Informing the Recommended Phase III Dose of Alnuctamab, a CD3 × BCMA T-Cell Engager, Using Population Pharmacokinetics and Exposure-Response Analysis.

Alnuctamab, a B-cell maturation antigen (BCMA)-targeting T-cell engager, has demonstrated encouraging antitumor activity in the phase I study CC-93269-MM-001 treating patients with relapsed or refractory multiple myeloma. Identification of a recommended Phase III dose (RP3D) was a key objective, as such population pharmacokinetic (PopPK) and exposure-response analysis was critical. Intravenous (IV) alnuctamab was administered in fixed doses (0.15-10 mg) or in step-up doses to a maximum 10-mg target dose. Subcutaneous (SC) step-up doses of 3 and 6 mg were followed by a target dose range of 10-60 mg. Concentration data from IV and SC alnuctamab administration was pooled and was well described by a two-compartment PopPK model with first-order absorption and elimination. Covariate analysis determined that the inclusion of baseline soluble BCMA (sBCMA) on clearance significantly improved model fitting. Individual exposure parameters were estimated from the final model to characterize exposure-response relationships. Switching from IV to SC administration improved the safety profile of alnuctamab by limiting the frequency of grade ≥2 CRS events. A significant exposure-CRS relationship was observed after the first SC dose, but not subsequent dose administrations. Exposure-safety analysis did not find a statistically significant relationship between increasing exposure and the probability of key safety events of interest. Logistic regression analysis for patients administered SC alnuctamab identified that increased exposure significantly increased the probability of response, although the additional benefit was minimal at exposures above 30 mg target dose. Considering the totality of exposure-response data, the clinical pharmacology assessment supported a SC RP3D of 3/6/30 mg.

LINE-1 ORF1p as a candidate biomarker in high grade serous ovarian carcinoma.

Long interspersed element 1 (LINE-1) open reading frame 1 protein (ORF1p) expression is a common feature of many cancer types, including high-grade serous ovarian carcinoma (HGSOC). Here, we report that ORF1p is not only expressed but also released by ovarian cancer and primary tumor cells. Immuno-multiple reaction monitoring-mass spectrometry assays showed that released ORF1p is confidently detectable in conditioned media, ascites, and patients' plasma, implicating ORF1p as a potential biomarker. Interestingly, ORF1p expression is detectable in fallopian tube (FT) epithelial precursors of HGSOC but not in benign FT, suggesting that ORF1p expression in an early event in HGSOC development. Finally, treatment of FT cells with DNA methyltransferase inhibitors led to robust expression and release of ORF1p, validating the regulatory role of DNA methylation in LINE-1 repression in non-tumorigenic tissue.

Oncolytic virus driven T-cell-based combination immunotherapy platform for colorectal cancer.

Colorectal cancer is the third most diagnosed cancer and the second leading cause of cancer mortality worldwide, highlighting an urgent need for new therapeutic options and combination strategies for patients. The orchestration of potent T cell responses against human cancers is necessary for effective antitumour immunity. However, regression of a limited number of cancers has been induced by immune checkpoint inhibitors, T cell engagers (TCEs) and/or oncolytic viruses. Although one TCE has been FDA-approved for the treatment of hematological malignancies, many challenges exist for the treatment of solid cancers. Here, we show that TCEs targeting CEACAM5 and CD3 stimulate robust activation of CD4 and CD8-positive T cells in in vitro co-culture models with colorectal cancer cells, but in vivo efficacy is hindered by a lack of TCE retention in the tumour microenvironment and short TCE half-life, as demonstrated by HiBiT bioluminescent TCE-tagging technology. To overcome these limitations, we engineered Bispecific Engager Viruses, or BEVirs, a novel tumour-targeted vaccinia virus platform for intra-tumour delivery of these immunomodulatory molecules. We characterized virus-mediated TCE-secretion, TCE specificity and functionality from infected colorectal cancer cells and patient tumour samples, as well as TCE cytotoxicity in spheroid models, in the presence and absence of T cells. Importantly, we show regression of colorectal tumours in both syngeneic and xenograft mouse models. Our data suggest that a different profile of cytokines may contribute to the pro-inflammatory and immune effects driven by T cells in the tumour microenvironment to provide long-lasting immunity and abscopal effects. We establish combination regimens with immune checkpoint inhibitors for aggressive colorectal peritoneal metastases. We also observe a significant reduction in lung metastases of colorectal tumours through intravenous delivery of our oncolytic virus driven T-cell based combination immunotherapy to target colorectal tumours and FAP-positive stromal cells or CTLA4-positive Treg cells in the tumour microenvironment. In summary, we devised a novel combination strategy for the treatment of colorectal cancers using oncolytic vaccinia virus to enhance immune-payload delivery and boost T cell responses within tumours.

Phase 1 study of anti-CD47 monoclonal antibody CC-90002 in patients with relapsed/refractory acute myeloid leukemia and high-risk myelodysplastic syndromes.

CC-90002 is an anti-CD47 antibody that inhibits CD47-SIRPα interaction and enables macrophage-mediated killing of tumor cells in hematological cancer cell lines. In this first clinical, phase 1, dose-escalation and -expansion study (CC-90002-AML-001; NCT02641002), we evaluated CC-90002 in patients with relapsed/refractory acute myeloid leukemia (AML) or high-risk myelodysplastic syndromes (MDS). CC-90002 was administered in escalating doses of 0.1-4.0 mg/kg, using a modified 3 + 3 design. Primary endpoints included dose-limiting toxicities (DLTs), non-tolerated dose (NTD), maximum tolerated dose (MTD), and recommended phase 2 dose. Secondary endpoints included preliminary efficacy, pharmacokinetics, and presence/frequency of anti-drug antibodies (ADAs). Between March 2016 and July 2018, 28 patients were enrolled (24 with AML and 4 with MDS) at 6 sites across the USA. As of July 18, 2018, all patients had discontinued, mainly due to death or progressive disease. The most common treatment-emergent adverse events were diarrhea (46.4%), thrombocytopenia (39.3%), febrile neutropenia (35.7%), and aspartate aminotransferase increase (35.7%). Four patients experienced DLTs (1 patient had grade 4 disseminated intravascular coagulation and grade 5 cerebral hemorrhage, 1 had grade 3 purpura, 1 had grade 4 congestive cardiac failure and grade 5 acute respiratory failure, and another had grade 5 sepsis). The NTD and MTD were not reached. No objective responses occurred. CC-90002 serum exposure was dose-dependent. ADAs were present across all doses, and the proportion of ADA-positive patients in cycle 1 increased over time. Despite no unexpected safety findings, the CC-90002-AML-001 study was discontinued in dose escalation for lack of monotherapy activity and evidence of ADAs. However, as other anti-CD47 agents in clinical trials are showing promising early results for AML and MDS, understanding preclinical and clinical differences between individual agents in this class will be of high importance.

Diagnostic testing in nontrauma patients presenting to the emergency department with recurrent seizures: A systematic review.

BACKGROUND: There is a lack of consensus regarding the role of investigations among patients presenting to the emergency department (ED) with recurrent seizures. The aim of this systematic review was to determine the frequency and utility of commonly requested investigations for nontrauma patients presenting to the ED with recurrent seizures. METHODS: The MEDLINE, EMBASE, and Cochrane Library databases were searched (March 2021) for articles on this topic using search terms related to recurrent seizures, investigations, and the ED. The inclusion criteria required that articles include adult nontrauma patients presenting to the ED. Studies exclusively investigating first-episode seizures, trauma patients, and status epilepticus were excluded. Eligible studies were assessed for bias using the Newcastle-Ottawa scale. Results of studies were presented using proportions. RESULTS: There were six cohort studies included that contributed data from 36,595 patients. All six studies assessed at least one of our primary outcomes for computed tomography (CT) brain scans. The proportion of patients who underwent a head CT ranged from 13% to 42%. The rates of abnormal head CT findings ranged from 8% to 21%. One study reported on magnetic resonance imaging (MRI) and found it used infrequently in 0.79% of cases. The proportion and yield of nonneuroimaging investigations were not well evaluated in this patient population. Only one study reported on the utility of sodium levels or blood glucose results for this population and reported abnormalities in sodium levels for 19% of patients and abnormalities in glucose levels in 50% of patients. CONCLUSIONS: In this population, CT brain scans appeared to be performed uncommonly but with moderate rates of abnormal findings. In the absence of prolonged alteration of consciousness, a history of brain tumor, or positive neurologic findings, however, neuroimaging was of low yield. Given the heterogeneity and potential limitations of these studies, further research on this topic is required.

A highly multiplexed quantitative phosphosite assay for biology and preclinical studies.

Reliable methods to quantify dynamic signaling changes across diverse pathways are needed to better understand the effects of disease and drug treatment in cells and tissues but are presently lacking. Here, we present SigPath, a targeted mass spectrometry (MS) assay that measures 284 phosphosites in 200 phosphoproteins of biological interest. SigPath probes a broad swath of signaling biology with high throughput and quantitative precision. We applied the assay to investigate changes in phospho-signaling in drug-treated cancer cell lines, breast cancer preclinical models, and human medulloblastoma tumors. In addition to validating previous findings, SigPath detected and quantified a large number of differentially regulated phosphosites newly associated with disease models and human tumors at baseline or with drug perturbation. Our results highlight the potential of SigPath to monitor phosphoproteomic signaling events and to nominate mechanistic hypotheses regarding oncogenesis, response, and resistance to therapy.

Describing Sources of Uncertainty in Cancer Drug Formulary Priority Setting across Canada.

Over the years, there have been significant advances in oncology. However, the rate that therapeutics come to market has increased, while the strength of evidence has decreased. Currently, there is limited understanding about how these uncertainties are managed in provincial funding decisions for cancer therapeutics. We conducted qualitative interviews with six senior officials from four different Canadian provinces (British Columbia, Alberta, Quebec, and Ontario) and a document review of the uncertainties found in submissions to the pan-Canadian Oncology Drug Review (pCODR). Participants reported considerable uncertainty related to a lack of solid clinical evidence (early-phase clinical trials: generalizability, immature data, and the use of unvalidated surrogate outcomes). Proposed strategies to deal with the uncertainty included risk-sharing agreements, collection of real-world evidence (RWE), and ongoing collaboration between federal groups and provinces. The document review added to the reported uncertainties by classifying them into five main categories: trial validity, population, comparators, outcomes, and intervention. This study highlights how decision makers must deal with significant amounts of uncertainty in funding decisions for cancer drugs, most of which stems from methodological limitations in clinical trials. There is a critical need for transparent priority-setting processes and mechanisms to reevaluate drugs to ensure benefit given the high level of uncertainty of novel therapeutics.

Layperson Views about the Design and Evaluation of Decision Aids: A Public Deliberation.

PURPOSE: We carried out the first public deliberation to elicit lay input regarding guidelines for the design and evaluation of decision aids, focusing on the example of colorectal ("colon") cancer screening. METHODS: A random, demographically stratified sample of 28 laypeople convened for 4 days, during which they were informed about key issues regarding colon cancer, screening tests, risk communication, and decision aids. Participants then deliberated in small and large group sessions about the following: 1) What information should be included in all decision aids for colon screening? 2) What risk information should be in a decision aid and how should risk information be presented? 3) What makes a screening decision a good one (reasonable or legitimate)? 4) What makes a decision aid and the advice it provides trustworthy? With the help of a trained facilitator, the deliberants formulated recommendations, and a vote was held on each to identify support and alternative views. RESULTS: Twenty-one recommendations ("deliberative conclusions") were strongly supported. Some conclusions matched current recommendations, such as that decision aids should be available for use with and without providers present (conclusions 1-4) and should support informed choice (conclusion 9). Some conclusions differed from current recommendations, at least in emphasis-for example, that decision aids should disclose cost of screening (conclusion 11) and should be kept simple and understandable (conclusion 14). Deliberants recommended that decision aids should disclose the baseline risk of getting colon cancer (conclusions 15, 17). LIMITATIONS: Single location and medical decision. CONCLUSIONS: Guidelines for design of decision aids should consider putting a greater focus on disclosing cost and keeping decision aids simple, and they possibly should recommend disclosing less extensive amounts of quantitative information than currently recommended.

Targeted degradation of transcription factors by TRAFTACs: TRAnscription Factor TArgeting Chimeras.

Many diseases, including cancer, stem from aberrant activation or overexpression of oncoproteins that are associated with multiple signaling pathways. Although proteins with catalytic activity can be successfully drugged, the majority of other protein families, such as transcription factors, remain intractable due to their lack of ligandable sites. In this study, we report the development of TRAnscription Factor TArgeting Chimeras (TRAFTACs) as a generalizable strategy for targeted transcription factor degradation. We show that TRAFTACs, which consist of a chimeric oligonucleotide that simultaneously binds to the transcription factor of interest (TOI) and to HaloTag-fused dCas9 protein, can induce degradation of the former via the proteasomal pathway. Application of TRAFTACs to two oncogenic TOIs, NF-κB and brachyury, suggests that TRAFTACs can be successfully employed for the targeted degradation of other DNA-binding proteins. Thus, TRAFTAC technology is potentially a generalizable strategy to induce degradation of other transcription factors both in vitro and in vivo.

Experiences and perspectives of individuals accessing CAR-T cell therapy: A qualitative analysis of online Reddit discussions.

INTRODUCTION: Several chimeric antigen receptor (CAR-T) T-cell therapies have been approved for use for haematological malignancies. Despite known safety, access, and cost issues, little is known about how patients and caregivers understand novel treatments such as CAR-T and their associated uncertainties. METHODS: We gathered data from Reddit, an online public social media site. We performed a keyword search in three relevant subreddit threads: r/cancer, r/lymphoma, r/leukemia. We systematically extracted threads and associated comments and reviewed against our inclusion criteria. RESULTS: We identified a total of 186 posts and 87 were included in the qualitative analysis from March 1, 2013, to April 15, 2021. Qualitative content analysis was used to identify themes. Of those excluded, 88 contained discussions of other immunotherapies and 11 were scientific profiles. We identified four themes: 1) navigating uncertainty with community, 2) finding a cure, 3) managing treatment-related uncertainties, and 4) overcoming uncertainties related to access. We found patients experience numerous barriers when seeking access to novel therapeutics, such as CAR-T therapies. CONCLUSIONS: The perceptions and struggles of patients and their families are relevant for developing technology assessments that are sensitive to patient experiences, as well as to inform policies for equitable resource allocation. POLICY SUMMARY: Our study underscores the importance of balanced decision making between patients and physicians to ensure patients understand the risk and benefits of cancer treatments. Study investigators might evaluate trial participants based on patient demographics to ensure equitable access to studies for individuals in settings where internet access is less common.

Increased mitochondrial apoptotic priming with targeted therapy predicts clinical response to re-induction chemotherapy.

Most patients with relapsed or refractory (R/R) acute myeloid leukemia (AML) do not benefit from current re-induction or approved targeted therapies. In the absence of targetable genetic mutations, there is minimal guidance on optimal treatment selection particularly in the R/R setting highlighting an unmet need for clinically useful functional biomarkers. Blood and bone marrow samples from patients treated on two clinical trials were used to test the combination of lenalidomide (LEN) and MEC (mitoxantrone, etoposide, and cytarabine) chemotherapy in R/R AML patients. The bone marrow samples were available to test the clinical utility of the mitochondrial apoptotic BH3 and dynamic BH3 profiling (DBP) assays in predicting response, as there was no clear genetic biomarker identifying responders. To test whether LEN-induced mitochondrial priming predicted clinical response to LEN-MEC therapy, we performed DBP on patient myeloblasts. We found that short-term ex vivo treatment with lenalidomide discriminated clinical responders from non-responders based on drug-induced change in priming (delta priming). Using paired patient samples collected before and after clinical LEN treatment (prior to MEC dosing), we confirmed LEN-induced increased apoptotic priming in vivo, suggesting LEN enhanced vulnerability of myeloblasts to cytotoxic MEC chemotherapy. This is the first study demonstrating the potential role of DBP in predicting clinical response to a combination regimen. Our findings demonstrate that functional properties of relapsed AML can identify active therapies.

Public perspectives on disinvestments in drug funding: results from a Canadian deliberative public engagement event on cancer drugs.

BACKGROUND: Decisions relating to the funding of new drugs are becoming increasingly challenging due to a combination of aging populations, rapidly increasing list prices, and greater numbers of drug-indication pairs being brought to market. This is especially true in cancer, where rapid list price inflation is coupled with steeply rising numbers of incident cancer cases. Within a publicly funded health care system, there is increasing recognition that resource allocation decisions should consider the reassessment of, and potential disinvestment from, currently funded interventions alongside new investments. Public input into the decision-making process can help legitimize the outcomes and ensure priority-setting processes are aligned with public priorities. METHODS: In September 2014, a public deliberation event was held in Vancouver, Canada, to obtain public input on the topic of cancer drug funding. Twenty-four members of the general public were tasked with making collective recommendations for policy-makers about the principles that should guide funding decisions for cancer drugs in the province of British Columbia. Deliberative questions and decision aids were used to elicit individuals' willingness to make trade-offs between expenditures and health outcomes. RESULTS: Participants discussed the implications of disinvestment decisions from cancer drugs in terms of its impact on patient choice, fairness and quality of life. Their discussions indicate that in order for a decision to disinvest from currently-funded cancer drugs to be acceptable, it must align with three main principles: the decision must be accompanied by significant gains, described both in terms of cost savings and opportunities to re-invest elsewhere in the health care system; those who are currently prescribed a cancer drug should be allowed to continue their course of treatment (referred to as a continuance clause, or "grandfathering" approach); and it must consider how access to care for specialized populations is impacted. CONCLUSIONS: The results from this deliberation event provide insight into what is acceptable to British Columbians with respect to disinvestment decisions for cancer drugs. These recommendations can be considered within wider health system decision-making frameworks for funding decisions relating to all drugs, as well as for cancer drugs.

Patterns of substrate affinity, competition, and degradation kinetics underlie biological activity of thalidomide analogs.

Pharmacologic agents that modulate ubiquitin ligase activity to induce protein degradation are a major new class of therapeutic agents, active in a number of hematologic malignancies. However, we currently have a limited understanding of the determinants of activity of these agents and how resistance develops. We developed and used a novel quantitative, targeted mass spectrometry (MS) assay to determine the relative activities, kinetics, and cell-type specificity of thalidomide and 4 analogs, all but 1 of which are in clinical use or clinical trials for hematologic malignancies. Thalidomide analogs bind the CRL4CRBN ubiquitin ligase and induce degradation of particular proteins, but each of the molecules studied has distinct patterns of substrate specificity that likely underlie the clinical activity and toxicities of each drug. Our results demonstrate that the activity of molecules that induce protein degradation depends on the strength of ligase-substrate interaction in the presence of drug, the levels of the ubiquitin ligase, and the expression level of competing substrates. These findings highlight a novel mechanism of resistance to this class of drugs mediated by competition between substrates for access to a limiting pool of the ubiquitin ligase. We demonstrate that increased expression of a nonessential substrate can lead to decreased degradation of other substrates that are critical for antineoplastic activity of the drug, resulting in drug resistance. These studies provide general rules that govern drug-dependent substrate degradation and key differences between thalidomide analog activity in vitro and in vivo.

Addressing the affordability of cancer drugs: using deliberative public engagement to inform health policy.

BACKGROUND: Health system expenditure on cancer drugs is rising rapidly in many OECD countries given the costly new treatments and increased rates of use due to a growing and ageing population. These factors put considerable strain on the sustainability of health systems worldwide, sparking public debate among clinicians, pharmaceutical companies, policy-makers and citizens on issues of affordability and equity. We engaged Canadians through a series of deliberative public engagement events to determine their priorities for making cancer drug funding decisions fair and sustainable in Canada's publicly financed health system. METHODS: An approach to deliberation was developed based on the McMaster Health Forum's citizen panels and the established Burgess and O'Doherty model of deliberative public engagement. Six deliberations were held across Canada in 2016. Transcripts were coded in NVivo and analysed to determine where participants' views converged and diverged. Recommendations were grouped thematically. RESULTS: A total of 115 Canadians participated in the deliberative events and developed 86 recommendations. Recommendations included the review and regular re-review of approved drugs using 'real-world' evidence on effectiveness and cost-effectiveness; prioritisation of treatments that restore patients' independence, mental health and general well-being; ensuring that decision processes, results and their rationales are transparent; and commitment to people with similar needs receiving the same care regardless of where in Canada they live. CONCLUSIONS: The next steps for policy-makers should be to develop mechanisms for (1) re-reviewing effectiveness and cost-effectiveness data for all cancer drugs; (2) making disinvestments in cancer drugs that satisfy requirements relating to grandfathering and compassionate access; (3) ensuring fair and equitable access to cancer drugs for all Canadians; and (4) fostering a pan-Canadian approach to cancer drug funding decisions.

Trade-offs, fairness, and funding for cancer drugs: key findings from a deliberative public engagement event in British Columbia, Canada.

BACKGROUND: Spending on cancer drugs has risen dramatically in recent years compared to other areas of health care, due in part to higher prices associated with newly approved drugs and increased demand for these drugs. Addressing this situation requires making difficult trade-offs between cost, harms, and ability to benefit when using public resources, making it important for policy makers to have input from many people affected by the issue, including citizens. METHODS: In September 2014, a deliberative public engagement event was conducted in Vancouver, British Columbia (BC), on the topic of priority setting and costly cancer drugs. The aim of the study was to gain citizens' input on the topic and have them generate recommendations that could inform cancer drug funding decisions in BC. A market research company was engaged to recruit members of the BC general public to deliberate over two weekends (four days) on how best to allocate resources for expensive cancer treatments. Participants were stratified based on the 2006 census data for BC. Participants were asked to discuss disinvestment, intravenous versus oral chemotherapy delivery, and decision governance. All sessions were audio recorded and transcribed. Transcripts were analyzed using NVivo 11 software. RESULTS: Twenty-four individuals participated in the event and generated 30 recommendations. Participants accepted the principle of resource scarcity and the need of governments to make difficult trade-offs when allocating health-care resources. They supported the view that cost-benefit thresholds must be set for high-cost drugs. They also expected reasonable health benefits in return for large expenditures, and supported the view that some drugs do not merit funding. Participants also wanted drug funding decisions to be made in a non-partisan and transparent way. CONCLUSION: The recommendations from the Vancouver deliberation can provide guidance to policy makers in BC and may be useful in challenging pricing by pharmaceutical companies.

Gene dosage effect of CUX1 in a murine model disrupts HSC homeostasis and controls the severity and mortality of MDS.

Monosomy 7 (-7) and del(7q) are high-risk cytogenetic abnormalities common in myeloid malignancies. We previously reported that CUX1, a homeodomain-containing transcription factor encoded on 7q22, is frequently inactivated in myeloid neoplasms, and CUX1 myeloid tumor suppressor activity is conserved from humans to Drosophila. CUX1-inactivating mutations are recurrent in clonal hematopoiesis of indeterminate potential as well as myeloid malignancies, in which they independently carry a poor prognosis. To determine the role for CUX1 in hematopoiesis, we generated 2 short hairpin RNA-based mouse models with ∼54% (Cux1mid) or ∼12% (Cux1low) residual CUX1 protein. Cux1mid mice develop myelodysplastic syndrome (MDS) with anemia and trilineage dysplasia, whereas CUX1low mice developed MDS/myeloproliferative neoplasms and anemia. In diseased mice, restoration of CUX1 expression was sufficient to reverse the disease. CUX1 knockdown bone marrow transplant recipients exhibited a transient hematopoietic expansion, followed by a reduction of hematopoietic stem cells (HSCs), and fatal bone marrow failure, in a dose-dependent manner. RNA-sequencing after CUX1 knockdown in human CD34+ cells identified a -7/del(7q) MDS gene signature and altered differentiation, proliferative, and phosphatidylinositol 3-kinase (PI3K) signaling pathways. In functional assays, CUX1 maintained HSC quiescence and repressed proliferation. These homeostatic changes occurred in parallel with decreased expression of the PI3K inhibitor, Pik3ip1, and elevated PI3K/AKT signaling upon CUX1 knockdown. Our data support a model wherein CUX1 knockdown promotes PI3K signaling, drives HSC exit from quiescence and proliferation, and results in HSC exhaustion. Our results also demonstrate that reduction of a single 7q gene, Cux1, is sufficient to cause MDS in mice.

The creatine kinase pathway is a metabolic vulnerability in EVI1-positive acute myeloid leukemia.

Expression of the MECOM (also known as EVI1) proto-oncogene is deregulated by chromosomal translocations in some cases of acute myeloid leukemia (AML) and is associated with poor clinical outcome. Here, through transcriptomic and metabolomic profiling of hematopoietic cells, we reveal that EVI1 overexpression alters cellular metabolism. A screen using pooled short hairpin RNAs (shRNAs) identified the ATP-buffering, mitochondrial creatine kinase CKMT1 as necessary for survival of EVI1-expressing cells in subjects with EVI1-positive AML. EVI1 promotes CKMT1 expression by repressing the myeloid differentiation regulator RUNX1. Suppression of arginine-creatine metabolism by CKMT1-directed shRNAs or by the small molecule cyclocreatine selectively decreased the viability, promoted the cell cycle arrest and apoptosis of human EVI1-positive cell lines, and prolonged survival in both orthotopic xenograft models and mouse models of primary AML. CKMT1 inhibition altered mitochondrial respiration and ATP production, an effect that was abrogated by phosphocreatine-mediated reactivation of the arginine-creatine pathway. Targeting CKMT1 is thus a promising therapeutic strategy for this EVI1-driven AML subtype that is highly resistant to current treatment regimens.

KRAS Allelic Imbalance Enhances Fitness and Modulates MAP Kinase Dependence in Cancer.

Investigating therapeutic "outliers" that show exceptional responses to anti-cancer treatment can uncover biomarkers of drug sensitivity. We performed preclinical trials investigating primary murine acute myeloid leukemias (AMLs) generated by retroviral insertional mutagenesis in KrasG12D "knockin" mice with the MEK inhibitor PD0325901 (PD901). One outlier AML responded and exhibited intrinsic drug resistance at relapse. Loss of wild-type (WT) Kras enhanced the fitness of the dominant clone and rendered it sensitive to MEK inhibition. Similarly, human colorectal cancer cell lines with increased KRAS mutant allele frequency were more sensitive to MAP kinase inhibition, and CRISPR-Cas9-mediated replacement of WT KRAS with a mutant allele sensitized heterozygous mutant HCT116 cells to treatment. In a prospectively characterized cohort of patients with advanced cancer, 642 of 1,168 (55%) with KRAS mutations exhibited allelic imbalance. These studies demonstrate that serial genetic changes at the Kras/KRAS locus are frequent in cancer and modulate competitive fitness and MEK dependency.

Osseointegrated implants into a variety of composite free flaps: A comparative analysis.

BACKGROUND: Significant oral function is often lost after surgical therapy for head and neck cancer. The use of osseointegrated implants for reconstruction in patients with head and neck surgery has shown to significantly improve the quality of life for these patients. Variable success rates range from 99% to 70%. METHODS: A retrospective audit of patient records was performed looking at cumulative survival of implants. Inclusion criteria were patients who were treated at 1 of 2 designated Australian Head and Neck Units and received oral osseointegrated implants. RESULTS: Fifty-nine patients were included for analysis. One hundred ninety-nine implants were placed into vascularized bone grafts (VBGs). There were 11 implant failures with an overall success rate of 94.5%. There was 1 significant adverse outcome with a pathological fracture of a flap after implant placement. Implant success in scapula and iliac crest flaps was comparable to fibula flaps. CONCLUSION: Implants placed into VBGs have a reasonable success rate in well-selected patients. © 2016 Wiley Periodicals, Inc. Head Neck 39: 443-447, 2017.