Medivir has posted data from a phase 2 trial of its histone deacetylase (HDAC) inhibitor in patients with cutaneous T-cell lymphoma (CTCL). One regimen of the treatment triggered responses in 40% of subjects, a finding that has encouraged the Swedish pharmaceutical company to push ahead with plans to start a phase 3 trial later this year.
Investigators enrolled 60 patients with the slow-growing mycosis fungoides form of CTCL, a type of non-Hodgkin lymphoma that initially manifests as eczemalike skin patches. Medivir randomized the participants to receive one of three regimens of topical HDAC inhibitor remetinostat. Patients took the drug for between six and 12 months—depending on whether they continued past the initial 26-week cutoff—and underwent assessments of lesion severity every four weeks.
Medivir saw the highest proportion of responders among the 20 patients who administered a 1% formulation of remetinostat gel twice a day. In this cohort, Medivir saw eight responses, including one complete response. The other cohorts received either a 1% formulation once a day or a 0.5% formulation twice a day. Those cohorts recorded response rates of 20% and 25%, respectively. Medivir said the drug was well tolerated and the trial saw no signs of systemic adverse effects.
The data build on interim results presented at the start of last year by TetraLogic Pharmaceuticals, the company Medivir bought the experimental asset from in November in a deal worth $12 million upfront. At the interim review, TetraLogic recorded eight responses among the 34 patients assessed at that time. Medivir sees the updated data as supporting the rationale that drove it to buy the asset.
"There are few drugs available for the treatment of the disease, and those currently available have generally poor tolerability,” Medivir CSO Richard Bethell said in a statement. “Remetinostat was designed to effectively inhibit HDACs within cutaneous lesions, but to be rapidly broken down in the bloodstream, preventing the side effects associated with systemically administered HDAC inhibitors.”
With Medivir interpreting the data as giving remetinostat a shot at meeting this therapeutic need, it plans to start talking to regulators with a view to getting into phase 3 before the end of the year. When Medivir bought the asset last year it predicted it could win approval with a phase 3 program of “modest size and cost,” but that it was unlikely to bring remetinostat to market before 2021.
If Medivir can execute that plan, it thinks a market worth $900 million in the U.S. will open up. As it stands, physicians take a watch-and-wait approach to some patients with early-stage CTCL, before going on to treat them with topical steroids. Later-line treatments include chemotherapy cream, ultraviolet light and radiotherapy. But, as Medivir sees it, there is a need for more tolerable, easier to use treatment options for patients with early-stage CTCL.