pharma · Ovarian Cancer · Breast Cancer · ZNTL
Zentalis Pharmaceuticals (United is a pharma organization headquartered in San Diego, USA. It trades on NYSE under ticker ZNTL. Primary therapeutic focus areas include Ovarian Cancer, Breast Cancer, High-Grade Serous Ova
Phase 1 · small molecule · Osteosarcoma
Azenosertib (internal code ZN-c3-003) is a small-molecule investigational oncology agent developed by Zentalis Pharmaceuticals for the treatment of osteosarcoma. The program is currently in Phase 1 development, with the most recent milestone dated April 3, 2026. Osteosarcoma is a rare, aggressive primary bone malignanc
Internal code ZN-c3-003
Azenosertib (internal code ZN-c3-003) is a small-molecule investigational oncology agent developed by Zentalis Pharmaceuticals for the treatment of osteosarcoma. The program is currently in Phase 1 development, with the most recent milestone dated April 3, 2026. Osteosarcoma is a rare, aggressive primary bone malignancy predominantly affecting adolescents and young adults, representing a significant unmet medical need despite existing standard-of-care chemotherapy regimens. Zentalis is advancing azenosertib as a potential therapeutic option in a competitive landscape that includes both established chemotherapy agents and emerging targeted therapies. The mechanism of action, specific molecular target, and detailed clinical data remain not yet disclosed. The Phase 1 trial (NCT04833582) is registered in the clinical trial database, indicating active clinical evaluation. As a Phase 1 program, azenosertib is in early-stage human safety and tolerability assessment, with regulatory approval timelines extending several years into the future. The program's advancement will depend on Phase 1 safety outcomes and subsequent Phase 2 efficacy signals in osteosarcoma patients.
Osteosarcoma remains a devastating malignancy with limited therapeutic options and significant morbidity despite multimodal treatment approaches. The standard of care relies on cisplatin-based neoadjuvant chemotherapy combined with surgical resection, with outcomes plateauing over the past two decades. Approximately 10–20% of patients develop metastatic disease at presentation or recurrence, and prognosis for these populations remains poor, creating a substantial unmet medical need for novel agents with improved efficacy and tolerability profiles.
Azenosertib enters a competitive landscape that includes multiple Phase 2 and Phase 3 programs. Phase 3 competitors include docetaxel plus lobaplatin (Xiyuan Hospital), cisplatin monotherapy (Children's Hospital of Fudan University), and zoledronic acid (Ningbo Cancer Hospital). Phase 2 programs include lenvatinib (Eisai), REOLYSIN (Oncolytics Biotech), omomyc (The George Institute), and mifamurtide (Takeda), among others. This competitive density underscores both the clinical urgency and commercial opportunity in osteosarcoma therapeutics.
The osteosarcoma patient population is relatively small but highly motivated, with strong advocacy and clinical interest in novel options. Zentalis's entry into this indication reflects strategic focus on rare oncology segments where unmet need is acute and regulatory pathways may be accelerated. Commercial significance is moderate relative to large-market oncology indications but substantial within the rare disease oncology segment.
Drug Class: Small-molecule investigational oncology agent
Modality: Small molecule
Mechanism of Action: Not yet disclosed
Molecular Target: Not yet disclosed
Route of Administration: Not yet disclosed
Sponsor: Zentalis Pharmaceuticals
Development Partner: None disclosed
Related Therapies: Azenosertib is being evaluated in osteosarcoma, a disease area with established chemotherapy standards (cisplatin, doxorubicin, methotrexate) and emerging targeted approaches including tyrosine kinase inhibitors and immunomodulatory agents.
Patent Status: Not yet disclosed
First Approval: Not applicable; program remains in Phase 1
Also known as: bone tissue neoplasm, osteogenic sarcoma, osteoid sarcoma, osteosarcoma (disease), osteosarcoma, malignant, sarcoma of osteoid
Prevalence: Point prevalence: 1-9 / 100 000 (Europe) — source: Orphanet, validated.
A usually aggressive malignant bone-forming mesenchymal neoplasm, predominantly affecting adolescents and young adults. It usually involves bones and less frequently extraosseous sites. It often involves the long bones (particularly distal femur, proximal tibia, and proximal humerus). Pain with or without a palpable mass is the most frequent clinical symptom. It may spread to other anatomic sites, particularly the lungs.
ClinicalTrials.gov lists 244 registered studies for Osteosarcoma (AACT aggregate).
Phase breakdown: NA (77), PHASE2 (71), PHASE1 (51), PHASE1/PHASE2 (25), PHASE3 (8), EARLY_PHASE1 (7), PHASE2/PHASE3 (4), PHASE4 (1)
Common investigational therapies:
Disease data sourced from MONDO Disease Ontology (MONDO:0009807), Orphanet — osteosarcoma, NCT00001209, NCT00001217, NCT00001436, NCT00026780, NCT00038207, AACT (ClinicalTrials.gov aggregate), ClinicalTrials.gov, Open Targets Platform (CC BY 4.0).
Phase 1 initiation
Azenosertib Phase 1 trial (NCT04833582) initiated to assess safety, tolerability, and preliminary efficacy in osteosarcoma patients.
Latest milestone
Most recent program update as of April 3, 2026; specific milestone details not yet disclosed.
Azenosertib competes in an increasingly crowded osteosarcoma therapeutic landscape. Phase 3 programs include docetaxel plus lobaplatin (Xiyuan Hospital of China Academy of Chinese Medical Sciences), cisplatin monotherapy (Children's Hospital of Fudan University), and zoledronic acid (Ningbo Cancer Hospital), representing both chemotherapy intensification and bone-targeted strategies. Phase 2 competitors include lenvatinib (Eisai), a multikinase inhibitor; REOLYSIN (Oncolytics Biotech), an oncolytic virus; omomyc (The George Institute), a c-Myc inhibitor; MK-7902-013 (Merck Sharp and Dohme); mifamurtide (Takeda); and multiple other agents including Sm-EDTMP (Jazz Pharmaceuticals), trilaciclib (The First People's Hospital of Lianyungang), and UC-0150/1704 (Ningbo Cancer Hospital). This competitive density reflects both the clinical urgency in osteosarcoma and the absence of transformative therapies in recent decades. Azenosertib's differentiation will depend on its mechanism of action, safety profile, and efficacy data relative to these programs, which remain to be disclosed as Phase 1 data mature.
| Therapy | Company | Mechanism | Status |
|---|---|---|---|
| Docetaxel+lobaplatin | Xiyuan Hospital of China Academy of Chinese Medical Sciences | small_molecule | phase_3 |
| Cisplatin | Children's Hospital of Fudan University | small_molecule | phase_3 |
| Zometa 4 mg/100 ml solution for infusion | Ningbo Cancer Hospital | small_molecule | phase_3 |
| Lenvatinib | Eisai Co., | small_molecule | phase_2 |
| REOLYSIN® | ONCOLYTICS BIOTECH INC | mab | phase_2 |
| Omomyc | The George Institute | small_molecule | phase_2 |
| MK-7902-013 | Merck Sharp and Dohme | small_molecule | phase_2 |
| IB 2020-02 | The George Institute | small_molecule | phase_2 |
| Mifamurtide | Takeda | small_molecule | phase_2 |
| Sm-EDTMP | Jazz Pharmaceuticals Ireland Limited | small_molecule | phase_2 |
| UC-0150/1704 | Ningbo Cancer Hospital | small_molecule | phase_2 |
| Trilaciclib | The First People's Hospital of Lianyungang | small_molecule | phase_2 |
| SOCAZOLIMAB | — | Programmed cell death 1 ligand 1 inhibitor | Phase 3 |
| PEGINTERFERON ALFA-2B | — | Interferon alpha/beta receptor agonist | Phase 3 |
| METHOTREXATE | — | Dihydrofolate reductase inhibitor | Phase 3 |
| ETOPOSIDE | — | DNA topoisomerase II inhibitor | Phase 3 |
| DOXORUBICIN HYDROCHLORIDE | — | DNA topoisomerase II alpha inhibitor | Phase 3 |
| DOXORUBICIN | — | DNA topoisomerase II alpha inhibitor | Phase 3 |
| ZOLEDRONIC ACID ANHYDROUS | — | Farnesyl diphosphate synthase inhibitor | Phase 2 |
| ZOLEDRONIC ACID | — | Farnesyl diphosphate synthase inhibitor | Phase 2 |
Additional associated therapies sourced from Open Targets Platform (CC0), linked to NovaPharmaNews drug profiles where matched.
FDA Status: Not yet disclosed. Azenosertib is in Phase 1 development; no regulatory submissions or designations have been announced.
EMA Status: Not yet disclosed.
PMDA (Japan) Status: Not yet disclosed.
NMPA (China) Status: Not yet disclosed.
Breakthrough Therapy Designation: Not yet disclosed.
Orphan Drug Designation: Not yet disclosed, though osteosarcoma's rarity may qualify for such status in relevant jurisdictions.
Regulatory strategy and any expedited pathways will likely be determined following Phase 1 data readout and Phase 2 trial design. No approval history is applicable at this early stage of development.
Azenosertib is an investigational small-molecule oncology agent being developed by Zentalis Pharmaceuticals for the treatment of osteosarcoma, a rare primary bone malignancy.
No. Azenosertib is currently in Phase 1 clinical development and has not been approved by the FDA or any other regulatory authority.
The mechanism of action of azenosertib has not yet been disclosed by Zentalis Pharmaceuticals.
Azenosertib is developed and sponsored by Zentalis Pharmaceuticals. No manufacturing partner has been disclosed.
The internal research code for azenosertib is ZN-c3-003.
Azenosertib is being evaluated in Phase 1 trial NCT04833582, registered in the clinical trial database. Specific trial design details have not been disclosed.
Azenosertib is in Phase 1 clinical development, the earliest stage of human testing focused on safety and tolerability assessment.
Osteosarcoma is a rare, aggressive primary bone malignancy that predominantly affects adolescents and young adults. It represents a significant unmet medical need despite existing standard-of-care chemotherapy regimens.
Competing therapies include Phase 3 programs (docetaxel plus lobaplatin, cisplatin, zoledronic acid) and Phase 2 programs (lenvatinib, REOLYSIN, omomyc, mifamurtide, and others). Standard of care includes cisplatin-based chemotherapy combined with surgical resection.
Orphan drug designation status for azenosertib has not been disclosed. Osteosarcoma's rarity may qualify the program for such status in relevant jurisdictions.
No approval timeline has been disclosed. Typical Phase 1 completion requires 12–24 months, with Phase 2 and regulatory review extending timelines to 2029–2031 or later.
No development partner has been disclosed for azenosertib. Zentalis is sponsoring the program independently.
The specific molecular target of azenosertib has not been disclosed by Zentalis Pharmaceuticals.
The route of administration for azenosertib has not been disclosed.
The latest milestone for azenosertib was recorded on April 3, 2026. Specific details of this milestone have not been disclosed.
Azenosertib is a small-molecule investigational agent, not a biologic therapy.
Azenosertib → Drug → Target → Indication → Company → Trials → Competitors
Strategic Positioning: Zentalis's entry into osteosarcoma represents a focused strategy in rare oncology where unmet medical need is acute and regulatory pathways may be accelerated. The Phase 1 stage indicates early-stage clinical validation; advancement will require demonstration of acceptable safety and preliminary efficacy signals in Phase 2.
Competitive Implications: The osteosarcoma landscape is increasingly competitive, with multiple Phase 2 and Phase 3 programs advancing. Azenosertib's differentiation will hinge on its mechanism of action (currently undisclosed), safety profile relative to standard chemotherapy, and efficacy in both chemotherapy-naive and refractory populations. The presence of Phase 3 programs suggests regulatory pathways may accelerate for Phase 2 programs demonstrating compelling signals.
Key Catalysts: Phase 1 safety and tolerability data readout; Phase 2 trial initiation and design; preliminary efficacy signals; regulatory designation decisions (orphan drug, breakthrough therapy); competitive trial readouts from Phase 2 and Phase 3 programs.
Timeline Considerations: Phase 1 completion typically requires 12–24 months; Phase 2 initiation and data readout would extend the timeline to 2027–2029 at earliest. Regulatory approval, if achieved, would likely occur in 2029–2031 or later, depending on Phase 2 efficacy and regulatory feedback.
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Intelligence compiled from public regulatory and clinical sources (FDA, EMA, ClinicalTrials.gov and company disclosures). Figures may be editorial or analyst estimates; verify against primary sources before relying on them.