A new report shows that Introgen Therapeutics has submitted marketing authorisation applications for Advexin p53 therapy on both sides of the Atlantic. However, Introgen may struggle to convince the regulatory authorities that the gene therapy drug will offer an improvement in the treatment of head and neck cancer.

While Introgen filed a Biologics License Application for Advexin p53 therapy with the FDA for the treatment of recurrent, refractory head and neck cancer, Gendux Molecular Limited, an Introgen subsidiary, submitted the equivalent application in Europe.

The Advexin p53 therapy combines the p53 tumour suppressor with a non-replicating, non-integrating adenoviral delivery system. Delivering large doses of the normal tumour suppressor p53 gene, it is designed to restore natural tumour suppressor mechanisms, which are often abnormal in cancer cells.

The regulatory application is based on pivotal Phase II and III study data, which evaluated survival, tumour response and safety in patients with recurrent, refractory squamous cell carcinoma of the head and neck (SCCHN). The Phase III study compared Advexin with methotrexate in SCCHN patients who had failed surgery, radiotherapy and chemotherapy with a platinum drug or a taxane.

Whether these results can form the basis of a regulatory approval remains to be seen. In the absence of a strikingly improved safety profile over methotrexate, a rather toxic chemotherapy, Advexin is expected to struggle to convince the regulatory authorities of its clinical benefit and cost effectiveness. In addition, the lack of precedence in the approval of cancer gene therapies may cause further delays and complications in Advexin’s path to regulatory approval. Along with the regulatory hurdles, Advexin will also face considerable skepticism generated by prior failures of gene therapies to improve the treatment of cancer.

For further information see Stakeholder Opinions: Head and Neck Cancer