Oncology · Clinical trials
Soft-Tissue Sarcoma Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About soft-tissue sarcoma — and why its trials are hard
Soft-tissue sarcomas are a heterogeneous family of more than 70 histological subtypes of mesenchymal origin (leiomyosarcoma, liposarcoma, synovial sarcoma, undifferentiated pleomorphic sarcoma and many others), collectively rare and biologically diverse. Surgery with adequate margins, often combined with radiotherapy, is the mainstay for localised disease; systemic therapy is reserved mainly for advanced or metastatic disease. Anthracycline-based chemotherapy, principally doxorubicin, has been the first-line backbone for decades, with limited response rates and modest survival gains. The heterogeneity of subtypes is the central obstacle to drug development: agents effective in one histology may be inert in another, and enrolling adequately powered trials across dozens of rare subtypes is extremely difficult. Progress has come from subtype- and biomarker-directed approvals (eribulin in liposarcoma, trabectedin in liposarcoma/leiomyosarcoma, tazemetostat in INI1-deficient epithelioid sarcoma) and the antiangiogenic pazopanib. Unmet need remains high: durable responses are uncommon, and the high-profile withdrawal of olaratumab underscored the difficulty of confirming benefit in this setting.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| Doxorubicin (Adriamycin (generic)) | pre-1980s (foundational) | First-line advanced STS backbone, alone or with ifosfamide | Historical cooperative-group studies | Objective response rate | Single-agent ORR ~15-20%; remains the reference standard |
| Pazopanib (Votrient) | 2012 | Advanced non-adipocytic STS after prior chemotherapy | PALETTE (phase 3) | Progression-free survival | Median PFS 4.6 vs 1.6 months vs placebo (HR ~0.31) |
| Trabectedin (Yondelis) | 2015 | Unresectable/metastatic liposarcoma or leiomyosarcoma after an anthracycline | ET743-SAR-3007 (phase 3 vs dacarbazine) | Progression-free survival | Median PFS 4.2 vs 1.5 months (HR ~0.55); OS not significantly improved |
| Eribulin (Halaven) | 2016 | Unresectable/metastatic liposarcoma after an anthracycline | Study 309 (phase 3 vs dacarbazine) | Overall survival | Median OS 15.6 vs 8.4 months in the liposarcoma subset (HR ~0.51) |
| Tazemetostat (Tazverik) | 2020 | Metastatic/locally advanced epithelioid sarcoma not eligible for complete resection | Phase 2 basket (EZH2 inhibitor; INI1/SMARCB1-deficient) | Objective response rate | ORR ~15% with durable responses (accelerated approval) |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in soft-tissue sarcoma development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Olaratumab — ANNOUNCE (phase 3, with doxorubicin) | Failed to confirm OS benefit seen in the phase 2 JGDG study; drug voluntarily withdrawn in 2019 | Small, potentially imbalanced phase 2 that supported accelerated approval did not replicate; PDGFR-alpha antibody added no survival over doxorubicin |
| Doxorubicin + ifosfamide (intensification) — EORTC 62012 (phase 3) | Combination improved response and PFS but not overall survival vs doxorubicin alone | Added toxicity without survival gain; reinforced single-agent doxorubicin as standard first-line for most patients |
Choosing the right endpoint
Primary endpoints that matter in soft-tissue sarcoma trials
- Progression-free survival (PFS) — Common primary endpoint (PALETTE, trabectedin) given long post-progression survival that dilutes OS; sensitive to disease stabilisation
- Overall survival (OS) — Definitive but hard to power across rare subtypes; achieved for eribulin in liposarcoma but not for several other agents
- Objective response rate (ORR) — Basis for subtype-specific accelerated approvals (tazemetostat); responses are frequently modest in this chemo-resistant family
- Histology-specific analysis — Pre-specified subtype analyses (liposarcoma vs leiomyosarcoma) are essential because efficacy is highly subtype-dependent
- Pathologic/radiologic response (neoadjuvant) — Used in localised-disease and perioperative studies as an early efficacy signal before survival readouts mature
How iNGENū runs soft-tissue sarcoma trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Soft-Tissue Sarcoma clinical trials — FAQs
Why are there so few approved drugs given how many people are affected?
What happened with olaratumab?
Is chemotherapy still central to treatment?
Ready to discuss your soft-tissue sarcoma trial?
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