Sitravatinib (MGCD516) is a receptor tyrosine kinases (RTK) inhibitor that blocks a wide array of RTKs known to be amplified/overexpressed in sarcomas, which are key regulators of signaling pathways that lead to cell growth, survival and tumor progression. It is involved in driving sarcoma cell growth with IC50 of 3980 nM and is superior to other multi-kinase inhibitors in inhibiting cell proliferation, RTK phosphorylation, and phosphorylation of downstream effectors. The efficacy of sitravatinib was tested using a wide panel of sarcoma cell lines, including malignant peripheral nerve sheath tumor (MPNST), Ewing sarcoma (A673), osteosarcoma (Saos2), and liposarcoma (DDLS, LS141). Both in vitro and in vivo efficacy sitravatinib was significantly better that the other two multi-kinase inhibitors, imatinib and crizotinib. Sitravatinib treatment not only inhibits tumor cell proliferation at low nanomolar concentrations in vitro but also results significant tumor growth suppression in vivo in mouse xenograft models. Sitravatinib is being evaluated in a Phase 1b dose expansion cohort in selected patients with specific genetic alterations that are drivers of tumor growth, with an initial focus on Non-Small-Cell Lung carcinoma (NSCLC) and in other solid tumors where sitravatinib may confer a benefit. Its efficacy and safety is also being tested in Phase II clinical trials in patients with advanced liposarcoma as a monotherapy and NSCLC in combination with nivolumab.

Racemetirosine is an orally active inhibitor of the enzyme tyrosine 3-monooxygenase, and consequently of the synthesis of catecholamine. At dosages of 600 to 3500mg daily, it is effective in controlling the hypertensive episodes and symptoms of catecholamine excess in phaeochromocytoma during preparation for surgery. Oral Racemetirosine is well absorbed and absorption appears constant in each individual over a wide dosage range. The drug is largely excreted via the kidneys, but extrarenal elimination has not been studied. Case reports on the clinical use of Racemetirosine in phaeochromocytoma indicate that the drug controls hypertension and symptoms of catecholamine excess in most patients during preparation for surgical removal of a tumor. In some cases, the addition of Racemetirosine to phenoxybenzamine plus propranolol has resulted in adequate control of symptoms previously unresponsive to the adrenergic blocking regimen. Drowsiness and sedation have been the most frequently reported side effects of Racemetirosine treatment.