The company Epizyme has announced the results of a Phase 2 clinical study of its lead candidate drug, tazemetostat, in the treatment of relapsed or refractory malignant mesothelioma with loss of BAP1 function. The full article can be read at Globe Newswire.
Mesothelioma is a form of cancer that affects the lining of certain body organs, most often the lungs. It is often linked to asbestos exposure. Asbestos is a material used in building and construction that is comprised of tiny fibres that can enter the lungs and cause damage. Often, mesothelioma will develop years, and sometimes decades, after exposure. Asbestos is now banned in many countries worldwide, although older buildings may still contain it. Approximately 12,400 people in the US, EU5, and Japan are estimated to be diagnosed with mesothelioma each year. Half of the patients have BAP1 loss of function. BAP1 is involved in regulating cell growth and death and acts as a tumour suppressor.
Epizyme’s Phase 2 clinical trial of tazemetostat on patients with relapsed or refractory malignant mesothelioma and BAP1 loss of function produced promising results. 61 patients took part, half of who achieved disease control by 12 weeks. Disease control was defined as complete response (cancer completely disappearing for a period), partial response (cancer shrinkage by a certain amount), or stable disease (cancer doesn’t change size). By 16th January 2018 16 of the patients had maintained disease control for at least 24 weeks since beginning treatment with tazemetostat.
The trial was carried out at multiple centres and was open-label (patients were aware which drug they were receiving). Patients were given 800mg tazemetostat monotherapy twice per day. In total, 74 patients were enrolled. 13 were enrolled regardless of BAP1 status and were given the drug to assess its safety. The other 61 patients all had BAP1 loss of function and were evaluated for the drug’s effect on disease control.
Tazemetostat functions by inhibiting EH2. It is being tested as a treatment for solid tumours, including several lymphomas, epithelioid sarcoma and other INI1-negative tumours, and mesothelioma, amongst others.