NANOBIOTIX Announces New Results From a Phase 1 Study Evaluating JNJ-1900 (NBTXR3) in Combination With Immune Checkpoint Inhibitors as a 2L+ Therapy for Patients With Primary Cutaneous Melanoma Resistant to Anti-PD-1

On September 17, 2025 NANOBIOTIX (Euronext: NANO –– NASDAQ: NBTX – the ‘‘Company’’), a late-clinical stage biotechnology company pioneering nanotherapeutic approaches to expand treatment possibilities for patients with cancer and other major diseases, reported new results focused on patients with primary cutaneous melanoma from the ongoing Phase 1 Study 1100 evaluating JNJ-1900 (NBTXR3) in combination with immune checkpoint inhibitors (pembrolizumab or nivolumab) for patients with advanced cancers (Press release, Nanobiotix, SEP 17, 2025, View Source [SID1234656034]). These findings were presented at the 2025 ImmunoRad conference in Paris, France on September 17.

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Patients with anti-PD-1 resistant primary cutaneous melanoma in the study had advanced disease that progressed despite multiple prior lines of therapy, including anti–PD-1, ipilimumab, T-VEC, TIL, and radiotherapy ("RT"), among others. All patients received a one-time intratumoral injection of JNJ-1900 (NBTXR3) followed by RT and sequential anti–PD-1 therapy. As of the August 21, 2025, data cutoff, 21 patients had been injected with JNJ-1900 and 19 were evaluable for tumor response (2 patients were not evaluable due to lack of post-treatment imaging).

"The patients in this analysis represent one of the more difficult clinical challenges we face as many have exhausted standard therapies, including checkpoint inhibitors," said Study 1100 Coordinating Investigator Colette Shen, MD, PhD, Assistant Professor of Radiation Oncology, University of North Carolina Lineberger Comprehensive Cancer Center. "While these data are preliminary, the responses we’re seeing provide a strong signal that this treatment approach could potentially offer a new possibility for patients who need more options."

Safety and Feasibility

All 21 patients with primary cutaneous melanoma had shown prior resistance to anti-PD-1 and treatment with RT-activated JNJ-1900 (NBTXR3) followed by anti-PD-1 showed a favorable safety profile:

Injection feasibility was confirmed at the recommended Phase 2 dose (33% GTV)
In total, 16 patients experienced grade 1, grade 2, or grade 3+ TEAEs related to the overall therapeutic regimen (RT, anti-PD-1, JNJ-1900 (NBTXR3), and injection procedure)
Of which 5 patients experienced grade 1, grade 2, or grade 3+ treatment-emergent adverse events (TEAEs) related to JNJ-1900 (NBTXR3) and/or the injection procedure
Of these patients, 1 patient experienced grade 3+ TEAEs (hypotension and pleuritic pain)
Early Signs of Efficacy

JNJ-1900 (NBTXR3) demonstrated preliminary signals of efficacy in 19 patients who were evaluable for tumor response:

A best observed objective response rate ("ORR") in all lesions of 47.4% (9/19) per RECIST 1.1, including 4 complete responses and 5 partial responses
A best observed disease control rate ("DCR") in all lesions of 78.9% (15/19) per RECIST 1.1
In JNJ-1900 injected & irradiated tumors, a DCR of 100% (19/19) was observed
A median Overall Survival (mOS) of 14.6 months [95% CI: 10.7 months; 16.7 months] in all patients treated (n=21)
Notably, a relationship was observed between the depth of local response and systemic tumor regression, suggesting a possible priming or re-activation of immune response.

"We are encouraged by these new findings and the potential signals of activity in this difficult-to-treat population," said Louis Kayitalire, MD, Chief Medical Officer of Nanobiotix. "Notably, the relationship we observed between the depth of local response and systemic tumor regression further supports our hypothesis regarding the potentially broad applicability of JNJ-1900 (NBTXR3) for patients with cancer. We look forward to further clinical evaluation of JNJ-1900 (NBTXR3) to better understand its capacity to drive both local and systemic responses in primary cutaneous melanoma."

Nanobiotix Conference Call

Nanobiotix will host a conference call and webcast featuring Nanobiotix chief executive officer, Laurent Levy, to discuss the new data on Thursday, September 18th, 2025, at 8:00 AM EDT / 2:00 PM CET.

Details for the call are as follows:

Webcast link: View Source

Audio-only dial-in link: View Source

Participants can use the audio-only link above to register and obtain dial-in instructions to listen to the presentation via phone and ask questions during the Q&A session, or participants can use the webcast link to register and listen and watch the slide presentation online; the replay version will be available under the same webcast link shortly after the presentation and will be archived on the Company’s website at www.nanobiotix.com. It is recommended to join 10 minutes prior to the event start. Participants are invited to email their questions in advance to [email protected].

About JNJ-1900 (NBTXR3)

JNJ-1900 (NBTXR3) is a novel, potentially first-in-class oncology product composed of functionalized hafnium oxide nanoparticles that is administered via one-time intratumoral injection and activated by radiotherapy. Its proof-of-concept was achieved in soft tissue sarcomas through a successful randomized Phase 2/3 study in 2018. The product candidate’s mechanism of action (MoA) is designed to induce significant tumor cell death in the injected tumor when activated by radiotherapy, subsequently triggering adaptive immune response and long-term anti-cancer memory. Given the physical MoA, Nanobiotix believes that JNJ-1900 (NBTXR3) could be scalable across any solid tumor that can be treated with radiotherapy and across any therapeutic combination, particularly immune checkpoint inhibitors.

Radiotherapy-activated JNJ-1900 (NBTXR3) is being evaluated across multiple solid tumor indications as a single agent or combination therapy. The program is led by NANORAY-312—a global, randomized Phase 3 study in locally advanced head and neck squamous cell cancers. In February 2020, the United States Food and Drug Administration granted regulatory Fast Track designation for the investigation of JNJ-1900 (NBTXR3) activated by radiation therapy, with or without cetuximab, for the treatment of patients with locally advanced HNSCC who are not eligible for platinum-based chemotherapy—the same population being evaluated in the Phase 3 study.

Given the Company’s focus areas, and balanced against the scalable potential of NBTXR3, Nanobiotix has engaged in a collaboration strategy to expand development of the product candidate in parallel with its priority development pathways. Pursuant to this strategy, in 2019 Nanobiotix entered into a broad, comprehensive clinical research collaboration with The University of Texas MD Anderson Cancer Center to sponsor several Phase 1 and Phase 2 studies evaluating JNJ-1900 (NBTXR3) across tumor types and therapeutic combinations. In 2023, Nanobiotix announced a license agreement for the global co-development and commercialization of JNJ-1900 (NBTXR3) with Janssen Pharmaceutica NV, a Johnson & Johnson company.