The 2025 Society of Gynecologic Oncology (SGO) Annual Meeting on Women’s Cancer advanced the field with updates of practice-changing trials and other research that challenges the conventional approaches to treating gynecologic cancers. We have briefly captured some of that research here for readers of The ASCO Post.
Ovarian Cancer: MIRASOL Final Analysis Confirms Survival Benefit
In the final analysis of the phase III MIRASOL trial, the antibody-drug conjugate mirvetuximab soravtansine-gynx reduced deaths by 32% and provided other clinical benefits over investigator’s choice of chemotherapy in patients with folate receptor α (FRα)-positive, platinum-resistant ovarian cancer.1 At a median follow-up of 30.5 months, the median overall survival with mirvetuximab soravtansine was 16.9 months vs 13.3 months with chemotherapy (hazard ratio [HR] = 0.68; P = .0004). A trend toward improved overall survival with mirvetuximab soravtansine was observed across key subgroups, irrespective of prior exposure to bevacizumab, maintenance with PARP inhibitors, the number of prior lines of therapy, and the type of chemotherapy received.
Toon Van Gorp, MD, PhD
“Mirvetuximab soravtansine is the first novel treatment to show statistically significant and clinically meaningful overall survival benefits over investigator’s choice of chemotherapy in platinum-resistant ovarian cancer. It continued to show superior survival compared with chemotherapy at this final analysis,” said Toon Van Gorp, MD, PhD, of University Hospital Leuven, Leuven Cancer Institute and BGOG, Belgium. “The same can also be said about progression-free survival, objective response rate, and duration of response…. It’s fair to say that mirvetuximab soravtansine should be the standard of care for patients with FRα-positive, platinum-resistant ovarian cancer.”
The 453 patients had received one to three prior lines of therapy, with previous exposure to bevacizumab or PARP inhibitors permitted. Based on MIRASOL’s findings, mirvetuximab soravtansine is approved for patients with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer after receipt of up to three regimens.
In the final analysis, the median progression-free survival with mirvetuximab soravtansine was 5.6 months vs 4.0 months with chemotherapy (HR = 0.63; P < .0001). The objective response rate was 41.9% vs 15.9%, respectively (odds ratio = 3.75); the median duration of response was 6.9 vs 4.4 months; and the median progression-free survival 2 was 11.0 vs 7.6 months, respectively (HR = 0.59), Dr. Van Gorp reported.
Almost twice as many patients on the chemotherapy arm discontinued treatment because of toxicity, and more hematologic toxicity was observed in this arm. “With mirvetuximab soravtansine, we do see some peripheral neuropathy, but it’s less severe compared with paclitaxel; it’s mainly grade 1 and 2,” Dr. Van Gorp noted. “We hardly see any alopecia, which is important for our patients. We do see some diarrhea and nausea, at the same level as what we see with chemotherapy. Of course, typical adverse events for mirvetuximab soravtansine are ocular events, but there is a mitigation strategy, and if necessary, there can be dose modifications.”
Ovarian Cancer: Another FRα-Targeted Antibody-Drug Conjugate
Treatment with the antibody-drug conjugate luveltamab tazevibulin generated responses, with a manageable safety profile, in 57 patients with FRα-positive, platinum-resistant ovarian cancer, including those with low-to-medium expression of FRα, in the phase II/III REFRαME-O1 study.2 The phase II portion enrolled patients with platinum-resistant ovarian cancer who had FRα expression of at least 25% at any staining intensity and were previously treated with one to three prior lines. Patients were treated with (1) luveltamab tazevibulin at 5.2 mg/kg plus prophylactic granulocyte colony-stimulating factor (G-CSF) for the first two cycles and then at 4.3 mg/kg or (2) chemotherapy.
The overall response rate was 32% (4% complete response rate), and the disease control rate was 96%. Of note, in patients with low-to-medium FRα expression (≥ 25% and < 75%), the response rate was 33.3%, and the disease control rate was 91.7%. In those with FRα expression of at least 75%, these rates were 30.8% and 100%, respectively. Responses were less robust with the lower dose.
Neutropenia, the most common grade ≥ 3 treatment-emergent adverse event, was seen in 28.1% of patients. “Neutropenia occurred with less frequency than in previous trials, with updated management and G-CSF prophylaxis guidelines,” said Jung-Yun Lee, MD, PhD, of Yonsei University College of Medicine in Seoul, South Korea. All other adverse events of that grade were limited to 10% or fewer patients. No ocular events were reported.
Jung-Yun Lee, MD, PhD
“Luveltamab tazevibulin demonstrated clinical activity, with an objective response rate higher than 30% in patients with platinum-resistant ovarian cancer and an FRα expression greater than 25% by tumor proportion score, which comprises 80% of all high-grade serous carcinomas,” he said.
Based on phase II data, the optimized dose of luveltamab tazevibulin was selected as 5.2 mg/kg once every 3 weeks plus G-CSF prophylaxis for the first two cycles, then 4.3 mg/kg once every 3 weeks, for a phase III trial, vs chemotherapy, of more than 500 patients.
Endometrial Cancer: Addition of Metformin to Other Treatments
Two studies presented at the meeting suggested there is a benefit in adding metformin to regimens for endometrial cancer. In the phase II RESOLVE study out of the Dana-Farber Cancer Institute,3 the addition of metformin to letrozole and abemaciclib induced deeper and more durable responses than letrozole and abemaciclib alone in patients with recurrent estrogen receptor–positive tumors, according to the investigators. Preclinical research has suggested there may be synergy among these drugs, based on inhibition of the estrogen receptor and the CDK4/6 and PI3K pathways, said Panagiotis Konstantinopoulos, MD, PhD.
Panagiotis Konstantinopoulos, MD, PhD
After a median follow-up of 17 months, the objective response rate to the three-drug regimen was 32%, including 12% complete responses; 64% of patients achieved stable disease (28% for at least 6 months). At 6 months, 73.8% of patients remained progression-free; the estimated median progression-free survival exceeded 19 months. Responses were observed regardless of progesterone receptor expression or prior receipt of hormonal therapy. Exploratory analysis suggests that TP53-mutated tumors and tumors with no specific molecular profile with RB1 or CCNE1 alterations do not respond to this regimen. Such observations may help to identify the best candidates for this treatment, Dr. Konstantinopoulos said.
In a real-world study of 15 patients, treatment with metformin plus standard-of-care levonorgestrel-releasing intrauterine devices demonstrated activity in patients with endometrial intraepithelial neoplasia or grade 1 endometrial cancer desiring fertility preservation or demonstrating an unacceptable surgery risk.4 This approach aims to produce complete responses through reversal of progestin resistance, said Jennifer Haag, MD, MPH, of the University of North Carolina, Chapel Hill.
Patients experiencing an adverse event during treatment or who experienced disease progression on treatment discontinued the therapy; those who had a complete response, tumor regression, or stable disease continued treatment with metformin plus a levonorgestrel-releasing intrauterine device for up to 12 months. The complete response rate at 6 months was 80% among all efficacy-evaluable patients, including complete responses in 100% of the intraepithelial neoplasia groups and 40% of the endometrial cancer subsets. The complete response rate at 12 months in all-comers was 87.5%. The investigators suggested this approach deserves further study in patients who desire fertility preservation or who have comorbidities that prohibit surgery for these conditions.
Gestational Trophoblastic Neoplasia: Use of Actinomycin D
As the first-line treatment for low-risk gestational trophoblastic neoplasia, a single dose of actinomycin D or an 8-day regimen of methotrexate plus leucovorin are both conventionally used, without a consensus as to which regimen is preferred. A study out of Peking Union Medical College Hospital in Beijing, China, has concluded that actinomycin D yields a higher complete remission rate with a shorter treatment duration—albeit with less tolerability.5
Biweekly actinomycin D achieved remission and normalized levels of β-hCG (beta–human chorionic gonadotropin) faster than methotrexate plus leucovorin with fewer treatment cycles, according to Jiang Fang, MD, PhD, who noted that a strength of the study is its large cohort. As such, she said, it provides “high-level evidence” that may inform clinical decision-making for these patients.
The multicenter trial enrolled 228 patients with FIGO (International Federation of Gynecology and Obstetrics) stages 1–3, low-risk gestational trophoblastic neoplasia. Patients were randomly assigned to receive actinomycin D (1.25 mg/m2, maximum 2 mg, every 14 days) or methotrexate plus leucovorin (50 mg intramuscularly on days 1, 3, 5, and 7, with leucovorin rescue on days 2, 4, 6, and 8), continued until normalizatino of β-hCG levels, followed by two to three consolidation cycles.
Actinomycin D achieved significantly higher, single-agent complete remission rates compared with methotrexate plus leucovorin (72.8% vs 54.4%, P = .0038). Both groups achieved 100% complete remission rates after resistant cases received combination chemotherapy. Ovarian function declined in both groups temporarily but fully recovered within 6 months. Future pregnancy rates were similar, Dr. Fang reported.
Most adverse events were grade 1 or 2. Grade ≥ 2 nausea and vomiting were more frequent with actinomycin D (49.1% vs 18.4%, P < .001), as was alopecia (6.1% vs 0%, P = .0142). Grade 3 events were rare but more frequent with actinomycin D during the single-agent chemotherapy phase, with nausea and vomiting observed in 14.0% vs 4.4% (P = .0118). Elevation of alanine aminotransferase levels was more common with methotrexate plus leucovorin (13.2% vs 4.4%, P = .0192).
Actinomycin D may be the preferred option for those prioritizing rapid remission and fewer treatment cycles, though methotrexate plus leucovorin may have a more favorable toxicity profile in many patients, she acknowledged.
High-Risk Gynecologic Cancers: Alternative to Salpingo-Oophorectomy
The TUBA-WISP II trial aims to answer an important question: Is removal of the fallopian tubes with delayed removal of the ovaries (which avoids early menopause) a safe alternative for the simultaneous removal of the fallopian tubes and ovaries in women at high risk for ovarian cancer? This trial is a collaboration between the United States and the Netherlands.
The rationale is that high-grade serous carcinoma actually originates in the fallopian tubes, not the ovaries, as a serous tubal intraepithelial carcinoma. “That is why, we thought, maybe there is another option: first remove the fallopian tubes—as soon as child-bearing is completed—and delay the removal of the ovaries until later on,” said Tamar Gootzen, MD, of Radboud University Medical Centre in the Netherlands.6
TUBA-WISP II has recruited 2,000 participants of a planned 3,000 from 14 different countries. The main pathogenic variants within this group were BRCA1 (52%) and BRCA2 (46%), with 2% comprising other moderate-penetrance genes. Under the preferential design, participants can choose their treatment approach: risk-reducing salpingectomy with delayed oophorectomy (chosen by more than 75%) or the conventional risk-reducing salpingo-oophorectomy (chosen by about 25%). First surgeries have been completed by 1,709 women, and 120 women have had second-stage surgery. Some of the early results in the first 2,000 women follow:
- High-grade serous carcinoma was found in 3 of 1,518 women (0.2%) in the experimental risk-reducing salpingectomy group and 4 (0.8%) of the conventional risk-reducing salpingo-oophorectomy group. An isolated serous tubal intraepithelial carcinoma was found in eight patients (0.5%) and three patients (0.6%), respectively.
- Of five women with high-grade serous carcinoma, there were three recurrences; all women are alive. Two had both high-grade serous carcinoma and serous tubal intraepithelial carcinoma, one of which recurred and the patient died. Some had lesions in the fallopian tubes, some in the ovaries, and some in both. Four of the high-grade serous carcinoma cases occurred after risk-reducing salpingo-oophorectomy and three after risk-reducing salpingectomy procedures, at follow-up times that varied considerably.
- Of the first 2,000 patients, 1 has died. She had BRCA2 mutation and underwent risk-reducing salpingectomy. She was diagnosed with stage IA high-grade serous carcinoma and also a serous tubal intraepithelial lesion at 54 months’ follow-up.
“Currently, we are happy no interval carcinomas have occurred,” said Dr. Gootzen. “This is great; however, the women are still young, and follow-up is still too short to draw conclusions. We think it’s very important that risk-reducing salpingectomy with delayed oophorectomy be done only within the limits of a clinical trial, because these women need to be monitored.”
TUBA-WISP II should conclude in 2027. The results will not be mature until 2037. “We will need to have a bit of patience,” she admitted.
DISCLOSURE: Dr. Van Gorp reported personal financial relationships with AbbVie, AstraZeneca, BioNTech, Cancer Communications and Consultancy Ltd, Daiichi Sankyo, Eisai, GSK, ImmunoGen, Incyte, Karyopharm Therapeutics, MSD/Merck, OncXerna Therapeutics, Seagen, Tubulis, Zentalis Pharmaceuticals, PharmaMar, and Roche. Dr. Lee reported personal financial relationships with AstraZeneca, Eisai, GSK, MSD, Roche, Takeda, CanariaBio, DS Biopharma, Genmab, ImmunoGen, Merck, Seagen, Sutro Biopharma, and Regeneron. Dr. Konstantinopoulos reported personal financial relationships with AstraZeneca, GSK, Merck, ImmunoGen, EMD Serono, Scorpion Therapeutics, Schrödinger, Nimbus Therapeutics, and Gilead Sciences. Dr. Haag,Dr. Fang, and Dr. Gootzen reported no conflicts of interest.
REFERENCES
1. Van Gorp T, Angelergues A, Konecny G, et al: Final overall survival analysis among patients with FRα-positive, platinum-resistant ovarian cancer treated with mirvetuximab soravtansine vs investigator’s choice chemotherapy in the phase 3 MIRASOL (GOG 3045/ENGOT-ov55) study. 2025 SGO Annual Meeting on Women’s Cancer. Abstract 939696. Presented March 14, 2025.
2. Lee JY, Oaknin A, Lorusso D, et al: Efficacy and safety of luveltamab tazevibulin in patients with recurrent platinum-resistant ovarian cancer: Results from the dose-optimization stage of the REFRαME-O1 (GOG-3086, ENGOT-79OV, and APGOT-OV9) phase 2/3 study. 2025 SGO Annual Meeting on Women’s Cancer. Abstract 922978. Presented March 15, 2025.
3. Konstantinopoulos PA, Zhou N, Penson RT, et al: Phase 2 study of letrozole, abemaciclib and metformin in estrogen receptor positive recurrent endometrial cancer. 2025 SGO Annual Meeting on Women’s Cancer. Abstract LBA6. Presented March 15, 2025.
4. Haag J, Moore D, Schuler K, et al: Metformin with the levonorgestrel-releasing intrauterine device for the treatment of endometrial intraepithelial neoplasia and endometrial cancer in non-surgical patients. 2025 SGO Annual Meeting on Women’s Cancer. Abstract 110. Presented March 16, 2025.
5. Fang J, Chongli G, Xin L, et al: Comparing efficacy and safety of biweekly single-dose actinomycin D versus multiday methotrexate therapy in low-risk gestational trophoblastic neoplasia: A prospective multicenter randomized trial. 2025 SGO Annual Meeting on Women’s Cancer. Abstract 927707. Presented March 15, 2025.
6. Gootzen T: Early salpingectomy with delayed oophorectomy as alternative for risk-reducing salpingo-oophorectomy: The first 2,000 participants in the ongoing international TUBA-WISP II study. 2025 SGO Annual Meeting on Women’s Cancer. Abstract 926320. Presented March 15, 2025.
