Study Design and Rationale for Marble Study: A Phase II Trial of Atezolizumab (MPDL3280A) Plus Carboplatin and Paclitaxel in Patients With Advanced or Recurrent Thymic Carcinoma (JTD2101).

BACKGROUND

Thymic carcinoma (TC) is a rare thymic epithelial tumor, and advanced or recurrent TC has limited prognosis. Treatment for chemotherapy-naïve, advanced, or recurrent TC remains unchanged with the combination of carboplatin and paclitaxel; therefore, a new treatment strategy is warranted. Immune checkpoint blockades inhibiting the programmed cell death-1 (PD-1) pathway (PD-1 and its ligand, PD-L1) have shown potential as a monotherapy for TC, although the efficacy of monotherapy was moderate for previously treated TC. We hypothesized that the combination of an anti-PD-L1 antibody, atezolizumab, with carboplatin and paclitaxel, would be effective in inducing immunogenic cell death in patients with advanced or recurrent TC.

METHODS

We initiated a multicenter, single-arm, open-label phase II study of atezolizumab combined with carboplatin and paclitaxel for metastatic or recurrent TC. Eligible patients will receive atezolizumab plus carboplatin and paclitaxel every 3 weeks for up to 6 cycles, followed by atezolizumab every 3 weeks for up to 2 years until progression or unacceptable toxicity. A total of 47 patients will be enrolled in this study, with a 24-month enrollment period and 12-month follow-up. The primary endpoint is the objective response rate (ORR), based on an independent central review. The secondary endpoints are the investigator-assessed ORR, disease control rate, progression-free survival, duration of response, overall survival, and safety.

RESULTS

This study aims to establish the safety and efficacy of atezolizumab combined with carboplatin and paclitaxel in patients with advanced or recurrent TC.

TRIAL REGISTRATION: Japan Registry of Clinical Trials (jRCT), jRCT2031220144. Registered on June 18, 2022, https://jrct.niph.go.jp/en-latest-detail/jRCT2031220144.