Durvalumab/SBRT May Limit Tumor Progression in Early-Stage NSCLC

Combining durvalumab (Imfinzi) with stereotactic body radiotherapy (SBRT) appeared to reduce tumor progression among patients with early-stage non–small cell lung cancer (NSCLC), although the value of adjuvant immunotherapy in this population remains uncertain, according to findings from the phase 2 ASTEROID trial (NCT03446547) presented at the European Lung Cancer Congress 2026.¹

Efficacy Results of Durvalumab/SBRT

Regarding time to progression, investigators noted progression in 10 patients who received SBRT alone in arm A (n = 55) vs 3 patients who received SBRT plus durvalumab in arm B (n = 49), which reflected a statistically significant difference (P = .045). Similar outcomes were reported in a competing risk analysis that accounted for death as a competing event (P = .033).

There were no significant differences in disease-free survival (DFS; P = .41) or overall survival (OS; P = .84) regardless of the addition of durvalumab to SBRT. Presenting investigator Andreas Hallqvist, MD, an associate professor in the Department of Oncology at Sahlgrenska University Hospital in Gothenburg, Sweden, noted that the study was not powered for these survival end points.

“This leaves a strong signal for the impact of tumor progression by adding PD-L1 blockage after SBRT. Whether this is meaningful for this patient group is very uncertain,” Hallqvist said in the presentation. “The next step for us will be to check for causes of death. Could there be some hidden toxicity? [We will] check for relapse patterns, PD-L1 expression, and other potential predictive factors.”

ASTEROID Trial Design

Investigators of the open-label ASTEROID trial enrolled 106 patients and evaluated whether adjuvant immunotherapy with durvalumab following SBRT could increase time to progression among 106 patients with stage T_1-2N0M0 NSCLC. Patients were assigned to receive high-dose SBRT at approximately 66 Gy in 3 or 4 fractions with follow-up in arm A or SBRT plus durvalumab at 1500 mg intravenously within 1 week of completing SBRT for every 4 weeks up to 12 months in arm B.

The trial’s primary end point was time to progression. Secondary end points included overall survival, local control, quality of life, and time to progression based on PD-L1 expression.²

Patients 18 years and older with histologically or cytologically confirmed NSCLC, stage I to IIA tumors of no more than 5 cm, peripheral tumors, and no prior chemotherapy or radiation for NSCLC were eligible for enrollment on the trial. Other eligibility criteria included having a WHO performance status of 0 to 2 and adequate organ and marrow function. Those with centrally located tumors, serious concomitant autoimmune or other systemic disorders incompatible with the trial, or other conditions necessitating systemic therapy with steroids consisting of more than 10 mg of prednisolone per day or an equivalent dose were ineligible for study entry.

The median age was 77 years (range, 58-89) in arm A and 79 years (range, 56-87) in arm B, and most patients in each arm were female (n = 30, 29). Most patients in each respective group had a performance status of 1 (n = 27, 22), a tumor stage of IA (n = 44, 42), and adenocarcinoma histology (n = 42, 32).

Is Durvalumab/SBRT Safe in Early-Stage NSCLC?

Any-grade treatment-related adverse effects (TRAEs) occurred in 42.6% and 40.1% of patients in arms A and B, respectively. The most common toxicities of any grade in each arm included fatigue (16.7% vs 22.4%), cough (16.7% vs 8.2%), and pain (11.1% vs 12.2%). Of note, a higher proportion of patients who received durvalumab plus SBRT in arm B experienced any-grade skin reactions (55.1%), pruritus (26.5%), and elevated liver enzymes (24.4%).

References

1. Hallqvist A. Stereotactic body radiotherapy (SBRT) followed by durvalumab in early-stage non-small cell lung cancer (NSCLC) patients: results from a randomized phase II trial (ASTEROID). Presented at the European Lung Cancer Congress 2026; March 25-28, 2026; Copenhagen, Denmark. Abstract 221MO.
2. Ablative STEreotactic RadiOtherapy wIth Durvalumab (MEDI4736) (ASTEROID). ClinicalTrials.gov. Updated November 14, 2023. Accessed March 26, 2026. https://tinyurl.com/29dvvfwc