Treatment for osteosarcoma has remained largely unchanged for decades, particularly for patients with metastatic or relapsed disease. Targeted therapies are now being explored as a way to improve outcomes.
One of these is cabozantinib, a drug currently being studied in multiple osteosarcoma clinical trials worldwide.
What is cabozantinib?
Cabozantinib is a targeted cancer therapy that blocks signals involved in tumour growth, blood vessel formation, and spread.
Unlike chemotherapy, which targets rapidly dividing cells, cabozantinib works by targeting the biological pathways that help cancer grow and metastasise.
Cabozantinib was developed by Exelixis and first approved by the U.S. Food and Drug Administration in 2012 for thyroid cancer. It is now also used in kidney and liver cancer.
Its ability to target multiple pathways led researchers to explore its use in sarcomas, including osteosarcoma.
What do we know so far?
Cabozantinib is not a cure, but it has shown activity in osteosarcoma, particularly in advanced disease.
Studies suggest:
- Around 10–15% of patients see tumour shrinkage
- Around 50–60% of patients experience disease stabilisation
- Some patients have months of disease control
This means the drug may help slow or control the cancer for a period of time in some patients.
What trials are available?
Cabozantinib is being studied at different stages of treatment:
- NCT05691478
For patients with newly diagnosed osteosarcoma
Typically includes children, teenagers and young adults (up to around age 40)
Testing cabozantinib with standard chemotherapy
Primarily recruiting in the United States - NCT06341712
For patients who have completed initial treatment
Testing cabozantinib to reduce the risk of relapse
Includes European and international sites - Additional early-phase studies are exploring combinations and use in relapsed disease
Eligibility for trials varies, but often includes factors such as:
- Age range (commonly children to young adults)
- StageA way to characterize the size and spread of cancer and help to guide treatment. of disease (newly diagnosed, post-treatment, or relapsed)
- Overall health and ability to tolerate treatment
Patients should always speak with their clinical team about suitability.
Where are these trials?
Trials are running across:
- United States – leading first-line studies in newly diagnosed patients
- Europe and international sites – particularly maintenance and collaborative trials
Access depends on location, eligibility, and referral pathways.
What about use in relapsed disease?
Additional studies are exploring cabozantinib in patients whose cancer has returned or not responded to treatment.
These include:
- Combination with chemotherapy, such as ifosfamide
- Studies alongside other treatments, including immunotherapy
- Early-phase trials testing safety and effectiveness
The aim is to understand whether combining cabozantinib with existing treatments can improve outcomes, particularly in more difficult-to-treat cases.
Can it be used outside trials?
Cabozantinib is approved for other cancers and may sometimes be used outside trials.
However, it is not currently standard treatment for osteosarcoma, and access depends on specialist decision-making.
Why this matters
Cabozantinib represents a different approach to treating osteosarcoma by targeting how the cancer grows and spreads.
Ongoing research is exploring how it can be used:
- At diagnosis
- After initial treatment
- In relapsed disease
Final thoughts
Cabozantinib is an established cancer drug now being actively studied in osteosarcoma.
While not a cure, it has shown the ability to control disease in some patients, and ongoing trials will help define its role in future treatment.
Find osteosarcoma clinical trials by visiting https://osteosarcomanow.org/clinical-trials/