ClinicalTrials.gov posted results on 2026-08-03 for NCT03281369, a terminated phase 1/2 study of atezolizumab-based combinations in locally advanced unresectable or metastatic gastric, gastroesophageal junction, and esophageal cancers. The trial enrolled 219 participants and reported objective response and progression-free survival results across several treatment groups.

Background

The study evaluated atezolizumab in patients with gastric adenocarcinoma or gastroesophageal junction adenocarcinoma or esophageal carcinoma. The posted record lists combinations that included 5-fluorouracil, leucovorin, oxaliplatin, and cobimetinib, along with atezolizumab and other partners.

Trial design

This was an open label, multi-center, randomized study designed to assess safety, tolerability, pharmacokinetics, and preliminary anti-tumor activity. The record describes a stage 1 analysis with comparator arms including ramucirumab + paclitaxel and cisplatin + 5-FU, alongside several atezolizumab-containing combinations.

Key results

For objective response, mFOLFOX6 + atezolizumab + cobimetinib showed 40.0% response, compared with 16.7% for ramucirumab + paclitaxel. The response difference was -16.67 with a 95% CI of -45.77 to 12.43.

In the same outcome set, atezolizumab + PEGPH20 had 0 response, atezolizumab + BL-8040 had 15.4%, and atezolizumab + linagliptin had 21.4%. The corresponding response differences were -1.28 with a 95% CI of -38.09 to 35.53 and 4.76 with a 95% CI of -33.09 to 42.61.

Against cisplatin + 5-FU, which had 47.8% objective response, atezolizumab + cisplatin + 5-FU had 53.8% and atezolizumab + tiragolumab + cisplatin + 5-FU had 67.7%. The posted hazard ratios were 6.74 with 95% CI 2.06 to 22.0, 0.97 with 95% CI 0.41 to 2.27, and 1.31 with 95% CI 0.58 to 2.97. Progression-free survival was 14.93 months for mFOLFOX6 + atezolizumab + cobimetinib, compared with 6.06 months for ramucirumab + paclitaxel, 1.84 months for atezolizumab + PEGPH20, and 1.97 months for atezolizumab + BL-8040.

What this means

The posted results show that atezolizumab combinations produced varied activity in upper gastrointestinal cancers, with some regimens reporting higher response rates and longer progression-free survival than comparator arms, while others performed poorly. Because the study was terminated and the record does not provide full subgroup context here, the findings should be read as exploratory rather than practice-changing.

Source

This information is based on ClinicalTrials.gov results for NCT03281369 posted on 2026-08-03. The record is available at clinicaltrials.gov.