Module 2.3 — Quality Overall Summary (TILA-278)

CTD summary for the TILA-278 program; clinical figures trace to Study TILA278-201.

Change History

2.3 Introduction

This Quality Overall Summary (QOS) presents a summary of the chemistry, manufacturing, and controls (CMC) information provided in Module 3 for TILA-278 drug substance and drug product. It has been prepared in accordance with ICH M4Q(R1) and does not introduce data or justifications beyond those contained in Module 3; cross-references to the corresponding Module 3 sections are provided throughout.

TILA-278 is a bispecific antibody engineered to combine two complementary mechanisms relevant to UC: antagonism of TL1A (TNFSF15) to dampen TH1/TH17-driven inflammation and intestinal fibrosis, and agonism of the IL-22 receptor to drive intestinal epithelial regeneration and mucosal-barrier repair. The drug product evaluated in the pivotal Phase 2b induction study (Protocol TILA278-201) was manufactured by the clinical process; its comparability to the current commercial-representative process described in this dossier is established in accordance with ICH Q5E (Section 2.3.S.2.6). The molecule is a bispecific IgG1 of approximately 148 kDa bearing a single conserved N-glycosylation site per heavy chain in the CH2 domain (Asn297 numbering).

The overall control strategy follows an enhanced (ICH Q8(R2)/Q11) development approach. A Quality Target Product Profile (QTPP) was defined, critical quality attributes (CQAs) were identified through quality risk management (ICH Q9), and control of CQAs is distributed across the manufacturing process, in-process controls, and release/stability specifications (ICH Q6B). Viral safety is assured in accordance with ICH Q5A(R2), and cell-substrate characterisation follows ICH Q5D.

2.3.QTPP Quality Target Product Profile and Critical Quality Attributes

QTPP

The QTPP (summarised from 3.2.P.2.1) establishes the prospective quality characteristics required to assure the clinical performance, safety, and stability of TILA-278.

CQA identification and risk ranking

CQAs were identified by assessing the potential impact of each quality attribute on safety and efficacy (potency, PK, immunogenicity), using prior knowledge of IgG1 antibodies, bispecific-format-specific considerations, and nonclinical/clinical experience with TILA-278 (3.2.P.2.3). Attributes are ranked High / Medium / Low based on severity and uncertainty.

2.3.S Drug Substance (TILA-278, Virtual Biopharma Inc.)

2.3.S.1 General Information

2.3.S.1.1 Nomenclature. Development name TILA-278; proposed INN tilarukimig; chemical/biological class: recombinant humanized IgG1 bispecific monoclonal antibody, kappa light chains (3.2.S.1.1).

2.3.S.1.2 Structure. TILA-278 is an asymmetric, heterodimeric full-length IgG1 antibody comprising two distinct heavy chains and two distinct light chains. Correct heavy-chain heterodimerisation is enforced by complementary knobs-into-holes (KiH) mutations in the CH3 domains, and cognate light-chain pairing on the anti-TL1A arm is directed by a CrossMab CH1–CL domain crossover. The Fc bears the native IgG1 N-linked glycosylation site (CH2, Asn297). Arm A confers TL1A (TNFSF15) neutralisation; arm B confers IL-22 receptor agonism. The disulfide framework, KiH mutation positions, and CrossMab crossover are described in 3.2.S.1.2, together with the theoretical mass (approximately 148 kDa) and the predicted amino-acid sequences of all four chains.

2.3.S.1.3 General Properties. TILA-278 is a colourless to slightly yellow protein solution. Key physicochemical properties (isoelectric point approximately 7.9; extinction coefficient A280 0.1% = 1.55 mL·mg⁻¹·cm⁻¹; well-defined higher-order structure by CD/DSC) and biological properties (dual, arm-specific binding and function) are summarised in 3.2.S.1.3. Solubility supports the high-concentration (150 mg/mL) SC formulation.

2.3.S.2 Manufacture

2.3.S.2.1 Manufacturer(s). The drug substance is manufactured, tested, and released at the designated drug-substance manufacturing site. Responsibilities of all sites involved in manufacture and testing are listed in 3.2.S.2.1.

2.3.S.2.2 Description of Manufacturing Process and Process Controls. The drug substance is produced by fed-batch mammalian cell culture followed by a platform purification train. A single vial of the Working Cell Bank (WCB) is thawed and expanded through seed-train and inoculum steps into a production bioreactor operated in fed-batch mode at nominal 2,000 L scale. Cell culture is controlled for temperature, pH, dissolved oxygen, and feed strategy; culture duration and harvest criteria are defined by in-process controls.

The harvest is clarified by continuous centrifugation and depth filtration, then processed through the following purification sequence:

1. Protein A affinity chromatography (capture; removes the majority of HCP, DNA, and media components).
2. Low-pH viral inactivation (hold at defined pH and time; dedicated viral clearance step).
3. Cation-exchange (CEX) chromatography (bind-elute polishing; resolves charge variants and reduces product-related species including homodimer, half-antibody, and mispaired forms — a bispecific-critical separation).
4. Anion-exchange (AEX) chromatography (flow-through polishing; clears residual HCP, DNA, endotoxin, and viruses).
5. Small-virus nanofiltration (20 nm; dedicated viral clearance).
6. Ultrafiltration/diafiltration (UF/DF) (concentration and buffer exchange into the drug-substance formulation buffer).
7. Formulation, bioburden-reduction filtration, and filling into drug-substance containers, followed by frozen storage.

Process parameters, their set-points and ranges, and in-process controls/acceptance criteria for each unit operation are provided in 3.2.S.2.2. Critical process parameters (CPPs) are distinguished from key/non-critical parameters based on impact on CQAs.

2.3.S.2.3 Control of Materials. Raw materials (media, feeds, buffers, chromatography resins, filters) are controlled to defined specifications; compendial materials meet Ph.Eur./USP requirements. Materials of biological origin are qualified for adventitious-agent safety, and the manufacturing process is animal-component-free where feasible (3.2.S.2.3, cross-referenced to 3.2.A.2).

Cell substrate / control of cell bank. A two-tiered Master Cell Bank (MCB)/Working Cell Bank (WCB) system was established from a clonally derived CHO cell line (3.2.S.2.3). MCB and WCB were characterised per ICH Q5A(R2) and Q5D for identity, viability, plasmid/expression-construct integrity, and adventitious agents (sterility, mycoplasma, in-vitro and in-vivo virus assays, transmission electron microscopy, retrovirus quantitation by TEM/infectivity). Genetic stability was demonstrated at and beyond the limit of in-vitro cell age used for production.

2.3.S.2.4 Controls of Critical Steps and Intermediates. Critical in-process controls (e.g., bioreactor harvest criteria, low-pH inactivation pH/time, chromatography pool criteria, viral-filtration integrity, UF/DF endpoint) with acceptance criteria are tabulated in 3.2.S.2.4. Hold times and storage conditions for process intermediates are qualified.

2.3.S.2.5 Process Validation and/or Evaluation. The manufacturing process was evaluated using a lifecycle approach (ICH Q8(R2)/Q9/Q10/Q11). Process characterisation studies (scale-down models, DoE) defined the design space and classified parameters; the commercial-scale process is being confirmed by process performance qualification (PPQ) as a campaign of ≥3 consecutive batches. Chromatography resin/membrane lifetime, hold times, and shipping are validated or under validation as summarised in 3.2.S.2.5.

2.3.S.2.6 Manufacturing Process Development. The clinical manufacturing history, process changes, and comparability across process versions are summarised in 3.2.S.2.6. Comparability between the material used in TILA278-201 and the commercial-representative process was assessed per ICH Q5E using release testing, extended physicochemical/biological characterisation, and stability, and demonstrated that the products are comparable.

2.3.S.3 Characterisation

2.3.S.3.1 Elucidation of Structure and Other Characteristics. An orthogonal panel established the primary structure, higher-order structure, post-translational modifications, and bispecific-specific attributes (3.2.S.3.1):

• Primary structure / identity: intact and reduced/deglycosylated mass by LC-MS confirming the expected heterodimer and individual chain masses; full-coverage tryptic and complementary peptide mapping confirming the amino-acid sequence and disulfide connectivity; N/C-terminal analysis (N-terminal pyroglutamate, C-terminal lysine variants).
• Bispecific integrity / chain pairing: determination of correctly paired heterodimer content and quantitation of homodimers, half-antibody, and light-chain-mispaired species by intact/subunit LC-MS, non-reduced CE-SDS, HIC, and dual-binding (bridging) assays confirming co-localisation of both binding functions on a single molecule.
• Higher-order structure: far-/near-UV CD, DSC (thermal transitions/Tm), and FTIR confirming consistent conformation.
• Glycosylation: released-glycan mapping (HILIC-FLR/MS) quantifying afucosylation, high-mannose, galactosylation, and sialylation.
• Charge heterogeneity: iCIEF/CEX resolving acidic and basic variants; peptide-map localisation of deamidation, isomerisation, and oxidation hotspots.
• Biological characterisation: arm-specific binding affinities (SPR/BLI) for TL1A and the IL-22 receptor; cell-based confirmation of TL1A neutralisation and IL-22R agonism; Fc/FcRn and FcγR binding to contextualise effector and PK-relevant functions.

2.3.S.3.2 Impurities. Product-related substances/impurities (charge variants, glycoforms, aggregates, fragments, product-related bispecific-format species) and process-related impurities (HCP, residual DNA, Protein A, media/buffer components) are described and, where appropriate, controlled by specification or cleared and demonstrated by the process (3.2.S.3.2). Levels observed are consistent with those qualified in nonclinical and clinical studies.

2.3.S.4 Control of Drug Substance

2.3.S.4.1 Specification (release). The drug-substance specification (ICH Q6B) is summarised below; full procedures and limits are in 3.2.S.4.1.

2.3.S.4.2 Analytical Procedures. Procedures are summarised in 3.2.S.4.2. Potency is measured by two orthogonal cell-based bioassays reflecting each mechanism (TL1A neutralisation and IL-22R agonism).

2.3.S.4.3 Validation of Analytical Procedures. Compendial methods are verified; non-compendial methods (SE-HPLC, CE-SDS, iCIEF, both potency assays, HCP, DNA, Protein A, LC-MS identity) are validated per ICH Q2(R2)/Q14 for the relevant characteristics (specificity, accuracy, precision, linearity, range, quantitation limits) (3.2.S.4.3).

2.3.S.4.4 Batch Analyses. Release data for representative clinical, engineering, and PPQ drug-substance batches are provided in 3.2.S.4.4 and demonstrate that the process consistently meets specification. Representative results:

2.3.S.4.5 Justification of Specification. Acceptance criteria are justified (3.2.S.4.5) by manufacturing capability, batch history, stability behaviour, method capability, and clinical/nonclinical qualification. Potency ranges bracket the material shown to be safe and efficacious in TILA278-201.

2.3.S.5 Reference Standards or Materials

A two-tiered reference standard system (primary and working standards) traceable to well-characterised clinical material is described in 3.2.S.5, including qualification and requalification protocols.

2.3.S.6 Container Closure System

The drug substance is stored frozen in single-use sterile bioprocess bags qualified for extractables/leachables, integrity, and freeze/thaw at the intended storage temperature (3.2.S.6).

2.3.S.7 Stability

Stability studies follow ICH Q5C/Q1A(R2). The drug substance is stored frozen at ≤ –40 °C. Long-term, accelerated, stress, and freeze/thaw data support the proposed re-test/hold period.

A proposed frozen storage period of ≥ 36 months at ≤ –40 °C is supported (3.2.S.7). The primary stability-indicating attributes are HMW (SE-HPLC), charge variants (iCIEF), fragmentation (CE-SDS), and both potencies.

2.3.P Drug Product (TILA-278 150 mg/mL solution for injection, PFS/AI)

2.3.P.1 Description and Composition

TILA-278 drug product is a sterile, preservative-free, colourless to slightly yellow aqueous solution supplied in a single-use 1 mL-long prefilled syringe with a staked needle; an autoinjector variant is assembled from the identical primary container. Each syringe delivers 1.0 mL containing 150 mg of TILA-278 (3.2.P.1).

No overage is included. The formulation is isotonic-range and compatible with SC administration.

2.3.P.2 Pharmaceutical Development

Formulation development (3.2.P.2) selected a histidine-buffered, sucrose-stabilised, polysorbate-80-containing formulation at pH ~5.5 to maximise conformational and colloidal stability of the bispecific at high concentration while controlling aggregation, fragmentation, and particle formation. Polysorbate 80 level and pH were optimised against interfacial and freeze/thaw stress. Viscosity, injection force, and glide were characterised to confirm suitability for SC self-administration with the PFS/AI device (device/human-factors information cross-referenced to 3.2.R and Module 5 as applicable). The manufacturing process was designed to protect CQAs (aggregates, particles, potency) — notably control of mixing, filtration, filling shear, and holding. The QTPP and CQA analysis in Section 2.3.QTPP was the basis for the drug-product control strategy. Overages, compatibility with in-line filters and contact materials, and photostability (ICH Q1B) are addressed in 3.2.P.2.

2.3.P.3 Manufacture

2.3.P.3.1 Manufacturer(s). Drug-product compounding, fill/finish, device assembly, packaging, and release are performed at (3.2.P.3.1).

2.3.P.3.2 Batch Formula. The batch formula for the commercial batch scale is provided in 3.2.P.3.2.

2.3.P.3.3 Description of Manufacturing Process and Process Controls. The process comprises: thaw and pooling of drug substance; compounding/dilution to target with formulation buffer and polysorbate adjustment; bioburden-reduction filtration; sterile filtration (redundant 0.22 µm filters with pre-/post-use integrity testing); aseptic filling into sterilised PFS barrels; plunger placement; 100% automated and/or statistical in-process checks (fill weight/volume, plunger placement); inspection; and assembly of the AI variant. It is a standard aseptic fill/finish process with no terminal sterilisation. In-process controls and their acceptance criteria are in 3.2.P.3.3.

2.3.P.3.4 Controls of Critical Steps and Intermediates. Critical controls (sterile-filter integrity, bioburden and endotoxin before sterile filtration, fill volume, holding times) with acceptance criteria are summarised in 3.2.P.3.4.

2.3.P.3.5 Process Validation and/or Evaluation. Aseptic processing is validated by media fills; sterile filtration, mixing, holding times, and filling are validated; PPQ confirms reproducible drug-product quality (3.2.P.3.5).

2.3.P.4 Control of Excipients

Excipients (L-histidine/histidine HCl, sucrose, polysorbate 80, water for injection) are compendial (Ph.Eur./USP-NF) and controlled to compendial specifications; no excipient is of human/animal origin, and no novel excipient is used (3.2.P.4). Control of polysorbate 80 quality (e.g., peroxide/oxidative markers) is addressed given its relevance to protein stability.

2.3.P.5 Control of Drug Product

2.3.P.5.1 Specification (release/shelf life). The drug-product specification (ICH Q6B) is summarised below; full detail in 3.2.P.5.1.

2.3.P.5.2–5.3 Analytical Procedures and Validation. Product-quality methods are shared with, or bridged to, the drug-substance methods and validated per ICH Q2(R2)/Q14 (3.2.P.5.2/5.3).

2.3.P.5.4 Batch Analyses. Release results for clinical, engineering, and PPQ drug-product batches — including the batches used in TILA278-201 — meet specification and demonstrate consistency (3.2.P.5.4):

2.3.P.5.5 Characterisation of Impurities. Product-related impurities in the drug product are consistent with those in the drug substance; no new degradants of concern arise on storage (3.2.P.5.5).

2.3.P.5.6 Justification of Specification. Limits are justified by batch history, stability, method capability, compendial requirements, and clinical qualification of the batches used in TILA278-201 (3.2.P.5.6).

2.3.P.6 Reference Standards or Materials

The drug-product reference standard is common with the drug-substance reference standard system described in 2.3.S.5 / 3.2.P.6.

2.3.P.7 Container Closure System

The primary container is a 1 mL-long glass PFS with a staked stainless-steel needle, a fluoropolymer-coated elastomeric plunger, and a rigid needle shield; the AI variant houses the identical PFS (3.2.P.7). Container-closure integrity, functional/device performance (break-loose and glide force, dose accuracy), and extractables/leachables have been evaluated and shown to be acceptable.

2.3.P.8 Stability

Stability studies follow ICH Q5C/Q1A(R2)/Q1B, with a photostability evaluation (Q1B). The recommended storage is 2–8 °C, protected from light, in the original carton.

A shelf life of 24 months at 2–8 °C protected from light is proposed, together with a defined room-temperature excursion allowance to support patient self-administration (3.2.P.8). Stability-indicating attributes are HMW (SE-HPLC), charge variants (iCIEF), sub-visible particles, and both potencies. Statistical trend analysis supports the proposed shelf life.

2.3.A Appendices

2.3.A.1 Facilities and Equipment. Manufacturing facilities, equipment, and multi-product/segregation and cleaning strategies are described in 3.2.A.1 .

2.3.A.2 Adventitious Agents Safety Evaluation. Viral safety is assured per ICH Q5A(R2) through a three-pronged strategy: (i) control/testing of the cell bank and raw materials; (ii) testing of unprocessed bulk for adventitious and endogenous agents; and (iii) demonstrated viral clearance across dedicated and contributing steps (low-pH inactivation, AEX, 20 nm nanofiltration), yielding a substantial cumulative log-reduction margin over the estimated endogenous retrovirus-like particle load. TSE/BSE risk is minimised by avoidance of ruminant-derived materials (3.2.A.2).

2.3.A.3 Novel Excipients. None; all excipients are compendial and well established (3.2.A.3).

2.3.R Regional Information

Region-specific information (e.g., executed batch records, comparability protocols, medical-device/combination-product and human-factors documentation for the PFS/AI, and process-validation lifecycle commitments) is provided in Module 3.2.R as applicable to each target region.

Summary and Conclusion (Summary of Module 3)

TILA-278 is a recombinant humanized IgG1 bispecific antibody (anti-TL1A antagonist arm and IL-22R agonist arm) produced in CHO cells and formulated as a 150 mg/mL sterile SC solution in a single-use PFS/AI. The drug substance is manufactured by a platform fed-batch culture and Protein A/CEX/AEX purification train incorporating dedicated viral-clearance steps; the drug product is produced by a conventional aseptic fill/finish and device-assembly process. A QTPP-driven, risk-based control strategy (ICH Q8(R2)/Q9/Q11) links the identified CQAs — including the bispecific-format-specific attributes (correct chain pairing / heterodimer content), aggregates, both potencies, glycosylation, charge heterogeneity, and process-related/safety impurities — to controls across the process and the release/stability specifications (ICH Q6B). Characterisation confirms the intended structure and dual function; batch analyses demonstrate a consistent process; stability data support the proposed drug-substance frozen storage period and a 24-month refrigerated drug-product shelf life. Comparability (ICH Q5E) confirms that commercial-representative material is comparable to the material evaluated in the pivotal induction study (Protocol TILA278-201). The information summarised here and detailed in Module 3 supports the quality, safety, and consistency of TILA-278 for its proposed use in moderate-to-severe ulcerative colitis.