Novaspira Biotherapeutics Reports Phase 1 Data for a Novel GPC3x4-1BB Bispecific in Late-Breaking Oral at SITC 2026

First-in-human Phase 1 results for BOS-342 (NS-342), a novel GPC3×4-1BB bispecific, demonstrate a manageable safety profile and durable antitumor activity.

CHATHAM, NJ, UNITED STATES, November 7, 2026 /EINPresswire.com/ -- Chatham, NJ, November 7, 2026: Novaspira Biotherapeutics today announced the presentation of first-in-human clinical data for BOS-342 (NS-342), a novel GPC3 × 4-1BB bispecific immunotherapy, in patients with advanced hepatocellular carcinoma (HCC). The results were featured in a late-breaking oral presentation (Abstract #1173) at the 41st Annual Meeting of the Society for Immunotherapy of Cancer (SITC) in Phoenix, Arizona, and were presented by Hong Jae Chon, M.D., Ph.D., of CHA Bundang Medical Center.

The presentation, titled “A Phase I First-in-Human Study of BOS-342, a Novel GPC3 × 4-1BB Bispecific Molecule, in Advanced Hepatocellular Carcinoma: Early Report of Safety, Immune, Biochemical and Durable Clinical Responses,” highlighted preliminary safety, pharmacodynamic, and clinical activity findings from the ongoing Phase 1 study.

BOS-342 is designed to selectively activate the costimulatory receptor 4-1BB only in the presence of GPC3-expressing tumor cells, with the goal of confining immune activation within the tumor microenvironment while minimizing systemic toxicity.

Key findings
12 patients with advanced HCC who had disease progression on prior PD-(L)1 inhibitors and VEGF-targeted therapy were treated with escalating doses of single agent BOS-342 administered every two weeks.

Safety
BOS-342 demonstrated a manageable safety profile across all dose levels evaluated.
• No dose-limiting toxicities (DLTs) were observed.
• No Grade 4 or Grade 5 treatment-related adverse events were reported.
• No cytokine release syndrome (CRS) or immune-related adverse events were observed.
• Infusion-related reactions were the most common treatment-related adverse event and were effectively managed with premedication and infusion-rate modification.

Clinical Activity
Encouraging antitumor activity was observed in this heavily pretreated patient population.
• At the highest dose level evaluated, the objective response rate (ORR) was 28.6% (2 of 7 patients).
• One patient achieved a durable partial response that has remained ongoing for more than 24 months with continued follow-up.
• Across all dose levels, the 12-week disease control rate (DCR) was 50%.

“These early clinical findings provide encouraging support for the potential of conditional, tumor-directed 4-1BB costimulation as a therapeutic strategy in hepatocellular carcinoma,” said Dr. Hong Jae Chon, principal investigator of the study. “BOS-342 demonstrated a well manageable safety profile together with preliminary evidence of durable antitumor activity in heavily pretreated patients. Further evaluation in larger patient cohorts will help define the full therapeutic potential of this approach.”

“Selection of these data for a late-breaking oral presentation at SITC underscores the growing interest in next-generation, tumor-targeted immunotherapies,” said Han Li, Ph.D., CEO of Novaspira Biotherapeutics. “We are encouraged by the emerging safety and efficacy profile of NS-342 and look forward to advancing development of this novel GPC3 × 4-1BB bispecific for patients with advanced liver cancer.”

Next Steps
A new Phase 1 clinical study, NS-342-101, is being initiated across South Korea, Taiwan, and the United States. Additional biomarker, immune pharmacodynamic, and translational analyses from the ongoing development program are planned for presentation at future scientific meetings.

About NS-342
NS-342 (formerly PRS-342, BOS-342) is a novel GPC3 × 4-1BB bispecific protein. Preclinical data has shown potent T-cell activation and tumor cell lysis that are strictly dependent on the presence of GPC3-positive tumor cells; increased production of IL-2, a pro-inflammatory cytokine associated with anti-tumor immune response; TIL infiltration in tumors in HCC Xenograft mice; and potent anti-tumor activities (1).

About NovaSpira Biotherapeutics, Inc.
NovaSpira Biotherapeutics is a clinical stage biotechnology company developing next generation immunotherapies for solid tumors with high unmet need. NS 342, the lead candidate, is in Phase 1 clinical development as a bispecific T cell and immune cell activator therapy for GPC3 positive solid tumors, including liver and lung cancers. For more information, visit www.novaspirabio.com

Cautionary Statement Regarding Forward-Looking Statements
Statements in this press release that are not purely historical in nature are “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. We use words such as “commitment,” “advancing,” “believe,” “potential,” and similar expressions to identify these forward-looking statements. These forward-looking statements are based on NovaSpira’s current expectations and involve assumptions that may never materialize or may prove to be incorrect; consequently, actual results may differ materially from those expressed or implied due to a number of factors, including risks related to NovaSpira’s ability to grow and advance its pipeline and execute on its business plan; and other risks and uncertainties inherent in drug development. The forward-looking statements included in this press release are made only as of the date of this press release. Except as required by law, NovaSpira assumes no obligation and does not intend to update any forward-looking statements included in this press release.
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1. Birgit Bossenmaier, Corinna Schlosser, Rachida-Siham Bel Aiba, Eva-Maria Hansbauer, Thomas Jaquin, Christian Barthels, Janet Peper, Markus Zettl, Benjamin Weiche, Costimulatory T-cell engagement by PRS-342, a GPC3/4-1BB bispecific molecule, leads to activation of T cells and tumor growth inhibition in a HCC humanized mouse model, AACR, 2019

Company Contact
Novaspira Biotherapeutics
info@novaspirabio.com