Onchilles Pharma Presents Preliminary Clinical Findings for N17350, an Investigational Intratumoral Cancer Therapy, at SITC 2026
Onchilles Pharma, a clinical-stage biotechnology company developing next-generation cancer therapies targeting the ELANE pathway, has announced preliminary clinical findings from its Phase 1/2 OP-NEU-101 trial evaluating N17350, an investigational intratumoral therapy, in patients with advanced solid tumors. The early clinical results provide encouraging evidence of potential antitumor activity beyond the directly treated tumor, supporting the company’s approach of transforming an injected tumor into a source of antigens that may stimulate the immune system to recognize and attack cancer throughout the body.
The findings will be presented at the Society for Immunotherapy of Cancer (SITC) 41st Annual Meeting in Phoenix, Arizona. The clinical data represent an important early evaluation of N17350, which is designed to use a naturally occurring cancer-killing enzyme found in human neutrophils to initiate a localized tumor-killing process and stimulate a broader immune response.
Unlike several personalized cancer immunotherapy approaches that require individual tumor sequencing, antigen identification, patient-specific treatment selection, and customized manufacturing, N17350 is being developed as a single investigational medicine intended to generate a personalized immune response using each patient’s own tumor.
The therapy is designed to work through a two-stage mechanism. Following direct injection into a tumor, N17350 is intended to selectively destroy cancer cells while preserving healthy tissues and immune cells. The destruction of cancer cells is then expected to release tumor-associated antigens, which may help train and activate the immune system to recognize cancer cells carrying similar antigens elsewhere in the body.
This approach could potentially offer a treatment strategy applicable across multiple solid tumor types without requiring the development of a separate customized therapy for every patient.
Court R. Turner, J.D., Co-Founder and Chief Executive Officer of Onchilles Pharma, highlighted the potential advantages of the company’s approach compared with existing personalized cancer immunotherapies.
According to Turner, many personalized immunotherapy treatments require sequencing individual tumors and manufacturing a separate therapeutic product for each patient. In contrast, N17350 is designed to generate a patient-specific immune response using a single medicine, with the patient’s own tumor serving as the source of antigens.
He further noted that if the local and distant antitumor activity observed in preclinical research can be reproduced and confirmed in clinical studies, N17350 could provide a broadly applicable approach to generating immune responses tailored to individual cancers across different solid tumor types.
N17350 Uses the ELANE Pathway to Activate Antitumor Immunity
N17350 is based on research involving neutrophils, which are among the most abundant immune cells in the human body and play an important role in the innate immune response.
The investigational therapy builds on breakthrough scientific research published in the journal Cell, which demonstrated that neutrophils contain a naturally occurring enzyme capable of destroying cancer cells while sparing healthy tissues, including immune cells.
Onchilles Pharma has developed its therapeutic approach around this cancer-killing enzyme and the biological pathway associated with neutrophil elastase (ELANE).
The company has engineered the enzyme into an investigational treatment designed to selectively target cancer cells following intratumoral administration.
The proposed mechanism of N17350 involves two interconnected stages.
First, selective destruction of cancer cells: Following injection directly into a tumor, N17350 is designed to use its cancer-killing activity to destroy malignant cells while minimizing damage to surrounding healthy tissue and immune cells. This localized activity is intended to initiate tumor destruction at the injection site.
Second, activation of a systemic immune response: As cancer cells are destroyed, tumor-associated antigens are expected to be released into the surrounding environment. These antigens may then help the immune system recognize cancer-specific targets and develop an immune response capable of identifying and attacking cancer cells at other locations in the body.
This second stage is particularly important because metastatic cancer frequently involves multiple tumors distributed across different organs and tissues. A therapy capable of stimulating systemic antitumor immunity after treating only one lesion could potentially provide benefits beyond the directly injected tumor.
The approach is intended to address a major challenge in cancer immunotherapy: the ability to stimulate effective immune responses against tumors that have developed mechanisms to evade immune recognition.
By using the patient’s own tumor as an antigen source, N17350 is designed to generate an immune response without requiring prior identification of specific tumor antigens or personalized manufacturing.
The company believes that targeting a biological vulnerability shared across multiple cancer types could create opportunities to investigate the therapy across a broad range of advanced solid tumors.
Early Clinical Findings Demonstrate Potential Activity Beyond the Injected Tumor
The preliminary clinical findings from the OP-NEU-101 trial include an encouraging observation in a patient with Merkel cell carcinoma, a rare and aggressive form of skin cancer.
The patient had experienced disease progression despite previous treatment with avelumab-based immunotherapy and radiotherapy, indicating a challenging clinical situation with limited treatment options.
Merkel cell carcinoma is an aggressive malignancy that can progress rapidly and spread to other parts of the body. Although immune checkpoint inhibitors have improved treatment options for some patients, disease progression following immunotherapy remains a significant clinical challenge.
In this case, investigators evaluated six tumor lesions. N17350 was administered directly into only one of the six lesions to assess whether localized treatment could potentially generate an immune response against tumors that were not directly exposed to the investigational therapy.
At Week 8, the investigator’s assessment using Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST 1.1) found that all five non-injected lesions were no longer detectable.
The five lesions included one lesion selected for precise measurement through imaging and four additional lesions that were monitored based on their presence or absence.
This observation is particularly noteworthy because the treatment was administered to only one tumor, while the remaining lesions demonstrated changes consistent with antitumor activity.
The findings provide preliminary clinical support for the possibility that N17350 may stimulate systemic immune activity rather than producing effects exclusively at the injection site.
However, these observations are based on an individual patient and require confirmation in additional participants and larger clinical studies.
FDG-PET Imaging Shows Reduced Tumor Metabolic Activity
Additional imaging findings provided further evidence of potential antitumor activity following N17350 administration.
Fluorodeoxyglucose positron emission tomography (FDG-PET) imaging demonstrated a reduction in the maximum standardized uptake value (SUVmax) ranging from 56% to 60% across all evaluated lesion groups.
SUVmax is an imaging measurement used to assess the uptake of a radioactive glucose tracer within tissues. Cancer cells frequently demonstrate increased glucose metabolism, allowing FDG-PET imaging to help identify metabolically active tumors.
A reduction in SUVmax can indicate decreased metabolic activity within a tumor and may provide evidence of a response to treatment.
In the Merkel cell carcinoma patient, the observed reductions in FDG uptake across the evaluated lesions provided additional support for the possibility of a broader antitumor effect.
Furthermore, an independent radiology review of a separate lesion also identified reduced FDG uptake. This provided an additional assessment consistent with the imaging findings observed by the investigators.
Taken together, the RECIST 1.1 assessments and FDG-PET imaging results suggest that N17350 may have generated activity extending beyond the directly treated tumor.
These findings are particularly relevant to the company’s proposed mechanism, which aims to convert an injected tumor into an in situ source of antigens that can stimulate immune responses against cancer elsewhere in the body.
Investigators Highlight the Potential of N17350 as an In Situ Cancer Vaccine
Alain Patrick Algazi, M.D., Professor of Clinical Medicine at the University of California San Francisco (UCSF) and presenting author of the clinical study, discussed the potential significance of the preliminary findings.
Dr. Algazi noted that several intratumoral cancer treatment approaches, including Toll-like receptor (TLR) agonists and oncolytic viruses, have demonstrated promising results in preclinical research but have faced challenges in establishing broad clinical benefits.
He emphasized that the early N17350 findings appear potentially differentiated because they include evidence of systemic immune activation and responses in tumors that were not directly injected.
According to Dr. Algazi, confirmation of these observations could represent meaningful progress in the development of intratumoral immunotherapies.
Professor Matteo Carlino, MBBS, Ph.D., FRACP, a medical oncologist at Westmead and Blacktown Hospitals and an investigator in the OP-NEU-101 clinical trial, also highlighted the significance of the clinical observation in the patient with Merkel cell carcinoma.
He noted that the disappearance of all five non-injected lesions following treatment of a single tumor was an encouraging early finding, particularly because the patient’s cancer had previously progressed despite aggressive treatment with immunotherapy and radiotherapy.
Professor Carlino explained that if these findings are confirmed and reproduced in additional patients, N17350 could demonstrate the ability to turn one treated tumor into an in situ vaccine and mobilize the immune system against cancer throughout the body.
The concept of an in situ cancer vaccine involves stimulating an immune response directly within the tumor environment. Rather than manufacturing a separate vaccine using selected tumor antigens, the approach uses antigens released from the patient’s own cancer cells following treatment.
This could potentially allow the immune system to recognize a broader range of cancer-associated targets while reducing the need for individualized treatment development.
Phase 1 Safety Evaluation Shows No Dose-Limiting Toxicities
The OP-NEU-101 clinical trial is a Phase 1/2 open-label study designed to evaluate the safety and effectiveness of intratumoral N17350 in patients with advanced solid tumors while determining an appropriate dose for further clinical development.
Preliminary findings from the first dose cohort included three heavily pretreated patients who received N17350 at a concentration of 1 mg/mL.
All three patients completed the dose-limiting toxicity assessment period without experiencing dose-limiting toxicities.
The absence of dose-limiting toxicities in this initial cohort supported progression to the next dose level under the study’s dose-escalation strategy.
This early safety observation is an important component of the clinical evaluation because Phase 1 studies are primarily designed to establish the safety and tolerability of an investigational treatment and identify appropriate dosing levels for subsequent development.
The findings will help investigators continue evaluating N17350 while gathering additional information regarding its potential therapeutic activity.
Although the initial cohort included only three patients, the absence of dose-limiting toxicities provides encouraging preliminary information about the treatment approach.
Further patient enrollment and continued dose evaluation will be required to establish a more comprehensive safety profile.
Pharmacokinetic Findings Suggest Limited Systemic Exposure
In addition to safety and preliminary efficacy, Onchilles Pharma evaluated the pharmacokinetic (PK) characteristics of N17350 to understand how the investigational enzyme behaves following intratumoral administration.
The preliminary PK analysis detected no active N17350 enzyme in plasma at any of the sampled time points.
This observation is consistent with the company’s preclinical pharmacokinetic findings and suggests that active N17350 may remain localized following administration into the tumor.
The study also reported that no treatment-emergent anti-drug antibodies were detected in the evaluated patients during the reported assessment period.
Anti-drug antibodies are immune responses generated against a therapeutic product. Their development can potentially affect treatment exposure, biological activity, or safety, depending on the characteristics of the investigational medicine.
The absence of detected treatment-emergent anti-drug antibodies in this preliminary analysis provides additional information regarding the early clinical behavior of N17350.
Importantly, the lack of detectable active enzyme in plasma may help explain the potential distinction between localized drug administration and the systemic antitumor activity observed in the Merkel cell carcinoma patient.
According to the company’s proposed mechanism, the effects in non-injected lesions may result from immune activation initiated at the treated tumor site rather than from active N17350 reaching distant tumors through the bloodstream.
This possibility is central to the development strategy because the company aims to stimulate systemic immune responses through localized treatment.
Nevertheless, additional clinical and translational studies will be necessary to establish the precise biological mechanisms responsible for the observed responses.
Immune Profiling Indicates Changes Toward an Effector-Dominant Environment
Initial immune profiling conducted in the Merkel cell carcinoma patient also provided preliminary evidence of changes in the immune environment following treatment.
The analysis showed a shift toward an effector-dominant and less immunosuppressive immune profile.
Effector immune cells play an important role in identifying and eliminating abnormal cells, including cancer cells. In contrast, immunosuppressive components of the tumor microenvironment can interfere with effective immune responses and allow tumors to evade immune surveillance.
A shift toward a more immune-active environment may therefore support the development of stronger antitumor responses.
These findings are consistent with the proposed mechanism of N17350, in which localized cancer-cell destruction releases tumor antigens that may help activate immune responses against additional cancer lesions.
When considered alongside the absence of detectable active N17350 enzyme in plasma and the imaging changes observed in non-injected lesions, the immune profiling results provide an initial biological rationale for the potential systemic effects of treatment.
However, the immune findings remain preliminary and will require further validation across a larger patient population.
SITC 2026 Presentation Details for N17350
Onchilles Pharma will present the preliminary OP-NEU-101 clinical findings at the SITC 41st Annual Meeting through a poster presentation.
The presentation details are as follows:
- Poster Number: 544
- Presentation Title: OP-NEU-101: A Phase 1/2 Open-Label, Dose Finding and Expansion Study to Investigate the Safety and Effectiveness and Determine the Optimal Dose of N17350 Administered Intratumorally in Participants With Advanced Solid Tumors
- Presenting Author: Alain Patrick Algazi, MD, University of California San Francisco
- Date: Saturday, November 7, 2026
- First Presentation Period: 12:15 PM–1:45 PM Mountain Time
- Second Presentation Period: 6:40 PM–8:10 PM Mountain Time
- Location: Phoenix Convention Center, North Building, Lower Level, Exhibition Halls 4–6, Phoenix, Arizona.
The presentation will provide researchers, clinicians, and oncology specialists with an opportunity to review the early safety, pharmacokinetic, imaging, and immune profiling findings from the ongoing clinical study.
Advancing a Potentially Broad Approach to Personalized Cancer Immunotherapy
The preliminary clinical findings represent an important milestone for Onchilles Pharma as it advances N17350 through early-stage clinical development.
The observation of reduced or undetectable non-injected tumor lesions in a patient with previously treated Merkel cell carcinoma provides an encouraging initial signal supporting the company’s in situ cancer vaccine concept.
The early safety findings, absence of detectable active enzyme in plasma, lack of treatment-emergent anti-drug antibodies, and immune profiling results further contribute to the growing understanding of the investigational therapy.
N17350 is being developed with the goal of addressing several limitations associated with existing personalized cancer immunotherapy approaches, particularly the need for tumor sequencing, antigen selection, and patient-specific manufacturing.
By using the patient’s own tumor as the source of antigens, the therapy could potentially generate individualized immune responses through a standardized investigational treatment.
As the OP-NEU-101 trial progresses, additional clinical data will be important to determine whether the encouraging local and distant antitumor activity observed in the initial findings can be reproduced across different patients and solid tumor types.
For Onchilles Pharma, the continued development of N17350 represents an effort to establish a differentiated immunotherapy approach based on the natural cancer-killing capabilities of neutrophil-derived enzymes and the potential to stimulate broader systemic antitumor immunity.
The upcoming clinical evaluation will help clarify the treatment’s safety, optimal dosing, biological activity, and potential role in the future management of advanced solid tumors.
About N17350
N17350 is a first-in-class, clinical-stage engineered therapeutic elastase designed for intratumoral administration. It targets the ELANE pathway, a cancer-selective killing mechanism that exploits altered histone H1 biology, a vulnerability shared across diverse cancers. By inducing immunogenic cancer cell death while largely preserving non-cancer and immune cells, N17350 is designed to deliver two complementary waves of activity: rapid, direct tumor killing and an adaptive immune response with the potential to attack tumors beyond the injection site. In preclinical models, N17350 produced broad, genotype-independent tumor regression, CD8+ T cell-mediated antitumor immunity, activity in non-injected tumors, and immune memory.
About OP-NEU-101
OP-NEU-101 (ClinicalTrials.gov Identifier: NCT07339176) is a Phase 1/2, first-in-human, multicenter, open-label study evaluating the safety, tolerability, pharmacokinetics, pharmacodynamics, immunogenicity, and preliminary clinical activity of intratumoral N17350 in patients with advanced solid tumors. The study is enrolling in Australia and the United States, with dose escalation and optimization in patients with injectable superficial lesions, followed by planned evaluation in visceral lesions and potential indication-specific expansion cohorts.
About Onchilles Pharma
Onchilles Pharma is a clinical-stage biotechnology company pioneering first-in-class cytotoxic therapies designed to selectively kill cancer cells while preserving and activating immune function. By harnessing the ELANE pathway, these next-generation therapeutics are designed to deliver potent and selective tumor cell destruction, overcoming the limitations of traditional chemotherapy and immunotherapy. The company’s pipeline includes N17350, a tumor-directed lead candidate in first-in-human studies, and the NEU-002 program extending ELANE pathway therapeutics to systemic delivery.