Nanobiotix SA Reports Promising Phase 1 Outcomes for NBTXR3 in Refractory Cutaneous Melanoma
Nanobiotix SA (Euronext: NANO, NASDAQ: NBTX) disclosed that its early‑stage clinical data for JNJ‑1900 (NBTXR3), the company’s flagship NanoXray® nanomedicine, demonstrate a favorable safety profile and encouraging antitumor activity when combined with immune‑checkpoint inhibitors (ICIs) in patients with secondary‑line or greater cutaneous melanoma resistant to anti‑PD‑1 therapy. The results were presented on 17 September 2025 at the Immunorad 2025 conference in Paris and Cambridge, and the company will hold a webcast on 18 September 2025 at 14:00 CEST to discuss the data in detail.
Key Efficacy Findings
| Metric | Result | Context |
|---|---|---|
| Objective Response Rate (ORR) | 47.4 % (9/19 lesions) | RECIST 1.1 criteria; measured across all treated lesions |
| Disease‑Control Rate (DCR) | 78.9 % (15/19 lesions) | Includes stable disease as well as partial and complete responses |
| Median Overall Survival (mOS) | 14.6 months | Across all 21 patients treated in the study |
The cohort comprised heavily pre‑treated patients whose disease progressed after multiple prior therapies, including anti‑PD‑1 agents. Despite this challenging population, nearly half achieved measurable tumor shrinkage, and the majority experienced disease control for a meaningful duration. Median survival beyond a year signals a potential shift in the therapeutic landscape for refractory melanoma, where options are currently limited.
Safety Profile
The combination of NBTXR3 with ICIs was well tolerated. No new safety signals emerged, and the adverse event profile aligned with what has been observed in earlier NBTXR3 monotherapy and combination studies. This reinforces the premise that NanoXray® can deliver radiation directly to tumor cells while sparing adjacent healthy tissue, thereby mitigating the dose‑limiting toxicities that traditionally accompany radiotherapy.
Phase 2 Design Implications
Based on these encouraging signals, Nanobiotix has defined the recommended dose for the upcoming Phase 2 trial as 33 % of the tumor volume. The company anticipates that this dose will maintain efficacy while preserving the safety advantages observed in Phase 1. The planned randomized study will evaluate NBTXR3 plus ICIs as a novel therapeutic option for both naïve and anti‑PD‑1–resistant cutaneous melanoma patients.
Market Impact
At the close of 16 September 2025, Nanobiotix’s share price stood at €9.06, trailing a 52‑week high of €9.17 but well above the low of €2.62 reached in early April. With a market capitalization of approximately €437 million, the company occupies a critical niche at the intersection of nanotechnology and oncology. Positive Phase 1 data in a high‑need indication are likely to bolster investor confidence, particularly as the biotech sector increasingly rewards companies that combine innovative delivery platforms with immuno‑oncology.
Forward‑Looking Perspective
Nanobiotix’s NanoXray® platform exemplifies a paradigm shift: enhancing radiotherapy efficacy within tumor cells while reducing collateral damage. The recent melanoma data not only validate this approach in a difficult-to‑treat patient group but also lay the groundwork for broader applications across solid tumors. If Phase 2 confirms the durability of these responses and the safety margin, Nanobiotix could position itself as a frontrunner in the next generation of combination therapies that integrate nanomedicine, radiation, and immunotherapy.
Investors and clinicians alike will be watching closely for the company’s forthcoming webcast and the progression of its clinical development program. The data presented today strengthen Nanobiotix’s strategic thesis and suggest a promising trajectory toward regulatory approval and commercial deployment of NBTXR3 as a transformative adjunct to standard oncology care.