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Safety Management Plan (OBX319-301)

Document ID: TMF-006
Version: 1.0
Change History: 1.0 — Initial issue.
Standard(s): ICH E2A / E6(R3)

Safety Management Plan — OBX319-301

Defines safety data collection and reporting for OBX-319 in OBX319-301: adverse-event and serious-adverse-event definitions and timelines, expedited reporting, the reference safety information, causality/expectedness assessment, and signal management. ICH E2A; E6(R3).

OBX-319 is a humanised IgG1 anti-CD19 × anti-CD20 bispecific monoclonal antibody produced by recombinant Chinese hamster ovary (CHO) cell culture, purified through a Protein A capture and polishing downstream train, and administered subcutaneously. Its mechanism — simultaneous engagement of CD19 and CD20 to achieve near-complete peripheral B-cell depletion — determines the safety profile that this plan is designed to detect, characterise and report. Study OBX319-301 is a randomised, double-blind, placebo-controlled, 1:1:1 study of 480 randomised subjects (162 OBX-319 High, 158 OBX-319 Low, 160 Placebo) with moderate-to-severe active Systemic Lupus Erythematosus (SLE), baseline SLEDAI-2K approximately 11, on background standard-of-care over a 52-week double-blind period. Because the pharmacology is that of a B-cell–depleting biologic, safety surveillance under this plan is directed at the identified and potential risks of the class — serious and opportunistic infections, hypogammaglobulinaemia, injection/administration and hypersensitivity reactions, and immunogenicity — rather than at toxicities characteristic of other therapeutic classes. The study is conducted under an active IND in accordance with 21 CFR 312, expedited safety reporting follows 21 CFR 312.32, and the eventual marketing application is a Biologics License Application under 21 CFR 601. This plan is owned by the sponsor, Virtual Biopharma Inc., and executed jointly with the delegated clinical research organisation (CRO) and pharmacovigilance (PV) service provider; it is read together with the clinical protocol, the Investigator's Brochure (IB), the Clinical Monitoring Plan (TMF-003), the DSMB Charter (TMF-004) and the Randomization/IWRS Plan (TMF-012).

1. Purpose and Scope

This plan establishes the end-to-end process for the identification, recording, medical assessment, documentation, reconciliation and regulatory reporting of safety information for every subject who signs informed consent at any participating site, from the moment of consent through the end of the protocol-defined safety follow-up. It defines adverse-event (AE) and serious-adverse-event (SAE) terminology and timelines, the causality and expectedness conventions, the Reference Safety Information (RSI), the adverse events of special interest (AESI) specific to B-cell depletion, expedited and aggregate reporting obligations, blinding/unblinding controls for individual-case reporting, and the signal-management workflow. It applies across all sites and covers all study treatment (OBX-319 High, OBX-319 Low, Placebo) and background standard-of-care. It is aligned with ICH E2A (clinical safety data management: definitions and standards for expedited reporting), ICH E6(R3) (Good Clinical Practice), ICH E2D (post-approval definitions, applied by analogy for consistency of terminology), ICH E2F (Development Safety Update Report), ICH E2B(R3) (electronic case transmission) and 21 CFR 312.32 (IND safety reporting).

2. Roles and Responsibilities

Investigator. Responsible for eliciting, documenting and grading AEs; assessing seriousness and causality for each event; providing source documentation; reporting all SAEs to the sponsor/PV provider within 24 hours of first becoming aware; and complying with local IRB/IEC reporting obligations. The investigator retains overall responsibility for subject safety and for protocol-specified management of infections, administration reactions and laboratory abnormalities.

Sponsor Medical Monitor. Provides 24/7 medical coverage, adjudicates protocol eligibility and safety queries, performs the sponsor causality and expectedness review, and advises on dose interruption/discontinuation and rechallenge in the context of the class risks of B-cell depletion (infection, hypogammaglobulinaemia, hypersensitivity).

Sponsor Pharmacovigilance / Drug Safety. Owns the safety database, performs MedDRA coding, maintains and version-controls the RSI, determines expectedness, prepares and submits expedited IND safety reports and the annual DSUR, conducts case-level and aggregate signal detection, and performs controlled unblinding of individual serious unexpected cases required for regulatory reporting while preserving the blind for the study team.

CRO / Clinical Operations. Supports SAE intake, source-data verification, EDC–safety database reconciliation, and site training on this plan.

Independent Data Safety Monitoring Board (DSMB). Reviews unblinded accumulating safety data per the DSMB Charter (TMF-004) and issues continue/modify/stop recommendations to the sponsor; its deliberations are recorded in the DSMB minutes (TMF-007). A firewall separates the DSMB and its unblinded statistician from the blinded study team.

Central Laboratory and IWRS. The central laboratory processes the safety and pharmacodynamic assays (CD19+ B-cell immunophenotyping, immunoglobulins, haematology, anti-dsDNA, complement C3/C4) and flags out-of-range values; the IWRS supports emergency unblinding at the site level when clinically required (TMF-012).

3. Safety Definitions

Adverse event (AE). Any untoward medical occurrence in a subject administered study treatment, whether or not considered related, per ICH E2A. Adverse drug reaction / suspected adverse reaction. An AE for which there is a reasonable possibility of a causal relationship to OBX-319. Serious adverse event (SAE). Any AE that results in death, is life-threatening, requires inpatient hospitalisation or prolongation of existing hospitalisation, results in persistent or significant disability/incapacity, is a congenital anomaly/birth defect, or is an important medical event that, based on medical judgement, may jeopardise the subject and require intervention to prevent one of the foregoing. Unexpected. An event whose nature, severity or frequency is not consistent with the current RSI. SUSAR. A serious, unexpected suspected adverse reaction — the trigger for expedited reporting. AESI. A pre-specified event (serious or non-serious) of scientific or medical concern for this modality that requires targeted monitoring and, where specified, prompt communication (Section 7). Disease-related events of SLE (for example lupus nephritis flare) are captured according to protocol conventions and are individually assessed for seriousness and causality; a treatment-arm gradient in disease flare that favours active treatment reflects disease control rather than a drug-related adverse effect.

4. Severity and Seriousness Assessment

Severity (intensity) is graded with the NCI Common Terminology Criteria for Adverse Events (CTCAE), or as mild/moderate/severe where a CTCAE term does not apply, and reflects the clinical intensity of a single event. Seriousness is a distinct regulatory determination against the ICH E2A criteria in Section 3. The two axes are independent: a mild event may be serious (for example, a medically important event) and a severe event may be non-serious. Fatal outcome is recorded as an outcome, not as a severity grade, and every death is handled as an SAE with expedited follow-up.

5. Causality and Expectedness Assessment

Causality is assessed first by the investigator as a binary judgement (reasonable possibility: related / not related) and independently by the sponsor. The assessment weighs temporal plausibility, the pharmacology of profound B-cell depletion, dechallenge/rechallenge information where available, and alternative aetiologies that are prominent in this population — active SLE itself and concomitant background immunosuppression. Expectedness is determined by the sponsor exclusively against the RSI current at the time of the event (Section 6). An event that is serious, assessed as having a reasonable possibility of relationship to OBX-319, and not listed or not consistent in nature/severity/frequency with the RSI is classified as a SUSAR and enters the expedited-reporting pathway (Section 9). The sponsor does not downgrade an investigator's assessment of relatedness for reporting purposes; where investigator and sponsor differ, both assessments are retained and the more conservative drives expedited reporting.

6. Reference Safety Information

The RSI is the designated reference-safety-information section of the current IB and is the sole basis for expectedness determinations. For OBX-319 the RSI reflects the anticipated class profile of a subcutaneously administered B-cell–depleting IgG1: injection-site reactions; infections, predominantly upper respiratory tract infection, urinary tract infection and nasopharyngitis; decline in serum immunoglobulins (most notably IgM, with smaller changes in IgG) and hypogammaglobulinaemia; cytopenias, including late-onset neutropenia; systemic administration/hypersensitivity reactions; and immunogenicity (anti-drug antibodies). The RSI is version-controlled; each individual case is assessed for expectedness against the RSI version in force at the time of the event, while the annual DSUR uses the RSI in effect at the start of the reporting interval. RSI changes are governed through IB updates and are propagated to sites and to the reporting workflow (cross-reference: IB in Module 5).

7. Adverse Events of Special Interest

The following AESIs derive directly from the anti-CD19 × anti-CD20 B-cell–depleting mechanism and are monitored proactively irrespective of seriousness, with defined collection and, where applicable, prompt sponsor notification:

• Serious and opportunistic infections — the principal identified risk of profound B-cell depletion, including vigilance for progressive multifocal leukoencephalopathy, tuberculosis reactivation and hepatitis B virus reactivation. Latent tuberculosis and hepatitis B serology are screened at entry; live or live-attenuated vaccines are prohibited during treatment; new or worsening neurological signs prompt evaluation for PML. Infection surveillance is interpreted alongside B-cell counts and immunoglobulins.
• Hypogammaglobulinaemia / persistent low immunoglobulins — scheduled monitoring of IgG, IgM and IgA; values below the lower limit of normal are tracked longitudinally, and persistent hypogammaglobulinaemia with recurrent or serious infection triggers protocol-specified management, up to dose interruption and consideration of immunoglobulin replacement.
• Injection-site and systemic administration / hypersensitivity reactions, including anaphylaxis — expected with subcutaneous IgG1 administration; a post-dose observation period applies, with particular attention to first-dose cytokine-release–type and hypersensitivity reactions, and management follows the protocol algorithm (observation, symptomatic treatment, and premedication or discontinuation as specified).
• Immunogenicity-associated events — anti-drug antibodies (binding and neutralising) are sampled on the protocol schedule; ADA is interpreted for its potential to alter exposure of this target-mediated-drug-disposition (TMDD) antibody and for association with hypersensitivity or loss of pharmacodynamic effect.
• Cytopenias, notably late-onset neutropenia — absolute neutrophil count and complete blood count are monitored, with defined thresholds for evaluation and management.
• Malignancy — retained as a potential long-term risk given the immunomodulatory mechanism; malignant events are collected, medically reviewed and followed.

Endpoints characteristic of other therapeutic classes — for example thyroid C-cell/medullary effects and the associated boxed warning that apply to GLP-1 receptor agonists — are mechanistically irrelevant to a B-cell–depleting antibody and are not part of AESI monitoring for OBX-319; there is no boxed warning for this class. Consistent with ICH guidance for biotechnology-derived products, a dedicated thorough-QT programme and hERG assessment are not warranted for a monoclonal antibody; cardiac safety is followed by routine electrocardiography.

8. Safety Data Collection and Follow-up

Safety information is collected from the signing of the informed consent form (TMF-001) and throughout the 52-week double-blind period. At each scheduled visit, AEs are elicited by non-leading enquiry and by review of protocol-specified assessments: CD19+ B-cell immunophenotyping, immunoglobulins (IgG/IgM/IgA), complete blood count with absolute neutrophil count, anti-dsDNA autoantibodies, complement C3/C4, vital signs, routine electrocardiography and structured injection-site evaluation. The pharmacodynamic context for interpretation is the near-complete peripheral B-cell depletion produced on both active arms — from approximately 210 cells/µL at baseline to approximately 7 cells/µL — sustained through Week 52, versus essentially unchanged counts on placebo, together with falling anti-dsDNA titres and normalisation of complement C3/C4 in responders. Because profound B-cell depletion and its infection and immunoglobulin sequelae can lag and persist, safety follow-up extends beyond the last dose in accordance with the protocol (including B-cell reconstitution and immunoglobulin recovery monitoring). SAEs identified after the end of study participation that the investigator considers related to OBX-319 remain reportable.

9. Expedited and Aggregate Reporting Timelines

The investigator reports every SAE to the sponsor/PV provider within 24 hours of first awareness, with follow-up information provided promptly thereafter. The sponsor submits IND safety reports to FDA under 21 CFR 312.32 for events that are serious, unexpected against the RSI, and suspected to be related: fatal or life-threatening SUSARs are reported as soon as possible but no later than 7 calendar days after the sponsor's first knowledge, followed by a complete report within a further 8 calendar days; other serious, unexpected suspected adverse reactions are reported within 15 calendar days. Corresponding notifications are issued to all participating investigators and, per institutional requirements, to IRBs/IECs. The double blind is maintained for the study team; individual SUSAR cases requiring submission are unblinded under controlled PV procedures without unblinding the wider team, and electronic transmission follows ICH E2B(R3). Aggregate safety reporting comprises the annual Development Safety Update Report per ICH E2F and the IND annual report, each integrating cumulative case data, the results of ongoing signal detection, and any RSI changes over the interval.

10. Pregnancy, Overdose, and Special Situations

Pregnancies in subjects (and, where applicable, partners) are reported on the same expedited timelines as SAEs and followed to outcome, because an effector-competent IgG1 directed at B-lineage antigens can cross the placenta in the second and third trimesters and transiently deplete infant B cells (as characterised in the enhanced pre-/post-natal development study); protocol-specified contraception and pregnancy-prevention measures and lactation precautions apply. Overdose, medication error, product-quality complaints, occupational exposure and lack of efficacy are captured as special situations, with any associated AE/SAE recorded and reported under the standard rules. Disease worsening (SLE flare, including lupus nephritis flare) is documented per protocol and individually assessed for seriousness and causality.

11. Protocol-Specified Safety Management and Stopping Guidance

Individual subject management follows protocol-defined criteria for dose interruption or permanent discontinuation, including serious or opportunistic infection, severe or recurrent hypersensitivity/anaphylaxis, severe or persistent hypogammaglobulinaemia accompanied by recurrent or serious infection, and severe neutropenia. Emergency unblinding at the site is available through the IWRS when knowledge of assignment is essential to manage an event. Study-level pause and stopping considerations are exercised through the DSMB, which reviews the unblinded accumulating safety experience against the emerging benefit profile.

12. Signal Management and Benefit–Risk Surveillance

Ongoing signal detection combines medical review of individual cases, periodic cumulative and aggregate review of AEs/SAEs/AESIs against the RSI and the established knowledge of the B-cell–depletion class, and laboratory-trend review (immunoglobulins, neutrophils, B-cell reconstitution). Signals are interpreted in the study's benefit–risk context: dose-ordered efficacy at Week 52 with low-disease-activity/SRI-4 response (SLEDAI-2K ≤ 4) of 52.4% (76/145) on OBX-319 High and 33.8% (49/145) on OBX-319 Low versus 6.0% (9/150) on Placebo, and SLEDAI-2K LS-mean change of -6.37 (High) and -5.62 (Low) versus -3.46 (Placebo) — differences of -2.91 and -2.17 versus placebo — set against the identified infection and immunoglobulin risks. A confirmed signal is actioned through RSI/IB update, protocol amendment, revised risk-minimisation measures, and communication to investigators and health authorities as appropriate, with the sponsor safety committee and the DSMB as the governing bodies.

13. Data Management, Coding, and Reconciliation

AEs are coded to the current MedDRA version and concomitant medications to WHO Drug; coding is medically reviewed for consistency. SAE data captured in the safety database are reconciled against the clinical (EDC) database on a scheduled basis and fully reconciled before database lock, with discrepancies resolved and documented. Data-handling controls follow ICH E6(R3) requirements for accuracy, attributability and traceability, and are consistent with the study's Data Management Plan (TMF-002), analysis datasets and define documentation in Module 5.

ICH E2A; ICH E2B(R3); ICH E2D; ICH E2F; ICH E6(R3); ICH S6(R1); 21 CFR 312.32; 21 CFR 601. Cross-references: TMF-001 (informed consent), TMF-003 (clinical monitoring), TMF-004 (DSMB charter), TMF-007 (DSMB minutes), TMF-012 (randomization/IWRS); Investigator's Brochure (RSI).