Trastuzumab Deruxtecan in Previously Treated HER2-Low Advanced Breast Cancer.

BACKGROUND: Among breast cancers without human epidermal growth factor receptor 2 (HER2) amplification, overexpression, or both, a large proportion express low levels of HER2 that may be targetable. Currently available HER2-directed therapies have been ineffective in patients with these "HER2-low" cancers. METHODS: We conducted a phase 3 trial involving patients with HER2-low metastatic breast cancer who had received one or two previous lines of chemotherapy. (Low expression of HER2 was defined as a score of 1+ on immunohistochemical [IHC] analysis or as an IHC score of 2+ and negative results on in situ hybridization.) Patients were randomly assigned in a 2:1 ratio to receive trastuzumab deruxtecan or the physician's choice of chemotherapy. The primary end point was progression-free survival in the hormone receptor-positive cohort. The key secondary end points were progression-free survival among all patients and overall survival in the hormone receptor-positive cohort and among all patients. RESULTS: Of 557 patients who underwent randomization, 494 (88.7%) had hormone receptor-positive disease and 63 (11.3%) had hormone receptor-negative disease. In the hormone receptor-positive cohort, the median progression-free survival was 10.1 months in the trastuzumab deruxtecan group and 5.4 months in the physician's choice group (hazard ratio for disease progression or death, 0.51; P<0.001), and overall survival was 23.9 months and 17.5 months, respectively (hazard ratio for death, 0.64; P = 0.003). Among all patients, the median progression-free survival was 9.9 months in the trastuzumab deruxtecan group and 5.1 months in the physician's choice group (hazard ratio for disease progression or death, 0.50; P<0.001), and overall survival was 23.4 months and 16.8 months, respectively (hazard ratio for death, 0.64; P = 0.001). Adverse events of grade 3 or higher occurred in 52.6% of the patients who received trastuzumab deruxtecan and 67.4% of those who received the physician's choice of chemotherapy. Adjudicated, drug-related interstitial lung disease or pneumonitis occurred in 12.1% of the patients who received trastuzumab deruxtecan; 0.8% had grade 5 events. CONCLUSIONS: In this trial involving patients with HER2-low metastatic breast cancer, trastuzumab deruxtecan resulted in significantly longer progression-free and overall survival than the physician's choice of chemotherapy. (Funded by Daiichi Sankyo and AstraZeneca; DESTINY-Breast04 ClinicalTrials.gov number, NCT03734029.).

Pharmacokinetics of quinacrine in the treatment of prion disease.

BACKGROUND: Prion diseases are caused by the accumulation of an aberrantly folded isoform of the prion protein, designated PrPSc. In a cell-based assay, quinacrine inhibits the conversion of normal host prion protein (PrPC) to PrPSc at a half-maximal concentration of 300 nM. While these data suggest that quinacrine may be beneficial in the treatment of prion disease, its penetration into brain tissue has not been extensively studied. If quinacrine penetrates brain tissue in concentrations exceeding that demonstrated for in vitro inhibition of PrPSc, it may be useful in the treatment of prion disease. METHODS: Oral quinacrine at doses of 37.5 mg/kg/D and 75 mg/kg/D was administered to mice for 4 consecutive weeks. Plasma and tissue (brain, liver, spleen) samples were taken over 8 weeks: 4 weeks with treatment, and 4 weeks after treatment ended. RESULTS: Quinacrine was demonstrated to penetrate rapidly into brain tissue, achieving concentrations up to 1500 ng/g, which is several-fold greater than that demonstrated to inhibit formation of PrPSc in cell culture. Particularly extensive distribution was observed in spleen (maximum of 100 microg/g) and liver (maximum of 400 microg/g) tissue. CONCLUSIONS: The documented extensive brain tissue penetration is encouraging suggesting quinacrine might be useful in the treatment of prion disease. However, further clarification of the distribution of both intracellular and extracellular unbound quinacrine is needed. The relative importance of free quinacrine in these compartments upon the conversion of normal host prion protein (PrPC) to PrPSc will be critical toward its potential benefit.

Phase I study to assess the pharmacokinetics and the effect on cardiac repolarization of amrubicin and amrubicinol in patients with advanced solid tumors.

PURPOSE: To evaluate the pharmacokinetics and cardiac repolarization effect (measured by QT/QTc interval) of amrubicin and its active metabolite amrubicinol in non-Japanese patients with advanced solid tumors. METHODS: Patients received amrubicin 40 mg/m(2)/day as a 5-min infusion on days 1-3 of a 21-day cycle. During cycle 1, serial blood and plasma samples were collected on days 1-9 and time-matched triplicate electrocardiograms on the "off-drug" visit (1-5 days prior to start of treatment) and days 1-9. RESULTS: Twenty-four patients were treated. Amrubicinol reached peak concentration 2-4 h after amrubicin administration and had a terminal half-life of 53 h. Distribution of amrubicinol into erythrocytes was fivefold greater than into plasma. The molar ratio of amrubicinol to amrubicin in blood was 0.67 on day 3. The presence of an NQO1 polymorphism did not alter drug exposure. The upper bound of the one-sided 95 % confidence interval for the time-matched, baseline-adjusted change from the off-drug day in QTcI (individual correction) was <10 ms at all times and was only >10 ms (10.20 ms) at a single time point for QTcF (Fridericia correction). No relationship was observed between blood amrubicin or amrubicinol concentrations and QTcF changes. All QTcF measurements were <480 ms, and none increased by >60 ms from baseline. CONCLUSIONS: Data suggest that amrubicinol is an important active metabolite in humans and that both compounds were not associated with clinically relevant QTc interval prolongation at the dose regimen studied.

Pharmacokinetic drug interaction between AEE788 and RAD001 causing thrombocytopenia in patients with glioblastoma.

PURPOSE: Treating glioblastoma through the simultaneous inhibition of multiple transduction pathways may prove more effective than single-pathway inhibition. We evaluated the safety, biologic activity, and pharmacokinetic profile of oral AEE788, a selective inhibitor of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF), plus oral RAD001, a mammalian target of rapamycin inhibitor, in glioblastoma patients. METHODS: This phase IB/II, open-label, multicenter, 2-arm, dose-escalation study enrolled adult glioblastoma patients at first or second recurrence/relapse. Primary objective was to determine the maximum tolerated dose (MTD) and dose-limiting toxicity (DLT) of AEE788 combined with RAD001. Secondary objectives included determining the safety/tolerability, pharmacokinetics, pharmacodynamics, and antitumor activity of the combination. RESULTS: Sixteen patients were enrolled (AEE788 200 mg/day + RAD001 5 mg/day, 2 patients; AEE788 150 mg/day + RAD001 5 mg every other day [qod], 14); all patients discontinued the study most commonly because of disease progression. Four patients experienced DLT (AEE788 200 mg/day + RAD001 5 mg/day, 1 patient; AEE788 150 mg/day + RAD001 5 mg qod, 3). Both patients receiving AEE788 (200 mg/day) plus RAD001 (5 mg/day) experienced clinically significant thrombocytopenia requiring a dose reduction/interruption. AEE788 appeared to inhibit the metabolism of RAD001. The study was terminated prematurely before an MTD was determined because of safety findings in other studies evaluating AEE788 monotherapy. CONCLUSIONS: The coadministration of AEE788 and RAD001 in glioblastoma patients caused a clinically significant thrombocytopenia and a higher-than-expected RAD001 area under the curve concentration when dosed at 200 and 5 mg/day, respectively. After a dose reduction to AEE788 (150 mg/day) and RAD001 (5 mg qod), the combination appeared to be better tolerated.