Vandetanib beneficial in advanced medullary thyroid cancer

In patients with advanced medullary thyroid cancer (MTC), treatment with vandetanib in the first- or second-line setting provides sustained clinical benefit, with predictors of durable response including younger age at diagnosis and absence of progression, according to a study.

The study involved 76 MTC patients treated with vandetanib, of which nine were excluded from the efficacy analysis due to lack of morphological data.  Efficacy was estimated by markers and imaging.

The median treatment duration was 17.6 months, while the median progression-free survival (PFS) was 22.7 months (95 percent confidence interval [CI], 13.9–37.3). There were 21 (27.6 percent) patients classified as long-term users, owing to having received vandetanib for >48 months, with a median treatment duration of 68.1 months (range, 49.1–130.6).

Among long-term users, the objective response rate was 85.7 percent. The median time to best response was 27.8 months (range, 11.6.1–110), while the median duration of response was 70.4 months (95 percent CI, 49.5–102.8); the median PFS was 73.2 months (95 percent CI, 53.1–105.6).

Duration of response negatively correlated with patient age at diagnosis (p=0.03) and was significantly higher in patients who had no confirmed tumour progression prior to initiation of treatment (p=0.007).

Over 48 months of vandetanib treatment, renal failure occurred in two patients. Other documented events were heart failure, cholecystitis, acute pancreatitis, posterior encephalopathy, and skin cancer.