ImmunoGen will show promising safety and efficacy data of its investigative treatment mirvetuximab soravtansine for the treatment of FRα-positive epithelial ovarian cancer (EOC).

The positive top-line data will be presented in three poster sessions at the American Society of Clinical Oncology (ASCO) 2017 Annual Meeting June 2-6 in Chicago.

Mirvetuximab soravtansine (IMGN853) belongs to a class of medications known as antibody-drug conjugates (ADCs). The therapy specifically targets folate receptor alpha (FRα)-expressing cancer cells and kills them with an anti-tumor agent known as DM4.

The results released by ImmunoGen include data from a pooled analyses of three Phase 1 expansion cohorts, as well as from a Phase 1b/2 study known as FORWARD II (NCT02606305).

Data from the pooled analyses was derived from 113 patients with EOC who were treated with mirvetuximab soravtansine. A subset of 36 patients meeting inclusion criteria, including platinum-resistant disease and medium or high levels of FRα, who had received prior therapy showed a response rate of 47 percent and a median progression-free survival of 6.7 months. Adverse events related to treatment were described as low grade and manageable.

“The data observed with mirvetuximab compare favorably with outcomes typically achieved with currently available single-agent therapies for platinum-resistant ovarian cancer,” Kathleen Moore, MD, associate professor at the University of Oklahoma Stephenson Cancer Center, said in a press release. “Current single-agent therapies for platinum-resistant ovarian cancer have low response rates of 15 to 20% and short median progression-free survival of three to four months.”

FORWARD II, a Phase 1b/2 study, combined mirvetuximab soravtansine with Avastin (bevacizumab), Paraplatin (carboplatin), Doxil (pegylated liposomal doxorubicin) or Keytruda (pembrolizumab) in patients with FRα-positive EOC, primary peritoneal or fallopian tube tumors.

According to ImmunoGen, the data shows that mirvetuximab soravtansine may complement available therapies, particularly Avastin and Keytruda, and the company is planning expansion cohorts based on encouraging data.

A Phase 3 trial (NCT02631876) based on previous results from FORWARD I is also underway, and intends to speed up the approval process for mirvetuximab soravtansine as a single-agent therapy.

The study will enroll 333 patients and compare mirvetuximab soravtansine against a physician’s preferred therapy, Doxil, Taxol (paclitaxel) or Hycamtin (topotecan). It is seeking participants in Europe and North America.

“Based on the consistent safety and efficacy seen with mirvetuximab soravtansine reflected in these pooled analyses, particularly in those patients meeting the eligibility criteria for the pivotal study, I am very encouraged about the potential of this compound in patients with platinum-resistant ovarian cancer and look forward to continued progress with the ongoing Phase 3 FORWARD I trial,” Moore said.