Patients with one of the deadliest gynecological cancers had dramatically improved survival when an experimental drug was added to treatment with a standard chemotherapy medication in a mid-stage trial in Belarus, researchers say.

The 30 women in the study had ovarian cancer resistant to first-line platinum-based chemo drugs, along with elevated blood levels of a cancer protein called CA-125.

All received standard gemcitabine chemotherapy, and half also received elenagen, being developed by CureLab Oncology, as a once-weekly injection into the muscle.

Patients in the elenagen group lived significantly longer, with a median survival of more than 25 months, compared to roughly 13 months with gemcitabine alone.

“Several patients survived years beyond expected survival for this disease setting,” the researchers said in a statement.

Treatment with elenagen also reduced mortality risk by nearly 60%, the researchers found.

“What makes these results remarkable is not only the magnitude of the survival benefit, but that it was achieved without added toxicity and without a specific biomarker,” study leader Dr. Sergei Krasny of the N. N. Alexandrov National Cancer Centre of Belarus in Minsk said in a statement.

Elenagen contains a protein called p62/SQSTM1 that reduces chronic inflammation and triggers an immune response against tumors.

The drug's effect points to the value of "a fundamentally different therapeutic approach, one that supports the body's biology rather than simply intensifying chemotherapy,” Krasny said.

Treatment intervals ranged from less than one month to more than 30 months, with longer duration of treatment strongly correlated with longer survival following treatment discontinuation, they also found.

The company said it is planning to conduct larger trials in the U.S.

Details from the trial were published in the International Journal of Gynecologic Cancer and will be presented on February 27 at the European Society of Gynaecological Oncology meeting in Copenhagen.