• 45 patients. 12-week lead-in stage PR: 14%, SD: 57%, PD: 21%; PFS at randomized stage: cabozantinib, 6.9 months, placebo, 0.9 months.
• Partial bone scan resolution: 4/10 pts (40%); bone pain improvement: 5/13 (38%). Adverse events were manageable.

Cabozantinib would be just another potentially promising targeted agent under investigation except for the weird observations that have been made in the bone scans of patients with a variety of tumors, particularly prostate cancer but also now renal cell carcinoma and breast cancer. Specifically, this TKI has been shown to cause rapid, marked and obvious changes/improvements in areas of metastatic disease on conventional bone scans, and although it is not completely clear whether patients also benefit clinically (they are said to), there is much future hope for cabozantinib across many solid tumors. Importantly, the recent FDA approval of the drug will give oncologists the opportunity to witness its impact and toxicities firsthand when (or much more likely if) they encounter a rare case of medullary thyroid cancer in their practice.