Half of patients with advanced ovarian cancer responded either fully or partially to a combination of quisinostat, Taxol (paclitaxel) and Paraplatin (carboplatin), according to a Phase 2 clinical trial.
The trial (NCT02948075) dealt with patients with metastatic or advanced ovarian cancer whose cancer had progressed after first-line platinum and Taxol-based chemotherapy.
The regression rate of a little more than half the patients who received the combo was much higher than researchers expected.
The poster-session presentation was titled “A multicenter phase II study of the efficacy and safety of quisinostat (an HDAC inhibitor) in combination with paclitaxel and carboplatin chemotherapy (CT) in patients (pts) with recurrent platinum resistant high grade serous epithelial ovarian, primarily peritoneal or fallopian tube carcinoma cancer (OC).”
Quisinostat inhibits a protein called histone deacetylase, or HDAC1, which helps regulate gene expression in cells. Expression is the process by which information from a gene is used to create a functional product like a protein.
By blocking HDAC1, quisinostat lowers production of the E-cadherin protein. That, in turn, decreases mechanisms associated with ovarian cancer’s resistance to platinum chemotherapies.
The trial was designed to investigate the safety and effectiveness of quisinostat, combined with Taxol and Paraplatin, in 31 patients with metastatic or advanced ovarian cancer. The patients’ cancer had progressed one to six months after they had completed first-line Taxol and platinum-based chemotherapy.
Patients were treated for about 18 weeks in up to six cycles. Researchers followed them for four weeks after treatment, looking at overall survival, the time it took for patients’ disease to progress, duration of response, and other measures of effectiveness.
Almost 52 percent of the patients achieved a full or partial response to quisinostat, meeting’s the trial’s primary objective. The median duration of response was five months, and the median time to disease progression or death was seven months.
Sixteen percent of patients had serious adverse responses to the combo, but they were mainly associated with chemotherapy. Nausea and neutropenia, or low levels of a type of white blood cell called a neutrophil, were the most frequent side effects.
“Quisinostat in combination with [Taxol] and [Paraplatin] in pts [patients] with recurrent platinum resistant ovarian cancer showed high efficacy and good tolerability,” researchers wrote in the presentation abstract.
NewVac now plans to investigate the effect of quisinostat, combined with other therapies, for the treatment of other tumor types, including lung and gynecologic cancers.