A Phase II Trial of Valproic Acid in Patients With Advanced Thyroid Cancers of Follicular Cell Origin
Status:
Completed
Trial end date:
2016-04-28
Target enrollment:
Participant gender:
Summary
Background:
- Patients who have advanced thyroid cancer have a low long-term survival rate. These
types of thyroid cancer do not respond well to conventional surgery or radiation, or to
specific thyroid cancer treatments such as radioactive iodine treatment and thyroid
hormone for thyroid stimulating hormone (TSH) suppression.
- Valproic acid has long been approved as an anticonvulsant to treat seizures in patients
with epilepsy. It has also been used to treat bipolar disorder. Recent studies have
shown that valproic acid has promising effects in thyroid cancer treatment because it
may help destroy cancer cells and help conventional treatments be more effective.
However, valproic acid is not approved for thyroid cancer and is therefore an
investigational drug.
Objectives:
- To determine whether valproic acid can inhibit tumor growth or induce tumor cell death.
- To determine whether valproic acid can make tumor cells increase their uptake of
radioiodine.
Eligibility:
- Individuals at least 18 years of age who have advanced-stage thyroid cancer that is either
unresponsive to conventional treatments or fails to absorb radioiodine.
Design:
- Eligible participants will continue on the standard thyroid hormone suppression therapy
and begin receiving valproic acid for a total of 10 weeks. Participants will keep a
study diary to record doses and side effects, and will have regular clinic visits to
provide blood samples and receive additional valproic acid.
- After 10 weeks, participants will have a Thyrogen scan to measure radioiodine uptake
after valproic acid therapy. Tumor biopsies and blood samples will be taken at this
time.
- If there is increased radioiodine uptake on the scan, participants will have additional
radioiodine therapy.
- If there is no increased uptake on the scan, participants will continue on valproic acid
for 7 more weeks. After 16 total weeks of treatment, additional blood samples and scans
will be taken. Participants may continue to take valproic acid if the thyroid cancer
appears to be responding to the treatment.
- Follow-up visits will be scheduled at 3, 6, 9 (for patients continuing on valproic acid
only), and 12 months.