Medivir delays pivotal HDAC trial as FDA discussions stall

A year ago, Medivir was riding high after reporting midstage data that encouraged it to press ahead with a pivotal trial of its HDAC inhibitor remetinostat in cutaneous T-cell lymphoma (CTCL). It’s hit a snag though—it can’t agree on a design for the study with the FDA.

The Swedish biotech issued a statement this morning saying it had "decided to continue the discussions" with the agency on the design, and that delay means it won’t be ready to start the study this year as planned.

Its shares went on the slide as investors digested the update and tried to work out the implications, with the stock trading down more than 11% at the time of writing. Medivir bought the rights to remetinostat from TetraLogic Pharma for $12 million upfront in November 2016, and the drug is currently its lead pipeline candidate.

Christine Lind, Medivir’s CEO, said "it is of utmost importance that we design a phase 3 study that meets the expectations of the regulatory agencies. Further discussions with the FDA are needed to ensure that we can initiate a pivotal study that will allow us to bring this drug through approval and to patients."

Medivir is hoping to open up a new CTCL market in the US for the drug worth an estimated $900 million, based on around 15,000 potential patients. It hopes it could provide an active treatment for early-stage CTCL patients who are currently just monitored until their symptoms progress sufficiently to need treatment with topical steroids, UV light and radiotherapy and topical chemotherapy—all of which have tolerability issues.  

Last year all seemed to be on track, with Medivir reporting phase 2 data with remetinostat that showed a 40% response rate in 60 patients with a slow-growing form of CTCL called mycosis fungoides (MF), with the highest responses seen in patients treated with a 1% gel formulation of the drug.

The delay is the second pipeline setback for Medivir in recent months, coming after Johnson & Johnson pulled the plug on a hepatitis C virus program partnered with the Swedish biotech after deciding there was little market opportunity. It also lost former chief medical officer John Öhd who departed the company in March who has yet to be replaced. The company’s share price has been cut in half over the last 12 months.

Meanwhile, the HDAC inhibitor class as a whole has come under pressure of late after one of the leaders in the category, Syndax, revealed less-than-stellar results for its entinostat candidate in a combination trial which spooked investors.

The Swedish biotech has however had some good pipeline news as well, including a positive phase 2a trial for osteoarthritis drug MIV-711-201, a cathepsin K inhibitor that the company is hoping to license to a development partner. The study showed that patients on the drug for six months or more had reduced bone destruction and cartilage thinning compared to placebo.

It’s also waiting on the results of a phase 1/2 combination study of immuno-oncology drug birinapant, a SMAC mimetic, in combination with Merck & Co’s Keytruda in treatment-resistant solid tumors. That drug also has a checkered history, having failed as a monotherapy in myelodysplastic syndromes when it was owned by TetraLogic in 2016.