Phase 3 Randomized Study of MK-7684A with Etoposide and Platinum vs. Atezolizumab for First-Line Treatment of Extensive-Stage Small Cell Lung Cancer

The primary objective of this study is to compare **overall survival** for MK-7684A in combination with etoposide/platinum followed by MK-7684A to atezolizumab in combination with etoposide/platinum followed by atezolizumab in patients with extensive-stage small-cell lung cancer. This is clinically relevant as it aims to determine the efficacy of MK-7684A in improving survival outcomes, which is a critical endpoint in the management of this aggressive cancer type.

Secondary objectives include:

• Comparing progression-free survival per RECIST 1.1 by blinded independent central review (BICR) for MK-7684A plus etoposide/platinum followed by MK-7684A to atezolizumab plus etoposide/platinum followed by atezolizumab.
• Evaluating objective response rate per RECIST 1.1 by BICR for MK-7684A plus etoposide/platinum followed by MK-7684A compared to atezolizumab plus etoposide/platinum followed by atezolizumab.
• Evaluating duration of response per RECIST 1.1 by BICR for MK-7684A plus etoposide/platinum followed by MK-7684A compared to atezolizumab plus etoposide/platinum followed by atezolizumab.
• Evaluating safety and tolerability based on the proportion of adverse events.
• Evaluating change from baseline and time to true deterioration in global health status/quality of life, physical functioning, dyspnea, cough, and chest pain for MK-7684A plus etoposide/platinum followed by MK-7684A compared to atezolizumab plus etoposide/platinum followed by atezolizumab.

The clinical trial involves a total of **194 participants** diagnosed with **extensive-stage small-cell lung cancer** (ES-SCLC). The study population includes both male and female subjects, with age categories ranging from adults to older adults. Participants were selected based on specific inclusion criteria, such as having a histologically or cytologically confirmed diagnosis of ES-SCLC requiring first-line therapy and a predicted life expectancy of more than three months. The trial includes individuals with ES-SCLC defined as Stage IV or T3-T4 due to extensive lung nodules. Both genders are required to adhere to contraceptive measures, with females needing to be non-pregnant and non-breastfeeding. The trial population is characterized by a vulnerable group, indicating the inclusion of individuals who may require additional considerations. Lifestyle factors such as diet and physical activity are not specified in the available data.

The clinical trial is designed as a **randomized**, **double-blind**, controlled study to evaluate the efficacy and safety of MK-7684A in combination with **etoposide** and platinum-based chemotherapy, compared to **atezolizumab** with the same chemotherapy regimen, for the first-line treatment of participants with extensive-stage small-cell lung cancer (ES-SCLC). The trial aims to assess overall survival as the primary endpoint, with secondary endpoints including progression-free survival, objective response rate, and various quality of life measures. The study is expected to run from March 2022 to July 2027, with participant involvement lasting up to 84 days, depending on the treatment arm.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as a histologically or cytologically confirmed diagnosis of ES-SCLC and a predicted life expectancy of more than three months. Following randomization, participants will receive treatment via **intravenous infusion** and attend regular follow-up visits to monitor treatment response and adverse events. The end-of-study visit will occur after the completion of the treatment period or upon early termination, which may be due to disease progression, unacceptable toxicity, or withdrawal of consent.

Throughout the trial, participants will be closely monitored for safety and efficacy outcomes, with specific attention to any adverse events that may necessitate discontinuation of the study treatment. The trial's design ensures that all participants receive either the investigational treatment or a comparator, with a saline placebo used to maintain blinding. The study's rigorous methodology and comprehensive endpoint assessment aim to provide valuable insights into the treatment of ES-SCLC.

The clinical trial involves the administration of several **experimental medications** and comparator treatments. **Etoposide** is utilized in this study, characterized by its chemical origin. It is administered as an intravenous infusion with a pharmaceutical form denoted as PHF675. The dosage is calculated based on body surface area, with a maximum daily dose of 100 mg/m² and a total maximum dose of 1200 mg/m² over a treatment period of up to 84 days.

**Atezolizumab**, a biological agent, is also employed in the trial. It is administered via intravenous infusion in a pharmaceutical form identified as PHF00230MIG. The maximum daily dose is 1200 mg, with a total maximum dose of 104 g over a 60-day treatment period. This medication is used in combination with etoposide and platinum-based therapies.

The investigational product **MK-7684A**, containing the active substances **pembrolizumab** and **vibostolimab**, is administered as a solution for infusion. This biological product is delivered intravenously, with a maximum daily dose of 490 mg and a total maximum dose of 34.6 g over a 60-day treatment period. It is used in combination with etoposide and platinum-based therapies.

**Cisplatin**, another chemical-origin medication, is administered as an intravenous infusion in the form PHF00230MIG. The dosage is based on body surface area, with a maximum daily dose of 75 mg/m² and a total maximum dose of 300 mg/m² over a treatment period of up to 84 days. It is used in combination with etoposide and other therapies.

**Carboplatin** is also included in the trial, characterized by its chemical origin. It is administered intravenously in the form PHF00230MIG, with a maximum daily dose of 750 mg and a total maximum dose of 3000 mg over a treatment period of up to 84 days. This medication is used in combination with etoposide and other therapies.

A **saline placebo** is utilized as a control in the study. It does not contain any active substances and is used to maintain the double-blind nature of the trial. The placebo is administered in a manner consistent with the other intravenous treatments, ensuring participant blinding is maintained throughout the study.

The efficacy of the clinical trial will be assessed using a combination of primary and secondary endpoints. The primary endpoint is **Overall Survival (OS)**, which will be measured to determine the effectiveness of the treatment regimens. Secondary endpoints include **Progression-Free Survival (PFS)**, **Objective Response Rate (ORR)**, and **Duration of Response (DOR)**. Additionally, the trial will evaluate the percentage of participants who experience an adverse event (AE) and those who discontinue study treatment due to an AE.

Patient-reported outcomes will be assessed using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30) and the Lung Cancer 13 (EORTC QLQ-LC13). Changes from baseline in global health status, physical functioning, dyspnea, cough, and chest pain scores will be measured. Time to True Deterioration (TTD) in these scores will also be evaluated. These assessments will provide insights into the impact of the treatment on patients' quality of life.