SARC041: A PHASE 3 RANDOMIZED DOUBLE-BLIND STUDY OF ABEMACICLIB VS. PLACEBO IN PATIENTS WITH ADVANCED DEDIFFERENTIATED LIPOSARCOMA
ASCO Annual Meeting, May 31, 2026:
Abemaciclib, a CDK4/6 targeted therapy, was shown to improve progression-free survival in people with advanced Dedifferentiated Liposarcoma (DDLPS), a highly aggressive cancer with few effective treatment options.
The plenary at ASCO 2026 (Chicago, IL) featured abemaciclib, a targeted CDK4/6 inhibitor, as a promising new therapy for advanced dedifferentiated liposarcoma (DDLPS).
Treatment options for recurrent or metastatic DDLPS remain limited. Surgery is common but DDLPS has a risk of recurrence and current approved drug treatments have not prevented or significantly delayed disease progression for prolonged periods.
Since tumor growth in DDLPS is driven by an overactive CDK4 gene, researchers tested abemaciclib to block CDK4 and hopefully lead to DDLPS stability or shrinkage.
The primary goal of this study was to determine whether abemaciclib could help patients have longer time between disease progression, calculated as progression-free survival (PFS).
How the Study Was Conducted
- Phase 3 clinical trial (SARC041)
- Randomized and double-blind (patients and researchers do not know who receives the drug vs. placebo)
- Conducted at 9 academic medical centers in the United States
Participant Requirements
A total of 108 patients with recurrent or metastatic DDLS participated.
To join the study, patients had to:
- Have DDLPS that had returned or spread
- Show disease progression within the previous 6 months
- Have adequate overall health and organ function
- Have received any number of previous cancer treatments
Key Results
1. Abemaciclib Significantly extended PFS, where patients who received abemaciclib had 6x longer time without disease progression than those receiving the placebo.
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Specifically, patients receiving abemaciclib had: 9.67 months without progression longer than those on placebo (1.5 months)
The difference was both clinically meaningful and statistically significant, indicating the result was unlikely to be due to chance.
2. More Tumor Responses With Abemaciclib was observed. Researchers measured how many patients experienced meaningful tumor shrinkage.
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9.3% of patients receiving Abemaciclib had partial or complete shrinkage (response rate) compared to none with the placebo
Responses occurred only in the abemaciclib group.
3. Survival Results Were Encouraging
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The study duration has not been very long, meaning long-term follow-up is needed. Because of that, the overall survival for the abemaciclib group had not yet been reached, meaning most patients were still alive at the end of the data cut-off.
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The middle duration for overall survival for the placebo group was 25.45 months.
Many patients on abemaciclib were still alive when the study results were analyzed, while median overall survival in the placebo group was about 25 months.
4. Patients benefited after switching from placebo to abemaciclib. Patients whose cancer progressed on placebo were allowed to switch to abemaciclib, whereas:
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For patients that switched from the placebo to abemaciclib, on abemaciclib, they had 3.44 months longer without progression than the placbeo.
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For patients that switched from placebo to abemaciclib, 4.3% of those patients had partial or complete shrinkage of their DDLPS
- Median overall survival was 24.03 months
This suggests abemaciclib can still provide benefit even after disease progression on placebo.
Safety Results:
- Rates of severe (grade 3 or higher) side effects were similar in both groups
- No unexpected safety concerns were identified
- No new safety signals were observed
Overall, the treatment was generally well tolerated.
What These Results Mean
This is one of the first studies to show a clear benefit from a targeted therapy in patients with DDLPS. In patients with recurrent or metastatic DDLPS, abemaciclib significantly improved the time patients lived without disease progression.
The treatment was generally safe, produced some tumor responses, and showed encouraging signs of improving overall survival. And, based on these findings, the researchers concluded that abemaciclib should be considered a new treatment option for patients with dedifferentiated liposarcoma.
Next Steps
Researchers plan to further analyze the study results to better understand why abemaciclib is more effective for some patients with DDLPS than others.
They will also search for biomarkers (measurable characteristics in tumors or blood) that could help identify which patients are most likely to benefit from the treatment.
In addition, future studies may evaluate newer CDK4-targeting therapies to determine whether they can provide even greater or longer-lasting control of DDLPS.
