Investigator's Brochure (TILA-278)

Clinical documentation for the TILA-278 program.

Change History

INVESTIGATOR'S BROCHURETILA-278 — anti-TL1A (TNFSF15) × IL-22 receptor humanized IgG1 bispecific monoclonal antibody

Confidentiality Statement

This Investigator's Brochure (IB) contains confidential and proprietary information of Virtual Biopharma Inc. It is provided to investigators, potential investigators, Institutional Review Boards / Independent Ethics Committees, and regulatory authorities solely for the evaluation and conduct of clinical investigations of TILA-278. The information herein may not be disclosed, published, or otherwise used for any other purpose without the prior written consent of Virtual Biopharma Inc., except to the extent necessary to obtain informed consent from persons receiving the investigational product or in the event of a medical emergency.

This edition has been prepared in accordance with the Investigator's Brochure requirements of ICH E6(R3) Good Clinical Practice. It summarises the quality, nonclinical, and clinical information relevant to the clinical investigation of TILA-278 — drawing on the data that populate Common Technical Document Modules 3, 4, and 5 — and integrates results from the completed Phase 2b induction study TILA278-201.

Table of Contents

1. Summary
2. Introduction
3. Physical, Chemical, and Pharmaceutical Properties and Formulation
4. Nonclinical Studies
5. Effects in Humans
6. Summary of Data and Guidance for the Investigator
7. References

Abbreviations

ADA, anti-drug antibody; ANCOVA, analysis of covariance; CHO, Chinese hamster ovary; CMH, Cochran–Mantel–Haenszel; CTD, Common Technical Document; DR3, death receptor 3 (TNFRSF25); FAS, Full Analysis Set; Fc, fragment crystallisable; IB, Investigator's Brochure; ICH, International Council for Harmonisation; IgG1, immunoglobulin G1; IL-10RB, IL-10 receptor subunit beta; IL-22, interleukin-22; IL-22RA1, IL-22 receptor subunit alpha 1; ISR, injection-site reaction; LS, least squares; mAb, monoclonal antibody; NOAEL, no-observed-adverse-effect level; PFS, prefilled syringe; PK, pharmacokinetics; SAE, serious adverse event; SC, subcutaneous; SEC, size-exclusion chromatography; SPR, surface plasmon resonance; STAT3, signal transducer and activator of transcription 3; TEAE, treatment-emergent adverse event; TL1A, TNF-like ligand 1A; TMDD, target-mediated drug disposition; TNFSF15, TNF superfamily member 15; UC, ulcerative colitis; URTI, upper respiratory tract infection.

1. Summary

TILA-278 is a recombinant, humanized immunoglobulin G1 (IgG1) bispecific monoclonal antibody in development by Virtual Biopharma Inc. for the treatment of moderate-to-severe ulcerative colitis (UC). The molecule engages two complementary pathways of intestinal immunopathology through independent antigen-binding arms:

• Anti-TL1A (TNFSF15) antagonist arm — neutralises TL1A signalling through death receptor 3 (DR3), dampening TH1/TH17-driven mucosal inflammation and attenuating the pro-fibrotic signalling implicated in intestinal fibrosis; and
• IL-22 receptor agonist arm — engages the IL-22RA1/IL-10RB heterodimer on intestinal epithelial cells to promote epithelial regeneration, antimicrobial-peptide and mucin production, and mucosal-barrier repair.

The design intent is a single agent that couples anti-inflammatory activity with active mucosal healing — addressing both the inflammatory drive and the epithelial repair deficit that characterise UC. TILA-278 is administered by subcutaneous (SC) injection using a single-use prefilled syringe/autoinjector.

Nonclinical pharmacology in disease models (conducted with a species-appropriate surrogate/knock-in system, as the human-specific target profile renders conventional rodents pharmacologically non-relevant) demonstrated dose-dependent reductions in colonic inflammation together with histological evidence of epithelial restitution. Repeat-dose SC toxicology in the cynomolgus monkey — the pharmacologically relevant species — established an acceptable safety margin with no target-organ toxicity of concern. Consistent with ICH S6(R1), genotoxicity and carcinogenicity studies are not warranted for this modality.

In the pivotal Phase 2b induction study TILA278-201 (900 subjects randomised 1:1:1 to TILA-278 High, TILA-278 Low, or placebo), TILA-278 met the primary endpoint with a large, dose-ordered treatment effect. Week 12 clinical remission (modified Mayo score ≤ 2, with no individual subscore > 1) was achieved by 37.3% of High-dose subjects and 16.2% of Low-dose subjects versus 0.7% on placebo (both p < 0.0001). The least-squares (LS) mean reduction from baseline in modified Mayo score relative to placebo was −2.36 (High) and −1.77 (Low), both p < 0.0001. TILA-278 was generally well tolerated; there was no dose-dependent safety signal, and the principal drug-attributable finding was mild-to-moderate injection-site reactions, more frequent on active SC treatment than on placebo.

Overall, the benefit-risk profile of TILA-278 supports continued clinical development in moderate-to-severe UC. Guidance for investigators — including recommended dosing, identified and potential risks, and their management — is provided in Section 6.

2. Introduction

Ulcerative colitis is a chronic, relapsing inflammatory disorder of the colonic mucosa characterised by immune dysregulation, epithelial barrier failure, and incomplete mucosal healing. Despite the availability of anti-TNF agents, anti-integrins, anti-IL-12/23 antibodies, and Janus kinase inhibitors, a substantial proportion of patients fail to achieve or maintain remission, and endoscopic/histologic mucosal healing remains difficult to attain. There is a continued need for therapies that simultaneously suppress the inflammatory drive and actively restore the epithelial barrier.

TILA-278 was designed to meet this need through a single bispecific antibody:

• TL1A (TNFSF15) is a member of the TNF superfamily that is upregulated in inflamed UC mucosa and amplifies TH1 and TH17 effector responses through DR3; it has been genetically and mechanistically linked to inflammatory bowel disease and to intestinal fibrostenosis. Antagonism is expected to reduce inflammatory cytokine output and pro-fibrotic remodelling.
• IL-22 is a member of the IL-10 cytokine family that acts selectively on epithelial cells through the IL-22RA1/IL-10RB receptor complex, signalling via STAT3 to drive proliferation, mucus and antimicrobial-peptide production, and barrier repair. Agonism of the IL-22 receptor is expected to accelerate mucosal healing.

By combining TL1A antagonism with IL-22 receptor agonism in one molecule, TILA-278 is intended to deliver complementary and potentially synergistic effects — inflammation control plus regenerative mucosal healing — with the convenience and exposure profile of a subcutaneously administered monoclonal antibody.

The clinical development programme is sponsored by Virtual Biopharma Inc. The completed pivotal study, TILA278-201 (a Phase 2b, randomised, double-blind, placebo-controlled induction study), is the primary source of human efficacy and safety data in this edition. The proposed indication is induction of clinical remission in adults with moderate-to-severe active UC.

3. Physical, Chemical, and Pharmaceutical Properties and Formulation

3.1 Nomenclature and General Description

3.2 Drug Substance

The drug substance is a recombinant humanized IgG1 bispecific antibody produced by fed-batch culture of a stably transfected CHO cell line. Downstream processing comprises Protein-A affinity capture, followed by orthogonal polishing chromatography steps and a dedicated viral clearance train (low-pH viral inactivation and viral-retentive filtration) to assure viral safety.

The drug substance is characterised using a panel of orthogonal, phase-appropriate methods:

• Identity — peptide mapping, intact and reduced mass analysis, and confirmation of correct bispecific heterodimer assembly.
• Purity / impurities — size-variant analysis for aggregates and fragments (SEC, CE-SDS), charge-variant analysis (icIEF/IEX), and product-related species including mispaired/homodimer content, as well as process-related impurities (host-cell protein, residual DNA, residual Protein-A).
• Glycosylation — released-glycan profiling of the Fc N-glycans (afucosylation, high-mannose, galactosylation, sialylation).
• Potency (dual bioactivity) — a TL1A neutralisation assay confirming inhibition of TL1A/DR3 signalling, and an IL-22 receptor agonism cell-based reporter assay confirming STAT3-dependent activity; both arms are release-tested to demonstrate the intended dual mechanism.

Key biophysical and potency attributes are summarised below.

3.3 Drug Product and Formulation

The drug product is a sterile, preservative-free solution for subcutaneous injection, presented in a single-use prefilled syringe (PFS) and a prefilled autoinjector configuration for patient/caregiver administration.

The clinical dose strengths evaluated in Study TILA278-201 correspond to a Low and a High SC dose level (see Section 6.1), supplied as the appropriate device presentation. The product is stored refrigerated (2–8 °C), protected from light, and must not be frozen or shaken; in-use stability at room temperature supports handling prior to injection. The appearance is a clear to slightly opalescent, colourless to pale-yellow solution.

4. Nonclinical Studies

The nonclinical programme was designed in accordance with ICH S6(R1) for biotechnology-derived pharmaceuticals. Because both target epitopes are human-specific, conventional rodent species are not pharmacologically relevant; accordingly, pharmacodynamic activity was characterised in disease models using a species-appropriate surrogate antibody / knock-in system, and pivotal toxicology was conducted in the cynomolgus monkey, in which target binding and pharmacology are conserved.

4.1 Nonclinical Pharmacology

Primary pharmacodynamics. In vitro, TILA-278 demonstrated potent, dual, and simultaneous activity: neutralisation of TL1A-induced DR3 signalling and pro-inflammatory cytokine release, together with concentration-dependent agonism of the IL-22 receptor as measured by STAT3 phosphorylation and the induction of epithelial antimicrobial peptides and mucins. Dual engagement was confirmed on cells co-expressing the relevant targets.

In vivo, in established models of colitis (e.g., DSS-induced and T-cell transfer colitis) evaluated with the surrogate/knock-in system, treatment produced dose-dependent reductions in disease activity index, colon weight/length ratio, and histological inflammation scores, accompanied by histological evidence of epithelial regeneration and restored crypt architecture. The combination of TL1A antagonism and IL-22 receptor agonism yielded greater mucosal healing than either mechanism alone in head-to-head model arms, supporting the therapeutic rationale for the bispecific design.

Secondary and safety pharmacology. Safety pharmacology endpoints (cardiovascular, respiratory, and central nervous system) were integrated into the repeat-dose cynomolgus toxicology studies per ICH S6(R1); no adverse effects on these organ systems were observed. A tissue cross-reactivity study using a full human tissue panel showed binding consistent with the known distribution of the targets, with no unexpected off-target binding.

4.2 Pharmacokinetics and Product Metabolism in Animals

Following SC administration in cynomolgus monkeys, TILA-278 exhibited pharmacokinetics typical of an IgG1 monoclonal antibody, with a component of target-mediated drug disposition (TMDD) at lower doses and more linear kinetics at higher, target-saturating doses. As a monoclonal antibody, TILA-278 is expected to be eliminated by intracellular catabolism to peptides and amino acids rather than by hepatic cytochrome-P450 metabolism or renal excretion; classical drug-metabolism and drug-interaction studies are therefore not applicable.

Anti-drug antibodies were monitored in nonclinical studies and, where present, were consistent with the expected immunogenicity of a humanized antibody in a non-human species; they did not preclude interpretation of the toxicology data.

4.3 Toxicology

The pivotal toxicology programme consisted of repeat-dose SC studies in cynomolgus monkeys of up to 26 weeks' duration, incorporating toxicokinetics, safety pharmacology endpoints, and immunogenicity monitoring.

Findings were limited to expected, reversible injection-site reactions and exaggerated-pharmacology-related observations, without evidence of adverse target-organ toxicity; the no-observed-adverse-effect level (NOAEL) was the highest dose tested, providing an adequate exposure multiple over the anticipated clinical exposure. Consistent with ICH S6(R1), dedicated genotoxicity and carcinogenicity studies were not conducted, as they are not scientifically warranted for a monoclonal antibody. A theoretical consideration arising from the IL-22 receptor agonist arm — sustained epithelial proliferative signalling — was evaluated by histopathology in the chronic study, with no proliferative or neoplastic findings; this remains a monitored potential risk in the clinical setting (Section 6). Reproductive and developmental toxicology is being addressed in a phase-appropriate manner consistent with ICH S5(R3)/S6(R1) and the intended population.

5. Effects in Humans

5.1 Pharmacokinetics and Product Metabolism in Humans

Human pharmacokinetics are consistent with a subcutaneously administered IgG1 monoclonal antibody whose disposition is dominated by target-mediated drug disposition at lower concentrations, transitioning toward linear kinetics as target is saturated at higher doses. Absorption after SC injection is slow, with an estimated SC bioavailability of approximately 60% and a time to maximum concentration of several days; the terminal half-life supports the induction dosing interval used in Study TILA278-201.

As a monoclonal antibody, TILA-278 is not metabolised by cytochrome-P450 enzymes and is not renally cleared; it is catabolised to peptides and amino acids. A dedicated thorough-QT study was not conducted; consistent with the principles of ICH E14/S7B and with the modality (a large, target-specific antibody with no expected ion-channel interaction), a QT liability is not anticipated and a waiver rationale applies.

5.2 Immunogenicity

Anti-drug antibodies (ADA) were assessed using a tiered assay (screening, confirmatory, and titre determination, with neutralising-antibody characterisation), with pre-specified evaluation of any impact on pharmacokinetics, efficacy, and safety. Across the induction period, treatment-emergent ADA incidence was low and, where detected, was generally low-titre and transient, without a discernible impact on exposure, on the clinical response reported below, or on safety (including no association with hypersensitivity or injection-site reactions). Immunogenicity will continue to be monitored in longer-term studies.

5.3 Safety and Efficacy — Study TILA278-201

5.3.1 Study Design

Study TILA278-201 was a Phase 2b, randomised, double-blind, placebo-controlled, parallel-group, 12-week induction study in adults with moderate-to-severe active UC.

Analysis populations and methods. Efficacy was analysed on the Full Analysis Set (FAS), defined as all randomised subjects who received at least one dose of study treatment and had at least one post-baseline efficacy assessment (284/283/273 for High/Low/Placebo). The safety population comprised all subjects who received at least one dose of study treatment (299/300/301). The binary primary endpoint (Week 12 clinical remission) was analysed using a Cochran–Mantel–Haenszel test stratified by the randomisation factors; the continuous change from baseline in modified Mayo score was analysed by analysis of covariance (ANCOVA) with treatment and stratification factors and baseline score as covariates. Percentages for the binary endpoint are based on the number of evaluable subjects shown as the denominator.

5.3.2 Efficacy

The study met its primary endpoint, with a large, statistically significant, and clearly dose-ordered treatment effect on Week 12 clinical remission.

Primary endpoint — clinical remission at Week 12 (FAS):

Change in modified Mayo score at Week 12 (FAS; ANCOVA, LS-mean):

Both TILA-278 dose levels were superior to placebo on the primary remission endpoint and on the LS-mean reduction in modified Mayo score, with a consistent dose-response favouring the High dose. The low placebo remission rate together with High-dose remission of 37.3% represents a large absolute treatment effect in an induction population that included biologic-experienced patients.

5.3.3 Safety

TILA-278 was generally well tolerated over the 12-week induction period. A total of 599 subjects received TILA-278 (299 High, 300 Low) and 301 received placebo. There was no dose-dependent safety signal; the frequency of subjects with treatment-emergent adverse events (TEAEs) was not higher on the High dose than on the Low dose or placebo.

Overall safety summary (safety population; High / Low / Placebo):

All deaths (2 High, 1 Placebo) were assessed as unrelated to study treatment, with no pattern suggestive of a treatment relationship. SAEs were infrequent and were not more common on active treatment than on placebo (numerically higher on placebo). Discontinuations were most frequent on placebo and were driven predominantly by lack of efficacy (worsening UC), consistent with the placebo remission rate.

The most frequently reported adverse events across the study were nasopharyngitis, headache, worsening UC, anaemia, arthralgia, upper respiratory tract infection (URTI), injection-site reaction, and nausea. Two directional patterns are of note:

• Worsening UC was more frequent on placebo, consistent with untreated disease activity and the efficacy findings; and
• Injection-site reactions were more frequent on active SC treatment than on placebo and represent the principal drug-attributable finding.

The most frequently reported treatment-emergent adverse events over the induction period are summarised below.

Injection-site reactions were predominantly mild-to-moderate, self-limiting, and did not commonly lead to discontinuation. No new or unexpected mechanism-related safety concerns (including infection or proliferative findings) emerged over the induction period.

5.4 Marketing Experience

TILA-278 is an investigational product and is not approved or marketed in any country. No post-marketing experience is available.

6. Summary of Data and Guidance for the Investigator

6.1 Overall Benefit-Risk and Dosing Guidance

TILA-278 is a first-in-class humanized IgG1 bispecific antibody combining TL1A antagonism with IL-22 receptor agonism, intended to control inflammation while actively promoting mucosal healing in UC. Nonclinical data support the dual mechanism with an acceptable safety margin, and the Phase 2b induction study TILA278-201 demonstrated a large, dose-ordered, statistically significant effect on clinical remission with a favourable and well-characterised safety profile. The available data support a positive benefit-risk balance for continued clinical investigation in moderate-to-severe UC.

Recommended dosing (induction) for ongoing studies:

Given the superior remission rate and greater reduction in modified Mayo score without an accompanying increase in adverse events, the High dose is the preferred induction regimen. Investigators must administer TILA-278 in accordance with the current protocol. The product is for subcutaneous use only; rotate injection sites (abdomen, thigh, or upper arm) and avoid areas that are tender, bruised, erythematous, indurated, or affected by disease. Refer to the protocol and pharmacy manual for preparation, storage (2–8 °C, protected from light; do not freeze or shake), and handling.

6.2 Identified and Potential Risks, and Their Management

• Injection-site reactions (identified risk). The principal drug-attributable finding; generally mild-to-moderate and self-limiting. Management: site rotation and local supportive care; evaluate and manage persistent or severe reactions per protocol.
• Hypersensitivity reactions (potential risk). As with any therapeutic antibody, hypersensitivity (including systemic reactions) may occur. Administer where appropriate medical support is available; discontinue and treat if a serious hypersensitivity reaction occurs.
• Infections (potential risk, mechanism-based). Modulation of TH1/TH17 immunity via TL1A antagonism carries a theoretical infection risk. Screen and manage per protocol (including screening for latent infections such as tuberculosis, as applicable); do not initiate in the presence of a clinically significant active infection; interrupt treatment for serious infection and monitor. Nasopharyngitis and URTI were among the most common TEAEs but were balanced across arms.
• Epithelial proliferation (theoretical risk, mechanism-based). Sustained IL-22 receptor agonism drives epithelial proliferation; no proliferative or neoplastic signal was observed nonclinically or over the 12-week induction period, but this remains a monitored potential risk and should be assessed per protocol surveillance.
• Immunogenicity. ADA incidence was low with no observed impact on PK, efficacy, or safety; continue monitoring per protocol.
• Worsening UC / lack of efficacy. Worsening UC occurred more often on placebo; investigators should monitor disease activity and follow protocol criteria for rescue or discontinuation.
• Live vaccines. Avoid live/live-attenuated vaccines during treatment, consistent with the immunomodulatory mechanism and protocol requirements.

Investigators must report adverse events and serious adverse events in accordance with the protocol and applicable regulations. Any medical questions regarding TILA-278 should be directed to the Sponsor's medical monitor as specified in the protocol.

7. References

1. ICH Harmonised Guideline E6(R3): Good Clinical Practice — requirements for the Investigator's Brochure.
2. ICH Harmonised Guideline S6(R1): Preclinical Safety Evaluation of Biotechnology-Derived Pharmaceuticals.
3. ICH Harmonised Guidelines E14 and S7B: Clinical and nonclinical evaluation of QT/QTc interval prolongation and proarrhythmic potential.
4. ICH Harmonised Guideline M4: Organisation of the Common Technical Document.
5. Virtual Biopharma Inc. Clinical Study Report, Protocol TILA278-201 — A Phase 2b, Randomised, Double-blind, Placebo-controlled Induction Study of TILA-278 in Moderate-to-Severe Ulcerative Colitis.
6. Virtual Biopharma Inc. Nonclinical study reports: primary/secondary pharmacology, cynomolgus repeat-dose toxicology, tissue cross-reactivity, and toxicokinetics.
7. Virtual Biopharma Inc. CMC documentation: drug substance and drug product development and characterisation reports.