A lot of distance lies between talking regulatory flexibility and actually being flexible. That message was driven home again after Uniqure NV disclosed in its latest earnings report March 2 that the U.S. FDA wants a sham-controlled study before it will consider approval of the company’s gene therapy AMT-130 in Huntington’s, a rare disease currently affecting about 41,000 people in the U.S.

Cure Rare Disease has entered into a multiyear partnership with the LGMD2L Foundation to develop a gene replacement therapy for anoctamin 5 (ANO5)-related disease, a rare genetic disorder.

Uniqure NV is the latest firm to get caught between the FDA’s shifting demands for “gold standard” science and regulatory flexibility for rare disease therapies. The company disclosed in its latest earnings report that U.S. regulators are calling for a sham-controlled study before they will consider approval of gene therapy AMT-130 in Huntington’s disease, a requirement that could set the program back by two to three years and raises potential ethical issues.