Selinexor in Combination with Hypomethylating Agent (HMA) in Patients with Refractory/Relapsed Acute Myeloid Leukemia (AML) Previously Exposed to Venetoclax: A Retrospective Study

Background

Acute myeloid leukemia (AML) is a heterogeneous hematologic tumor with varied clinical manifestations. Venetoclax combination regimens have shown promising results as a first-line treatment for AML. However, for patients who fail venetoclax treatment, the prognosis remains poor, necessitating the exploration of new therapeutic approaches. Selinexor, a selective inhibitor of XPO1, has shown potential as a therapeutic strategy to overcome resistance to conventional chemotherapy for AML. Here, we report the safety and efficacy data from a real-world study of selinexor + HMA in patients with refractory/relapsed (R/R) AML previously exposed to venetoclax.

Methods

We conducted a monocentric retrospective analysis on adult patients with unfit R/R AML or those with comorbidities preventing the use of intensive induction chemotherapy. The patients received selinexor-based combinations between May 2021 and December 2022. AML genetic risk stratification and response criteria were assessed according to the 2022 European Leukemia Net (ELN) consensus. The selinexor + HMA regimen consisted of selinexor 40 mg twice weekly for 3 weeks orally, and either decitabine (DAC, 10 mg/dfor 7-10 days intravenously) or azacytidine (AZA, 75 mg/m ²/d for 7 days subcutaneously, halved for patients over 60 years). Supportive treatments and dose adjustments were administered based on individual clinical indications. Some patients underwent allogeneic hematopoietic stem-cell transplantation.

Results

A total of 12 patients with R/R AML treated with selinexor-based combinations were considered in this study, including 7 patients with refractory AML and 5 patients with relapsed AML (one with post-transplant recurrence). The median age of the patients was 36 years (range 18-68 years). All patients had intermediate or adverse ELN genetic risk. All patients had previously received venetoclax-based combinations, and 58% (7/12) had been treated with HMAs. The overall response rate (ORR) was 66.7% (8/12) with a combined CR rate (CRc) of 50% (6/12). Among the 6 patients with CRc, 3 (50%) achieved negative minimal residual disease (MRD,≤1*10 ^-3). CRc was 42.9% (3/7) in patients previously exposed to HMA-based therapy and 100% in patients without exposure history. The most common grade 3 or 4 adverse events were neutropenia (83.3%) and thrombocytopenia (58%), with the median recovery time of 14 (8-21) and 16 (8-24) days, respectively. Common non-hematologic toxicities included infection (66.7%) and gastrointestinal reactions (66.7%). As of Jun 20, 2023, with a median follow-up of 11.3 months (range 0.7-19.5 months), 50% (6/12) of the patients died due to disease progression or severe infections. 66.7% (8/12) of the patients received transplants after achieving remission. The median overall survival (OS) was significantly longer in the transplantation group compared to the non-transplantation group (p=0.009) (Figure.1a). Patients without previous HMA exposure seemed to have a better efficacy benefit from the X+HMA combination regimen, although the difference was not statistically significant due to the llimited sample size (Figure.1b).

Conclusion

The real-life study demonstrated that the combination of selinexor and HMAs is a viable and safe option for patients with unfit R/R AML who were previously exposed to venetoclax. X+HMA salvage therapy followed by transplantation showed durable survival benefits in R/R AML patients, especially those without prior HMA exposure, suggesting a potential efficacy advantage.