Hafnium Oxide Nanoparticles Show Feasibility in Stage 3 Lung Cancer

Initial data from part 1 of the ongoing CONVERGE clinical trial (NCT06667908) demonstrate that the potential first-in-class radioenhancer functionalized hafnium oxide nanoparticles (NBTXR3; JNJ-1900) can be successfully integrated into standard-of-care concurrent chemoradiotherapy (cCRT) for patients with stage 3 unresectable non–small cell lung cancer (NSCLC). The early results suggest that single-dose intratumoral or intranodal administration of the agent is both feasible and safe without disrupting planned systemic or radiation-based therapy.¹

The findings were presented at the 2026 European Society for Radiotherapy and Oncology (ESTRO 2026) Annual Meeting (presentation #116). The evaluation represents an expansion of the physics-based nanoparticle platform into thoracic oncology via a randomized trial design sponsored by Johnson & Johnson.

Favorable Feasibility and Safety Profiles

The initial phase of the study focused primarily on verifying the safety and technical execution of administering functionalized hafnium oxide nanoparticles into thoracic tumor lesions or involved regional lymph nodes. Investigators reported that the injection procedure met protocol standards for feasibility and was performed safely in the evaluated patient cohort.

Crucially, the administration of the localized radioenhancer did not result in serious treatment-emergent adverse events (TEAEs). It did not negatively impact the ability of patients to initiate or sustain their prescribed course of cCRT, nor did it delay subsequent consolidation immunotherapy with the PD-L1 inhibitor durvalumab (Imfinzi). This safety profile is vital because advanced thoracic interventions alongside chemoradiation run a historical risk of exacerbating severe toxicities, such as radiation pneumonitis or esophagitis.

High Efficacy Rates and Deepening Responses

In addition to foundational safety metrics, preliminary efficacy outcomes were reported for seven patients who had completed the full, multi-modality therapeutic regimen. The combination of cCRT, a one-time nanoparticle injection, and consolidation durvalumab achieved an overall response rate (ORR) of 85.7% (6 of 7 patients) and a disease control rate (DCR) of 100.0% (all 7 patients).

Notably, the complete response rate (CRR) stood at 57.1% (4 of 7 patients). In the standard-of-care setting using cCRT with or without consolidation immunotherapy, the depth of response remains historically limited, yielding complete response rates below 5% according to benchmark clinical data.² Investigators observed no progressive disease among the evaluable patients and highlighted a pattern of deepening radiographic response over time, indicating potential long-term durability of the treatment effect.

Physical Mechanism and Clinical Trial Framework

Functionalized hafnium oxide nanoparticles utilize a purely physical mechanism of action designed to augment the local cytotoxic effects of radiotherapy. Composed of high-atomic-number crystalline hafnium oxide, the nanoparticles are taken up into the cytoplasm of cancer cells via endocytosis. When exposed to external beam radiation, the dense hafnium core interacts with incoming photons far more efficiently than surrounding organic tissue, significantly amplifying the localized production of secondary electrons and reactive oxygen species (ROS). This results in increased tumor cell death within the irradiated area while sparing adjacent healthy structures from increased radiation doses.

The ongoing randomized phase 2 CONVERGE study is evaluating functionalized hafnium oxide nanoparticles across multiple arms to determine optimal dosing and comparative benefit against standard cCRT and consolidation immunotherapy. Although the preliminary dataset is constrained by a small sample size (n = 7), the absence of disease progression and the unexpectedly high rate of deep radiographic responses support continued enrollment. Future analyses will confirm if this localized radioenhancement translates to statistically significant progression-free and overall survival advantages in a broader patient population.

REFERENCES

1. Nanobiotix Announces Presentation of Part 1 Data From a Randomized Phase 2 Clinical Trial Evaluating JNJ-1900 (NBTXR3) in Stage 3 Inoperable Lung Cancer. News release. Nanobiotix. May 17, 2026. Accessed May 22, 2026. https://tinyurl.com/58zc4kfb

2. Antonia SJ, Villegas A, Daniel D, et al. Durvalumab after Chemoradiotherapy in Stage III Non-Small-Cell Lung Cancer. N Engl J Med. 377(20), 1919–1929. doi:10.1056/NEJMoa1709937