A phase II, single-arm trial of adebrelimab plus nab-paclitaxel and carboplatin as first-line therapy for advanced thymic carcinoma: Interim efficacy and safety results.

Abstract

e20171 Background: Thymic carcinoma (TC) is a rare and aggressive malignancy with poor prognosis in advanced stages. Given the limited efficacy of standard first-line regimen (carboplatin/paclitaxel), there remains an urgent unmet need for novel treatment approaches. This study evaluated the efficacy and safety of the PD-L1 inhibitor adebrelimab in combination with nanoparticle albumin-bound (nab)-paclitaxel and carboplatin as first-line therapy for advanced or recurrent TC. Methods: Patients (pts) with unresectable UICC stage III or IV, recurrent, or metastatic TCs without any previous anti-tumor therapy were enrolled.During the induction phase, pts received adebrelimab (20 mg/kg) plus nab-paclitaxel (260 mg/m 2 ) and carboplatin (AUC 5) every 3 weeks for up to 4-6 cycles. This was followed by the maintenance phase, adebrelimab (20 mg/kg) every 3 weeks for up to 2 years (including the induction phase), until progression or unacceptable toxicity. The primary endpoint was objective response rate (ORR), and secondary endpoints included progression free survival (PFS), disease control rate (DCR), overall survival (OS), and safety. Results: Between August 15, 2023, and June 3, 2025, this study was conducted at two centers and enrolled a total of 37 pts. All pts were included in safety and efficacy analysis. The median age was 60.0 years old (range 29-71). A total of 26 pts (70.3%) pts completed the induction therapy and were transitioned to maintenance therapy while 11 pts (29.7%) remained on treatment at data cutoff (December 1, 2025). Four (10.8%) of 37 pts had complete response, 16 (43.2%) had partial response, and 17 (45.9%) had stable disease. The ORR was 54.1% (20/37) and DCR was 100% (37/37). The median PFS was 10.9 months (95% CI, 9.1-NA). Treatment-related adverse events (TRAEs) of any grade and of grade ≥3 severity occurred in 100% and 54.1% (20/37) of pts, respectively. The most common TRAEs were anemia, lymphocyte count decreased, and white blood cell count decreased. The immune-related AEs of grade ≥3 severity occurred in 16.2% (6/37) of pts, including immune-mediated rash, myositis and amylase increased. No grade 5 TRAEs were reported. Conclusions: Adebrelimab combined with nab-paclitaxel and carboplatin demonstrates promising efficacy and a manageable safety profile as first-line therapy for advanced or recurrent thymic carcinoma, offering a new potential treatment option for this patient population. Trial Registration: ChiCTR2300072705.