- Preliminary data from an investigator-initiated Phase 1 study reinforce feasibility and suggest upstream innate-to-Th1 proof of mechanism for systematic immune reprogramming therapy (XIRT™)
- XIRT is built on Novastra’s proprietary OmniAntigen™ Platform (OAP) designed to encapsulate a broad spectrum of cold tumor antigens for immune activation
CAMBRIDGE, Mass., Nov. 09, 2026 (GLOBE NEWSWIRE) — Novastra Therapeutics, a clinical-stage biotechnology company developing a novel category of cancer immune therapy, reported further encouraging data from an ongoing investigator-initiated Phase 1 study expanding early clinical evidence for its systematic immune reprogramming therapy (XIRT™) based on its proprietary OmniAntigen™ Platform (OAP). The data were presented on Saturday, November 7, at the Society for Immunotherapy of Cancer (SITC) 41st Annual Meeting, held November 4-8, 2026, in Phoenix, Arizona. They complement initial data from the same study reported at the ESMO 2026 Congress in October.
The interim analysis describes outcomes from three heavily pretreated patients — each with advanced and metastatic melanoma refractory to different lines of therapy, and with poor-prognosis features. In these patients, repeat dosing of candidate OAP-101 was feasible and well tolerated with a good safety profile, and with a consistent innate-to-Th1 pharmacodynamic signature recurring across all three consistent with the OAP platform’s proposed immune reprogramming mechanism.
“We believe the consistent, treatment-timed immune activation observed across three distinct patients is an early signal that XIRT could work as designed, as a new way to systematically reprogram the immune system against cold solid tumors,” said Junling Guo, PhD, Chief Executive Officer of Novastra Therapeutics. “Because this mechanism is shared across OAP, its recurrence across different resistance mechanisms strengthens our confidence in the potential of OAP across the broad spectrum of cold tumors it is designed to address through the autologous and in situ approaches it is designed to enable.”
Key findings of the interim analysis
These data build on previously reported results, analyzed through a mechanistic lens and focusing on how consistently the OAP/XIRT approach engages its intended upstream biology:
Consistent feasibility and tolerability. Repeat dosing was feasible, with 11 of 12 planned doses delivered, and no treatment-related cytokine release syndrome, dose-limiting toxicities, or grade ≥3 immune-related adverse events were observed to date.
Consistent innate-to-Th1 pharmacodynamic signature across resistance mechanisms. A treatment-timed innate-to-Th1 shift — including a decrease in the immunosuppressive cytokine IL-10 alongside IL-12p70, interferon-axis, and CD8/NK changes — was observed in all three patients despite their differing resistance mechanisms. This consistency across distinct disease biology aligns with the proposed mechanism for OAP/XIRT of linking innate (cGAS-STING) and adaptive immunity.
Exploratory imaging. In a deliberately stringent cohort, patient-level lesion measures showed periods of slower growth or stabilization during the OAP-101 treatment window. In the one radiotherapy-naive patient evaluable by standard imaging, investigator-assessed RECIST 1.1 stable disease was observed within the treatment window, and patient-level measures in the cohort included periods of slower tumor growth. Larger cohorts and formal response assessment are needed to evaluate clinical activity.
Reaching patients with cold solid tumors who are currently left behind
Despite advances in checkpoint inhibitors and ADCs, many patients with solid tumors still experience treatment resistance. For immunotherapy, a central challenge is the absence of an effective anti-tumor immune response, because the tumor hides from immune recognition.1-3
Built on OAP, XIRT is designed to overcome this challenge by priming the immune system. OAP enables rapid antigen encapsulation with a supramolecular nanocloak for effective presentation to the immune system. The nanocloak is designed to combine antigen delivery with innate immune stimulation, including activation of the cGAS-STING pathway, connecting the innate and adaptive immune systems.4 For off-the-shelf in situ use, the nanocloak is designed to self-assemble within the tumor, capturing tumor-derived antigens released by ADCs, chemotherapy, or radiotherapy. For autologous application, the nanocloak is designed to encapsulate whole tumor cells and preserve a broad antigen repertoire, overcoming resistance to checkpoint inhibitors.
About the Phase 1 study
The ongoing investigator-initiated Phase 1 proof-of-concept study is evaluating OAP-101, Novastra’s autologous OAP candidate, in patients with advanced melanoma refractory to anti-PD-1 checkpoint inhibition and other prior lines of therapy. It is designed to enroll a total of nine patients. OAP-101 consists of the patient’s own tumor cells encapsulated in the platform’s supramolecular nanocloak to preserve whole-tumor antigens and co-deliver innate immune activation. OAP-101 is administered subcutaneously, alone or in combination with anti-PD-1, on days 1, 15, 29, and 57, with assessments of safety, serial immune biomarkers (cytokines and T-, B-, and NK-cell subsets), and tumor response by RECIST 1.1, together with exploratory measures including tumor-growth rate. The study is conducted at West China Hospital, Sichuan University (NCT06878612).
The abstract (Abstract No. 568) is published as part of the SITC 2026 abstract supplement in the Journal for ImmunoTherapy of Cancer (JITC), SITC’s official open-access journal. The poster is available on the SITC virtual meeting platform to registered attendees and from Novastra on request.
About Novastra Therapeutics
Novastra is a clinical-stage biotechnology company developing systematic immune reprogramming therapy (XIRT™) as a novel category of cancer therapy to overcome the resistance of cold solid tumors to current therapies by priming the immune system. XIRT is built on Novastra’s proprietary OmniAntigen™ Platform (OAP). Novastra is advancing a pipeline of off-the-shelf in situ and autologous programs. The platform is supported by preclinical evidence and initial results from an investigator-initiated Phase 1 study of autologous OAP-101 in patients with advanced and metastatic melanoma refractory to multiple lines of therapy, including anti-PD-1 checkpoint inhibition.
OAP enables rapid antigen encapsulation with a supramolecular nanocloak for effective presentation to the immune system. The nanocloak is designed to combine antigen delivery with innate immune stimulation, including activation of the cGAS-STING pathway, connecting the innate and adaptive immune systems. For off-the-shelf in situ use, the nanocloak self-assembles within the tumor, capturing tumor-derived antigens released by ADCs, chemotherapy, or radiotherapy. For autologous application, the nanocloak encapsulates whole tumor cells and preserves a broad antigen repertoire, overcoming resistance to checkpoint inhibitors.
Novastra Therapeutics is headquartered in Cambridge, Massachusetts, with an operations hub in Shanghai. Explore more at www.novastra.bio.
Forward-Looking Statements
This press release contains forward-looking statements regarding Novastra Therapeutics, including statements about the development of its therapy candidates, the conduct and timing of clinical studies, anticipated regulatory milestones, and the company’s strategic and financial plans. Forward-looking statements are based on current expectations and involve risks and uncertainties, including but not limited to clinical study outcomes, regulatory decisions, and availability of capital, that could cause actual results to differ materially from those expressed or implied. Interim or early clinical data may not be predictive of future results. Novastra undertakes no obligation to update forward-looking statements except as required by law.
Contact
Arne Naeveke, PhD
Head of Strategic Communications
media@novastra.bio
References
- Shen et al. J Immunother Cancer. 2024
- Haslam & Prasad, JAMA Netw Open. 2019
- Haslam et al. Int J Cancer. 2025
- He et al. Angew Chem Int Ed. 2024;63:e202314501
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