Study of ARC-520 With or Without Other Drugs Used in the Treatment of Chronic Chronic Hepatitis B Virus (HBV)

1. Is the biology right?

• Somatic driver evidence: no · None of IFNAR1, IFNAR2 has somatic-mutation evidence in hepatitis B virus infection

  Rule: Open Targets has somatic-mutation evidence for the target in this cancer. Source: Open Targets: IFNAR1 in hepatitis B virus infection, 2026-11-11
• Human genetic evidence: no · No germline or somatic evidence for IFNAR1, IFNAR2 in hepatitis B virus infection

  Rule: Any germline or somatic human genetic evidence for the target in this cancer, counted apart from animal-model and literature evidence. Source: Open Targets: IFNAR1 in hepatitis B virus infection, 2026-11-11
• Pediatric target: no · Not on the FDA list

  Rule: Target is on FDA's Pediatric Molecular Target List (relevant targets); membership alone neither requires nor waives a study. Source: FDA Pediatric Molecular Target List (Listed as February 2026 on the FDA Pediatric Oncology page; the file served is 9.7.22_the_relevant_molecular_target_list.xlsx, whose Summary of Changes sheet is headed 'SEPTEMBER 2022 UPDATE' (footnote date 2022-09-01)), 2026-11-11
• Haematologic cancer: no · Solid tumour

  Rule: From the indication, or the registry conditions when no indication matches. Source: ClinicalTrials.gov NCT02577029, 2026-11-11

  Published context: Likelihood of approval from phase 1: 7.5% haematologic vs 4.6% solid (BIO / Informa / QLS 2021, 2011–2020). Population-level, not a prediction.

• IFNAR1 (via pegylated interferon alpha 2a): Evidence types in hepatitis B virus infection: literature, clinical; literature listed separately from human genetics. Datasources: clinical_precedence, europepmc. · Open Targets: IFNAR1 in hepatitis B virus infection
• IFNAR2 (via pegylated interferon alpha 2a): Evidence types in hepatitis B virus infection: literature, clinical; literature listed separately from human genetics. Datasources: clinical_precedence, europepmc. · Open Targets: IFNAR2 in hepatitis B virus infection

• Not loaded on this app yet: Normal-tissue expression in vital organs. Source: Human Protein Atlas (ticket 36).
• Not loaded on this app yet: Pan-essential in cell lines. Source: DepMap (ticket 36).
• Not loaded on this app yet: Approved drug on this target. Source: Drugs@FDA (ticket 30).

2. Can the result be trusted?

• Randomised: no · Non-randomised

  Rule: Registry allocation field. Source: ClinicalTrials.gov NCT02577029, 2026-11-11
• Small denominator: no · 79 enrolled; each patient moves a rate by 100 ÷ 79 = 1.3 points

  Rule: Enrolment under 30; the arithmetic is shown, not a benchmark. Source: ClinicalTrials.gov NCT02577029, 2026-11-11
• Primary endpoint is overall survival: no · Percentage of Participants Achieving a 1-log Reduction in Hepatitis B Surface Antigen (HBsAg) at Week 60 Compared to …

  Rule: A registered primary outcome measure names overall survival. Source: ClinicalTrials.gov NCT02577029, 2026-11-11

  Published context: Non-OS primary endpoint: odds ratio 2.79 for a positive phase 3 (Otsuka 2021, 400 phase 3 oncology trials, to 2020). Shown with the next figure: a surrogate is easier to hit, and often a weak guide to survival.

  Published context: 52% of surrogate-to-OS correlations are low (Prasad 2015, published to 2014). Shown with the figure above.
• Results overdue: no · Results posted 2019-04-12

  Rule: Primary completion (actual) more than 12 months ago and no results posted to the registry. Source: ClinicalTrials.gov NCT02577029, 2026-11-11

• Not loaded on this app yet: Treated and evaluable counts, assessor, confirmed response, follow-up and data cutoff. Source: Readout extraction (ticket 32).
• Not loaded on this app yet: Primary endpoint changed between registry versions. Source: Registry versions in the store (ticket 32).

3. What must it beat?

• Not loaded on this app yet: Control-arm result and approved therapies for the same segment, with label links. Source: Drugs@FDA, FDA labels and readouts (tickets 30, 32).

4. Too crowded, or too late?

• Stopped on this target: 99 terminated, withdrawn or suspended trials of drugs against IFNAR1; 24 give no reason. Reasons are quoted as the registry gives them on the target page. · IFNAR1: what already stopped

• Not loaded on this app yet: Programs on the target by phase and months behind the leader. Source: Programs and Drugs@FDA (ticket 33).

5. Can it be approved, and stay approved?

• Single-country: no · 33 sites in 8 countries; 0 in the United States (0%)

  Rule: All listed sites are in one country; the share of US sites is shown. Source: ClinicalTrials.gov NCT02577029, 2026-11-11
• EU paediatric investigation plan: yes · EMEA-000533-PIP01-08-M11 (tenofovir disoproxil fumarate, Treatment of chronic viral hepatitis B;Treatment of human immunodeficiency virus (HIV-1) infection): PM: decision on the application for modification of an agreed PIP, 11 Mar 2022; compliance positive 20 Jan 2023; EMEA-001695-PIP01-14-M05 (doravirine;lamivudine;tenofovir disoproxil fumarate, Treatment of human immunodeficiency virus (HIV-1) infection): PM: decision on the application for modification of an agreed PIP, 2 Dec 2022; EMEA-000774-PIP01-09-M03 (emtricitabine;rilpivirine hydrochloride;tenofovir disoproxil fumarate, Treatment of human immunodeficiency virus (HIV-1) infection): W: decision granting a waiver in all age groups for all conditions or indications, 23 Aug 2018; EMEA-000970-PIP01-10-M01 (elvitegravir;emtricitabine;cobicistat;tenofovir disoproxil fumarate, Treatment of human immunodeficiency virus (HIV-1) infection): PM: decision on the application for modification of an agreed PIP, 4 Nov 2016; compliance positive 16 Dec 2016; +2 more

  Rule: An EMA PIP decision (agreement, modification or waiver) lists the drug as its active substance, exact name. Source: EMA data download (dated snapshot), 2026-11-11
• EU orphan designation: yes · EU/3/14/1419 positive 15 Jan 2015: Treatment of Aicardi-Goutières syndrome

  Rule: An EU orphan designation lists the drug as its active substance (exact name) or belongs to a medicine that does; withdrawn and expired designations are listed with their status. Source: EMA EU/3/14/1419, 2026-11-11
• Authorised in the EU: yes · Delstrigo: authorised since 22 Nov 2018; Tenofovir disoproxil Viatris (previously Tenofovir disoproxil Mylan): authorised since 8 Dec 2016; Entecavir Viatris (previously Entecavir Mylan): authorised since 18 Sept 2017; Emtricitabine/Tenofovir disoproxil Mylan: authorised since 16 Dec 2016; +14 more

  Rule: An EMA medicine record lists the drug as its active substance or INN, exact name; national-only authorisations are not in this file. Source: EMA data download (dated snapshot), 2026-11-11
• FDA orphan designation: not published · FDA's orphan designation database turns away automated requests, so this app does not read it; search it by hand at the link

  Rule: Would be: an FDA orphan designation names the drug. Source: FDA orphan designations search
• FDA pediatric oncology approval: no · FDA's table lists no pediatric approval of ARC-520, entecavir, pegylated interferon alpha 2a, tenofovir disoproxil

  Rule: FDA's Pediatric Oncology Drug Approvals table names the drug. Source: FDA Pediatric Oncology Drug Approvals (content current as of 2026-03-03), 2026-11-11
• Registered studies open to children: yes · 161 interventional studies of ARC-520, entecavir, pegylated interferon alpha 2a, tenofovir disoproxil include patients under 18; 30 are recruiting, not yet recruiting or active

  Rule: The registry's age group includes Child (birth to 17 years), which also counts studies that set no minimum age. Source: ClinicalTrials.gov search, 2026-11-11

• Caveat: Site counts are not patients per country, and trials registered only outside ClinicalTrials.gov are not covered. Where the sites are is a fact about the record, not a judgement of its quality.
• Rare pediatric disease voucher: FDA, content current as of 29 Apr 2026: “As of February 3, 2026, enactment of the Consolidated Appropriations Act, 2026, the rare pediatric disease PRV program will sunset after September 30, 2029. FDA may not award any PRVs under this program after September 30, 2029.” Voucher sale prices are not shown here; they appear only as company-reported news. · FDA: Rare Pediatric Disease Designation and Priority Review Voucher Programs

• Not loaded on this app yet: Precedent approvals for target, modality and endpoint; accelerated-approval status. Source: Drugs@FDA and FDA accelerated-approval tables (ticket 30).

6. Can the sponsor finish?

• Sponsor: Arrowhead Pharmaceuticals (industry) · ClinicalTrials.gov NCT02577029

• Not loaded on this app yet: Filed cash, quarterly spend and the runway arithmetic. Source: SEC XBRL company facts (ticket 37).
• Not loaded on this app yet: Sponsor's completed vs stopped oncology trials and results-reporting record. Source: Registry, by company (ticket 37).

What public data cannot tell you

Public records cannot show: sales forecasts; a probability of success for this asset; full deal terms and net prices; FDA designations and action dates before approval (shown only as company-reported); clinical holds unless the company disclosed them; manufacturing; patents on unapproved drugs; whether preclinical findings have been replicated.