The cancer immunotherapy GALE-301 is a promising therapeutic approach to prevent cancer recurrence in women with ovarian and endometrial cancers who underwent surgery, according to data from the final analysis of a Phase 1/2a trial.
Two years after undergoing surgery, 77% of women receiving the optimal dose of GALE-301 in the trial remained disease-free, compared with 44% of women who had not received the vaccine.
The findings were recently presented by Dr. Larry Maxwell at the Annual Meeting on Women’s Cancer 2017 hosted by the Society of Gynecologic Oncology. The presentation was titled, “Analysis of a Phase I/IIa Trial Assessing E39+GM-CSF, a Folate Binding Protein Vaccine, to Prevent Recurrence in Ovarian and Endometrial Cancer Patients.”
Galena Biopharma’s GALE-301 is a combination of a peptide (E39) derived from the folate binding protein (FBP) and the immune adjuvant granulocyte macrophage-colony stimulating factor (GM-CSF).
FBP is highly expressed in ovarian, endometrial, and breast cancers, and is a well-validated target for cancer therapies. Small portions of this protein, like the E39 peptide, have the ability to stimulate cytotoxic T-cells that recognize and destroy FBP-positive cells.
The single-center, randomized Phase 1/2a trial (NCT01580696) was designed to assess the safety and effectiveness of GALE-301 in patients with primary or recurrent endometrial, ovarian, fallopian tube, or peritoneal cancer.
The trial enrolled 51 patients, 40 of whom had just received standard of care surgery. The remaining 11 had been treated for recurrent disease. All patients were disease-free at the time of enrollment.
The vaccine is designed to work only on patients with an HLA-A2 subtype, which accounts for nearly half of the American population. Patients who were HLA-A2-negative were used as matched controls.
The primary vaccination series consisted of six total vaccinations given every three to four weeks, in 100 microgram, 500 microgram, and 1,000 microgram doses, in combination with 250 micrograms GM-CSF. Patients then received two booster GALE-301 doses, one every six months.
Patients were monitored every three months to assess if their tumors had returned.
The study’s primary endpoint was disease-free survival (DFS) after two years. The overall 24-month DFS was not significantly increased in the treated group (50% vs. 44%). But patients who received the optimal dose of 1,000 mcg had a 77% 24-month DFS, which was significantly higher than the 44% seen in the control group.
This was particularly evident in patients with primary disease, but not in patients treated for recurrent disease. But given the small number of patients included in the recurrence group, the researchers advocate for larger trials to confirm the findings.
Only one patient experienced grade 3 toxicity from treatment. The most common local toxicities were induration at the injection site, redness of the skin, and itching. Systemic toxicities included muscle pain, headache, and fatigue.
“This final data from our early stage clinical trial demonstrates that GALE-301 is well tolerated and we were able to obtain statistically significant disease free survival in a small number of patients treated with the optimal dose,” Bijan Nejadnik, MD, executive vice president and chief medical officer of Galena Biopharma, said in a press release.
“The results of the trial also reiterate our focus on treating patients with primary disease after their initial standard of care treatment where we believe GALE-301 may provide the most benefit,” he said.