Ras Inhibitors Research Articles

Facts and Hopes on RAS Inhibitors and Cancer Immunotherapy.

Although the past decade has seen great strides in the development of immunotherapies that reactivate the immune system against tumors, there have also been major advances in the discovery of drugs blocking oncogenic drivers of cancer growth. However, there has been very little progress in combining immunotherapies with drugs that target oncogenic driver pathways. Some of the most important oncogenes in human cancer encode RAS family proteins, although these have proven challenging to target. Recently drugs have been approved that inhibit a specific mutant form of KRAS: G12C. These have improved the treatment of patients with lung cancer harboring this mutation, but development of acquired drug resistance after initial responses has limited the impact on overall survival. Because of the immunosuppressive nature of the signaling network controlled by oncogenic KRAS, targeted KRAS G12C inhibition can indirectly affect antitumor immunity, and does so without compromising the critical role of normal RAS proteins in immune cells. This serves as a rationale for combination with immune checkpoint blockade, which can provide additional combinatorial therapeutic benefit in some preclinical cancer models. However, in clinical trials, combination of KRAS G12C inhibitors with PD-(L)1 blockade has yet to show improved outcome, in part due to treatment toxicities. A greater understanding of how oncogenic KRAS drives immune evasion and how mutant-specific KRAS inhibition impacts the tumor microenvironment can lead to novel approaches to combining RAS inhibition with immunotherapies.

Deep learning-based characterization of the drug tolerant persister cell state in lung cancer.

141 Background: Lung cancer is the leading cause of cancer-related lethality globally. Targeted therapies improve the clinical outcome of cancer treatment; however, a subpopulation of cancer cells survive during initial therapy and evolve into drug tolerant persister cells (DTPs) that maintain a residual disease reservoir. Residual disease preludes acquired resistance and tumor progression; therefore, identifying and eliminating DTPs could benefit future treatment paradigms. We have shown that Hippo pathway effector YAP1 (Yes Associated Protein-1) is activated in oncogene-driven lung cancers when cancer cells are exposed to various targeted therapies, such as EGFR, ALK, and RAS inhibitors. YAP1 transcriptional activation during targeted therapy is characterized by its increased nuclear localization and interaction with transcription factors. This activation promotes the expression of genes involved in cell survival, cellular plasticity, and metabolic reprogramming at the residual disease state. We hypothesized that detection of intrinsic or acquired persister cells may aid the development of optimized treatment regimens. In this study, we are building image-based deep learning models to identify YAP1 activation-mediated DTPs from histologically stained slides. Methods: H&E or YAP-stained immunohistochemistry (IHC) images from clinical lung cancer and patient-derived tumor xenograft samples were collected throughout targeted therapy and were annotated with semi-automation using high performance computing clusters. A deep learning model (U-Net algorithm) was used for image segmentation, training, validation, and testing. Results: 1638 images were annotated and over 80,000 patches from these images for YAP positive cells (or regions of interest) comprised the training dataset with semi-supervised automation. Subsequently, we built a customized deep-learning model to detect YAP-mediated DTP cell states from whole histopathological image slides. The deep learning-based model achieved excellent accuracy of 0.8238 and 0.9091 in training, and 0.8040 and 0.8949 in validation datasets for two different annotations, respectively. For a test dataset, the model obtained 0.81 and 0.902 accuracy for the two annotations, respectively. Conclusions: We have constructed a deep learning convolutional neural network model to infer the presence of the YAP1 activation-mediated drug tolerant persister cell state prior to or during targeted treatment of lung cancer. Implementing our AI-based model into routine lung cancer care in the future could identify patient subpopulations with YAP1 activated tumors who would most benefit from receiving YAP1-targeted small molecule inhibitors.

Direct K-Ras Inhibitors to Treat Cancers: Progress, New Insights, and Approaches to Treat Resistance.

Here we discuss approaches to K-Ras inhibition and drug resistance scenarios. A breakthrough offered a covalent drug against K-RasG12C. Subsequent innovations harnessed same-allele drug combinations, as well as cotargeting K-RasG12C with a companion drug to upstream regulators or downstream kinases. However, primary, adaptive, and acquired resistance inevitably emerge. The preexisting mutation load can explain how even exceedingly rare mutations with unobservable effects can promote drug resistance, seeding growth of insensitive cell clones, and proliferation. Statistics confirm the expectation that most resistance-related mutations are in cis, pointing to the high probability of cooperative, same-allele effects. In addition to targeted Ras inhibitors and drug combinations, bifunctional molecules and innovative tri-complex inhibitors to target Ras mutants are also under development. Since the identities and potential contributions of preexisting and evolving mutations are unknown, selecting a pharmacologic combination is taxing. Collectively, our broad review outlines considerations and provides new insights into pharmacology and resistance.

RAS‑stimulated release of exosomal miR‑494‑3p promotes the osteolytic bone metastasis of breast cancer cells.

RAS activation is a key determinant of breast cancer progression and metastasis. However, the role of the interaction among exosomes, RAS and microRNAs (miRNAs/miRs) in the osteolytic bone metastasis of breast cancer remains unclear. Therefore, the present study aimed to examine the role of activated RAS (KRAS, HRAS and NRAS) in the release of exosome‑mediated osteoclastogenic miRNAs and to elucidate their functional role in bone microenvironment remodeling invitro and invivo. Exosomes derived from RAS‑activated breast cancer cells promoted RANKL‑induced osteoclastogenesis; however, RAS inhibition abolished this effect. miR‑494‑3p, miR‑4508 and miR‑6869‑5p were identified as osteoclastogenic miRNAs in the exosomes secreted by RAS‑activated breast cancer cells. The levels of these osteoclastogenic miRNAs in the sera of patients with human epidermal growth factor receptor 2‑positive luminal breast cancer were significantly higher than those in the sera of patients with triple‑negative breast cancer. miR‑494‑3p exhibited both osteoclastogenic and anti‑osteoblastogenic activity. Treatment with a miR‑494‑3p inhibitor abolished the exosome‑mediated increase in RANKL‑induced osteoclastogenesis. Treatment with a miR‑494‑3p mimic enhanced RANKL‑induced osteoclast formation; however, treatment with its inhibitor suppressed this effect by targeting leucine‑rich repeat‑containing G‑protein coupled receptor 4 in osteoclast precursors. Furthermore, miR‑494‑3p inhibited bone morphogenetic protein 2‑induced osteoblast formation by targeting semaphorin 3A. In a mouse model, exosomes derived from breast cancer cells promoted osteolytic bone lesions; however, treatment with a miR‑494‑3p inhibitor significantly suppressed this effect. On the whole, the present study provides a novel mechanism, demonstrating that the RAS activation of breast cancer cells induces osteolytic bone metastasis by stimulating the exosome‑mediated transfer of osteoclastogenic miRNAs, including miR‑494‑3p to bone cells.

A phase I/IB trial of binimetinib in combination with erlotinib in NSCLC harboring activating KRAS or EGFR mutations

BackgroundActivating mutations in EGFR or KRAS are highly prevalent in NSCLC, share activation of the MAPK pathway and may be amenable to combination therapy to prevent negative feedback activation. MethodsIn this phase 1/1B trial, we tested the combination of binimetinib and erlotinib in patients with advanced NSCLC with at least 1 prior line of treatment (unless with activating EGFR mutation which could be treatment-naïve). A subsequent phase 1B expansion accrued patients with either EGFR- or KRAS-mutation using the recommended phase 2 dose (RP2D) from Phase 1. The primary objective was to evaluate the safety of binimetinib plus erlotinib and establish the RP2D. Results43 patients enrolled (dose-escalation = 23; expansion = 20). 17 harbored EGFR mutation and 22 had KRAS mutation. The RP2D was erlotinib 100 mg daily and binimetinib 15 mg BID × 5 days/week. Common AEs across all doses included diarrhea (69.8%), rash (44.2%), fatigue (32.6%), and nausea (32.6%), and were primarily grade 1/2. Among KRAS mutant patients, 1 (5%) had confirmed partial response and 8 (36%) achieved stable disease as best overall response. Among EGFR mutant patients, 9 were TKI-naïve with 8 (89%) having partial response, and 8 were TKI-pretreated with no partial responses and 1 (13%) stable disease as best overall response. ConclusionsBinimetinib plus erlotinib demonstrated a manageable safety profile and modest efficacy including one confirmed objective response in a KRAS mutant patient. While clinical utility of this specific combination was limited, these results support development of combinations using novel small molecule inhibitors of RAS, selective EGFR- and other MAPK pathway inhibitors, many of which have improved therapeutic indices. Clinical Trial RegistrationNCT01859026

Targeting RAF Isoforms and Tumor Microenvironments in RAS or BRAF Mutant Colorectal Cancers with SJ-C1044 for Anti-Tumor Activity.

Colorectal cancer (CRC) is a significant global health issue characterized by a high prevalence of KRAS gene mutations. The RAS/MAPK pathway, involving KRAS, plays a crucial role in CRC progression. Although some RAS inhibitors have been approved, their efficacy in CRC is limited. To overcome these limitations, pan-RAF inhibitors targeting A-Raf, B-Raf, and C-Raf have emerged as promising therapeutic strategies. However, resistance to RAF inhibition and the presence of an immunosuppressive tumor microenvironment (TME) pose additional obstacles to effective therapy. Here, we evaluated the potential of a novel pan-RAF inhibitor, SJ-C1044, for targeting mutant KRAS-mediated signaling and inhibiting CRC cell proliferation. Notably, SJ-C1044 also exhibited inhibitory effects on immunokinases, specifically, CSF1R, VEGFR2, and TIE2, which play crucial roles in immune suppression. SJ-C1044 demonstrated potent antitumor activity in xenograft models of CRC harboring KRAS or BRAF mutations. Importantly, treatment with SJ-C1044 resulted in increased infiltration of T cells and reduced presence of tumor-associated macrophages and regulatory T cells within the TME. Thus, SJ-C1044 shows immunomodulatory potential and the ability to enhance antitumor responses. The study underscores the therapeutic potential of SJ-C1044 as a novel pan-RAF inhibitor capable of targeting oncogenic signaling pathways and overcoming immune suppression in CRC.

Reducing Ischemic Stroke in Diabetes: The Role of GLP-1 RAs.

Stroke is a significant cause of mortality worldwide, and diabetes is an independent risk factor for ischemic stroke occurrence and recurrence. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) lower the risk of ischemic stroke through beneficial effects on traditional stroke risk factors such as hyperglycemia, hypertension, and dyslipidemia. Primary care practitioners (PCPs) can play a substantial role in reducing ischemic stroke; studies have indicated that patients who have a PCP at the time of first stroke have a lower risk of stroke recurrence. Clinical practice guidelines recommend treating type 2 diabetes in patients with or at risk for cardiovascular (CV) disease with glucose-lowering agents with proven CV benefit, such as GLP-1 RAs and sodium-glucose cotransporter-2 (SGLT2) inhibitors. Based on meta-analyses of CV outcomes trials, GLP-1 RAs have a substantial and statistically significant benefit on ischemic stroke risk reduction, whereas SGLT2 inhibitors have a nonsignificant effect. The use of GLP-1 RAs, in addition to non-pharmacologic and pharmacologic management of traditional stroke risk factors, is a key component of complex therapy for ischemic stroke risk reduction.

Targeting Ras with protein engineering.

Ras proteins are small GTPases that regulate cell growth and division. Mutations in Ras genes are associated with many types of cancer, making them attractive targets for cancer therapy. Despite extensive efforts, targeting Ras proteins with small molecules has been extremely challenging due to Ras's mostly flat surface and lack of small molecule-binding cavities. These challenges were recently overcome by the development of the first covalent small-molecule anti-Ras drug, sotorasib, highlighting the efficacy of Ras inhibition as a therapeutic strategy. However, this drug exclusively inhibits the Ras G12C mutant, which is not a prevalent mutation in most cancer types. Unlike the G12C variant, other Ras oncogenic mutants lack reactive cysteines, rendering them unsuitable for targeting via the same strategy. Protein engineering has emerged as a promising method to target Ras, as engineered proteins have the ability to recognize various surfaces with high affinity and specificity. Over the past few years, scientists have engineered antibodies, natural Ras effectors, and novel binding domains to bind to Ras and counteract its carcinogenic activities via a variety of strategies. These include inhibiting Ras-effector interactions, disrupting Ras dimerization, interrupting Ras nucleotide exchange, stimulating Ras interaction with tumor suppressor genes, and promoting Ras degradation. In parallel, significant advancements have been made in intracellular protein delivery, enabling the delivery of the engineered anti-Ras agents into the cellular cytoplasm. These advances offer a promising path for targeting Ras proteins and other challenging drug targets, opening up new opportunities for drug discovery and development.

Long-term outcome of combination therapy with corticosteroids, mizoribine and RAS inhibitors as initial therapy for severe childhood IgA vasculitis with nephritis.

Patients with severe IgA vasculitis with nephritis (IgAVN) typically receive aggressive therapy as an initial approach. We have consistently performed combination therapy including corticosteroids and immunosuppressants as initial therapy for severe IgAVN over a 20-year-plus period, with only minor changes to the treatment protocol. This study seeks to reveal the efficacy of combination therapy for severe IgAVN. We retrospectively studied 50 Japanese children diagnosed between 1996 and 2019 with clinicopathologically severe IgAVN who were defined as ISKDC classification grade IIIb-V and/or serum albumin < 2.5g/dL. The median age at the onset of IgAVN was 8.0years (IQR: 6.0-10.0). At biopsy, 44% of patients had nephrotic syndrome and 14% had kidney dysfunction. All patients were treated with combination therapy after biopsy. Abnormal proteinuria resolved after initial therapy in all 50 patients. However, eight patients (16%) had recurrence of proteinuria. Abnormal proteinuria was again resolved in three of these patients with additional treatment. At the last follow-up (median 59.5months; IQR, 26.2-84.2), the median urine protein-to-creatine ratio was 0.08g/gCr (IQR, 0.05-0.15), and only one patient had kidney dysfunction. Combination therapy provided good kidney outcomes for Japanese children with severe IgAVN. Even including recurrent cases, the degree of proteinuria was slight, and kidney function was good at the last follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.

791-P: Comparing the Real-World Effects of Once-Weekly GLP-1 RAs and DPP-4 Inhibitors on Ischemic Stroke and Myocardial Infarction in Individuals with T2D and ASCVD

Despite guidelines advocating for their use, there is limited real-world evidence comparing the effects of once-weekly (OW) glucagon-like peptide-1 receptor agonists (GLP-1 RAs) and dipeptidyl peptidase 4 inhibitors (DPP-4is) on the risk of cardiovascular events in individuals with type 2 diabetes (T2D) and atherosclerotic cardiovascular disease (ASCVD). This retrospective cohort study compared the time to incidence of ischemic stroke, myocardial infarction (MI), and 2-point major adverse cardiovascular events (MACE; ischemic stroke or MI) while on treatment in new adult users of OW GLP-1 RAs and DPP-4is who had T2D and ASCVD using data from the Optum Clinformatics® Data Mart (2017-2021). Patients were followed until drug discontinuation, enrollment end, or an event. Inverse probability of treatment weighting was used to balance baseline characteristics, and survival analyses were conducted to compare risks during exposure, defined as continuous use of either drug. We found that users of OW GLP-1 RAs (weighted N=25,287) had significantly lower risks of ischemic stroke (HR=0.74 [95% CI, 0.63, 0.87]), MI (0.78 [0.67, 0.92]), and 2-point MACE (0.76 [0.68, 0.86]) compared with users of DPP-4is (weighted N=39,684; all P&amp;lt;0.01). This study suggests that OW GLP-1 RAs reduce the risk of MI and stroke relative to DPP-4is in individuals with T2D and ASCVD. Disclosure X. Tan: Employee; Merck &amp; Co., Inc. Stock/Shareholder; Merck &amp; Co., Inc. Employee; Novo Nordisk. Stock/Shareholder; Novo Nordisk. Y. Liang: Employee; Novo Nordisk. J.R. Rajpura: Employee; Novo Nordisk. L. Yedigarova: Employee; Novo Nordisk. Stock/Shareholder; AbbVie Inc. J. Noone: Employee; Novo Nordisk. L. Xie: Employee; Pfizer Inc., Novo Nordisk A/S. A. de Havenon: Consultant; Novo Nordisk, Integra Lifesciences Holdings Corp. Other Relationship; UpToDate. Stock/Shareholder; TitinKM, Certus.

RAS inhibitors: additional precautions for use in women of child-bearing potential issued in Japan

RAS inhibitors: additional precautions for use in women of child-bearing potential issued in Japan

#3610 EPIDEMIOLOGY AND CLINICAL CORRELATES OF POST-AKI PROTEINURIA IN CHINESE HOSPITALIZED ADULTS

Abstract Background and Aims Acute kidney injury (AKI) has been associated with increased risks of new-onset and worsening proteinuria. However, the epidemiologic data of post-AKI proteinuria was still lacking. This study aimed to determine the incidence, risk factors and clinical correlations of post-AKI proteinuria among hospitalized patients. Method This study conducted a multicenter cohort from Chinese Renal disease Data System (CRDS), including patients aged 18–100 years with hospital-acquired AKI (HA-AKI) hospitalized at 19 medical centers throughout China. AKI was defined according to the Kidney Disease Improving Global Outcomes (KDIGO) creatine criteria. The results of both quantitative and qualitative urinary protein tests were used to determine post-AKI proteinuria. The primary outcome was the incidence of post-AKI proteinuria. Secondary outcomes included AKI recovery and kidney disease progression. Cox proportional hazard model with stepwise regression was used to determine the risk factors for post-AKI proteinuria. The associations of post-AKI proteinuria with kidney disease progression were analyzed by logistic regression models. Results Of 6,206 HA-AKI patients without proteinuria at baseline, 2,102 (33.9%) had new-onset proteinuria, whereas, of 5,137 HA-AKI with baseline proteinuria, 894 (17.4%) had worsening proteinuria after AKI (Table 1). Higher AKI stage and preexisting CKD diagnosis were risk factors for new-onset proteinuria and worsening proteinuria, whereas treatment with RAS inhibitors was associated with an 11% lower risk of incident proteinuria. About 60% and 75% of patients with post-AKI new-onset and worsening proteinuria, respectively, recovered within 3 months. Worsening proteinuria was associated with a lower incidence of AKI recovery and a higher risk of kidney disease progression (Table 2). Conclusion Post-AKI proteinuria is common and usually transient among hospitalized patients. The risk profiles for new-onset and worsening post-AKI proteinuria differed markedly. Worsening proteinuria after AKI was associated with adverse kidney outcomes, which emphasized the need for close monitoring of proteinuria after AKI.

#2976 CHRONIC KIDNEY DISEASE WITH COMORBIDITY IN PRIMARY CARE: CARDIORENAL TREATMENT, QUALITY OF CARE AND PROGNOSIS

Abstract Background and Aims Diabetes, heart failure, hypertension and cardiovascular disease are common in primary care, and frequently coexist with impaired kidney function (CKD), further increasing risk of cardiovascular- and renal events as well as premature death. These comorbidities therefore call for more complex treatment regimens and monitoring. Our aim was to describe the prevalence, management, and prognosis of individuals with CKD and additional comorbidity in a large primary care cohort. Method Individuals were included from the Copenhagen Primary Care Laboratory (CopLab) Database, which contains 112 million biochemistry results from persons followed in primary care between 2000 and 2015 and divided into three groups based on (CKD-EPI) eGFR (&amp;gt;60 ml/min, 30-59 ml/min and &amp;lt;30 ml/min) with or without comorbidity in the form of diabetes or heart failure. We included all individuals with at least two measurements of creatinine. The date of the second measurement of creatinine was considered index date (baseline). The database has been combined with pharmacological data (The Danish National Prescription Registry), outpatient clinic visits and hospitalizations (The Danish National Patient Registry - NPR), and mortality information (The Danish Civil Registration System). Heart Failure was defined by ICD-codes in NPR from outpatient clinic visits and hospitalizations and we calculated crude event rates for a range of outcomes according to comorbidity. Diabetes was defined as at least one measurement of plasma or serum glucose ≥11 mmol/l or HbA1c ≥48 mmol/mol in CopLab. We evaluated monitoring of eGFR, albuminuria (UACR) and use of guideline-recommended pharmacological therapy (i.e. RAS-blockers and statins) in each group. Results In the total primary care population of 171,134 individuals of which 63.8% were female, 8.3% had impaired kidney function (eGFR&amp;lt;60ml/min). The median follow-up for the three eGFR groups was 8.4, 4.7 and 2.0 years, respectively. Overall, event rates were higher in individuals with impaired kidney function and comorbidity, i.e. mortality in the group with eGFR&amp;lt;30 ml/min with concurrent heart failure; 42.8 per 100 patient-years (PY). Event rates for ESKD were low in general (0.03 to 0.51 per 100 PY) except for individuals with eGFR&amp;lt;30 ml/min (2.1 to 3.5 per 100 PY). Annual monitoring of eGFR was high in all groups (&amp;gt;90%) with increasing frequency in individuals with impaired kidney function, and measurement of UACR was low in groups with non-diabetic CKD (10-30%). Antihypertensive treatment was frequently prescribed in eGFR &amp;lt;30 ml/min; overall 87.6% and 94.8% with coexisting diabetes and 92.8% with coexisting heart failure. The use of RAS inhibition was more used in diabetes and in heart failure (&amp;gt;50%) but less with low eGFR. Statin therapy was used in approximately 50% of individuals with diabetes, regardless of CKD group, but was used to a much less extent in non-diabetic CKD (20-24%). Conclusion Our data from a large primary care cohort demonstrate a high prevalence of coexisting diabetes and/or heart failure with CKD, increasing the risk for adverse outcomes. The quality of CKD care in general practice may be improved, especially in the non-diabetic population.

Impact of novel pan-RAS inhibitors on efficacy and resistance to AMG-510 and MRTX-1133 in pancreatic cancer cell lines.

4155 Background: Mutant-activated RAS genes are the most frequently mutated gene family associated with cancer (almost 30% of all cancers contain a mutant RAS gene). KRAS is the predominant isoform mutated in cancer and is the isoform exclusively mutated in pancreatic ductal carcinoma (PDAC). Since almost all PDAC cases harbor a mutant RAS, it is arguably the most RAS-addicted tumor type. There is now considerable evidence implicating mutant KRAS as a driver of PDAC. Recently, several mutant KRAS-targeted therapies (sotorasib and adagrasib) have been developed and show promise in PDAC patients. We have developed a direct inhibitor of RAS with a predicted unique interaction region capable of directly binding to wild-type H- and K-RAS, but which shows preferential binding for KRAS G12D and G12C mutants. This novel inhibitor disrupts the RAS effector domain and blocks the ability of RAS to signal through its effectors. Methods: We used in silico virtual library screening to identify an initial candidate inhibitor which was effective at inhibiting the 3D growth of PDAC cells without affecting their growth in 2D. Subsequent iterative rounds of medicinal chemistry was then performed to identify a series of derivatives with enhanced activity, as determined by 3D growth inhibition assays and effects on Ras signaling, as determined by Western blot analysis of phosphor-ERK, phosphor-Akt and activation of Ral A. Results: Our series of RAS inhibitors effectively block PDAC cell growth in 3D without impacting their 2D proliferation and suppress the interaction of KRAS with its effector cRAF. The inhibitors also effectively inhibit RAS signaling in mutant RAS containing PDAC cells. Since our novel compounds are predicted to bind to RAS at a different site to either AMG-510 (G12C specific inhibitor) and MRTX-1133 (G12D specific inhibitor), we tested the co-operativity of our compounds with these existing agents. Our compounds enhanced the anti-proliferative effects of both MRTX-113 and AMG-510 in mutant KRAS G12D and G12C PDAC cells, respectively. Conclusions: We have developed a series of novel RAS inhibitors that directly bind preferentially to mutant KRAS that may serve as new mutant KRAS-targeted therapeutics, and that may also have the potential to enhance the efficacy or suppress the resistance of AMG-510 and MRTX-1133.

The dynamics of hypertension and renal function in CKD and non-CKD patients affected with COVID-19 – final results of BIRCOV trial

Introduction and aim. There is evidence in the literature about a change in the effectiveness of inhibitors of the renin-angiotensin system (iRAS) in people with COVID-19. Considering different mechanisms of pressure reduction by different iRAS groups, one can expect differences in people with COVID-19 receiving these drugs. The aim of angiotensin-converting enzyme inhibitors (ACEi), angiotensin II receptor blockers (ARB) and direct renin inhibitors (DRi) usage in COVID-19 (BIRCOV study) was to pinpoint clinical and laboratory differences in people with hypertension who received iRAS and suffered coronavirus infection. Material and methods. An open prospective trial of 108 patients was performed in subjects suffering from COVID-19 who have been receiving iRAS: ACEi, ARB or DRi as basic antihypertensive therapy. The disease follow-up was 12 and 24 weeks. A blood pressure (BP) measurement was performed the week before COVID-19 and up to 24 weeks from the disease onset. Subanalysis in patients with chronic kidney disease (CKD) was performed. Results. In patients with COVID-19, a change in the effectiveness of antihypertensive therapy depending on the type of drug in the iRAS group has been documented in the first 4 weeks from the onset of the disease. The use of ACEi had significantly increased the risk of severe hypotension, unlike ARBs that do not cause hypotension. The synchronous decline of estimated glomerular filtration rate (eGFR) and systolic BP was more pronounced in CKD patients followed by albuminuria incidence. The greatest decrease in eGFR was in people taking ACEi. Conclusion. People with grade 1-2 hypertension who are constantly receiving RAS inhibitors suffering from COVID-19 may develop hypotension with ACEi. COVID-19 leads to transient albuminuria and decreased glomerular filtration rate, which is especially dangerous for people with CKD 4-5.

SPARK, studying pathways of resistance in KRAS-driven cancers: A remote plasma ctDNA participation study to identify mechanisms of resistance to KRAS inhibitors.

TPS3166 Background: KRAS mutations account for a significant proportion of oncogenic mutations in cancers of the lung, colon, pancreas, and other organs. Cancers with KRASG12C mutations are now targetable with direct KRASG12C inhibitors, and other allele-specific and pan-KRAS inhibitors are in clinical development. Recent work has shown that complex resistance mechanisms can arise after treatment with KRASG12C inhibitors, including polyclonal KRAS alterations, acquired bypass mechanisms, and acquired fusions. The SPARK protocol is a remote participation ctDNA collection study that will evaluate mechanisms of resistance to RAS inhibitors and combination therapies. Methods: SPARK (NCT05272423) is a non-interventional, single coordinating center, decentralized biospecimen collection study, with a planned accrual of up to 250 patients with a diagnosis of KRAS-mutant cancer who are experiencing disease progression on a specific KRAS inhibitor or combination of inhibitors. The study will enable a web-based remote consent (https://alcmi.net/research/spark/) and subjects will be sent blood collection kits with the necessary materials for local phlebotomy for the FoundationOne Liquid CDx (F1LCDx) Biopsy Assay. Plasma NGS results will be returned to the treating physician and the study team. Patients will initially be enrolled into two cohorts: Cohort 1A will be restricted to KRAS G12C mutant cancers who progressed after being treated with KRAS G12C inhibitors. Cohort 1B will enroll patients with KRAS mutant cancers whose tumors progressed on any KRAS inhibitor (other than a direct KRAS G12C inhibitor). Cohort 2 will enroll KRAS mutant patients that have progressed on KRAS inhibitors and who have already had a sequencing assay performed to determine the resistance mechanism to KRAS inhibitors. These patients will be invited to share their data and medical history with the study team. Plasma for F1LCDX analysis will be optional for Cohort 2. Mechanisms of acquired resistance will be summarized with descriptive statistics, and compared across drugs (e.g., sotorasib vs adagrasib), between tumor types (e.g., NSCLC vs CRC), and by regimen (e.g. monotherapy vs combination therapy) to determine if different resistance mutations arise in these settings. Progression-free survival (PFS), and overall survival (OS) with KRAS inhibitors will be analyzed depending on the resistance mechanism (e.g. on-target vs off-target). Kaplan-Meier method will be used estimate median survival, and log-rank test will be used to compare groups of interests. Cox-regression model will be used to estimate univariable and multivariable hazard ratios. Outcomes from subsequent treatment after the development of acquired resistance will also be explored with descriptive statistics. No interim analysis is planned. The study activated on November 1st 2022. Clinical trial information: NCT05272423 .

Epidemiology and outcomes of post-AKI proteinuria.

Acute kidney injury (AKI) has been associated with increased risks of new-onset and worsening proteinuria. However, epidemiologic data for post-AKI proteinuria was still lacking. This study aimed to determine the incidence, risk factors and clinical correlations of post-AKI proteinuria among hospitalized patients. This study was conducted in a multicenter cohort including patients aged 18-100 years with hospital-acquired AKI (HA-AKI) hospitalized at 19 medical centers throughout China. The primary outcome was the incidence of post-AKI proteinuria. Secondary outcomes included AKI recovery and kidney disease progression. The results of both quantitative and qualitative urinary protein tests were used to define post-AKI proteinuria. Cox proportional hazard model with stepwise regression was used to determine the risk factors for post-AKI proteinuria. Of 6206 HA-AKI patients without proteinuria at baseline, 2102 (33.9%) had new-onset proteinuria, whereas of 5137 HA-AKI with baseline proteinuria, 894 (17.4%) had worsening proteinuria after AKI. Higher AKI stage and preexisting CKD diagnosis were risk factors for new-onset proteinuria and worsening proteinuria, whereas treatment with renin-angiotensin system inhibitors was associated with an 11% lower risk of incident proteinuria. About 60% and 75% of patients with post-AKI new-onset and worsening proteinuria, respectively, recovered within 3 months. Worsening proteinuria was associated with a lower incidence of AKI recovery and a higher risk of kidney disease progression. Post-AKI proteinuria is common and usually transient among hospitalized patients. The risk profiles for new-onset and worsening post-AKI proteinuria differed markedly. Worsening proteinuria after AKI was associated with adverse kidney outcomes, which emphasized the need for close monitoring of proteinuria after AKI.

Outcomes of discontinuing renin-angiotensin system inhibitors: a study protocol for conducting systematic review and meta-analysis

IntroductionRenin-angiotensin system (RAS) plays a key role in various types of cardiovascular disease and many kinds of RAS inhibitors have been developed. The effect of discontinuation of RAS inhibitors on...

Abstract B023: Inhibition of RAS signaling and tumorigenesis through targeting novel vulnerabilities

Abstract RAS GTPases are important mediators of oncogenesis with nearly 30% of human tumors harboring mutant RAS proteins. However, pharmacological inhibition of RAS has proven challenging. We have employed Monobody technology to discover novel vulnerabilities in RAS that can be exploited to inhibit RAS signaling and tumorigenesis. Monobodies are single-domain synthetic binding proteins that achieve levels of affinity and selectivity similar to antibodies. In contrast to antibodies, Monobodies are fully functional in the reducing environment of the cytoplasm and thus are particularly suitable as genetically encoded “tool biologics”. We previously developed the NS1 Monobody that inhibited RAS by targeting the α4-α5 allosteric lobe to prevent RAS self-association and nanoclustering, and NS1 has become a widely used tool in the RAS research community. Following on this success, we sought to identify additional vulnerabilities in RAS. Based on our discovery that nucleotide-free RAS (apoRAS) inhibits PIK3C2B function, we assessed the feasibility of selectively targeting this state of RAS as an approach to inhibit oncogenic RAS function. Here, we have developed several Monobodies and extensively characterized one of them, R15. Although NS1 was agnostic to the nucleotide state of RAS, R15 bound exclusively to the apo state of all three RAS isoforms but did not interact with nucleotide-loaded RAS. When expressed in cells, R15 selectively inhibited the signaling and transforming activity of RAS mutants with elevated intrinsic nucleotide exchange rates (i.e., “fast exchange mutants”), such as G13D and Q61L. Surprisingly, R15 bound and inhibited RAS(G12D) mutants which are not reported to be fast exchange. Biochemical studies demonstrated that RAS captured with R15 from cell lysates was indeed nucleotide free, suggesting that R15 traps apoRAS and prevents nucleotide reloading. Finally, intracellularly expressed R15 selectively inhibited the tumor forming capacity of human cell lines driven by fast exchange RAS mutants but not RAS(G12V) in mouse xenografts. Thus, in contrast to conventional wisdom, our approach has established a new opportunity to selectively inhibit certain RAS mutants by targeting the apo state of RAS with drug-like molecules. Citation Format: Imran Kahn, Akiko Koide, Mariyam Zuberi, Gayatri Ketavarapu, Eric Denbaum, Kai Wen Teng, J. Matthew Rhett, Russell Spencer-Smith, G. Aaron Hobbs, Earnest Ramsay Camp, Shohei Koide, John P. O'Bryan. Inhibition of RAS signaling and tumorigenesis through targeting novel vulnerabilities [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr B023.

Abstract B033: Wild-type RAS signaling is an essential therapeutic target in RAS-mutated cancers

Abstract Single-agent targeting of RAS-mutated cancers using RAF/MEK/ERK or PI3K/AKT pathway inhibitors is ineffective; blocking one pathway relieves negative feedback control of RTK signaling and hyperactivates parallel effector pathways. While combined MEK and PI3K inhibition is effective in preclinical models, toxicity of this combination prevents its clinical use. Alternative strategies for treating RAS-mutated cancers are essential. Therapeutics directly targeting mutated RAS proteins have the potential to spare normal cellular function thereby lessening overall toxicity. Unfortunately, direct RAS inhibition as a monotherapy does not fully block RAS effector signaling. RAS proteins show differential activation of RAF and PI3K pathways: KRAS potently activates RAF but poorly activates PI3K, whereas HRAS effectively activates PI3K but poorly activates RAF. Further, mutant RAS inhibition relieves negative feedback controls leading to rapid hyperactivation of RTK−WT RAS signaling. A more comprehensive understanding of the interplay between mutant RAS and RTK−WT RAS signaling is essential to developing rational therapeutic approaches to treat RAS-mutated cancers. We found that WT RAS enhanced mutant RAS-driven transformation by activating RAS effectors poorly engaged by mutated RAS. Further, inhibition of RAS effectors activated poorly by mutant RAS synergized with and limited resistance to mutant HRAS and KRAS inhibitors. The mutant HRAS inhibitor tipifarnib blocked PI3K signaling and synergized with MEK inhibitors in HRAS-mutated cancer cell lines; covalent KRASG12C inhibitors blocked MEK signaling and synergized with PI3K inhibitors in KRASG12C-mutated cell lines. Synergy between inhibitors of mutant RAS and RAS effectors was dependent on intact RTK/WT RAS signaling and was lost in both RASless or SOSless MEFs. These results should inform the design of clinical trials for patients with RAS-mutated cancers. Citation Format: Nancy Sealover, Bridget Finniff, Robert Kortum. Wild-type RAS signaling is an essential therapeutic target in RAS-mutated cancers [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr B033.