A phase 2 trial of durvalumab treatment following radiation monotherapy in patients with non-small cell lung cancer ineligible for stage III chemoradiotherapy: The SPIRAL-RT study.

BACKGROUND

Although concurrent chemoradiotherapy (CCRT) followed by durvalumab is the standard treatment for patients with stage III non-small cell lung cancer (NSCLC), only half of the patients are allowed to receive CCRT in real-world settings. We evaluated the efficacy and safety of durvalumab after radiation monotherapy for NSCLC patients who are ineligible for chemoradiotherapy.

METHODS

A single-arm, prospective, open-label, multicenter phase II trial was conducted in Japan. The patients received radiation (54-66 Gy) followed by durvalumab (10 mg/kg every 2 weeks for up to 12 months). The primary endpoint was the 1-year progression-free survival (PFS) rate. The secondary endpoints were the objective response rate (ORR), PFS, overall survival (OS), and safety.

RESULTS

Between September 2019 and April 2021, 33 patients were enroled from eight institutions. The median patient age was 79 years, and the majority of patients were male (78.8%). The 1-year PFS rate was 39.1% (90% confidence interval [CI]: 24.7-54.6%). Three patients (9.1%) had a performance status of 2. The ORR was 42.4% (95% CI: 27.2-59.2%). The median PFS and OS were 8.9 (95% CI: 7.4-19.4) and 20.8 (95% CI: 15.8-not estimable) months, respectively. The most common adverse event was radiation pneumonitis (51.5%). The median treatment duration was 6.4 (range: 0.50-12.0) months for durvalumab. At the endpoint, 30.3% (10/33) of the patients had completed 1 year of durvalumab therapy.

CONCLUSIONS

Durvalumab is an effective treatment with tolerable toxicity following radiation monotherapy in stage III NSCLC patients who are ineligible for chemoradiotherapy.

TRIAL REGISTRATION: JMA-IIA00434 (jRCT).