A randomized phase II trial of everolimus and letrozole or hormonal therapy in women with advanced, persistent or recurrent endometrial carcinoma: A GOG Foundation study.

BACKGROUND

Blocking the PI3K/AKT/mTOR pathway decreases resistance to hormonal therapy in endometrial carcinoma (EC).

OBJECTIVE

In this study, the aim was to assess the efficacy and tolerability of everolimus(E)/letrozole (L) or medroxyprogesterone acetate(M)/tamoxifen(T) in the treatment of metastatic EC.

STUDY

DESIGN

This single stage, open-label two arm randomized phase II trial accrued women with advanced/persistent/recurrent EC. Treatment with E (10 mg daily) and L (2.5 mg daily) or T (20 mg twice daily) and M (200 mg daily alternating weeks) was randomly assigned, and stratified by prior adjuvant therapy. Treatments were administered orally. Primary endpoint was response rate.

RESULTS

Between February 2015 and April 2016, everolimus/letrozole (n = 37) or MT (n = 37) was assigned to 74 patients. Median follow-up was 37 months. Eight (22%; 95% CI 11% to 37%) patients responded on EL (one CR) and nine (25%; 95% CI 14% to 41%) patients responded on MT (three CRs). Median PFS for EL and MT arms was 6 months and 4 months, respectively. On EL, chemo-nave patients demonstrated a 28 month median PFS; prior chemotherapy patients had a 4-month median PFS. On MT, patients without prior therapy had a 5-month median PFS; those with prior chemotherapy demonstrated a 3-month PFS. Common grade 3 adverse events were anemia (9 [24%] patients EL vs 2 [6%] MT) and mucositis (2 [5%] vs 0 [0%]). Grade 3/4 thromboembolic events were observed with MT but not with EL (0 [0%] vs 4 [11%]).

CONCLUSIONS

EL and MT demonstrated clinically meaningful efficacy in recurrent EC patients. The higher PFS observed in chemo-naïve patients is worthy of confirmation in future studies.