FDA Grants Fast Track Designation for the Investigation of Zactima (ZD6474) for the Treatment of Thyroid Cancer

Drug company AstraZeneca announced this week that the US Food and Drug Administration (FDA) has granted fast track designation for the investigation of the drug Zactima, (ZD6474) in treating medullary thyroid carcinoma. Advanced hereditary medullary thyroid cancer, a rare malignancy, has a poor prognosis and there are currently very limited therapeutic options available, so Zactima is entering a market where there are limited treatments available. It is estimated that 2-3% of the estimated 25,000 new cases of thyroid cancer diagnosed in the USA in 2005 are medullary thyroid cancer and of these, around a quarter are hereditary. The incidence in Europe is similar.

Zactima also received orphan-drug designation last year for the treatment of patients with follicular, medullary, anaplastic, and locally advanced and metastatic papillary thyroid cancer.

"We are pleased to receive fast track designation for Zactima for the treatment of medullary thyroid cancer, and are committed to evaluating the potential of Zactima as a new treatment option for patients with this disease," said Peter Langmuir, MD, Senior Director, Medical Science, AstraZeneca.

The fast-track designation is intended to facilitate the development and expedite the review of investigational drugs that are intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs.

Zactima is currently being evaluated in a Phase II clinical trial in medullary thyroid cancer, and AstraZeneca is currently enrolling patients in a single arm Phase II Zactima study in locally advanced or metastatic hereditary medullary thyroid cancer. For more information on this trial, please call the AstraZeneca Cancer Support Network at 1-866-992-9276.

This fall, AstraZeneca reported "encouraging" preliminary results in a trial of Zactima to treat follicular, medullary, anaplastic, and locally advanced and metastatic papillary thyroid cancer.

In the current trial, nine of the first 11 thyroid cancer patients taking Zactima had stable disease -- where the advancement of their cancer was halted -- after three months, and two showed a partial response, where their measurable tumour shrank by 30% or more.

According to AstraZeneca, patients taking Zactima also showed lower levels, on average, of an antigen considered a thyroid cancer marker. Plasma 'biomarkers' calcitonin and carcinoembryonic antigen - which generally reflect the amount of cancer in patients with medullary thyroid cancer - were reduced by an average of 72% and 25% respectively, following treatment with Zactima.

Zactima is a once-daily oral treatment. It works by selectively targeting key cell signalling pathways involved in tumour growth and spread, including VEGF (Vascular endothelial growth factor) receptor signalling and EGF (Epidermal growth factor) receptor signalling. Zactima also inhibits RET kinase, which drives the growth and survival of certain tumors, and is believed to be an important pathway in medullary thyroid cancer.

Lead trial investigator Professor Samuel Wells, MD, Duke University Medical Center, Durham NC, USA, commented, "These data are very encouraging for patients with this rare form of thyroid cancer. Neither standard chemotherapeutic regimens, nor radiation therapy, provide substantial benefits to these patients. In this small ongoing study, ZD6474 has shown promising results in patients with this disease."

Source: AstraZeneca