Safety and Efficacy of NBTXR3 in R/M HNSCC: Results from Study 1100

In an interview with Targeted Oncology, Colette Shen, MD, PhD, assistant professor at the University of North Carolina (UNC) Chapel Hill and radiation oncologist at the UNC Lineberger Comprehensive Cancer Center, recaps the most noteworthy safety and efficacy findings from the phase 1 Study 1100 (NCT03589339) assessing the novel radioenhancer NBTXR3 (JNJ-1900) in recurrent or metastatic (R/M) head and neck squamous cell carcinoma (HNSCC), reflecting on clinical implications.

Watch part 1, part 2, and part 3 of Dr Shen’s interview.

The primary end point of the dose-expansion portion was safety of NBTXR3 at the recommended dosage,¹ which was established in the preceding dose-escalation portion of the study. The agent was found to be safe and well tolerated for most patients, with standard adverse events and toxicities consistent with events observed in anti–PD-1 therapy.

“I think the fact that [NBTXR3] was very well tolerated for most patients was reassuring to see. Most of the patients we treated mentioned how well they did with this therapy compared with some of the other treatments they had had,” remarked Shen in the interview.

While efficacy was a secondary end point in the study, Shen noted 2 surprising findings regarding antitumor response. Firstly, Shen was surprised by the positive response and survival outcomes among patients who previously developed resistance to anti–PD-1 therapy, who normally would not have derived much clinical benefit from such therapy. Another unexpected and uncommon efficacy finding, Shen noted, was the occurrence of responses outside of the injected tumor, or out-of-field responses, in several patients. This finding indicates to Shen and the investigators that the treatment may have potentially generated a broader systemic response, rather than a localized response, prompting further investigation.

REFERENCE:

1. NBTXR3 activated by radiotherapy for patients with advanced cancers treated with an anti-PD-1 therapy. ClinicalTrials.gov. Updated January 14, 2025. Accessed October 9, 2025. https://clinicaltrials.gov/study/NCT03589339