Ruxolitinib and Chemotherapy in Adolescents and Young Adults With Ph-like Acute Lymphoblastic Leukemia

1. Is the biology right?

• Somatic driver evidence: no · None of JAK1, JAK2, JAK3, PPAT, IMPDH1, IMPDH2 has somatic-mutation evidence in childhood acute lymphoblastic leukemia

  Rule: Open Targets has somatic-mutation evidence for the target in this cancer. Source: Open Targets: JAK1 in childhood acute lymphoblastic leukemia, 2026-11-11
• Human genetic evidence: no · No germline or somatic evidence for JAK1, JAK2, JAK3, PPAT, IMPDH1, IMPDH2 in childhood acute lymphoblastic leukemia

  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: JAK1 in childhood acute lymphoblastic leukemia, 2026-11-11
• Pediatric target: yes · JAK1, JAK2, JAK3 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: yes · Haematologic

  Rule: From the indication, or the registry conditions when no indication matches. Source: ClinicalTrials.gov NCT03571321, 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.

• Background therapy: Cyclophosphamide, Cytarabine, Vincristine, Rituximab, Methotrexate, Doxorubicin: standard agents, not counted in these flags.
• JAK1 (via Ruxolitinib): Open Targets has no association between JAK1 and childhood acute lymphoblastic leukemia. · Open Targets: JAK1 in childhood acute lymphoblastic leukemia
• JAK2 (via Ruxolitinib): Open Targets has no association between JAK2 and childhood acute lymphoblastic leukemia. · Open Targets: JAK2 in childhood acute lymphoblastic leukemia
• JAK3 (via Ruxolitinib): Open Targets has no association between JAK3 and childhood acute lymphoblastic leukemia. · Open Targets: JAK3 in childhood acute lymphoblastic leukemia
• PPAT (via Mercaptopurine): Open Targets has no association between PPAT and childhood acute lymphoblastic leukemia. · Open Targets: PPAT in childhood acute lymphoblastic leukemia
• IMPDH1 (via Thioguanine): Open Targets has no association between IMPDH1 and childhood acute lymphoblastic leukemia. · Open Targets: IMPDH1 in childhood acute lymphoblastic leukemia
• IMPDH2 (via Thioguanine): Open Targets has no association between IMPDH2 and childhood acute lymphoblastic leukemia. · Open Targets: IMPDH2 in childhood acute lymphoblastic leukemia

• 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 · Single group

  Rule: Registry allocation field. Source: ClinicalTrials.gov NCT03571321, 2026-11-11
• Small denominator: yes · 15 planned; each patient moves a rate by 100 ÷ 15 = 6.7 points

  Rule: Enrolment under 30; the arithmetic is shown, not a benchmark. Source: ClinicalTrials.gov NCT03571321, 2026-11-11
• Primary endpoint is overall survival: no · Feasibility of adding ruxolitinib to a standard-of-care pediatric-based chemotherapy regimen in adolescents and young…

  Rule: A registered primary outcome measure names overall survival. Source: ClinicalTrials.gov NCT03571321, 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 · Primary completion expected 2026-09-01; not yet due

  Rule: Primary completion (actual) more than 12 months ago and no results posted to the registry. Source: ClinicalTrials.gov NCT03571321, 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: 130 terminated, withdrawn or suspended trials of drugs against JAK1; 13 give no reason. Reasons are quoted as the registry gives them on the target page. · JAK1: 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: yes · All 2 sites in United States

  Rule: All listed sites are in one country; the share of US sites is shown. Source: ClinicalTrials.gov NCT03571321, 2026-11-11
• EU paediatric investigation plan: yes · EMEA-002618-PIP02-20-M01 (ruxolitinib (phosphate), Treatment of vitiligo): PM: decision on the application for modification of an agreed PIP, 12 Apr 2024; EMEA-002618-PIP04-23 (ruxolitinib (phosphate), Treatment of prurigo nodularis): W: decision granting a waiver in all age groups for all conditions or indications, 31 Jan 2024; EMEA-000901-PIP04-17-M02 (ruxolitinib (phosphate), Treatment of chronic Graft versus Host Disease (cGvHD)): PM: decision on the application for modification of an agreed PIP, 3 Dec 2021; compliance positive 13 Oct 2023; EMEA-000901-PIP03-16-M02 (ruxolitinib (phosphate), Treatment of acute graft-versus-host disease (aGvHD)): PM: decision on the application for modification of an agreed PIP, 9 Apr 2021; compliance positive 13 Oct 2023; +1 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/3/09/628 expired 30 Apr 2009: Treatment of acute lymphoblastic leukaemia; EU/3/14/1244 withdrawn 19 Feb 2014: Treatment of polycythaemia vera; EU/3/07/496 positive 22 Oct 2007: Treatment of acute lymphoblastic leukaemia

  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 data download (dated snapshot), 2026-11-11
• Authorised in the EU: yes · Ruxolitinib Zentiva: opinion; Opzelura: authorised since 19 Apr 2023; Oncaspar: authorised since 14 Jan 2016; Jakavi: authorised since 23 Aug 2012; +2 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: yes · Mercaptopurine [Purinethol tablet] &, 11 Sept 1953: Treatment of adult and pediatric patients with acute lymphoblastic leukemia (ALL) as part of a combination chemotherapy maintenance regimen; Pegaspargase [Oncaspar], 24 Jul 2006: As a component of a multi-agent chemotherapeutic regimen for the first-line treatment of pediatric and adult patients with acute lymphoblastic leukemia (ALL); Pegaspargase [Oncaspar], 1 Feb 1994: As a component of a multi-agent chemotherapeutic regimen for the treatment of pediatric and adult patients with ALL and hypersensitivity to native forms of L-asparaginase; +1 more

  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 · 395 interventional studies of Ruxolitinib, Mercaptopurine, Pegaspargase, Thioguanine include patients under 18; 110 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: University of Chicago (academic or other) · ClinicalTrials.gov NCT03571321
• principal investigator: Wendy Stock, MD, University of Chicago · Person page

• 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.