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Purpose:This phase 1 study (NCT03440437) evaluated the safety, tolerability, pharmacokinetics (PK), and activity of FS118, a bispecific antibody–targeting LAG-3 and PD-L1, in patients with advanced cancer resistant to anti–PD-(L)1 therapy.Patients and Methods:Patients with solid tumors, refractory to anti–PD-(L)1–based therapy, received intravenous FS118 weekly with an accelerated dose titration design (800 μg to 0.3 mg/kg) followed by 3+3 ascending dose expansion (1 to 20 mg/kg). Primary objectives were safety, tolerability, and PK. Additional endpoints included antitumor activity, immunogenicity, and pharmacodynamics.Results:Forty-three patients with a median of three prior regimens in the locally advanced/metastatic setting, including at least one anti–PD-(L)1 regimen, received FS118 monotherapy. FS118 was well tolerated, with no serious adverse events relating to FS118 reported. No dose-limiting toxicities (DLT) were observed, and an MTD was not reached. The recommended phase 2 dose of FS118 was established as 10 mg/kg weekly. The terminal half-life was 3.9 days. Immunogenicity was transient. Pharmacodynamic activity was prolonged throughout dosing as demonstrated by sustained elevation of soluble LAG-3 and increased peripheral effector cells. The overall disease control rate (DCR) was 46.5%; this disease control was observed as stable disease, except for one late partial response. Disease control of 54.8% was observed in patients receiving 1 mg/kg or greater who had acquired resistance to PD-(L)1–targeted therapy.Conclusions:FS118 was well tolerated with no DLTs observed up to and including 20 mg/kg QW. Further studies are warranted to determine clinical benefit in patients who have become refractory to anti–PD-(L)1 therapy.See related commentary by Karapetyan and Luke, p. 835

Supplementary Materials (clean)

Hyperpolarized 13C-MRI is an emerging tool for probing tissue metabolism by measuring 13C-label exchange between intravenously injected hyperpolarized [1–13C]pyruvate and endogenous tissue lactate. Here, we demonstrate that hyperpolarized 13C-MRI can be used to detect early response to neoadjuvant therapy in breast cancer. Seven patients underwent multiparametric 1H-MRI and hyperpolarized 13C-MRI before and 7–11 days after commencing treatment. An increase in the lactate-to-pyruvate ratio of approximately 20% identified three patients who, following 5–6 cycles of treatment, showed pathological complete response. This ratio correlated with gene expression of the pyruvate transporter MCT1 and lactate dehydrogenase A (LDHA), the enzyme catalyzing label exchange between pyruvate and lactate. Analysis of approximately 2,000 breast tumors showed that overexpression of LDHA and the hypoxia marker CAIX was associated with reduced relapse-free and overall survival. Hyperpolarized 13C-MRI represents a promising method for monitoring very early treatment response in breast cancer and has demonstrated prognostic potential.Significance:Hyperpolarized carbon-13 MRI allows response assessment in patients with breast cancer after 7–11 days of neoadjuvant chemotherapy and outperformed state-of-the-art and research quantitative proton MRI techniques.

Supplementary Table S1: Representativeness of Study Participants.Supplementary Table S2: Immunogenicity in patients treated with FS118.Supplementary Table S3: PK of FS118 by Dose Level.

Supplementary information

Supplementary Figure S1: Study design for the evaluation of FS118 in subjects with advanced solid tumors whoprogressed on or after prior PD-(L)1 therapy.Supplementary Figure S2: Time on FS118 treatment in patients with primary or acquired resistance to prioranti-PD-(L)1 therapies.Supplementary Figure S3: Total time on prior ICB therapies compared to the timeon FS118 treatment in patients with primary or acquired resistance to prior antiPD-(L)1 therapies.Supplementary Figure S4: Levels of soluble LAG-3 (sLAG-3) detected inthe serum of patients in the FS118 phase 1 trial.Supplementary Figure S5: Changes in circulating immune cells in FS118-treated patients.

Purpose:This phase 1 study (NCT03440437) evaluated the safety, tolerability, pharmacokinetics (PK), and activity of FS118, a bispecific antibody–targeting LAG-3 and PD-L1, in patients with advanced cancer resistant to anti–PD-(L)1 therapy.Patients and Methods:Patients with solid tumors, refractory to anti–PD-(L)1–based therapy, received intravenous FS118 weekly with an accelerated dose titration design (800 μg to 0.3 mg/kg) followed by 3+3 ascending dose expansion (1 to 20 mg/kg). Primary objectives were safety, tolerability, and PK. Additional endpoints included antitumor activity, immunogenicity, and pharmacodynamics.Results:Forty-three patients with a median of three prior regimens in the locally advanced/metastatic setting, including at least one anti–PD-(L)1 regimen, received FS118 monotherapy. FS118 was well tolerated, with no serious adverse events relating to FS118 reported. No dose-limiting toxicities (DLT) were observed, and an MTD was not reached. The recommended phase 2 dose of FS118 was established as 10 mg/kg weekly. The terminal half-life was 3.9 days. Immunogenicity was transient. Pharmacodynamic activity was prolonged throughout dosing as demonstrated by sustained elevation of soluble LAG-3 and increased peripheral effector cells. The overall disease control rate (DCR) was 46.5%; this disease control was observed as stable disease, except for one late partial response. Disease control of 54.8% was observed in patients receiving 1 mg/kg or greater who had acquired resistance to PD-(L)1–targeted therapy.Conclusions:FS118 was well tolerated with no DLTs observed up to and including 20 mg/kg QW. Further studies are warranted to determine clinical benefit in patients who have become refractory to anti–PD-(L)1 therapy.See related commentary by Karapetyan and Luke, p. 835

Word Document with legends for supplementary figures

Glucuronidation is an enzymatic process that terminally inactivates steroid hormones, including estrogens and androgens, thereby influencing carcinogenesis in hormone-dependent cancers. While estrogens drive breast carcinogenesis via the estrogen receptor alpha (ERα), androgens play a critical role as prohormones for estrogen biosynthesis and ligands for the androgen receptor (AR). In this study, the expression and regulation of two androgen-inactivating enzymes, the UDP-glucuronosyltransferases UGT2B15 and UGT2B17, was assessed in breast cancer. In large clinical cohorts, high UGT2B15 and UGT2B17 levels positively influenced disease-specific survival in distinct molecular subgroups. Expression of these genes was highest in cases positive for ERα. In cell line models, ERα, AR, and the transcription factor FOXA1 cooperated to increase transcription via tandem binding events at their proximal promoters. ERα activity was dependent on FOXA1, facilitated by AR activation, and potently stimulated by estradiol as well as estrogenic metabolites of 5α-dihydrotestosterone. AR activity was mediated via binding to an estrogen receptor half-site 3′ to the FOXA1 and ERα-binding sites. Although AR and FOXA1 bound the UGT promoters in AR-positive/ERα-negative breast cancer cell lines, androgen treatment did not influence basal transcription levels. Ex vivo culture of human breast tissue and ERα+ tumors provided evidence for upregulation of UGT2B15 and UGT2B17 by estrogen or androgen treatment. ERα binding was evident at the promoters of these genes in a small cohort of primary tumors and distant metastases. Collectively, these data provide insight into sex steroid receptor-mediated regulation of androgen-inactivating enzymes in ERα+ breast cancer, which may have subtype-specific consequences for disease progression and outcomes. Cancer Res; 76(19); 5881–93. ©2016 AACR.

Word document containing additional details of materials and methods

Supplementary Figure 1. Correlation plots depicting the relationship between UGT2B15 and UGT2B17 mRNA expression in breast cancer. Supplementary Figure 3. Steroid-mediated regulation of GREB1, UGTB215 and UGTB17 in MCF7 cells. Supplementary Figure 4. Effect of ERα, FOXA1 or AR knockdown on UGT2B15 and UGT2B17 mRNA expression in MCF7 cells. Supplementary Figure 5. Genome browser images of showing FOXA1, ERα and AR chromatin occupancy at the UGT2B15 and UGT2B17 promoters in ZR75-1 and MCF7 cells. Supplementary Figure 6. Regulation of UGT2B15 and UGT2B17 mRNA expression by the AR agonist Enobosarm in MCF7 cells (A and B) and steroid-mediated regulation of UGT2B15 and UGT2B17 mRNA expression in normal breast tissues (C).

Supplementary Figure 2. Kaplan-Meier survival plots showing relationship between UGTB215 and UGTB17 levels and outcome in distinct breast cancer subtypes.

Supplementary Methods from Two Novel Determinants of Etoposide Resistance in Small Cell Lung Cancer

BackgroundBreast cancer (BC) genome-wide association studies (GWAS) have identified hundreds of risk-loci that require novel approaches to reveal the causal variants and target genes within them. As causal variants are most likely regulators of gene expression, we hypothesize that their identification is facilitated by pinpointing the variants with greater regulatory potential within risk-loci.MethodsWe performed genome-wide differential allelic expression (DAE) analysis using microarrays data from 64 normal breast tissue samples. Then, we mapped the variants associated with DAE (daeQTLs) and intersected these with GWAS data to reveal candidate risk regulatory variants. Finally, we validated our approach by functionally analysing the 5q14.1 breast cancer risk-locus.ResultsWe found widespread gene expression regulation by cis-acting variants in breast tissue, with 80% of coding and non-coding expressed genes displaying DAE (daeGenes). We identified over 23K daeQTLs for 2753 (16%) daeGenes, including at 154 known BC risk- loci. And in 31 of these risk-loci, we found risk-associated variant(s) and daeQTLs in strong linkage disequilibrium suggesting that the risk-causing variants are cis-regulatory, and in 27 risk-loci we propose 37 candidate target genes. As validation, we identified five candidate causal variants at the 5q14.1 risk-locus targeting the ATG10, RPS23, and ATP6AP1L genes, likely via modulation of miRNA binding, alternative transcription, and transcription factor binding.ConclusionOur study shows the power of DAE analysis and daeQTL mapping to identify causal regulatory variants and target genes at BC risk loci, including those with complex regulatory landscapes, and provides a genome-wide resource of variants associated with DAE for future functional studies.