📚 Part of the TILA-278 Regulatory Dossier — Reader's Guide. This article shows the live document; edits to the source appear here automatically.

---

End-of-Phase-2 Briefing Book (TILA-278)

Document ID: MTG-EOP2
Version: 1.0
Change History: 1.0 — Initial issue.
Standard(s): FDA meetings

End-of-Phase-2 Meeting Briefing Book — TILA-278

End-of-Phase-2 briefing for TILA-278: the Phase 2 results, the proposed pivotal design and endpoints for TILA278-201, statistical and estimand strategy, and the safety-database plan, with questions to align the registration program.

1. Purpose of the Meeting and Requested Agreements

This briefing book supports a Type B End-of-Phase-2 (EOP2) meeting between Virtual Biopharma Inc. and the U.S. Food and Drug Administration (FDA) to align on the confirmatory registration program for TILA-278 in adults with moderate-to-severe ulcerative colitis (UC). TILA-278 is a recombinant humanized immunoglobulin G1 (IgG1) bispecific monoclonal antibody that couples anti-TL1A (TNFSF15) antagonism with interleukin-22 receptor (IL-22R) agonism in a single molecule, administered subcutaneously (SC).

The Phase 2b dose-finding induction study (Protocol TILA278-201) is complete. Both active dose levels met the primary endpoint of clinical remission at Week 12 with a clear, dose-ordered response and no dose-dependent safety signal, establishing proof of concept and supporting selection of the High dose for confirmatory evaluation. The purpose of this meeting is to obtain the Agency's agreement on the design and adequacy of the proposed Phase 3 program to establish substantial evidence of effectiveness and to support a Biologics License Application (BLA) under section 351(a) of the Public Health Service Act, reviewed under 21 CFR Part 601.

Specifically, the Sponsor seeks the Agency's concurrence on the following:

• The adequacy of two replicate double-blind, placebo-controlled induction studies (TILA278-301 and TILA278-302) plus a randomized-withdrawal maintenance study (TILA278-303) to constitute the adequate and well-controlled evidence for both an induction and a maintenance claim.
• Selection of the Phase 2b High dose as the Phase 3 induction dose and the proposed maintenance interval.
• The primary and key secondary endpoints and their operational definitions for induction and maintenance.
• The estimand framework, intercurrent-event handling, and multiplicity control.
• The size and duration of the clinical safety database relative to ICH E1.
• The immunogenicity assessment strategy.
• The nonclinical package supporting Phase 3 and registration, including the position that standalone genotoxicity, carcinogenicity, and thorough-QT studies are not warranted for this modality.
• The Chemistry, Manufacturing, and Controls (CMC) comparability and control strategy and the proposed drug-product presentations.
• The pediatric plan and the proposed expedited-program strategy.

2. Background, Unmet Medical Need, and Regulatory History

UC is a chronic, relapsing immune-mediated inflammatory disease of the colonic mucosa characterized by rectal bleeding, urgency, and diarrhea, with a lifelong risk of colectomy, dysplasia, and disability. Despite anti-TNF agents, anti-integrin therapy, IL-12/23 inhibitors, sphingosine-1-phosphate modulators, and JAK inhibitors, a substantial proportion of patients with moderate-to-severe disease fail to achieve or sustain corticosteroid-free remission, and response rates diminish in biologic-experienced patients. Endoscopic and, increasingly, histologic mucosal healing are recognized as principal determinants of durable remission and reduced colectomy risk, yet remain difficult to attain with agents that suppress inflammation without directly promoting epithelial repair. A persistent unmet need therefore exists for therapies that combine potent control of inflammatory drivers with active restoration of the mucosal barrier.

TILA-278 was designed to address both arms of this pathophysiology through a single molecule. The development program to date comprises a first-in-human single- and multiple-ascending-dose SC study characterizing safety, tolerability, pharmacokinetics (PK), and immunogenicity, followed by the completed Phase 2b induction study TILA278-201. A Pre-IND interaction supported the first-in-human program, and this EOP2 interaction is intended to align the confirmatory design. A parallel EMA Scientific Advice procedure is being pursued, with the option of an FDA/EMA parallel scientific-advice track. Because moderate-to-severe UC is a serious, chronic condition with meaningful unmet need in the advanced-therapy-experienced population, the Sponsor intends to request Fast Track designation to enable a rolling BLA review (Section 13).

3. Product Description, Mechanism of Action, and Manufacturing Overview

TILA-278 is a recombinant humanized IgG1 bispecific monoclonal antibody expressed in a Chinese hamster ovary (CHO) cell line and formulated as a sterile solution for SC injection. The molecule engages two complementary, non-redundant pathways:

• Anti-TL1A (TNFSF15) antagonist arm. Neutralizes TL1A signaling through death receptor 3 (DR3), dampening TH1/TH17-driven mucosal inflammation and attenuating the pro-fibrotic signaling associated with intestinal fibrosis and a stricturing disease course.
• IL-22 receptor (IL-22R) agonist arm. Engages the IL-22RA1/IL-10RB receptor complex on intestinal epithelial cells to drive epithelial regeneration, mucin and antimicrobial-peptide production, and mucosal-barrier repair.

The dual mechanism couples an anti-inflammatory effect (TL1A antagonism) with an active mucosal-healing effect (IL-22R agonism), addressing both the inflammatory and barrier-dysfunction components of UC that mono-mechanistic biologics do not simultaneously target. The therapeutic hypothesis is that this combination delivers deeper, more durable remission — including endoscopic and histologic healing — than anti-inflammatory blockade alone.

The drug substance is manufactured by fed-batch CHO cell culture followed by a purification train comprising Protein A affinity capture, polishing chromatography, dedicated viral-clearance steps (low-pH viral inactivation and viral filtration), and ultrafiltration/diafiltration. Given the bispecific format, the control strategy explicitly manages heterodimer assembly fidelity and product-related variants (aggregates/high-molecular-weight species, half-antibody and mispaired species, charge variants, fragments, and glycoforms). The molecule is characterized for identity, higher-order structure, purity and product-/process-related impurities, and for both functional activities — anti-TL1A neutralization and IL-22R agonism — by orthogonal potency assays, with Fc-mediated effector function characterized as part of the functional profile. Development is consistent with ICH Q5A(R2) (viral safety), Q5C (stability), Q6B (specifications), and Q8–Q11. The drug product is presented as a single-use prefilled syringe and, for maintenance self-administration, an autoinjector (Section 12).

4. Summary of the Nonclinical Program

The nonclinical program follows ICH S6(R1) for biotechnology-derived pharmaceuticals. Because TILA-278 is specific for human TL1A and human IL-22R, conventional rodents are not pharmacologically relevant; the cynomolgus monkey is confirmed as the sole pharmacologically relevant species on the basis of demonstrated cross-reactivity to both targets and is used for repeat-dose SC toxicology and toxicokinetics. Disease-model pharmacology is addressed through a surrogate/knock-in approach. A tissue cross-reactivity assessment using a full panel of human and cynomolgus tissues supports the absence of unexpected off-target binding, and safety-pharmacology endpoints (cardiovascular, respiratory, and central nervous system parameters) are integrated into the repeat-dose toxicology studies rather than conducted as a standalone core battery, consistent with ICH S6(R1) and S7A for a monoclonal antibody.

Reproductive and developmental toxicity is evaluated by an enhanced pre- and postnatal development (ePPND) study in the cynomolgus monkey, accounting for FcRn-mediated placental transfer of IgG in late gestation. Consistent with ICH S6(R1), standalone genotoxicity studies and 2-year rodent carcinogenicity studies are not warranted for a monoclonal antibody. Given the proliferative pharmacology intrinsic to IL-22R agonism, carcinogenic potential is addressed through a weight-of-evidence assessment supplemented by evaluation of proliferative and pre-neoplastic endpoints, with particular attention to gastrointestinal epithelium, in the chronic cynomolgus toxicology study. In vitro hERG assessment and a thorough-QT study are not warranted, as there is no expectation of direct ion-channel interaction for an antibody of this class; the ICH E14/S7B waiver rationale for large-molecule biotherapeutics applies. The Sponsor seeks the Agency's confirmation that this nonclinical package is adequate to support the Phase 3 program and registration (Question 7 and Question 8).

5. Summary of Clinical Pharmacology, PK, and Immunogenicity

Following SC administration, TILA-278 exhibited exposure consistent with an IgG bispecific antibody, with dose-ordered systemic exposure across the Low and High dose levels supporting the evaluated induction regimen (SC dosing at Weeks 0, 2, 4, and 8) through Week 12. PK is expected to be governed by target-mediated drug disposition (TMDD), with characteristic non-linearity at lower concentrations as target-mediated clearance saturates, transitioning to linear catabolic elimination at higher concentrations. The observed separation in clinical response between the two active dose levels is consistent with an exposure-response relationship across the studied range and informs dose selection. Population-PK and exposure-response modeling anchored to TILA278-201 observed exposures — incorporating SC bioavailability, TMDD, and the effect of anti-drug antibodies (ADA) on exposure — will justify the Phase 3 induction and maintenance regimens.

Pharmacodynamic effects were concordant with the intended dual mechanism. Objective markers of intestinal inflammation — C-reactive protein (CRP) and faecal calprotectin — declined in the active arms in proportion to the improvement in modified Mayo score, providing evidence of TL1A-pathway antagonism and downstream suppression of mucosal inflammation, while the accompanying endoscopic improvement is consistent with the IL-22-mediated mucosal-healing component.

Immunogenicity is assessed using a validated tiered strategy (screening, confirmatory, titer, and neutralizing-antibody tiers), with pre-specified evaluation of the relationship between ADA status and PK, efficacy, and safety. Over the 12-week induction period, no dose-dependent safety signal and no loss of the dose-ordered efficacy response were observed. Immunogenicity will continue to be characterized over the longer treatment durations planned for Phase 3, and the maintenance regimen is chosen to maintain exposure above the target-saturation threshold. No dedicated QT study is planned (Section 4).

6. Summary of Phase 2b Efficacy (Study TILA278-201)

TILA278-201 was a multicenter, randomized, double-blind, placebo-controlled, parallel-group, 12-week induction study in adults aged 18–75 years with moderate-to-severe active UC (baseline modified Mayo score 4–9, centrally read endoscopy subscore ≥2, rectal bleeding subscore ≥1). Of 1,700 subjects screened, 900 were randomized 1:1:1 to TILA-278 High (n=299), TILA-278 Low (n=300), or placebo (n=301), with randomization performed centrally via interactive response technology and stratified by baseline modified Mayo severity (4–6 vs 7–9) and prior biologic exposure (yes vs no). An independent Data Safety Monitoring Board provided ongoing safety oversight.

The Full Analysis Set (FAS), comprising 840 subjects who received at least one dose and had a baseline and at least one post-baseline efficacy assessment, was TILA-278 High 284, TILA-278 Low 283, and placebo 273; sixty randomized subjects (High 15, Low 17, placebo 28) were not dosed or lacked a post-baseline assessment. The primary endpoint was clinical remission at Week 12, defined as a modified Mayo score ≤2 with no individual subscore >1. Key secondary endpoints were change from baseline in modified Mayo score and endoscopic improvement at Week 12. The binary primary endpoint was analyzed by a stratified Cochran-Mantel-Haenszel (CMH) test with non-responder imputation (NRI); the continuous key secondary endpoint was analyzed by analysis of covariance (ANCOVA) with treatment and baseline as covariates.

Both active doses met the primary endpoint with a clear, dose-ordered response (High > Low > placebo) and were statistically superior to placebo.

Table 1. Week-12 efficacy (FAS)

Analysis	TILA-278 High (N=284)	TILA-278 Low (N=283)	Placebo (N=273)
Primary — clinical remission (modified Mayo ≤2, no subscore >1; CMH, NRI)
Clinical remission, n/N (%)	106/284 (37.3%)	46/283 (16.2%)	2/273 (0.7%)
Risk difference vs placebo, pp (95% CI)	+36.6 (30.9, 42.3)	+15.5 (11.1, 19.9)	—
p-value vs placebo	<0.0001	<0.0001	—
Key secondary — change in modified Mayo (ANCOVA)
LS-mean change from baseline	−3.36	−2.76	−1.00
LS-mean difference vs placebo (95% CI)	−2.36 (−2.49, −2.23)	−1.77 (−1.90, −1.64)	—
p-value vs placebo	<0.0001	<0.0001	—
Key secondary — endoscopic improvement
Endoscopic improvement, %	48.9%	27.9%	6.2%
Difference vs placebo, pp	+42.7	+21.7	—

The High dose achieved clinical remission in 37.3% of subjects versus 0.7% on placebo — a risk difference of +36.6 percentage points (95% CI 30.9 to 42.3; p<0.0001) — with the Low dose intermediate at 16.2% (+15.5 percentage points; 95% CI 11.1 to 19.9; p<0.0001). The continuous key secondary endpoint was concordant (LS-mean difference vs placebo −2.36 [High] and −1.77 [Low], both p<0.0001), and endoscopic improvement was dose-ordered (48.9% High, 27.9% Low, 6.2% placebo). The near-nil placebo remission rate, the consistent dose-ordering across the responder-based, continuous, and endoscopic analyses, and concordant reductions in CRP and faecal calprotectin together provide robust proof of concept and a firm basis for dose selection.

7. Summary of Phase 2b Safety

Safety was evaluated over the 12-week induction period in all randomized subjects who received at least one dose (Safety Set, identical to the FAS: High 284, Low 283, placebo 273). Treatment-emergent adverse events (TEAEs) occurred at a similar overall frequency across arms and did not increase with TILA-278 dose; serious adverse events (SAEs), deaths, and study discontinuations were each numerically more frequent on placebo than on either active dose. No dose-dependent safety signal was identified.

Table 2. Overview of treatment-emergent adverse events (Safety Set; subjects, n [%])

Parameter	TILA-278 High (N=284)	TILA-278 Low (N=283)	Placebo (N=273)
≥1 TEAE	109 (38.4%)	131 (46.3%)	130 (47.6%)
Serious adverse events	3 (1.1%)	0	4 (1.5%)
Deaths (all assessed as unrelated)	2 (0.7%)	0	1 (0.4%)
Discontinued study	17 (6.0%)	17 (6.0%)	29 (10.6%)

Table 3. Most frequent adverse events (Safety Set; number of subjects)

Preferred term	TILA-278 High	TILA-278 Low	Placebo
Nasopharyngitis	22	35	20
Headache	21	23	27
Worsening of ulcerative colitis	13	19	35
Anaemia	21	17	28
Arthralgia	10	19	20
Upper respiratory tract infection	11	20	17
Injection site reaction	23	17	3
Nausea	6	10	6

The most frequently reported events were nasopharyngitis, headache, and worsening of UC; the latter, along with anaemia, was more frequent on placebo, consistent with inadequate disease control in that arm. The principal drug-attributable finding was injection site reactions, more frequent with active SC drug (High 23, Low 17) than placebo (3), consistent with the SC route and the antibody class. The few deaths (High 2, Low 0, placebo 1) were all investigator-assessed as unrelated to study drug, and SAEs were numerically lower on both active doses than on placebo. No dose-dependent increase in infections, malignancy, or other events of special interest was observed over the induction period.

8. Dose Selection for Phase 3

On the totality of the data — a substantially higher clinical remission rate, the largest LS-mean reduction in modified Mayo score, dose-ordered efficacy corroborated by endoscopic and biomarker findings, and the absence of a dose-dependent safety signal — the TILA-278 High dose is selected as the Phase 3 induction dose. Exposure-response modeling anchored to TILA278-201 supports that the High dose lies on the plateau of the efficacy-exposure relationship while remaining well tolerated. The Phase 3 maintenance study will evaluate a less-frequent SC interval consistent with the molecule's PK, with the induction regimen administered every 2 weeks (Q2W) SC and a Q4W SC maintenance interval justified by population-PK and exposure-response modeling. The Sponsor seeks the Agency's agreement that carrying the single High dose into confirmatory testing is appropriate (Question 2).

9. Proposed Phase 3 Registration Program

The Phase 3 program comprises two replicate induction studies, one maintenance study using a randomized-withdrawal (responder re-randomization) design, and a long-term extension. This structure supports separate induction and maintenance claims within a single integrated label, consistent with regulatory expectations for advanced therapies in UC. An independent Data Monitoring Committee provides ongoing safety oversight across the program.

Table 4. Proposed Phase 3 program

Study	Design	Phase / duration	Population	Planned N	Primary objective
TILA278-301	Randomized (2:1, TILA-278:placebo), double-blind, placebo-controlled	Induction, 12 weeks	Moderate-to-severe UC; conventional- and biologic-experienced strata	~700	Clinical remission at Week 12
TILA278-302	Randomized (2:1), double-blind, placebo-controlled (replicate)	Induction, 12 weeks	As TILA278-301	~700	Clinical remission at Week 12
TILA278-303	Randomized-withdrawal, double-blind, placebo-controlled	Maintenance, through Week 52	Week-12 clinical responders from 301/302	~600 re-randomized	Clinical remission at Week 52
TILA278-304	Open-label long-term extension	Up to Week 152	Completers of 303	All eligible	Long-term safety and durability

Two identically designed, geographically distributed induction studies randomize subjects 2:1 to TILA-278 High or placebo, stratified by baseline modified Mayo severity, prior biologic/advanced-therapy exposure, and concomitant corticosteroid use. The 12-week induction period mirrors TILA278-201 to preserve comparability of the efficacy estimate, and the replicate studies provide the two adequate and well-controlled trials expected to establish substantial evidence of effectiveness. Subjects achieving clinical response at Week 12 are re-randomized in a double-blind fashion to continued TILA-278 or withdrawal to placebo and followed through Week 52; this randomized-withdrawal design isolates the maintenance effect of continued therapy and supports a corticosteroid-free remission claim. Sample sizes are anchored to the Phase 2b treatment effect using deliberately conservative placebo-remission and treatment-difference assumptions, and are powered to support the ranked key secondary endpoints in addition to the primary endpoint. Central endoscopy reading and rigorous eligibility requiring objective inflammation are employed to control placebo response. The open-label extension characterizes durability, long-term safety, and immunogenicity. The Sponsor seeks the Agency's agreement that this program constitutes adequate and well-controlled evidence for both claims (Question 1).

10. Endpoints, Estimands, and Statistical Considerations

Phase 3 endpoints are defined to satisfy contemporary FDA expectations for UC, requiring objective (endoscopic) and, increasingly, histologic evidence of healing in addition to symptomatic control. The Phase 3 remission definition adopts the regulator-preferred component-based modified Mayo definition, harmonized with the definition used in TILA278-201 (modified Mayo ≤2 with no individual subscore >1); the precise operational definition is a designated topic for alignment at this meeting.

Table 5. Proposed Phase 3 endpoint hierarchy

Tier	Induction (Week 12)	Maintenance (Week 52)
Primary	Clinical remission — rectal bleeding subscore 0, stool-frequency subscore ≤1 and not increased from baseline, endoscopy subscore ≤1	Clinical remission at Week 52 among Week-12 responders
Key secondary	Endoscopic improvement; clinical response; symptomatic remission; bowel-urgency improvement	Corticosteroid-free clinical remission; durable remission (Week 12 and Week 52); endoscopic improvement
Additional	Endoscopic-histologic mucosal improvement; IBDQ quality of life; biomarkers (faecal calprotectin, CRP)	Maintenance of endoscopic-histologic healing; sustained corticosteroid-free remission

Estimands are defined per ICH E9(R1). For the binary primary endpoint, the primary estimand adopts a composite strategy: pre-specified intercurrent events — discontinuation of study treatment for lack of efficacy, initiation of prohibited rescue medication or advanced therapy, and UC-related surgery — are incorporated into the endpoint as treatment failure (NRI), and subjects with missing Week-12 status are likewise classified as non-responders. Tipping-point and multiple-imputation analyses assess robustness. For continuous endpoints, a treatment-policy strategy estimated by a mixed-model repeated-measures (MMRM) approach serves as the principal sensitivity framework. Strong control of the family-wise type I error rate at two-sided 0.05 is maintained across the primary and ranked key secondary endpoints via a pre-specified graphical (hierarchical) multiplicity procedure spanning both induction studies and the maintenance study. The Sponsor seeks the Agency's agreement on the endpoints, their operational definitions, and the estimand and multiplicity strategy (Question 3 and Question 4).

11. Safety Database and Pharmacovigilance Plan

The integrated clinical safety database is designed to meet ICH E1 expectations for a chronic-use biologic: at least 1,500 subjects exposed to TILA-278, with at least 300–600 subjects treated for a minimum of 6 months and at least 100 subjects treated for a minimum of 12 months at the intended dose. The two induction studies, the maintenance study, and the long-term extension (TILA278-304) together provide the exposure required to characterize the safety profile over induction and continued dosing.

Based on the mechanism and the Phase 2b profile, the safety specification and adverse events of special interest track: injection-site reactions and hypersensitivity; serious and opportunistic infections associated with immunomodulation, including tuberculosis reactivation, managed by protocol screening and monitoring; immunogenicity and its potential impact on exposure, efficacy, and safety; and, as an important potential risk warranting long-term surveillance, gastrointestinal epithelial proliferation and neoplasia, given the proliferative pharmacology of IL-22R agonism. Malignancy and hepatic events are monitored as standard events of interest for the class. Pharmacovigilance is maintained across development and into the post-approval period, documented in the US risk-management assessment (with a REMS assessment as applicable), periodic safety reporting (DSUR during development), and, consistent with ICH E2E, an integrated risk-management strategy; the long-term extension together with routine and additional pharmacovigilance activities characterizes these topics over extended exposure. The Sponsor seeks the Agency's agreement that the proposed database size and duration are adequate to support the BLA (Question 5) and on the immunogenicity assessment strategy (Question 6).

12. Chemistry, Manufacturing, and Controls Status

The drug substance is the recombinant humanized IgG1 bispecific monoclonal antibody expressed in CHO and purified by Protein A capture, polishing chromatography, and dedicated viral-clearance steps, with a control strategy that manages heterodimer assembly and bispecific-related product variants (Section 3). A quality target product profile and the associated critical quality attributes and control strategy are established consistent with ICH Q5A(R2), Q5C, Q6B, and Q8–Q11, with orthogonal potency assays for both functional activities — anti-TL1A neutralization and IL-22R agonism. The drug product is a sterile SC solution (formulation buffer with polysorbate) presented as a single-use prefilled syringe for induction and an autoinjector to support maintenance self-administration, with human-factors support planned for the self-administration presentation. Process performance qualification and comparability across the clinical and intended commercial presentations and scales are on the critical path to filing. The Sponsor seeks the Agency's agreement on the comparability and control-strategy plan and the proposed presentations (Question 9).

13. Pediatric and Regulatory Strategy

Marketing applications will seek approval for both induction and maintenance of clinical remission in adults with moderate-to-severe UC. In the United States the application will be a BLA under section 351(a) of the Public Health Service Act, filed in eCTD format and reviewed under 21 CFR Part 601; the two replicate induction studies plus the maintenance study are intended to constitute the substantial evidence of effectiveness. Given the serious, chronic nature of moderate-to-severe UC and the unmet need in advanced-therapy-experienced patients, the Sponsor intends to request Fast Track designation to enable rolling BLA review, and will consider Breakthrough Therapy designation if the confirmatory data demonstrate substantial improvement over available therapy on a clinically significant endpoint, particularly in the biologic-experienced subgroup.

An initial Pediatric Study Plan (iPSP) will be submitted proposing deferral of pediatric studies until adult efficacy and safety are established, with a pediatric UC development program to follow. Lifecycle plans include the long-term extension (TILA278-304), evaluation of an alternative maintenance interval, self-administration/autoinjector human-factors support, and assessment of label expansion into adjacent indications leveraging the dual anti-inflammatory/mucosal-healing mechanism. The Sponsor seeks the Agency's agreement on the pediatric plan and expedited-program strategy (Question 10).

14. Proposed Questions to the Agency

1. Does the Agency agree that two replicate double-blind, placebo-controlled induction studies (TILA278-301 and TILA278-302) plus the randomized-withdrawal maintenance study (TILA278-303) constitute adequate and well-controlled evidence to support both an induction and a maintenance claim for moderate-to-severe UC?
2. Does the Agency agree that the Phase 2b High dose is the appropriate Phase 3 induction dose, with a Q2W SC induction regimen and a Q4W SC maintenance interval justified by exposure-response and population-PK modeling anchored to TILA278-201?
3. Does the Agency agree with the proposed primary endpoint of clinical remission by the component-based modified Mayo definition (harmonized with TILA278-201) for induction (Week 12) and maintenance (Week 52), and with the proposed key secondary endpoints including endoscopic and endoscopic-histologic healing?
4. Does the Agency agree with the estimand framework (composite strategy with NRI for the binary primary endpoint; treatment-policy MMRM sensitivity for continuous endpoints), the intercurrent-event handling, and the graphical multiplicity procedure controlling the family-wise error rate at two-sided 0.05 across the induction and maintenance studies?
5. Does the Agency agree that the proposed clinical safety database (≥1,500 exposed, with ≥300–600 for ≥6 months and ≥100 for ≥12 months) satisfies ICH E1 to support the BLA?
6. Does the Agency agree with the tiered immunogenicity assessment strategy (screening, confirmatory, titer, and neutralizing-antibody tiers) and the pre-specified evaluation of ADA impact on PK, efficacy, and safety?
7. Does the Agency agree that standalone genotoxicity and 2-year rodent carcinogenicity studies, in vitro hERG assessment, and a thorough-QT study are not warranted for this monoclonal antibody, with carcinogenic potential addressed through a weight-of-evidence assessment and evaluation of proliferative and pre-neoplastic endpoints in the chronic cynomolgus study?
8. Does the Agency agree that the nonclinical package — with the cynomolgus monkey as the sole pharmacologically relevant species, tissue cross-reactivity and integrated safety-pharmacology assessments, and an ePPND study — is adequate to support the Phase 3 program and registration?
9. Does the Agency agree with the CMC comparability and control strategy (consistent with ICH Q5A(R2)/Q5C/Q6B, orthogonal potency assays for both binding activities, and management of bispecific-related product variants) and with the prefilled-syringe and autoinjector presentations?
10. Does the Agency agree with the proposed pediatric plan (iPSP with deferral) and with the request for Fast Track designation to enable a rolling BLA review?

---

Abbreviations: ADA, anti-drug antibody; ANCOVA, analysis of covariance; BLA, Biologics License Application; CHO, Chinese hamster ovary; CI, confidence interval; CMC, Chemistry, Manufacturing, and Controls; CMH, Cochran-Mantel-Haenszel; CRP, C-reactive protein; DR3, death receptor 3; DSUR, Development Safety Update Report; eCTD, electronic Common Technical Document; EMA, European Medicines Agency; EOP2, End of Phase 2; ePPND, enhanced pre- and postnatal development; FAS, Full Analysis Set; FcRn, neonatal Fc receptor; FDA, U.S. Food and Drug Administration; IBDQ, Inflammatory Bowel Disease Questionnaire; IgG1, immunoglobulin G1; IL-22(R), interleukin-22 (receptor); iPSP, initial Pediatric Study Plan; LS, least-squares; MMRM, mixed-model repeated measures; NRI, non-responder imputation; PK, pharmacokinetics; pp, percentage points; Q2W/Q4W, every 2/4 weeks; REMS, Risk Evaluation and Mitigation Strategy; SAE, serious adverse event; SC, subcutaneous; TEAE, treatment-emergent adverse event; TL1A, TNF-like ligand 1A (TNFSF15); TMDD, target-mediated drug disposition; UC, ulcerative colitis.