Health-economic evaluation of orthogeriatric co-management for patients with pelvic or vertebral fragility fractures.

BACKGROUND: Orthogeriatric co-management (OGCM) addresses the special needs of geriatric fracture patients. Most of the research on OGCM focused on hip fractures while results concerning other severe fractures are rare. We conducted a health-economic evaluation of OGCM for pelvic and vertebral fractures. METHODS: In this retrospective cohort study, we used German health and long-term care insurance claims data and included cases of geriatric patients aged 80 years or older treated in an OGCM (OGCM group) or a non-OGCM hospital (non-OGCM group) due to pelvic or vertebral fractures in 2014-2018. We analyzed life years gained, fracture-free life years gained, healthcare costs, and cost-effectiveness within 1 year. We applied entropy balancing, weighted gamma and two-part models. We calculated incremental cost-effectiveness ratios and cost-effectiveness acceptability curves. RESULTS: We included 21,036 cases with pelvic (71.2% in the OGCM, 28.8% in the non-OGCM group) and 33,827 with vertebral fractures (72.8% OGCM, 27.2% non-OGCM group). 4.5-5.9% of the pelvic and 31.8-33.8% of the vertebral fracture cases were treated surgically. Total healthcare costs were significantly higher after treatment in OGCM compared to non-OGCM hospitals for both fracture cohorts. For both fracture cohorts, a 95% probability of cost-effectiveness was not exceeded for a willingness-to-pay of up to €150,000 per life year or €150,000 per fracture-free life year gained. CONCLUSION: We did not obtain distinct benefits of treatment in an OGCM hospital. Assigning cases to OGCM or non-OGCM group on hospital level might have underestimated the effect of OGCM as not all patients in the OGCM group have received OGCM.

Health-economic evaluation of orthogeriatric co-management for patients with forearm or humerus fractures: an analysis of insurance claims data from Germany.

Orthogeriatric co-management (OGCM) describes a collaboration of orthopedic surgeons and geriatricians for the treatment of fragility fractures in geriatric patients. While its cost-effectiveness for hip fractures has been widely investigated, research focusing on fractures of the upper extremities is lacking. Thus, we conducted a health economic evaluation of treatment in OGCM hospitals for forearm and humerus fractures.In a retrospective cohort study with nationwide health insurance claims data, we selected the first inpatient stay due to a forearm or humerus fracture in 2014-2018 either treated in hospitals that were able to offer OGCM (OGCM group) or not (non-OGCM group) and applied a 1-year follow-up. We included 31,557 cases with forearm (63.1% OGCM group) and 39,093 cases with humerus fractures (63.9% OGCM group) and balanced relevant covariates using entropy balancing. We investigated costs in different health sectors, length of stay, and cost-effectiveness regarding total cost per life year or fracture-free life year gained.In both fracture cohorts, initial hospital stay, inpatient stay, and total costs were higher in OGCM than in non-OGCM hospitals. For neither cohort nor effectiveness outcome, the probability that treatment in OGCM hospitals was cost-effective exceeded 95% for a willingness-to-pay of up to €150,000.We did not find distinct benefits of treatment in OGCM hospitals. Assigning cases to study groups on hospital-level and using life years and fracture-free life years, which might not adequately reflect the manifold ways these fractures affect the patients' health, as effectiveness outcomes, might have underestimated the effectiveness of treatment in OGCM hospitals.

Association of two geriatric treatment systems with anti-osteoporotic drug treatment and second hip fracture in patients with an index hip fracture: retrospective cohort study.

BACKGROUND: In Germany, geriatricians deliver acute geriatric care during acute hospital stay and post-acute rehabilitation after transfer to a rehabilitation clinic. The rate patients receive acute geriatric care (AGC) or are transferred to post-acute rehabilitation (TPR) differs between hospitals. This study analyses the association between the two geriatric treatment systems (AGC, TPR) and second hip fracture in patients following an index hip fracture. METHODS: Nationwide health insurance data are used to identify the rate of AGC and TPR per hospital following hip fracture surgery in patients aged ≥ 80 years. Outcomes are a second hip fracture after surgery or after discharge within 180 or 360 days and new specific anti-osteoporotic drugs. Cox proportional hazard models and generalised linear models are applied. RESULTS: Data from 29,096 hip fracture patients from 652 hospitals were analysed. AGC and TPR are not associated with second hip fracture when follow-up started after surgery. However, during the first months after discharge patients from hospitals with no AGC or low rates of TPR have higher rates of second hip fracture than patients from hospitals with high rates of AGC or high rates of TPR (Hazard Ratio (95% CI) 1.35 (1.01-1.80) or 1.35 (1.03-1.79), respectively). Lower rates of AGC are associated with lower probabilities of new prescriptions of specific anti-osteoporotic drugs. CONCLUSIONS: Our study suggests beneficial relationships of geriatric treatment after hip fracture with a) the risk of second hip fractures during the first months after discharge and b) an improvement of anti-osteoporotic drug treatment.

Discovery of Novel Allosteric EGFR L858R Inhibitors for the Treatment of Non-Small-Cell Lung Cancer as a Single Agent or in Combination with Osimertinib.

Addressing resistance to third-generation EGFR TKIs such as osimertinib via the EGFRC797S mutation remains a highly unmet need in EGFR-driven non-small-cell lung cancer (NSCLC). Herein, we present the discovery of the allosteric EGFR inhibitor 57, a novel fourth-generation inhibitor to overcome EGFRC797S-mediated resistance in patients harboring the activating EGFRL858R mutation. 57 exhibits an improved potency compared to previous allosteric EGFR inhibitors. To our knowledge, 57 is the first allosteric EGFR inhibitor that demonstrates robust tumor regression in a mutant EGFRL858R/C797S tumor model. Additionally, 57 is active in an H1975 EGFRL858R/T790M NSCLC xenograft model and shows superior efficacy in combination with osimertinib compared to the single agents. Our data highlight the potential of 57 as a single agent against EGFRL858R/C797S and EGFRL858R/T790M/C797S and as combination therapy for EGFRL858R- and EGFRL858R/T790M-driven NSCLC.

Association of two geriatric treatment systems on care home admission and mortality in patients with hip fracture.

BACKGROUND: In Germany, geriatricians deliver acute geriatric care during an acute hospital stay and subacute rehabilitation after transfer to a rehabilitation clinic. However, the proportion of patients who receive acute geriatric care (AGC) or are transferred to subacute rehabilitation (TSR) differs considerably between hospitals. The aim of this study was to analyse the association between the two geriatric treatment systems and care home admission or mortality in patients following hip fracture. METHODS: Health insurance claims data were used to identify the rate of AGC per hospital and the rate of TSR per hospital following hip fracture surgery in patients aged ≥ 80 years. Outcomes were cumulative admission to a care home and cumulative mortality within 6 months after hospital admission. RESULTS: Data from 23,046 hip fracture patients from 561 hospitals were analysed. The rate of AGC was not associated with care home admission. However, compared to high rates of AGC medium rates or no AGC were associated with increased death rates by 12% or 20%, respectively. Treatment in hospitals with low rates of TSR was associated with a 8% higher risk of care home admission and a 10% increased risk of death compared to treatment in hospitals with high rates of TSR. CONCLUSIONS: Our study suggests potential effects of geriatric treatment: reduction of mortality in hospitals with high rates of AGC or reduction of care home admission and mortality in hospitals with high rates of TSR.

BET Inhibition Enhances TNF-Mediated Antitumor Immunity.

Targeting chromatin binding proteins and modifying enzymes can concomitantly affect tumor cell proliferation and survival, as well as enhance antitumor immunity and augment cancer immunotherapies. By screening a small-molecule library of epigenetics-based therapeutics, BET (bromo- and extra-terminal domain) inhibitors (BETi) were identified as agents that sensitize tumor cells to the antitumor activity of CD8+ T cells. BETi modulated tumor cells to be sensitized to the cytotoxic effects of the proinflammatory cytokine TNF. By preventing the recruitment of BRD4 to p65-bound cis-regulatory elements, BETi suppressed the induction of inflammatory gene expression, including the key NF-κB target genes BIRC2 (cIAP1) and BIRC3 (cIAP2). Disruption of prosurvival NF-κB signaling by BETi led to unrestrained TNF-mediated activation of the extrinsic apoptotic cascade and tumor cell death. Administration of BETi in combination with T-cell bispecific antibodies (TCB) or immune-checkpoint blockade increased bystander killing of tumor cells and enhanced tumor growth inhibition in vivo in a TNF-dependent manner. This novel epigenetic mechanism of immunomodulation may guide future use of BETi as adjuvants for immune-oncology agents.

Preclinical Characterization of a Next-Generation Brain Permeable, Paradox Breaker BRAF Inhibitor.

PURPOSE: Disease progression in BRAF V600E/K positive melanomas to approved BRAF/MEK inhibitor therapies is associated with the development of resistance mediated by RAF dimer inducing mechanisms. Moreover, progressing disease after BRAFi/MEKi frequently involves brain metastasis. Here we present the development of a novel BRAF inhibitor (Compound Ia) designed to address the limitations of available BRAFi/MEKi. EXPERIMENTAL DESIGN: The novel, brain penetrant, paradox breaker BRAFi is comprehensively characterized in vitro, ex vivo, and in several preclinical in vivo models of melanoma mimicking peripheral disease, brain metastatic disease, and acquired resistance to first-generation BRAFi. RESULTS: Compound Ia manifested elevated potency and selectivity, which triggered cytotoxic activity restricted to BRAF-mutated models and did not induce RAF paradoxical activation. In comparison to approved BRAFi at clinical relevant doses, this novel agent showed a substantially improved activity in a number of diverse BRAF V600E models. In addition, as a single agent, it outperformed a currently approved BRAFi/MEKi combination in a model of acquired resistance to clinically available BRAFi. Compound Ia presents high central nervous system (CNS) penetration and triggered evident superiority over approved BRAFi in a macro-metastatic and in a disseminated micro-metastatic brain model. Potent inhibition of MAPK by Compound Ia was also demonstrated in patient-derived tumor samples. CONCLUSIONS: The novel BRAFi demonstrates preclinically the potential to outperform available targeted therapies for the treatment of BRAF-mutant tumors, thus supporting its clinical investigation.

Increased Geriatric Treatment Frequency Improves Mobility and Secondary Fracture Prevention in Older Adult Hip Fracture Patients-An Observational Cohort Study of 23,828 Patients from the Registry for Geriatric Trauma (ATR-DGU).

Interdisciplinary orthogeriatric care of older adult hip fracture patients is of growing importance due to an ageing population, yet there is ongoing disagreement about the most effective model of care. This study aimed to compare different forms of orthogeriatric treatment, with focus on their impact on postoperative mobilization, mobility and secondary fracture prevention. In this observational cohort study, patients aged 70 years and older with a proximal femur fracture requiring surgery, were included from 1 January 2016 to 31 December 2019. Data were recorded from hospital stay to 120-day follow-up in the Registry for Geriatric Trauma (ATR-DGU), a specific designed registry for older adult hip fracture patients. Of 23,828 included patients from 95 different hospitals, 72% were female, median age was 85 (IQR 80-89) years. Increased involvement of geriatricians had a significant impact on mobilization on the first day (OR 1.1, CI 1.1-1.2) and mobility seven days after surgery (OR 1.1, CI 1.1-1.2), initiation of an osteoporosis treatment during in-hospital stay (OR 2.5, CI 2.4-2.7) and of an early complex geriatric rehabilitation treatment (OR 1.3, CI 1.2-1.4). These findings were persistent after 120 days of follow-up. Interdisciplinary treatment of orthogeriatric patients is beneficial and especially during in-patient stay increased involvement of geriatricians is decisive for early mobilization, mobility and initiation of osteoporosis treatment. Standardized treatment pathways in certified geriatric trauma departments with structured data collection in specific registries improve outcome monitoring and interpretation.

Effect of the COVID-19 Pandemic in German Trauma Centres and Geriatric Trauma Centres DGU. / Einfluss der COVID-19-Pandemie auf die deutschen TraumaZentren und AltersTraumaZentren DGU.

BACKGROUND: The COVID 19 pandemic is a major challenge to all social systems, particularly the healthcare system. Within an international study, German Trauma Centres DGU and Geriatric Trauma Centres DGU have been questioned about their situation. METHOD: The questionnaire was translated from English into German and sent to all contacts. The evaluation was performed descriptively. RESULTS: 71 of 692 centres participated in this study. Government instructions to avoid elective treatments have been adhered to by 68% of the hospitals, and the remaining performed only urgent elective treatments. There was also a decline in the number of traumatological patients. In more than 90% of the hospitals, only 0 - 4% of all patients treated for proximal femur fracture were tested positive for COVID-19. It appears that 84% of these hospitals have or will have financial deficits. Almost all hospitals were organised and ready to fight the pandemic with their personal and/or infrastructural resources they possess. CONCLUSION: Our questionnaire shows that the pandemic had an enormous effect on Trauma Centres DGU and Geriatric Trauma Centres DGU. The hospitals expect financial losses. Almost all the hospitals have provided personal and infrastructural resources to be used in the fight against the pandemic with a better outcome in Germany in comparison with international standards.

Implementation of an integrated care programme to avoid fragility fractures of the hip in older adults in 18 Bavarian hospitals - study protocol for the cluster-randomised controlled fracture liaison service FLS-CARE.

BACKGROUND: The economic and public health burden of fragility fractures of the hip in Germany is high. The likelihood of requiring long-term care and the risk of suffering from a secondary fracture increases substantially after sustaining an initial fracture. Neither appropriate confirmatory diagnostics of the suspected underlying osteoporosis nor therapy, which are well-recognised approaches to reduce the burden of fragility fractures, are routinely initiated in the German healthcare system. Therefore, the aim of the study FLS-CARE is to evaluate whether a coordinated care programme can close the prevention gap for patients suffering from a fragility hip fracture through the implementation of systematic diagnostics, a falls prevention programme and guideline-adherent interventions based on the Fracture Liaison Services model. METHODS: The study is set up as a non-blinded, cluster-randomised, controlled trial with unequal cluster sizes. Allocation to intervention group (FLS-CARE) and control group (usual care) follows an allocation ratio of 1:1 using trauma centres as the unit of allocation. Sample size calculations resulted in a total of 1216 patients (608 patients per group distributed over 9 clusters) needed for the analysis. After informed consent, all participants are assessed directly at discharge, after 3 months, 12 months and 24 months. The primary outcome measure of the study is the secondary fracture rate 24 months after initial hip fracture. Secondary outcomes include differences in the number of falls, mortality, quality-adjusted life years, activities of daily living and mobility. DISCUSSION: This study is the first to assess the effectiveness and cost-effectiveness/utility of FLS implementation in Germany. Findings of the process evaluation will also shed light on potential barriers to the implementation of FLS in the context of the German healthcare system. Challenges for the study include the successful integration of the outpatient sector as well as the future course of the coronavirus pandemic in 2020 and its influence on the intervention. TRIAL REGISTRATION: German Clinical Trial Register (DRKS) 00022237 , prospectively registered 2020-07-09.

Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps.

The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps.

[120-day follow-up after proximal femoral fractures-first results from the Geriatric Trauma Registry DGU®]. / 120-Tage-Follow-up nach hüftgelenknahen Frakturen ­ erste Daten aus dem AltersTraumaRegister DGU®.

BACKGROUND: Geriatric trauma centers which are certified to the status of a Geriatic Trauma Center DGU® based on the criteria catalogue as outlined by the German Trauma Society (DGU), are required to participate in the Geriatric Trauma Register (ATR-DGU) for quality management and outcome analyses. The evaluation is pseudoanonymous and includes data on all treated hip fracture patients over 70 years old. This has been in regular use since 2016. This study analyzed the postoperative evaluation of gait, mortality, quality of life, hospital readmission and treatment of osteoporosis after 120 days. METHODS: A voluntary retrospective data evaluation of the ATR-DGU 120-day follow-up from 2017 was carried out. Written consent for the analysis and publication of the data was obtained from six clinics that already participated in the follow-up. The primary target parameters were mortality rate, readmission and revision rates, gait quality, osteoporosis treatment and quality of life according to EQ-5D-3L. The patient data were completely pseudonymized and a descriptive analysis was carried out. RESULTS: In this study 957 patients from the 6 hospitals were included. The average age was 84.5 years (±6.8 years). The mortality rate during the acute treatment phase was 5%. The 120-day follow-up could be evaluated in 412 patients, 10% of these required hospital readmission due to complications oft he same fracture and of these 6% required revision surgery. The mortality rate at 120 days was 12%. In 54% of the patients the fracture led to deterioration of mobility and 49% of patients received osteoporosis treatment after 120 days. The results of the EQ-5D-3L at 120 days revealed improvement as compared to the values on postoperative day 7; however, the preoperative status with respect to mobility and quality of life could not be regained. CONCLUSION: Despite the clear advantages of interdisciplinary treatment, the results are still limited concerning mobilization and quality of life. Further analysis of causative and influencing factors is necessary.

[Online survey for assessment of geriatric early rehabilitation complex treatment in geriatric trauma centers of the DGU by the medical services of the health funds]. / Onlinebefragung zur Prüfung der geriatrisch frührehabilitativen Komplexbehandlung durch den Medizinischen Dienst der Krankenversicherung in AltersTraumaZentren DGU®.

BACKGROUND: Orthogeriatric co-management of proximal femoral fractures has been proven to effectively reduce mortality rates. This involves extending resources in hospitals treating these patients as well as dealing with the possibility of prolonged periods of hospitalization. The increase in costs of orthogeriatric co-management are best illustrated by the implementation of geriatric early rehabilitation complex treatment. In view of the problems concerning billing this complex treatment, an online survey was carried among certified geriatric trauma centers of the German Trauma Society (DGU®). METHODS: Based on a trauma-geriatric consensus 20 questions were formulated by the Academy of Trauma Surgery (AUC) as an online questionnaire and sent to all 75 certified geriatric trauma centers. Apart from a description of the results, a subanalysis based on the figures presented by the case closing departments (geriatrics or trauma surgery) was included. The questions covered a 2-year period of experiences from 2016 to 2018. RESULTS: A total of 26 of the 75 certified geriatric trauma centers participated (35%). A continuous increase in cost analysis evaluations by the medical services of the health funds was observed. A rise from 38% in 2016 to 45% in 2018 was seen. An analogous rejection trend from 16% to 24% during this period was evident as well. Subanalysis revealed significantly higher cost evaluation by the medical services of the health funds and cost rejection rates if trauma departments were the case closing disciplines. CONCLUSION: The online survey revealed significantly higher assessment and rejection rates when compared to other hospital services. This could prove potentially detrimental to the future of orthogeriatric co-management.

Translation and evaluation of a pre-clinical 5-protein response prediction signature in a breast cancer phase Ib clinical trial.

Human protein biomarker discovery relies heavily on pre-clinical models, in particular established cell lines and patient-derived xenografts, but confirmation studies in primary tissue are essential to demonstrate clinical relevance. We describe in this study the process that was followed to clinically translate a 5-protein response signature predictive for the activity of an anti-HER3 monoclonal antibody (lumretuzumab) originally measured in fresh frozen xenograft tissue. We detail the development, qualification, and validation of the multiplexed targeted mass spectrometry assay used to assess the signature performance in formalin-fixed, paraffin-embedded human clinical samples collected in a phase Ib trial designed to evaluate lumretuzumab in patients with metastatic breast cancer. We believe that the strategy delineated here provides a path forward to avoid the time- and cost-consuming step of having to develop immunological reagents against unproven targets. We expect that mass spectrometry-based platforms may become part of a rational process to rapidly test and qualify large number of candidate biomarkers to identify the few that stand a chance for further development and validation.

[Results of the pilot phase of the Age Trauma Registry DGU®]. / Ergebnisse der Pilotphase des AltersTraumaRegister DGU®.

BACKGROUND: Since 2014, hospitals with ortho-geriatric fracture centres could be certified as AltersTraumaZentrum DGU® in Germany. To measure the quality of treatment in these centres, a geriatric trauma registry (AltersTraumaRegister DGU®) was established. OBJECTIVES: The aim of this work was to report the results of the pilot phase of the AltersTraumaRegister DGU® from the year 2015. MATERIALS AND METHODS: Included were 118 patients >70 years with hip fracture or implant-related femoral fractures. Apart from other parameters, the point of surgery, initiation of anti-osteoporotic treatment and the EQ-5D one week post-surgery was measured. RESULTS: Surgery was performed in 87% of patients within 24 h. Specific osteoporotic therapy could be increased from 4 to 63 patients. The EQ-5D was strongly restricted to one week post-surgery. CONCLUSION: Based on the timing of surgery and anti-osteoporotic therapy, the treatment seems to be successful in the ortho-geriatric fracture centres. For a better evaluation of treatment quality in the AltersTraumaZentren DGU®, implementation of follow-up examinations in the AltersTraumaRegister DGU® is essential.

Targeting Tumor Cells with Anti-CD44 Antibody Triggers Macrophage-Mediated Immune Modulatory Effects in a Cancer Xenograft Model.

CD44, a transmembrane receptor reported to be involved in various cellular functions, is overexpressed in several cancer types and supposed to be involved in the initiation, progression and prognosis of these cancers. Since the sequence of events following the blockage of the CD44-HA interaction has not yet been studied in detail, we profiled xenograft tumors by RNA Sequencing to elucidate the mode of action of the anti-CD44 antibody RG7356. Analysis of tumor and host gene-expression profiles led us to the hypothesis that treatment with RG7356 antibody leads to an activation of the immune system. Using cytokine measurements we further show that this activation involves the secretion of chemo-attractants necessary for the recruitment of immune cells (i.e. macrophages) to the tumor site. We finally provide evidence for antibody-dependent cellular phagocytosis (ADCP) of the malignant cells by macrophages.

Superior anti-tumor activity of the MDM2 antagonist idasanutlin and the Bcl-2 inhibitor venetoclax in p53 wild-type acute myeloid leukemia models.

BACKGROUND: Venetoclax, a small molecule BH3 mimetic which inhibits the anti-apoptotic protein Bcl-2, and idasanutlin, a selective MDM2 antagonist, have both shown activity as single-agent treatments in pre-clinical and clinical studies in acute myeloid leukemia (AML). In this study, we deliver the rationale and molecular basis for the combination of idasanutlin and venetoclax for treatment of p53 wild-type AML. METHODS: The effect of idasanutlin and venetoclax combination on cell viability, apoptosis, and cell cycle progression was investigated in vitro using established AML cell lines. In vivo efficacy was demonstrated in subcutaneous and orthotopic xenograft models generated in female nude or non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. Mode-of-action analyses were performed by means of cell cycle kinetic studies, RNA sequencing as well as western blotting experiments. RESULTS: Combination treatment with venetoclax and idasanutlin results in synergistic anti-tumor activity compared with the respective single-agent treatments in vitro, in p53 wild-type AML cell lines, and leads to strongly superior efficacy in vivo, in subcutaneous and orthotopic AML models. The inhibitory effects of idasanutlin were cell-cycle dependent, with cells arresting in G1 in consecutive cycles and the induction of apoptosis only evident after cells had gone through at least two cell cycles. Combination treatment with venetoclax removed this dependency, resulting in an acceleration of cell death kinetics. As expected, gene expression studies using RNA sequencing showed significant alterations to pathways associated with p53 signaling and cell cycle arrest (CCND1 pathway) in response to idasanutlin treatment. Only few gene expression changes were observed for venetoclax treatment and combination treatment, indicating that their effects are mediated mainly at the post-transcriptional level. Protein expression studies demonstrated that inhibition of the anti-apoptotic protein Mcl-1 contributed to the activity of venetoclax and idasanutlin, with earlier inhibition of Mcl-1 in response to combination treatment contributing to the superior combined activity. The role of Mcl-1 was confirmed by small hairpin RNA gene knockdown studies. CONCLUSIONS: Our findings provide functional and molecular insight on the superior anti-tumor activity of combined idasanutlin and venetoclax treatment in AML and support its further exploration in clinical studies.

RG7386, a Novel Tetravalent FAP-DR5 Antibody, Effectively Triggers FAP-Dependent, Avidity-Driven DR5 Hyperclustering and Tumor Cell Apoptosis.

Dysregulated cellular apoptosis and resistance to cell death are hallmarks of neoplastic initiation and disease progression. Therefore, the development of agents that overcome apoptosis dysregulation in tumor cells is an attractive therapeutic approach. Activation of the extrinsic apoptotic pathway is strongly dependent on death receptor (DR) hyperclustering on the cell surface. However, strategies to activate DR5 or DR4 through agonistic antibodies have had only limited clinical success. To pursue an alternative approach for tumor-targeted induction of apoptosis, we engineered a bispecific antibody (BsAb), which simultaneously targets fibroblast-activation protein (FAP) on cancer-associated fibroblasts in tumor stroma and DR5 on tumor cells. We hypothesized that bivalent binding to both FAP and DR5 leads to avidity-driven hyperclustering of DR5 and subsequently strong induction of apoptosis in tumor cells but not in normal cells. Here, we show that RG7386, an optimized FAP-DR5 BsAb, triggers potent tumor cell apoptosis in vitro and in vivo in preclinical tumor models with FAP-positive stroma. RG7386 antitumor efficacy was strictly FAP dependent, was independent of FcR cross-linking, and was superior to conventional DR5 antibodies. In combination with irinotecan or doxorubicin, FAP-DR5 treatment resulted in substantial tumor regression in patient-derived xenograft models. FAP-DR5 also demonstrated single-agent activity against FAP-expressing malignant cells, due to cross-binding of FAP and DR5 across tumor cells. Taken together, these data demonstrate that RG7386, a novel and potent antitumor agent in both mono- and combination therapies, overcomes limitations of previous DR5 antibodies and represents a promising approach to conquer tumor-associated resistance to apoptosis. Mol Cancer Ther; 15(5); 946-57. ©2016 AACR.