Facts and Hopes on Biomarkers for Successful Early Clinical Immunotherapy Trials: Innovative Patient Enrichment Strategies

Despite the clinical validation and unequivocal benefit to patients, the development of cancer immunotherapies is facing some key challenges and the attrition rate in early phases of development remains high. Identifying the appropriate patient population that would benefit most from the drug is on the critical path for successful clinical development. We believe that a systematic implementation of patient enrichment strategies early in the drug development process and trial design, is the basis for an innovative, more efficient, and leaner clinical development to achieve earlier a clear proof of concept or proof of failure. In this position article, we will describe and propose key considerations for the implementation of patient enrichment strategies as an opportunity to provide decision-enabling data earlier in the drug development process. We introduce an innovative multidimensional tool for immuno-oncology drug development that focuses on facilitating the identification and prioritization of enrichment-relevant biomarkers, based on the drug mechanism of action. To illustrate its utility, we discuss patient enrichment examples and use a case in the field of cancer immunotherapy, together with technical and regulatory considerations. Overall, we propose to implement fit for purpose enrichment strategies for all investigational drugs as early as possible in the development process. We believe that this will increase the success rate of immuno-oncology clinical trials, and eventually bring new and better medicines to patients faster.

Immunogenicity and safety of BNT162b2 mRNA vaccine in Chinese adults: A phase 2 randomised clinical trial

BACKGROUND

BNT162b2, an mRNA vaccine against COVID-19, is being utilised worldwide, but immunogenicity and safety data in Chinese individuals are limited.

METHODS

This phase 2, randomised, double-blind, placebo-controlled trial included healthy or medically stable individuals aged 18-85 years enrolled at two clinical sites in China. Participants were stratified by age (≤55 or >55 years) and randomly assigned (3:1) by an independent randomisation professional to receive two doses of intramuscular BNT162b2 30 μg or placebo, administered 21 days apart. Study participants, study personnel, investigators, statisticians, and the sponsor's study management team were blinded to treatment assignment. Primary immunogenicity endpoints were the geometric mean titers (GMTs) of neutralising antibodies to live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and seroconversion rates (SCR) 1 month after the second dose. Safety assessments included reactogenicity within 14 days of vaccination, adverse events (AEs), and clinical laboratory parameters. Randomised participants who received at least one dose were included in the efficacy and safety analyses on a complete case basis (incomplete/missing data not imputed). Results up to 6 months after the second dose are reported.

FINDINGS

Overall, 959 participants (all of Han ethnicity) who were recruited between December 5th, 2020 and January 9th, 2021 received at least one injection (BNT162b2, n=720; placebo, n=239). At 1 month after the second dose, the 50% neutralising antibody GMT was 294.4 (95% CI; 281.1-308.4) in the BNT162b2 group and 5.0 (95% CI; 5.0-5.0) in the placebo group. SCRs were 99.7% (95% CI; 99.0%-100.0%) and 0% (95% CI; 0.0%-1.5%), respectively (p<0.0001 vs placebo). Although the GMT of neutralising antibodies in the BNT162b2 group was greatly reduced at 6 months after the second dose, the SCR still remained at 58.8%. BNT162b2-elicited sera neutralised SARS-CoV-2 variants of concern. T-cell responses were detected in 58/73 (79.5%) BNT162b2 recipients. Reactogenicity was mild or moderate in severity and resolved within a few days after onset. Unsolicited AEs were uncommon at 1 month following vaccine administration, and there were no vaccine-related serious AEs at 1 month or 6 months after the second dose.

INTERPRETATION

BNT162b2 vaccination induced a robust immune response with acceptable tolerability in Han Chinese adults. However, follow-up duration was relatively short and COVID-19 rates were not assessed. Safety data collection is continuing until 12 months after the second dose.

FUNDING

BioNTech - sponsored the trial. Shanghai Fosun Pharmaceutical Development Inc. (Fosun Pharma) - conducted the trial, funded medical writing.

CLINICALTRIALSGOV REGISTRATION NUMBER

NCT04649021. Trial status: Completed.

Safety and Efficacy of a Third Dose of BNT162b2 Covid-19 Vaccine

BACKGROUND

Active immunization with the BNT162b2 vaccine (Pfizer-BioNTech) has been a critical mitigation tool against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during the coronavirus disease 2019 (Covid-19) pandemic. In light of reports of waning protection occurring 6 months after the primary two-dose vaccine series, data are needed on the safety and efficacy of offering a third (booster) dose in persons 16 years of age or older.

METHODS

In this ongoing, placebo-controlled, randomized, phase 3 trial, we assigned participants who had received two 30-μg doses of the BNT162b2 vaccine at least 6 months earlier to be injected with a third dose of the BNT162b2 vaccine or with placebo. We assessed vaccine safety and efficacy against Covid-19 starting 7 days after the third dose.

RESULTS

A total of 5081 participants received a third BNT162b2 dose and 5044 received placebo. The median interval between dose 2 and dose 3 was 10.8 months in the vaccine group and 10.7 months in the placebo group; the median follow-up was 2.5 months. Local and systemic reactogenicity events from the third dose were generally of low grade. No new safety signals were identified, and no cases of myocarditis or pericarditis were reported. Among the participants without evidence of previous SARS-CoV-2 infection who could be evaluated, Covid-19 with onset at least 7 days after dose 3 was observed in 6 participants in the vaccine group and in 123 participants in the placebo group, which corresponded to a relative vaccine efficacy of 95.3% (95% confidence interval, 89.5 to 98.3).

CONCLUSIONS

A third dose of the BNT162b2 vaccine administered a median of 10.8 months after the second dose provided 95.3% efficacy against Covid-19 as compared with two doses of the BNT162b2 vaccine during a median follow-up of 2.5 months. (Funded by BioNTech and Pfizer; C4591031 ClinicalTrials.gov number, NCT04955626.).

Preclinical Characterization and Phase I Trial Results of a Bispecific Antibody Targeting PD-L1 and 4-1BB (GEN1046) in Patients with Advanced Refractory Solid Tumors

Checkpoint inhibitors (CPI) have revolutionized the treatment paradigm for advanced solid tumors; however, there remains an opportunity to improve response rates and outcomes. In preclinical models, 4-1BB costimulation synergizes with CPIs targeting the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) axis by activating cytotoxic T-cell-mediated antitumor immunity. DuoBody-PD-L1×4-1BB (GEN1046) is an investigational, first-in-class bispecific immunotherapy agent designed to act on both pathways by combining simultaneous and complementary PD-L1 blockade and conditional 4-1BB stimulation in one molecule. GEN1046 induced T-cell proliferation, cytokine production, and antigen-specific T-cell-mediated cytotoxicity superior to clinically approved PD-(L)1 antibodies in human T-cell cultures and exerted potent antitumor activity in transplantable mouse tumor models. In dose escalation of the ongoing first-in-human study in heavily pretreated patients with advanced refractory solid tumors (NCT03917381), GEN1046 demonstrated pharmacodynamic immune effects in peripheral blood consistent with its mechanism of action, manageable safety, and early clinical activity [disease control rate: 65.6% (40/61)], including patients resistant to prior PD-(L)1 immunotherapy.

SIGNIFICANCE

DuoBody-PD-L1×4-1BB (GEN1046) is a first-in-class bispecific immunotherapy with a manageable safety profile and encouraging preclinical and early clinical activity. With its ability to confer clinical benefit in tumors typically less sensitive to CPIs, GEN1046 may fill a clinical gap in CPI-relapsed or refractory disease or as a combination therapy with CPIs. See related commentary by Li et al., p. 1184. This article is highlighted in the In This Issue feature, p. 1171.

Clinical development and approval of COVID-19 vaccines

Introduction

The coronavirus 19 (COVID-19) pandemic triggered a simultaneous global demand for preventative vaccines, which quickly became a high priority among governments as well as academia and the pharmaceutical industry. Within less than a year after COVID-19 was declared a pandemic, vaccines had received emergency approvals and vaccination campaigns were initiated.

Areas covered

We discuss the several factors that led to the unprecedented, accelerated development and approval of COVID-19 vaccines, which includes optimization of processes by regulatory authorities, redesign of sequential development processes, learnings from previous pandemics, and prior development of novel vaccine platforms.

Expert Opinion

Despite unanticipated and complex challenges presented by real-time vaccine development in the context of the evolving COVID-19 pandemic and subsequent ever-changing landscape of public health measures and recommendations, important milestones were reached within extraordinarily short periods and, following roll-out to billions worldwide, the approved vaccines have proven to be well tolerated and effective. Whilst this is an exceptional feat and an example of what can be achieved with collaboration and innovation, there are lessons that can still be learned, including the need for further harmonization between regulatory authorities, modes to react to the pandemic’s ever-evolving challenges, and ensuring equitable vaccine access among low-income countries.

Evaluation of the BNT162b2 Covid-19 Vaccine in Children 5 to 11 Years of Age

BACKGROUND

Safe, effective vaccines against coronavirus disease 2019 (Covid-19) are urgently needed in children younger than 12 years of age.

METHODS

A phase 1, dose-finding study and an ongoing phase 2-3 randomized trial are being conducted to investigate the safety, immunogenicity, and efficacy of two doses of the BNT162b2 vaccine administered 21 days apart in children 6 months to 11 years of age. We present results for 5-to-11-year-old children. In the phase 2-3 trial, participants were randomly assigned in a 2:1 ratio to receive two doses of either the BNT162b2 vaccine at the dose level identified during the open-label phase 1 study or placebo. Immune responses 1 month after the second dose of BNT162b2 were immunologically bridged to those in 16-to-25-year-olds from the pivotal trial of two 30-μg doses of BNT162b2. Vaccine efficacy against Covid-19 at 7 days or more after the second dose was assessed.

RESULTS

During the phase 1 study, a total of 48 children 5 to 11 years of age received 10 μg, 20 μg, or 30 μg of the BNT162b2 vaccine (16 children at each dose level). On the basis of reactogenicity and immunogenicity, a dose level of 10 μg was selected for further study. In the phase 2-3 trial, a total of 2268 children were randomly assigned to receive the BNT162b2 vaccine (1517 children) or placebo (751 children). At data cutoff, the median follow-up was 2.3 months. In the 5-to-11-year-olds, as in other age groups, the BNT162b2 vaccine had a favorable safety profile. No vaccine-related serious adverse events were noted. One month after the second dose, the geometric mean ratio of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing titers in 5-to-11-year-olds to those in 16-to-25-year-olds was 1.04 (95% confidence interval [CI], 0.93 to 1.18), a ratio meeting the prespecified immunogenicity success criterion (lower bound of two-sided 95% CI, >0.67; geometric mean ratio point estimate, ≥0.8). Covid-19 with onset 7 days or more after the second dose was reported in three recipients of the BNT162b2 vaccine and in 16 placebo recipients (vaccine efficacy, 90.7%; 95% CI, 67.7 to 98.3).

CONCLUSIONS

A Covid-19 vaccination regimen consisting of two 10-μg doses of BNT162b2 administered 21 days apart was found to be safe, immunogenic, and efficacious in children 5 to 11 years of age. (Funded by BioNTech and Pfizer; ClinicalTrials.gov number, NCT04816643.).

A randomized study to evaluate safety and immunogenicity of the BNT162b2 COVID-19 vaccine in healthy Japanese adults

We report interim safety and immunogenicity findings from an ongoing phase 1/2 study of BNT162b2 in healthy Japanese adults. Participants were randomized 3:1 to receive 2 intramuscular injections of 30 μg BNT162b2 or placebo 21 days apart. Overall, 160 individuals were randomized: 119 received BNT162b2, and 41 received placebo. Participants were stratified by age: 20–64 years (n = 130) and 65–85 years (n = 30). More than 97% of BNT162b2 recipients received 2 doses. Local reactions and systemic events were generally transient and mild to moderate. Severe adverse events were uncommon; there were no serious adverse events. One month after dose 2, SARS-CoV-2 50% serum neutralizing geometric mean titers were 571 and 366, and geometric mean fold rises were 55.8 and 36.6, in the younger and older age groups, respectively. In summary, BNT162b2 has an acceptable safety profile and produces a robust immune response, regardless of age, in Japanese adults. (ClinicalTrials.gov, NCT04588480).

Here the authors provide the interim analysis of an ongoing phase 1/2 study of the BNT162b2 vaccine in healthy Japanese adults. They report mainly mild to moderate local reactions and no serious adverse events as well as good antibody induction one month after the second dose.

493 First-in-human phase 1/2 trial to evaluate the safety and initial clinical activity of DuoBody®-CD40×4–1BB (GEN1042) in patients with advanced solid tumors

Background

Despite the preclinical promise of CD40 and 4-1BB as immuno-oncologic targets, clinical efforts evaluating these agonists as monotherapy have had limited success due to minimal efficacy and/or severe toxicity. DuoBody-CD40×4-1BB (GEN1042) is a first-in-class, bispecific, agonistic antibody that combines targeting and conditional activation of CD40 and 4-1BB on immune cells, resulting in enhanced priming and (re-)activation of tumor-specific immunity. Furthermore, preclinical data suggest that combination with anti–PD-1 can enhance antitumor activity. We present preliminary data from the ongoing, first-in-human, open-label, phase 1/2 trial of DuoBody-CD40×4-1BB in advanced solid tumors (NCT04083599).

Methods

During dose escalation, patients with metastatic/unresectable non-CNS solid tumors who had exhausted standard therapies received flat-dose DuoBody-CD40×4-1BB (0.1–400 mg) intravenously every 3 weeks until disease progression or unacceptable toxicity. Primary endpoint was dose-limiting toxicity (DLT). Secondary endpoints included adverse events (AEs), pharmacokinetic parameters, and preliminary antitumor activity (RECIST v1.1). Pharmacodynamic biomarkers were assessed as exploratory endpoints.

Results

As of June 11, 2021, 50 patients were enrolled (median age, 57 years). The most common cancer types were colorectal (22%), melanoma (20%), and non–small-cell lung cancer (8%). Patients received a median (range) of 2.5 (1–21) treatment cycles; Cmax was observed shortly after end of infusion. Treatment-related AEs occurring in ≥10% of patients (all grades; grade ≥3) were fatigue (22%; 0%), pyrexia (16%; 0%), nausea (10%; 0%), and transaminase elevation (10%; 6%). Maximum tolerated dose was not reached. One DLT of elevated transaminases (grade 4) was observed at the 200-mg dose that resolved upon corticosteroid administration. No drug-related grade ≥3 thrombocytopenia events were reported. Disease control, defined as best overall response of complete/partial response and stable disease, was achieved in 51% of patients (25/49), including 2 confirmed partial responses per RECIST v1.1 in melanoma and neuroendocrine lung cancer. Modulation of pharmacodynamic endpoints was observed across dose levels, with more pronounced effects near the 100-mg dose. Increases in peripheral IFN-y, TARC (monocyte/DC chemokine), and proliferating CD8+ total and effector memory T cells were observed during cycle 1. Using physiologically based pharmacokinetic/pharmacodynamic modeling and available safety, efficacy, and pharmacodynamic data, 100 mg every 3 weeks was identified as the expansion dose for further evaluation.

Conclusions

DuoBody-CD40×4-1BB demonstrated biologic and early antitumor activity with a favorable safety profile in patients with advanced solid tumors. Expansion cohorts, including combination therapy with PD-1 inhibitors, are currently enrolling.

Acknowledgements

This trial was funded by Genmab A/S and BioNTech SE.

Trial Registration

NCT04083599

Ethics Approval

This trial is undertaken following full approval of the final protocol, amendments, informed consent form, applicable recruiting materials, and subject compensation programs by the Independent Ethics Committee/Institutional Review Board.

786 Dose selection for DuoBody®-PD-L1×4-1BB (GEN1046) using a semimechanistic pharmacokinetics/pharmacodynamics model that leverages preclinical and clinical data

Background

DuoBody-PD-L1×4-1BB (GEN1046) is a class-defining bispecific antibody, designed to elicit an anti-tumor immune response by simultaneous and complementary blockade of PD-L1 on tumor cells and conditional stimulation of 4-1BB on T-cells and NK cells. Optimizing target engagement for a bispecific antibody is challenging, as it involves binding with two targets, and predicting trimer levels in tumors based on affinity of individual arms and target expression. Here we describe a semimechanistic, physiologically based pharmacokinetic/pharmacodynamic (PK/PD) model that predicts a dosing regimen for DuoBody-PD-L1×4-1BB, which results in the formation of maximum levels of a therapeutically active 4-1BB-bispecific antibody-PD-L1 trimolecular complex (trimer), and optimal PD-L1 receptor occupancy (RO).

Methods

An integrated semimechanistic PK/PD model that describes the distribution of DuoBody-PD-L1×4-1BB into central and peripheral compartments and partitioning into tumor/lymph nodes was developed. The model used PK/PD data and physiological parameters from the literature for parameterizations of PD-L1 and 4-1BB expression levels and T-cell trafficking. The model incorporates dynamic binding of DuoBody-PD-L1×4-1BB to its targets to predict trimer formation and RO for PD-L1 in tumors. Model parameters were calibrated to match in vitro PD studies, such as analyses of T-cell proliferation and cytokine release, as well as clinical PK data. Sensitivity to model assumptions were assessed by varying PK/PD parameters, and assessing their impact on trimer formation and PD-L1 RO. The model was subsequently used to explore in vivo trimer levels and PD-L1 RO in tumors at various dosing regimens.

Results

The model was able to adequately describe the PK of DuoBody-PD-L1×4-1BB in the central compartment. Simulations showed a bell-shaped response for average trimer levels in tumors that peaked at 100 mg every 3 weeks (Q3W), with doses >100 mg resulting in reduced trimer formation. Average PD-L1 receptor occupancy at the 100 mg dose was predicted to be approximately 70% over 21 days and increased at higher doses. Based on these model predictions, and available safety, anti-tumor activity, and PD data from the ongoing GCT1046-01 trial (NCT03917381), 100 mg Q3W was chosen as the expansion dose for further evaluation in Part 2 of the study.

Conclusions

This semimechanistic PK/PD model provides a novel approach for dose selection of bispecific antibodies such as DuoBody-PD-L1×4-1BB, by using preclinical and clinical PK/PD data to predict formation of optimal trimer levels and PD-L1 receptor occupancy.

Acknowledgements

The authors thank Friederike Gieseke and Zuzana Jirakova at BioNTech SE; Kalyanasundaram Subramanian at Applied Biomath LLC for their valuable contributions.

Trial Registration

Written informed consent, in accordance with principles that originated in the Declaration of Helsinki 2013, current ICH guidelines including ICH-GCP E6(R2), applicable regulatory requirements, and sponsor policy, was provided by the patients.

516 Peripheral and tumoral immune activity in the expansion part of the first-in-human DuoBody®-PD-L1×4–1BB (GEN1046) trial

Background

DuoBody-PD-L1×4-1BB (GEN1046) is a class-defining, bispecific immunotherapy designed to induce an antitumor immune response by simultaneous and complementary PD-L1 blockade and conditional 4-1BB stimulation. Encouraging clinical activity and manageable safety were observed during dose escalation in the ongoing phase 1/2a trial in patients with advanced solid tumors (NCT03917381). We report exploratory pharmacodynamic analyses and potential biomarkers of response in an expansion cohort of patients with PD-(L)1–R/R NSCLC.

Methods

Patients with metastatic/unresectable NSCLC who had multiple lines of prior systemic therapy, including a checkpoint inhibitor, received flat-dose DuoBody-PD-L1×4-1BB (100 mg) intravenously every 3 weeks. Immunophenotyping of peripheral blood and measurements of soluble immune mediators were evaluated in serial blood samples in cycles 1–2. Tumor PD-L1 and 4-1BB expression and additional immune markers were evaluated by immunohistochemistry in core needle tumor biopsy specimens collected before treatment and at cycle 2.

Results

As of May 2021, 40 patients with PD-(L)1–R/R NSCLC were enrolled (median age, 63 years). Treatment with DuoBody-PD-L1×4-1BB elicited pharmacodynamic modulation of immune endpoints within the first 2 cycles. Induction of peripheral IFN-y, CXCL9/10, and expansion of peripheral CD8+ effector memory T cells and activated NK cells were observed starting at cycle 1 (>2-fold from baseline) and maintained or increased through cycle 2. Based on 9 paired tumor biopsy samples, increased PD-L1 and 4-1BB expression and cytotoxic CD8+/GZMB+ cell density were detected following treatment. In a subset of patients with clinical response (n=5 confirmed PRs), a trend of greater induction of IFN-y, CXCL9/10, and activated NK cells was observed vs nonresponders. Disease control rates were higher in patients who had progressed on prior anti–PD-1 therapy within 8 months (64% [16/25]) from the first dose of DuoBody-PD-L1×4-1BB. As expected, among patients with evaluable baseline tumors (n=26), most with any degree of tumor reduction (best change, <0%) harbored PD-L1+ tumors (≥1% tumor positive score; 7/10) and showed close spatial proximity between PD-L1+ and 4-1BB+ cells. Conversely, most patients without any degree of tumor reduction presented with PD-L1− tumors (12/16).

Conclusions

In patients with NSCLC who progressed on PD-(L)1 therapy, DuoBody-PD-L1×4-1BB elicited pharmacodynamic effects consistent with its proposed mechanism of action. Relationships between disease control and PD-L1 tumoral expression, as well as time from last prior anti–PD-1 therapy, were observed. These findings support that patient selection and/or anti–PD-1 combination therapy may lead to improved clinical efficacy. Further analyses are ongoing and updated results will be presented.

Acknowledgements

The authors thank Hrefna Kristin Johannsdottir, Lei Pang, and Kate Sasser at Genmab A/S and Friederike Gieseke at BioNTech SE for their valuable contributions. This trial was funded by Genmab A/S and BioNTech SE.

Trial Registration

NCT03917381

Ethics Approval

This trial is undertaken following full approval of the final protocol, amendments, informed consent form, applicable recruiting materials, and subject compensation programs by the Independent Ethics Committee/Institutional Review Board.

Consent

Written informed consent, in accordance with principles that originated in the Declaration of Helsinki 2013, current ICH guidelines including ICH-GCP E6(R2), applicable regulatory requirements, and sponsor policy, was provided by the patients.

Safety and immunogenicity of the SARS-CoV-2 BNT162b1 mRNA vaccine in younger and older Chinese adults: a randomized, placebo-controlled, double-blind phase 1 study

An effective vaccine is needed to end the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Here, we assess the preliminary safety, tolerability and immunogenicity data from an ongoing single-center (in Jiangsu province, China), parallel-group, double-blind phase 1 trial of the vaccine candidate BNT162b1 in 144 healthy SARS-CoV-2-naive Chinese participants. These participants are randomized 1:1:1 to receive prime and boost vaccinations of 10 µg or 30 µg BNT162b1 or placebo, given 21 d apart, with equal allocation of younger (aged 18-55 years) and older adults (aged 65-85 years) to each treatment group (ChiCTR2000034825). BNT162b1 encodes the SARS-CoV-2 spike glycoprotein receptor-binding domain (RBD) and is one of several messenger RNA-based vaccine candidates under clinical investigation. Local reactions and systemic events were generally dose dependent, transient and mild to moderate. Fever was the only grade 3 adverse event. BNT162b1 induced robust interferon-γ T cell responses to a peptide pool including the RBD in both younger and older Chinese adults, and geometric mean neutralizing titers reached 2.1-fold (for younger participants) and 1.3-fold (for the older participants) that of a panel of COVID-19 convalescent human sera obtained at least 14 d after positive SARS-CoV-2 polymerase chain reaction test. In summary, BNT162b1 has an acceptable safety profile and produces high levels of humoral and T cell responses in an Asian population.

Phase I Assessment of Safety and Therapeutic Activity of BAY1436032 in Patients with IDH1-Mutant Solid Tumors

PURPOSE

BAY1436032, an inhibitor of mutant isocitrate dehydrogenase 1 (mIDH1), was active against multiple IDH1-R132X solid tumors in preclinical models. This first-in-human study was designed to determine the safety and pharmacokinetics of BAY1436032, and to evaluate its potential pharmacodynamics and antitumor effects.

PATIENTS AND METHODS

The study comprised of dose escalation and dose expansion cohorts. BAY1436032 tablets were orally administered twice daily on a continuous basis in subjects with mIDH1 solid tumors.

RESULTS

In dose escalation, 29 subjects with various tumor types were administered BAY1436032 across five doses (150-1,500 mg twice daily). BAY1432032 exhibited a relatively short half-life. Most evaluable subjects experienced target inhibition as indicated by a median maximal reduction of plasma R-2-hydroxyglutarate levels of 76%. BAY1436032 was well tolerated and an MTD was not identified. A dose of 1,500 mg twice daily was selected for dose expansion, where 52 subjects were treated in cohorts representing four different tumor types [lower grade glioma (LGG), glioblastoma, intrahepatic cholangiocarcinoma, and a basket cohort of other tumor types]. The best clinical outcomes were in subjects with LGG (n = 35), with an objective response rate of 11% (one complete response and three partial responses) and stable disease in 43%. As of August 2020, four of these subjects were in treatment for >2 years and still ongoing. Objective responses were observed only in LGG.

CONCLUSIONS

BAY1436032 was well tolerated and showed evidence of target inhibition and durable objective responses in a small subset of subjects with LGG.

First-in-Human Trial of the Oral Ataxia Telangiectasia and RAD3-Related (ATR) Inhibitor BAY 1895344 in Patients with Advanced Solid Tumors

Targeting the ataxia telangiectasia and RAD3-related (ATR) enzyme represents a promising anticancer strategy for tumors with DNA damage response (DDR) defects and replication stress, including inactivation of ataxia telangiectasia mutated (ATM) signaling. We report the dose-escalation portion of the phase I first-in-human trial of oral ATR inhibitor BAY 1895344 intermittently dosed 5 to 80 mg twice daily in 21 patients with advanced solid tumors. The MTD was 40 mg twice daily 3 days on/4 days off. Most common adverse events were manageable and reversible hematologic toxicities. Partial responses were achieved in 4 patients and stable disease in 8 patients. Median duration of response was 315.5 days. Responders had ATM protein loss and/or deleterious ATM mutations and received doses ≥40 mg twice daily. Overall, BAY 1895344 is well tolerated, with antitumor activity against cancers with certain DDR defects, including ATM loss. An expansion phase continues in patients with DDR deficiency. SIGNIFICANCE: Oral BAY 1895344 was tolerable, with antitumor activity in heavily pretreated patients with various advanced solid tumors, particularly those with ATM deleterious mutations and/or loss of ATM protein; pharmacodynamic results supported a mechanism of action of increased DNA damage. Further study is warranted in this patient population.See related commentary by Italiano, p. 14.This article is highlighted in the In This Issue feature, p. 1.

Abstract CT015: Phase I dose-escalation study of the allosteric AKT inhibitor BAY 1125976 in advanced solid cancer

This open-label, phase I first-in-human study (NCT01915576) of BAY 1125976, a highly specific and potent allosteric inhibitor of AKT1/2, was conducted to evaluate the safety, pharmacokinetics, and maximum tolerated dose (MTD) of BAY 1125976 in patients with advanced solid tumors. A dose expansion in hormone receptor (HR) positive metastatic breast cancer (MBC) patients, enriched for patients harboring the AKT1E17K mutation, was included to evaluate the clinical benefit at the recommended Phase II dose (R2D).79 patients (including 39 MBC patients) were enrolled. Mean age was 56.7 years and 61 (77.2%) patients were female. All patients, except one, had received ≥1 prior line of systemic anticancer therapy. Response was measured using RECIST v.1.1.Oral dose escalation was initiated with a continuous once daily (OD) dosing (21 days/cycle), starting with a liquid formulation for the first two dose steps (10 mg and 20 mg OD) and bridging to a tablet formulation for further dose steps (40 mg, 80mg and 120mg OD). Based on toxicity assessment during cycle 1, and additional pharmacokinetic and pharmacodynamic (p-AKT, p-PRAS40 in platelet rich plasma) data, a separate dose escalation using twice daily (BID) dosing tested 40 mg, 60mg and 80mg BID, respectively. The following dose limiting toxicities (DLT) occurred: At 120 mg OD, grade 3 and 4 liver enzyme elevation in two out of 6 patients (2/6) and grade 3 alkaline phosphatase elevation in one patient; at 80mg BID, grade 3 liver enzyme elevation in two out of 4 patients and grade 3 hyperglycemia in one patient. After dose de-escalation according to the continuous reassessment method based study design at 60 mg BID, two out of 6 patients experienced grade 3 liver enzyme elevation. The MTD of BAY 1125976 was determined as 80 mg OD and 60 mg BID, respectively. 28 patients with HR+ MBC were enrolled in the expansion cohort using BAY 1125976 60 mg BID, including nine patients with the AKT1E17K mutation.Pharmacological inhibition of AKT1/2 as shown by inhibition of p-AKT and p-PRAS40 was seen in platelet rich plasma samples. However, among the 78 patients evaluable for response, only 1 (1%) patient with HR+ MBC (AKT1 wild-type) had a partial response (PR), 30 (38%) patients had stable disease (SD) and 38 (49%) patients had progressive disease as best response (data missing from 9 patients). Among 43 patients treated at the R2D, CBR was 27.9%. AKT1E17K mutation status was not associated with tumor response. Molecular characterization of archived tumor samples revealed additional mutations (e.g. PIK3CA, BRCA1/2, KRAS, MYC or FGFR1/2), which may have influenced therapeutic response.In conclusion: Tolerable doses of BAY 1125976 resulted in inhibition of AKT1/2 signaling in platelet rich plasma samples. A notable CBR of 27.9% was achieved at the R2D of BAY 1125976; however PR was seen in only 1 patient with HR+ MBC. Clinical benefit did not correlate with presence of AKT mutations.

Citation Format: Andreas Schneeweiss, Dagmer Hess, Markus Joerger, Andrea Varga, Stacy Moulder, Cynthia Ma, Ian Krop, Sara Hurvitz, Christine Rentzsch, Marion Rudolph, Oliver Boix, Gary Wilkinson, Lars Lindbom, Eleni Lagkadinou, Matthias Ocker. Phase I dose-escalation study of the allosteric AKT inhibitor BAY 1125976 in advanced solid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT015.

First-in-human trial of the oral ataxia telangiectasia and Rad3-related (ATR) inhibitor BAY 1895344 in patients (pts) with advanced solid tumors

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Background: The ATR kinase is a key regulator of the DNA damage response (DDR) machinery, activated by DNA damage and replication stress. BAY 1895344 is a novel, potent, and selective ATR inhibitor with anti-tumor activity in preclinical models with DDR defects. Methods: Pts with advanced metastatic solid tumors resistant or refractory to standard treatment, with and without DDR defects, received BAY 1895344 BID, 3 days (d) on/4 d off continuously in 3-weekly cycles. Results: As of December 20, 2018, 18 pts with colorectal (4), breast (3), prostate (2), and ovarian (2) cancers were enrolled across 6 cohorts (5 mg, 10 mg, 20 mg, 40 mg, 60 mg, and 80 mg BID). Median prior lines of treatment was 5. No dose-limiting toxicities (DLTs) were reported in the 5-40 mg cohorts. 2/3 pts had DLTs in the 80 mg cohort (grade [G] 4 neutropenia, G4 neutropenia and G4 thrombocytopenia) and 2/7 had DLTs in the 60 mg cohort (G4 neutropenia, G2 fatigue). 40 mg BID 3 on/4 off was defined as the maximum tolerated dose. Most common treatment-emergent adverse events included anemia, neutropenia, nausea, and fatigue. Pharmacokinetics appeared dose proportional. Pharmacodynamic analyses showed modulation of pH2AX and/or pKAP1 in paired tumor biopsies at exposures associated with preclinical anti-tumor activity. In 13 pts with and without DDR defects treated at dose levels ≥40 mg BID, the objective response rate was 30.7%, including 2/2 pts at 40 mg (appendix and urothelial cancer), 1/8 pts at 60 mg (breast), and 1/3 pts at 80 mg (endometrial). All responders had ATM protein loss of expression and/or ATM mutation; median treatment duration was 347 d (range 293-364 d). A BRCA1-mutant, olaparib-resistant ovarian cancer pt (60 mg) had a CA125 response and stable disease >10 months. 41 additional pts have been enrolled in ongoing expansion cohorts in cancers with DDR defects (prostate, breast, gynecologic, colorectal) or ATM protein loss (all comers) with responses observed. Conclusions: The ATR inhibitor BAY 1895344 is tolerated at biologically active doses with anti-tumor activity against cancers with certain DDR defects, including ATM protein loss. Clinical trial information: NCT03188965.

Abstract 1887: Preclinical evaluation of a novel interleukin-1 receptor-associated kinase 4 (IRAK4) inhibitor in combination with PI3K inhibitor copanlisib or BTK inhibitors in ABC-DLBCL

Activated B-cell-like diffuse large B-cell lymphoma (ABC-DLBCL) is frequently characterized by aberrant activation of both B-Cell Receptor (BCR) & TLR/MYD88 signaling pathways. Constitutive BCR signaling via Bruton's tyrosine kinase (BTK) and PI3K pathways leads to downstream activation of NF-κB and AKT signaling. In addition, IRAK4 mediated activation of the TLR/MYD88 pathway further activates NF-κB signaling and pro-survival pathways. Simultaneous blockade of TLR/MYD88 signaling via IRAK4 inhibition in combination with pharmacological blockade of PI3K/BCR signaling pathways may therefore provide a novel treatment strategy in ABC-DLBCL.

BAY 1830839 is a novel small molecule inhibitor of IRAK4 identified by a medicinal chemistry optimization program. Key features of the compound are high potency (IC50 of 3 nM) in a biochemical assay, excellent kinase selectivity and a good overall PK profile making the compound a valuable tool for in vivo studies.

In vitro, treatment of IRAK4 inhibitor BAY 1830839 in combination with BTK inhibitors or copanlisib, a pan class I PI3K inhibitor with predominant activity towards PI3Kα and PI3Kδ, synergistically inhibited NF-κB activation and cell viability in human ABC-DLBCL cell lines. In vivo, IRAK4 inhibition alone did not exhibit anti-tumor effects but in combination treatment with ibrutinib, a covalent inhibitor of BTK, synergistic anti-tumor activity with significantly improved efficacy over ibrutinib monotherapy was observed in the human ABC-DLBCL xenograft models TMD-8 and OCI-LY10 (MYD88mut/CD79A/Bmut). Moreover, IRAK4 inhibitor BAY 1830839 showed synergistic anti-tumor activity in combination with copanlisib with significant improvement of copanlisib monotherapy efficacy in the ABC-DLBCL PDX models LY2988 and LY2266 (MYD88mut/CD79A/Bmut and MYD88wt/CD79A/Bwt, respectively). In addition, the combination of IRAK4 inhibition with pharmacological blockade of PI3K-/ BCR signaling led to reduced activity of the downstream pro-survival STAT3 pathway and IL-6/IL-10 production as detected in tumor xenografts, validating our biological rationale and the expected mechanism of action.

In summary, IRAK4 inhibition in combination with pharmacological blockade of PI3K or BCR signaling blocks pro-survival NF-κB & JAK-STAT pathway activation and subsequent IL-6/IL-10 production. Enhancing activity of clinically used PI3K or BTK inhibitors by combination with IRAK4 inhibition indicates a potential new treatment approach for ABC-DLBCL patients progressing on Standard of Care therapy.

Citation Format: Martin Lange, Antje Margret Wengner, Ulrich Bothe, Ulf Boemer, Reinhard Nubbemeyer, Holger Siebeneicher, Holger Steuber, Judith Guenther, Lisette Potze, Nicole Schmidt, Oliver Politz, Wolf-Dietrich Doecke, Eleni Lagkadinou, Thomas M. Zollner, Franz von Nussbaum, Dominik Mumberg, Andreas Steinmeyer, Michael Brands, Karl Ziegelbauer. Preclinical evaluation of a novel interleukin-1 receptor-associated kinase 4 (IRAK4) inhibitor in combination with PI3K inhibitor copanlisib or BTK inhibitors in ABC-DLBCL [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1887.

Abstract 321: Synergistic activity of the ATR inhibitor BAY 1895344 in combination with DNA damage inducing and DNA repair compromising therapies in preclinical tumor models

The DNA damage response (DDR) system consists of complex signalling pathways that secure the integrity of the genome in eukaryotic cells. DDR pathway activation follows recognition of DNA damage and results in cell cycle arrest, suppression of general translation, induction of DNA repair, cell survival or even cell death. Proteins that directly recognize aberrant DNA structures recruit and activate kinases of the DDR, such as ATR (ataxia telangiectasia and Rad3-related). ATR responds to a broad spectrum of DNA damages, including double-strand breaks (DSB) and lesions derived from interference with DNA replication as well as increased replication stress. Therefore, inhibition of ATR kinase activity could be the basis for a novel anti-cancer therapy in tumors with increased DNA damage, deficiency in DDR or replication stress. The potential of combining ATR kinase inhibitor with DNA damage inducing or DNA repair compromising anti-cancer therapeutics was studied in preclinical tumor models. We assessed the novel ATR kinase inhibitor (ATRi) BAY 1895344 in combination with external beam radiation therapy (EBRT), poly ADP ribose polymerase (PARP) inhibition or anti-androgen (AA) therapy. In cellular anti-proliferation assays as well as in tumor xenograft studies we could demonstrate synergistic activity of BAY 1895344 in combination treatment with the PARP inhibitor AZD-2281 in the homologous recombination (HR) defective breast cancer model MDA-MB-436, and with the non-steroidal AA darolutamide in the hormone-dependent prostate cancer model LAPC-4. Strong synergistic anti-tumor activity of BAY 1895344 could be further demonstrated in combination with EBRT inducing long-lasting tumor growth inhibition in the colorectal cancer xenograft model LOVO. The mechanism-based potential of combining DNA damage induction by EBRT with ATRi BAY 1895344 suggests a potential new treatment option for radiation therapy-resistant patients. Furthermore, the inhibition of parallel DDR pathways, as a combination of ATRi BAY 1895344 with a PARP inhibitor, indicates novel treatment opportunities in breast cancer patients with homologous recombination deficiencies, as does the synergism of BAY 1895344 and AA darolutamide therapy in hormone-dependent prostate cancer patients. BAY 1895344 is currently under clinical investigation in patients with advanced solid tumors and lymphomas (NCT03188965).

Citation Format: Antje Margret Wengner, Gerhard Siemeister, Ulrich Luecking, Julien Lefranc, Kirstin Meyer, Eleni Lagkadinou, Bernard Haendler, Pascale Lejeune, Dominik Mumberg. Synergistic activity of the ATR inhibitor BAY 1895344 in combination with DNA damage inducing and DNA repair compromising therapies in preclinical tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 321.

Abstract 838: Synergistic in vivo activity of the ATR inhibitor BAY 1895344 in combination with the targeted alpha therapy radium-223 dichloride in a preclinical tumor model mimicking bone metastatic castration-resistant prostate cancer (mCRPC)

The integrity of the genome in eukaryotic cells is secured by complex signalling pathways, known collectively as DNA damage response (DDR). Recognition of DNA damage activates DDR pathways resulting in cell cycle arrest, suppression of general translation, induction of DNA repair, cell survival, or even cell death. Proteins that directly recognize aberrant DNA structures recruit and activate kinases of the DDR pathway, such as ATR (ataxia telangiectasia and Rad3-related). The ATR kinase is activated by a broad spectrum of DNA damages, including double-strand breaks (DSBs) and lesions derived from interference with DNA replication as well as increased replication stress. Therefore, inhibition of ATR kinase activity could be the basis for a novel anti-cancer therapy in cancers characterized by increased DNA damage, deficiency in DNA damage repair or replication stress. Radium-223 dichloride (Xofigo®) is the first approved targeted alpha therapy. It is indicated for the treatment of patients with castration-resistant prostate cancer (CRPC), symptomatic bone metastases and no known visceral metastatic disease, based on improvement of overall survival. It is a calcium-mimetics that selectively binds to hydroxyapatite targeting areas of high bone turnover such as bone metastases, thereby exhibiting strong cytotoxic effects on adjacent cells via induction of DNA DSBs. We assessed the anti-tumor efficacy of combination treatment with ATR inhibitor (ATRi) BAY 1895344 and radium-223 dichloride in an intratibially injected prostate cancer model mimicking CRPC with bone metastases. In vivo analyses addressed the optimization of the dosing schedule as well as dose-response of BAY 1895344 in radium-223 combination setting. Levels of intra-tumor DNA damage (P-H2AX) were assessed to demonstrate the proposed mode-of-action. Here, we show that combination treatment with ATRi BAY 1895344 and radium-223 exhibits synergistic anti-tumor activity in the intratibial LNCaP xenograft model of mCRPC, achieving best efficacy when BAY 1895344 is applied 24 hours after treatment with radium-223, as indicated by direct reduction of tumor burden in the bone, lower serum tumor marker (PSA), and smaller areas of tumor-induced changes in bone. With this optimized schedule, a very low dose of BAY 1895344 (3% of single-agent MTD) was effective in combination with radium-223. Our findings strongly suggest that the combination of DNA damage induction by radium-223 with DDR inhibition by ATRi BAY 1895344 creates a potential new treatment option for CRPC patients with bone metastases. BAY 1895344 is currently under clinical investigation in patients with advanced solid tumors and lymphomas (NCT03188965).

Citation Format: Antje Margret Wengner, Gerhard Siemeister, Ulrich Luecking, Julien Lefranc, Arne Scholz, Mari Suominen, Kirstin Meyer, Eleni Lagkadinou, Dominik Mumberg. Synergistic in vivo activity of the ATR inhibitor BAY 1895344 in combination with the targeted alpha therapy radium-223 dichloride in a preclinical tumor model mimicking bone metastatic castration-resistant prostate cancer (mCRPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 838.

Abstract 836: ATR inhibitor BAY 1895344 shows potent anti-tumor efficacy in monotherapy and strong combination potential with the targeted alpha therapy Radium-223 dichloride in preclinical tumor models

The integrity of the genome of eukaryotic cells is secured by complex signaling pathways, known as DNA damage response (DDR). Recognition of DNA damage activates DDR pathways resulting in cell cycle arrest, induction of DNA repair, or cell death. Proteins that directly recognize aberrant DNA structures recruit and activate kinases of the DDR pathway, such as ATR (ataxia telangiectasia and Rad3-related). ATR responds to a broad spectrum of DNA damage, including double-strand breaks (DSB) and lesions derived from interference with DNA replication as well as increased replication stress. Therefore, inhibition of ATR kinase activity could be the basis for a novel anti-cancer therapy in tumors with increased DNA damage, deficiency in DNA damage repair or replication stress. Radium-223 dichloride (Xofigo®) is the first and only approved targeted alpha therapy so far. It is indicated for the treatment of patients with castration-resistant prostate cancer (CRPC), symptomatic bone metastases and no known visceral metastatic disease, based on improvement of overall survival. It exhibits strong cytotoxic effects on adjacent cells via the induction of DNA DSB.

Here, we disclose for the first time the structure and functional characterization of the novel ATR kinase inhibitor BAY 1895344. In vitro, BAY 1895344 is a selective low-nanomolar inhibitor of ATR kinase activity, potently inhibiting proliferation of a broad spectrum of human tumor cell lines (median IC50 of 78 nM). A clear separation between highly sensitive (IC50 &lt;10 nM) and less sensitive cell lines was observed. The majority of the sensitive cell lines are characterized by mutations affecting the ATM (ataxia telangiectasia mutated) pathway. In cellular mechanistic assays BAY 1895344 inhibited hydroxyurea-induced H2AX phosphorylation demonstrating the anticipated mode of action. BAY 1895344 is an ATR inhibitor that exhibits strong in vivo anti-tumor efficacy in monotherapy in a variety of xenograft models of different indications that are characterized by DDR deficiencies, inducing stable disease in ovarian and colorectal cancer or even complete tumor remission in mantle cell lymphoma models. In addition, we could demonstrate that combination treatment with BAY 1895344 and Radium-223 exhibits clear synergistic anti-tumor activity in a bone metastases xenograft model of CRPC.

Our findings validate the concept of synthetic lethality of genetically determined DNA repair deficiency and ATR blockade by demonstrating strong monotherapy efficacy of the highly potent ATR inhibitor BAY 1895344 in a variety of tumor indications. Furthermore, the mechanism-based combination potential of DNA damage induction by Radium-223 with BAY 1895344 creates a powerful new treatment option for CRPC patients with bone metastases.

The start of clinical investigation of BAY 1895344 is planned early 2017.

Citation Format: Antje Margret Wengner, Gerhard Siemeister, Ulrich Luecking, Julien Lefranc, Philip Lienau, Gesa Deeg, Eleni Lagkadinou, Li Liu, Sven Golfier, Christoph Schatz, Arne Scholz, Franz von Nussbaum, Michael Brands, Dominik Mumberg, Karl Ziegelbauer. ATR inhibitor BAY 1895344 shows potent anti-tumor efficacy in monotherapy and strong combination potential with the targeted alpha therapy Radium-223 dichloride in preclinical tumor models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 836. doi:10.1158/1538-7445.AM2017-836

Abstract 4746: Pharmacological characterization of BAY-876, a novel highly selective inhibitor of glucose transporter (GLUT)-1 in vitro and in vivo

One hallmark of cancer is the accelerated metabolism, high energy requirements, and increased glucose uptake by the tumor cells, the latter being the first and rate-limiting step for glucose metabolism. Glucose transport into the tumor cell is mediated by facilitative high-affinity glucose transporter (GLUT) proteins. Among the 14 GLUT proteins, expression of GLUT1 in normal organs is nearly exclusively restricted to the blood brain barrier, while other GLUTs are also expressed in a wide variety of vital organs such as liver and heart. Interestingly, GLUT1 expression is highly regulated by hypoxia-inducible factor (HIF)-1α, a key driver of tumor progression. In line with this finding, GLUT1 over-expression was found to be associated with tumor progression and poor overall survival in various tumor indications. Consequently, GLUT1 represents a potential target for cancer treatment. Therefore, we have developed a highly-selective GLUT1 inhibitor, namely BAY-876, with selectivity over GLUT2, 3, and 4 of 4700-, 800-, and 135-fold, respectively. We here show for the first time the pharmacological characterization of BAY-876, comprising inhibition of glucose-uptake, anti-proliferative activity in vitro, and anti-tumor efficacy in vivo in models of different tumor indications in monotherapy as well as first results on the combinability of BAY-876. Furthermore, at the therapeutic dose, BAY-876 treatment did not show any relevant finding on the behavior of treated mice in the Irwin test, assuming no or only minor effects on brain function. In conclusion, BAY-876 is the first GLUT1-selective inhibitor which reduces glucose uptake and growth of tumor cells with sufficient tolerability at the efficacious dose in preclinical models.

Citation Format: Charlotte Kopitz, Luisella Toschi, Carolyn Algire, Mélanie Héroult, Anna-Lena Frisk, Kirstin Meyer, Arndt Schmitz, Eleni Lagkadinou, Heike Petrul, Iring Heisler, Roland Neuhaus, Bernd Buchmann, Herbert Himmel, Marcus Bauser, Andrea Haegebarth, Karl Ziegelbauer. Pharmacological characterization of BAY-876, a novel highly selective inhibitor of glucose transporter (GLUT)-1 in vitro and in vivo. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4746.

Abstract 569: AKT1 (E17K) mutation: coexistence with oncogenic alterations, prevalence, and correlation to clinical parameter in a large series of breast cancer patients

The AKT1 (E17K) mutation is rare and occurs in colon, ovarian, lung, and especially breast cancer where its frequency ranges between 1.4% and 8.2%. It's precise role in cancer development and progression in clinical context is still unknown.

To increase our understanding of the AKT1 (E17K) mutation in breast cancer we analyzed more than 600 tumor samples from breast cancer patients (UICC I - IV, including untreated and neoadjuvantly treated patients) which were provided by the non-profit organization PATH (Patients’ Tumor Bank of Hope, Germany). Extensive clinical data with a median follow-up time of 4.8 years to record disease progression were available for 95% of the patients included in this study.

The AKT1 (E17K) mutation was detected in ∼6% of samples in the analyzed cohort using the BEAMing technology. Correlation with clinical parameters showed that the prevalence of the AKT1 (E17K) mutation was statistically independent of age or post-/pre-menopausal stage and was comparable between HER-2 positive and negative patients. In addition, FOUNDATION ONE® targeted exome Next Generation Sequencing (NGS) analysis of some of the tumor samples was done to demonstrate the fingerprint of individual tumors in correlation with the AKT1 (E17K) mutation. NGS and BEAMing technology had a ∼98% concordance for AKT1 (E17K) mutated and non-mutated samples. In 12 out of 36 AKT1 (E17K) mutated samples no additional somatic mutations (SNVs, indels) described to drive cancer development were detected. Moreover, neither amplification nor deletion of tested genes known to be recurrently amplified or deleted in cancer were found in 10 out of these 12 samples. This supports the hypothesis that AKT1 (E17K) can be a driver mutation. However, in all of these samples mutations with yet unannotated function in additional oncogenes were detected. It remains open whether these aberrations impact the role of AKT1 (E17K) as a driver mutation in tumor growth.

Analyses of patient cohort data from large databases, as demonstrated here, holds promise for discovering the role of rare somatic mutations in known oncogenes (such as AKT1 (E17K)) in the development of breast cancer.

Citation Format: Marion Rudolph, Tobias Anzeneder, Matthias Ocker, Eleni Lagkadinou, Oliver Politz, Martin Michels, Anke Schulz, Georg Beckmann, Michael Teufel, Henrik Seidel, Richie Soong, Heinz Bodenmüller, Ulla Ohlms, Khusru Asadullah, Joachim Reischl. AKT1 (E17K) mutation: coexistence with oncogenic alterations, prevalence, and correlation to clinical parameter in a large series of breast cancer patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 569. doi:10.1158/1538-7445.AM2014-569