Phase Ib Study of the Oral Proteasome Inhibitor Ixazomib ( MLN9708 ) and Fulvestrant in Advanced ER+ Breast Cancer Progressing on Fulvestrant .
Phase Ib Study of the Oral Proteasome Inhibitor Ixazomib ( MLN9708 ) and Fulvestrant in Advanced ER+ Breast Cancer Progressing on Fulvestrant . fulvestrant is a selective estrogen receptor (ER)-downregulating anti-estrogen that blocks ER transcriptional activity and is approved for ER+ breast cancer. fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. ### background fulvestrant is a selective estrogen receptor (ER)-downregulating anti-estrogen that blocks ER transcriptional activity and is approved for ER+ breast cancer. fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. ### methods This is a single-center phase Ib study with a 3+3 design of fulvestrant and the proteasome inhibitor ixazomib (MLN9708) in patients with advanced ER+ breast cancer that was progressing on fulvestrant. A dose-escalation design allowed establishment of the ixazomib maximum tolerated dose (MTD). Secondary objectives included progression-free survival, pharmacokinetics, and tumor molecular analyses. ### results Among nine evaluable subjects, treatment was well-tolerated without dose-limiting toxicities The MTD of ixazomib was 4 mg in combination with fulvestrant. Plasma concentrations of the active form of ixazomib (MLN2238) in the 4-mg dose cohort had a median (range) Cmax of 155 (122-171) ng/mL; Tmax of 1 (1-1.5) h; terminal elimination half-life of 66.6 (57.3-102.6) hr after initial dose; AUC of 5,025 (4,160-5,345) ng*h/mL. One partial response was observed, and median progression-free survival was 51 days (range 47-137). ### conclusion This drug combination has a favorable safety profile and anti-tumor activity in patients with fulvestrant-resistant advanced ER+ breast cancer that justifies future testing.
### Instruction:
            Given the context about compound efficacy for the given treatment mentioned within the input, mentioned the compounds 
            that can co-occur for the mentioned treatment

            ### Input:
            Phase Ib Study of the Oral Proteasome Inhibitor Ixazomib ( MLN9708 ) and Fulvestrant in Advanced ER+ Breast Cancer Progressing on Fulvestrant . fulvestrant is a selective estrogen receptor (ER)-downregulating anti-estrogen that blocks ER transcriptional activity and is approved for ER+ breast cancer. fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. ### background fulvestrant is a selective estrogen receptor (ER)-downregulating anti-estrogen that blocks ER transcriptional activity and is approved for ER+ breast cancer. fulvestrant also induces accumulation of insoluble ER and activates an unfolded protein response; proteasome inhibitors have been shown to enhance these effects in preclinical models. ### methods This is a single-center phase Ib study with a 3+3 design of fulvestrant and the proteasome inhibitor ixazomib (MLN9708) in patients with advanced ER+ breast cancer that was progressing on fulvestrant. A dose-escalation design allowed establishment of the ixazomib maximum tolerated dose (MTD). Secondary objectives included progression-free survival, pharmacokinetics, and tumor molecular analyses. ### results Among nine evaluable subjects, treatment was well-tolerated without dose-limiting toxicities The MTD of ixazomib was 4 mg in combination with fulvestrant. Plasma concentrations of the active form of ixazomib (MLN2238) in the 4-mg dose cohort had a median (range) Cmax of 155 (122-171) ng/mL; Tmax of 1 (1-1.5) h; terminal elimination half-life of 66.6 (57.3-102.6) hr after initial dose; AUC of 5,025 (4,160-5,345) ng*h/mL. One partial response was observed, and median progression-free survival was 51 days (range 47-137). ### conclusion This drug combination has a favorable safety profile and anti-tumor activity in patients with fulvestrant-resistant advanced ER+ breast cancer that justifies future testing.

            ### Response:
            Ixazomib, Fulvestrant, Fulvestrant
            