Abstract Background: In the Phase III MONALEESA-3 (NCT02422615) study, ribociclib (RIB; cyclin-dependent kinase 4/6 inhibitor) + fulvestrant (FUL) significantly prolonged progression-free survival (PFS) vs placebo (PBO) + FUL in postmenopausal women with hormone receptor-positive (HR+), HER2-negative (HER2–) advanced breast cancer (ABC). Here we present MONALEESA-3 efficacy data by molecular alterations detected in circulating tumor DNA (ctDNA) at baseline. Methods: Postmenopausal women (N=726) with HR+, HER2– ABC (treatment naïve or received ≤1 line of prior endocrine therapy for ABC) were randomized 2:1 to RIB or PBO (600 mg/day; 3-weeks-on/1-week-off) + FUL (500 mg per label). Biomarker analysis of baseline ctDNA was an exploratory endpoint. Baseline plasma samples were collected from 692 patients (pts), and plasma ctDNA was analyzed using next-generation sequencing with a targeted panel of ˜550 genes. The subgroup analysis was performed in 600 pts (RIB + FUL n=400; PBO + FUL n=200) with evaluable ctDNA data. Results were not adjusted for multiple testing. Results: Alterations (frequency) were observed in the following genes: PIK3CA (35%), ESR1 (14%), TP53 (18%), CDH1 (12%), FGFR1 (5%), FGFR1/ZNF703/WHSC1L1 (11%), cell cycle-related (CCC) genes (16%), and genes involved in receptor tyrosine kinase (RTK) signaling (20%), and the mitogen-activated protein kinase (MAPK) pathway (10%). PFS hazard ratios favored RIB vs PBO regardless of baseline ctDNA gene alteration status (Table). Events, n/NMedian PFS, months Gene(s)RIB + FULPBO + FULRIB + FULPBO + FULHazard ratio; 95% confidence intervalPIK3CAWT108/26570/12422.3416.490.67; 0.49–0.91Altered75/13549/7616.3611.100.75; 0.52–1.08ESR1WT141/33899/17622.3414.880.66; 0.51–0.85Altered42/6220/249.236.110.71; 0.41–1.23TP53WT132/32598/17022.3414.880.62; 0.47–0.80Altered51/7521/309.177.390.75; 0.44–1.27CDH1WT156/35697/17320.6316.490.70; 0.54–0.90Altered27/4422/2712.095.130.46; 0.24–0.86FGFR1WT165/378113/19221.3214.550.65; 0.51–0.83Altered18/226/88.346.110.64; 0.23–1.75FGFR1/ZNF703/WHSC1L1WT155/356105/18121.3214.650.67; 0.52–0.85Altered28/4414/1910.976.670.73; 0.37–1.43CCCWT138/331103/17422.0814.650.61; 0.47–0.79Altered45/6916/2612.659.130.92; 0.51–1.65RTKWT126/31595/16622.3414.820.61; 0.47–0.80Altered57/8524/349.175.780.82; 0.50–1.35MAPKWT158/357105/18320.0414.820.69; 0.54–0.89Altered25/4314/1714.723.610.47; 0.22–1.00 Numerically shorter PFS was observed in pts with altered vs wildtype (WT) genes, irrespective of treatment. A slight trend towards limited RIB benefit vs PBO was observed in pts with altered CCC and RTK genes. RIB benefit was more pronounced vs PBO in pts with altered CDH1 and MAPK genes. PIK3CA and ESR1 analyses for pts receiving treatment in the first- or second-line setting will be presented at the meeting. Conclusions: Generally consistent PFS benefit for RIB + FUL vs PBO + FUL was observed irrespective of baseline ctDNA alterations; altered status trended to correlate with a shorter PFS. Results are hypothesis generating and should be interpreted with caution for some subgroups due to small sample sizes. Citation Format: Neven P, Petrakova K, Val Bianchi G, De la Cruz-Merino L, Jerusalem G, Sonke GS, Nusch A, Beck JT, Chia S, Solovieff N, Rodriguez Lorenc K, Miller M, Su F, Lm S-A. Biomarker analysis by baseline circulating tumor DNA alterations in the MONALEESA-3 study [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD2-05.
Introduction: Cellular retinoic acid (RA)-binding protein 1 (CRABP1) is a highly conserved protein comprised of an anti-parallel, beta-barrel, and a helix-turn-helix segment outside this barrel. Functionally, CRABP1 is thought to bind and sequester cytosolic RA. Recently, CRABP1 has been established as a major mediator of rapid, non-genomic activity of RA in the cytosol, referred to as “non-canonical” activity. Previously, we have reported that CRABP1 interacts with and dampens the activation of calcium-calmodulin (Ca 2+ -CaM)-dependent kinase 2 (CaMKII), a major effector of Ca 2+ signaling. Through biophysical, molecular, and cellular assays, we, herein, elucidate the molecular and structural mechanisms underlying the action of CRABP1 in dampening CaMKII activation. Results: We identify an interaction surface on CRABP1 for CaMKII binding, located on the beta-sheet surface of the barrel, and an allosteric region within the helix segment outside the barrel, where both are important for interacting with CaMKII. Molecular studies reveal that CRABP1 preferentially associates with the inactive form of CaMKII, thereby dampening CaMKII activation. Alanine mutagenesis of residues implicated in the CaMKII interaction results in either a loss of this preference or a shift of CRABP1 from associating with the inactive CaMKII to associating with the active CaMKII, which corresponds to changes in CRABP1’s effect in modulating CaMKII activation. Conclusions: This is the first study to elucidate the molecular and structural basis for CRABP1’s function in modulating CaMKII activation. These results further shed insights into CRABP1’s functional involvement in multiple signaling pathways, as well as its extremely high sequence conservation across species and over evolution.
Abstract The emerging significance of lectins for pathophysiological processes provides incentive for the design of potent inhibitors. To this end, systematic assessment of contributions to affinity and selectivity by distinct types of synthetic tailoring of glycosides is a salient step, here taken for the aglyconic modifications of two disaccharide core structures. Firstly we report the synthesis of seven N‐linked‐lactosides and of eight O‐linked N ‐acetyllactosamines, each substituted with a 1,2,3‐triazole unit, prepared by copper‐catalyzed azide–alkyne cycloaddition (CuAAC). The totally regioselective β‐ D ‐(1→4) galactosylation of a 6‐ O ‐TBDPSi‐protected N ‐acetylglucosamine acceptor provided efficient access to the N ‐acetyllactosamine precursor. The resulting compounds were then systematically tested for lectin reactivity in two binding assays of increasing biorelevance (inhibition of lectin binding to a surface‐presented glycoprotein and to cell surfaces). As well as a plant toxin, we also screened the relative inhibitory potential with adhesion/growth‐regulatory galectins (total of eight proteins). This type of modification yielded up to 2.5‐fold enhancement for prototype proteins, with further increases for galectins‐3 and ‐4. Moreover, the availability of 15 N‐labeled proteins and full assignments enabled 1 H, 15 N HSQC‐based measurements for hu‐ man galectins‐1, ‐3, and ‐7 against p ‐nitrophenyl lactopyranoside, a frequently tested standard inhibitor containing an aromatic aglycone. The measurements confirmed the highest affinity against galectin‐3 and detected chemical shift differences in its hydrophobic core upon ligand binding, besides common alterations around the canonical contact site for the lactoside residue. What can be accomplished in terms of affinity/selectivity by this type of core extension having been determined, the applied combined strategy should be instrumental for proceeding with defining structure–activity correlations at other bioinspired sites in glycans and beyond the tested lectin types.
Highlights•This trial provides analysis of the biological activity of ribociclib + letrozole.•Ribociclib + letrozole was well tolerated over a 2-week treatment period.•Pharmacokinetic data suggest no ribociclib–letrozole drug interaction.•Reduced Ki67 expression is reported in patients with HR+, HER2– breast cancer.•Pharmacodynamic data provide evidence for on-target inhibition by ribociclib.AbstractObjectivesCyclin D–cyclin-dependent kinase (CDK) 4/6–inhibitor of CDK4/6–retinoblastoma (Rb) pathway hyperactivation is associated with hormone receptor-positive (HR+) breast cancer (BC). This study assessed the biological activity of ribociclib (LEE011; CDK4/6 inhibitor) plus letrozole compared with single-agent letrozole in the presurgical setting.Materials and methodsPostmenopausal women (N = 14) with resectable, HR+, human epidermal growth factor receptor 2-negative (HER2–) early BC were randomized 1:1:1 to receive 2.5 mg/day letrozole alone (Arm 1), or with 400 or 600 mg/day ribociclib (Arm 2 or 3). Circulating tumor DNA and tumor biopsies were collected at baseline and, following 14 days of treatment, prior to or during surgery. The primary objective was to assess antiproliferative response per Ki67 levels in Arms 2 and 3 compared with Arm 1. Additional assessments included safety, pharmacokinetics, and genetic profiling.ResultsMean decreases in the Ki67-positive cell fraction from baseline were: Arm 1 69% (range 38–100%; n = 2), Arm 2 96% (range 78–100%; n = 6), Arm 3 92% (range 75–100%; n = 3). Decreased phosphorylated Rb levels and CDK4, CDK6, CCND2, CCND3, and CCNE1 gene expression were observed following ribociclib treatment. Ribociclib and letrozole pharmacokinetic parameters were consistent with single-agent data. The ribociclib plus letrozole combination was well tolerated, with no Grade 3/4 adverse events over the treatment.ConclusionThe results suggest absence of a drug–drug interaction between ribociclib and letrozole and indicate ribociclib plus letrozole may reduce Ki67 expression in HR+, HER2– BC (NCT01919229).
SARS-CoV-2 vaccines play an important role in reducing disease severity, hospitalization, and death, although they failed to prevent the transmission of SARS-CoV-2 variants. Therefore, an effective inhibitor of galectin-3 (Gal-3) could be used to treat and prevent the transmission of COVID-19. ProLectin-M (PL-M), a Gal-3 antagonist, was shown to interact with Gal-3 and thereby prevent cellular entry of SARS-CoV-2 in previous studies.The present study aimed to further evaluate the therapeutic effect of PL-M tablets in 34 subjects with COVID-19.The efficacy of PL-M was evaluated in a randomized, double-blind, placebo-controlled clinical study in patients with mild to moderately severe COVID-19. Primary endpoints included changes in the absolute RT-PCR Ct values of the nucleocapsid and open reading frame (ORF) genes from baseline to days 3 and 7. The incidence of adverse events, changes in blood biochemistry, inflammatory biomarkers, and levels of antibodies against COVID-19 were also evaluated as part of the safety evaluation.PL-M treatment significantly (p = 0.001) increased RT-PCR cycle counts for N and ORF genes on days 3 (Ct values 32.09 ± 2.39 and 30.69 ± 3.38, respectively) and 7 (Ct values 34.91 ± 0.39 and 34.85 ± 0.61, respectively) compared to a placebo treatment. On day 3, 14 subjects in the PL-M group had cycle counts for the N gene above the cut-off value of 29 (target cycle count 29), whereas on day 7, all subjects had cycle counts above the cut-off value. Ct values in placebo subjects were consistently less than 29, and no placebo subjects were RT-PCR-negative until day 7. Most of the symptoms disappeared completely after receiving PL-M treatment for 7 days in more patients compared to the placebo group.PL-M is safe and effective for clinical use in reducing viral loads and promoting rapid viral clearance in COVID-19 patients by inhibiting SARS-CoV-2 entry into cells through the inhibition of Gal-3.
Abstract Background: In the Phase III MONALEESA-2 study (NCT01958021), ribociclib (RIB; cyclin-dependent kinase 4/6 inhibitor [CDK4/6i]) + letrozole (LET) significantly prolonged progression-free survival (PFS) vs placebo (PBO) + LET in postmenopausal women with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC). The optimal treatment sequence following first-line CDK4/6i-based therapy is not yet known. Here we report the subsequent therapies received following discontinuation from MONALEESA-2. Methods: The MONALEESA-2 study enrolled 668 patients (pts) with HR+, HER2– ABC. Pts were randomized 1:1 to receive RIB (600 mg/day; 3-weeks-on/1-week-off) + LET (2.5 mg/day; continuous) or PBO + LET. Following discontinuation of MONALEESA-2 study treatment, pts were followed for information regarding post-study treatment, including type and duration of therapy. Results: At data cut-off (January 2, 2017), the median duration of follow-up was 26.4 months. Median PFS was 25.3 vs 16.0 months in the RIB + LET vs PBO + LET arms (hazard ratio=0.568; 95% confidence interval [CI]: 0.457–0.704; p=9.63x10–8). 203 (60.8%) vs 246 (73.7%) pts had discontinued RIB + LET vs PBO + LET. The median time to end of treatment was 20.3 months in the RIB + LET arm vs 13.7 months in the PBO + LET arm. First subsequent antineoplastic treatment was reported for 172/203 (84.7%) vs 212/246 (86.2%) pts who received RIB + LET vs PBO + LET; second subsequent therapy was reported for 45/203 (22.2%) vs 68/246 (27.6%) pts. The median time to first subsequent therapy (from randomization to the first post-study dose of therapy) was 24.2 (95% CI: 20.9–27.6) vs 16.7 (95% CI: 14.8–19.3) months in pts who received RIB + LET vs PBO + LET; median time to initiation of second subsequent therapy was not reached in either arm. The most common type of first subsequent therapy was single-agent hormonal therapy in 90 (44.3%) vs 87 (35.4%) pts who discontinued RIB + LET vs PBO + LET; chemotherapy was the most common second subsequent therapy in 20 (9.9%) vs 36 (14.6%) pts. Chemotherapy alone was the first subsequent treatment after MONALEESA-2 discontinuation in 32 (15.8%) vs 55 (22.4%) pts treated with RIB + LET vs PBO + LET. Conclusions: RIB + LET significantly prolongs PFS and delays the start of subsequent lines of therapy vs PBO + LET in pts with HR+, HER2– ABC. The most common first subsequent therapy following discontinuation of RIB + LET or PBO + LET was single-agent hormonal therapy, and fewer pts treated with RIB + LET received subsequent chemotherapy compared with those who received PBO + LET. Citation Format: Blackwell KL, Paluch-Shimon S, Campone M, Conte P, Petrakova K, Favret A, Blau S, Beck JT, Miller M, Sutradhar S, Monaco M, Burris HA. Subsequent treatment for postmenopausal women with hormone receptor-positive, HER2-negative advanced breast cancer who received ribociclib + letrozole vs placebo + letrozole in the phase III MONALEESA-2 study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P5-21-18.
