Shares in Zeltia have taken a battering after staff at the US Food and Drug Administration said that more data may be required before the Spanish firm’s Yondelis can be approved for ovarian cancer.

The FDA’s Oncologic Drugs Advisory Committee will meet to discuss a filing which is being presented by Zeltia’s US partner Johnson & Johnson on July 15. The companies are hoping to get approval for Yondelis (trabectedin) for the treatment of relapsed ovarian cancer, in combination with J&J’s Doxil/Caelyx (doxorubicin).

However documents released on the FDA’s website reveal that FDA staff believe there are discrepancies in radiology readings which raise the question of whether patients' status was reliably assessed in the main study of the drug, which measured time to disease progression. Specifically, J&J data includes imaging scans to show a halt in cancer progression, but the agency’s staff noted that radiology experts hired by the company disagreed on the interpretation of those findings 39% of the time.

J&J, in notes prepared for the panel review, said that the Yondelis and Doxil combination is safe and effective, especially for women with relapsed ovarian cancer who cannot take other platinum-based regimens. Whether the panel agrees remains to seen, but fears about the reliability and clinical significance of the data meant that Zeltia shares tumbled 11.1% to 4.89 euros.

Last week, the Madrid-headquartered firm was boosted by the news that regulators in the Philippines have approved Yondelis for the treatment of recurrent ovarian cancer as well as advanced soft tissue sarcoma. The drug is already available for the latter indication in Europe and a number of other territories, including Argentina, Venezuela, South Korea and Russia.