This is another possibility for maintenance therapy. It will require further study.
Selinexor inhibits exportin-1 (XPO1) resulting in nuclear accumulation of tumor suppressor proteins including p53 and has clinical activity in endometrial cancer (EC). The primary end point was to assess progression-free survival (PFS) with once-weekly oral selinexor in patients with advanced or recurrent EC.
ENGOT-EN5/GOG-3055/SIENDO was a randomized, prospective, multicenter, double-blind, placebo-controlled, phase III study at 107 sites in 10 countries. Patients 18 years or older with histologically confirmed EC were enrolled. All had completed a single line of at least 12 weeks of taxane-platinum combination chemotherapy and achieved partial or complete response. Patients were assigned to receive 80 mg oral selinexor once weekly or placebo with 2:1 random assignment (ClinicalTrials.gov identifier: NCT03555422).
Between January 2018 and December 2021, 263 patients were randomly assigned, with 174 allocated to selinexor and 89 to placebo. The median PFS was 5.7 months (95% CI, 3.81 to 9.20) with selinexor versus 3.8 months (95% CI, 3.68 to 7.39) with placebo (hazard ratio [HR], 0.76 [95% CI, 0.54 to 1.08]; two-sided P = .126), which did not meet the criteria for statistical significance in the intent-to-treat population. Incorrect chemotherapy response stratification data for 7 (2.7%) patients were identified. In a prespecified exploratory analysis of PFS in audited stratification data, PFS for selinexor met the threshold for statistical significance (HR, 0.71; 95% CI, 0.499 to 0.996; two-sided P = .049). Furthermore, patients with the TP53 wild-type (wt) EC had a median PFS of 13.7 and 3.7 months with selinexor and placebo. The most common grade 3 treatment-related adverse events were nausea (9%), neutropenia (9%), and thrombocytopenia (7%).
The significance level for PFS was only met in the audited analysis. However, a preliminary analysis of a prespecified exploratory subgroup of patients with TP53wt EC showed promising results with selinexor maintenance therapy.
For patients with local recurrences of endometrial cancer, XRT alone is extremely effective, and the addition of cisplatin does not offer any benefit while increasing toxicity. These patients with low-grade and vaginal recurrences have a good prognosis and most should be treated with XRT alone.
Initial results from the DUO-E study in metastatic endometrial cancer. The preliminary report suggests that maintenance durvalumab and maintenance durvalumab + olaparib were superior to standard observation after systemic carbo/taxol. As the trial data matures, the question will be: is this in all patients or driven by those with dMMR or HDR mutations?
An interesting study where the authors performed a post hoc analysis of randomized trials using molecular classification of endometrial cancers. There was good evidence to omit RT for those with POLE mutations and def-MMR. There seems to be a higher degree of benefit in those with a p53 mutation.
Large phase III study of carbo/taxol+pembro x 6 followed by pembro alone x 14 cycles in metastatic endometrial cancer. There was a benefit in both pMMR and dMMR patients, although the magnitude was unsurprisingly higher in those with dMMR. OS results are still pending, and carcinosarcoma-type histology was excluded. This combination has been approved and is on NCCN as a cat-1 recommendation.
Chemo + IO may become the SOC for 1L treatment of met-endometrial adenoCa. For pembro + chemo, there was a 70% lower risk of disease progression in dMMR and a 46% lower risk in pMMR compared to placebo + chemo. For pMMR patients, the impact on 2L therapy responses will need to be considered carefully, as lenvantinib + pembro has been found to be superior to either agent alone after chemo.
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