Instabilities of rotating inclined buoyancy layers

The boundary layer near a cooled inclined plate, which is immersed in a stably stratified fluid rotating about an axis parallel to the direction of gravity, is a model for katabatic flows at high latitudes. In this paper the base flow of such an inclined buoyancy layer is solved analytically for arbitrary Prandtl numbers. By applying linear stability analyses, five unstable modes are identified for both the fixed temperature and the isoflux boundary conditions, i.e., the stationary longitudinal roll (LR) mode, the oblique roll with low streamwise wave-number (OR-1) and high streamwise wave-number (OR-2) modes, and the Tolmien-Schlichting (TS) wave with low streamwise wave-number (TS-1) and high streamwise wave-number (TS-2) modes. It is indicated that the Coriolis effect induced by the rotation leads the critical modes to be three dimensional, and a larger tilt angle of the plate and stronger Coriolis effect cause both TS wave modes to be more unstable for both thermal boundary conditions. When the Coriolis effect is considered, the OR-1 and OR-2 modes are the most unstable mode at low and high tilt angles, respectively, but the TS-1 wave mode may be the most unstable one when the plate is nearly vertical. In addition, the spanwise phase velocities of the TS wave modes change directions as the tilt angle passes some threshold values for both thermal boundary conditions except for the TS-1 wave mode with a fixed temperature boundary condition, which propagates in the same spanwise direction for all explored tilt angles.

Abstract PD13-12: PD13-12 Imlunestrant, an oral selective estrogen receptor degrader, in combination with abemaciclib with or without an aromatase inhibitor, in estrogen receptor-positive advanced breast cancer: Results from the phase 1a/b EMBER study

Background: Imlunestrant is a novel, orally bioavailable selective estrogen receptor degrader (SERD) with pure antagonistic properties that result in sustained inhibition of estrogen receptor (ER)-dependent gene transcription and cell growth. Preclinically, imlunestrant has favorable efficacy and pharmacokinetic (PK) properties, including antitumor activity in ESR1-mutant models, along with enhanced efficacy when combined with abemaciclib. In dose escalation (Phase 1a) and dose expansion (Phase 1b) in the EMBER study, imlunestrant monotherapy was well tolerated with favorable safety, PK and encouraging antitumor activity in heavily pre-treated ER+, HER2- advanced breast cancer (aBC) patients (Jhaveri, ASCO 2022); imlunestrant recommended phase 2 dose (RP2D) was determined as 400mg QD. Here, we present the phase 1b dose expansion of imlunestrant with abemaciclib ± aromatase inhibitor (AI) in EMBER (NCT04188548).

Methods: Phase 1b enrolled patients with ER-positive (ER+), HER2-negative (HER2-) aBC [shown prior endocrine therapy (ET) sensitivity or untreated de novo aBC; ≤1 prior therapies for aBC but must not have received a prior CDK4/6 inhibitor]. Patients were randomized, based on menopausal status and presence of visceral metastases, to receive imlunestrant + abemaciclib OR imlunestrant + abemaciclib + AI. Men and premenopausal women received a concomitant GnRH agonist. Serial plasma samples were obtained for PK and ctDNA analysis. Key endpoints included safety and tolerability, PK, objective response rate (ORR) per RECIST v1.1 (ORR: complete response [CR] or partial response [PR]) in patients with measurable disease), and clinical benefit rate (CBR: CR or PR, or stable disease ≥24 weeks) in patients enrolled ≥24 weeks prior to data cut.

Results: As of 26 May 2022, 85 patients have received imlunestrant [n=80 at 400 mg (RP2D); n=5 at 800 mg] in combination with abemaciclib (150mg twice daily) ± AI. Forty-eight (56%) patients had visceral disease and 9% had at least 1 ESR1 mutation detected in ctDNA at baseline. Patients were predominantly (75%) ET pre-treated, 51% with an AI; and 8% and 5%, respectively, had received prior chemotherapy or fulvestrant, for aBC. The most common treatment-emergent adverse events were diarrhea (87%), nausea (58%), fatigue (45%), neutropenia (39%) and abdominal pain (34%). The majority of treatment-related AEs (TRAEs) were Grade 1 or 2, with Grade ≥3 TRAEs occurring in 36% of patients. Most common TRAEs at RP2D (400mg) were diarrhea (81%), nausea (45%), fatigue (33%) and neutropenia (35%). No patient discontinued treatment due to an AE. Dose reductions were required of both imlunestrant and abemaciclib in 6 (7%) patients and of either imlunestrant in 3 (4%) or abemaciclib in 22 (26%) patients. Preliminary efficacy is presented in Table 1.

Conclusion: Imlunestrant in combination with abemaciclib ± AI showed acceptable safety and tolerability, comparable to the MONARCH 2 trial of fulvestrant + abemaciclib, along with evidence of clinical activity in ER+, HER2- aBC patients. These data suggest no additive toxicity of imlunestrant when administered in combination with abemaciclib, along with comparable clinical benefit to that observed in MONARCH 2. Further data will be presented at the meeting. The phase 3, EMBER-3 study is ongoing; evaluating imlunestrant, investigator’s choice ET, and imlunestrant + abemaciclib in ET pre-treated ER+, HER2- aBC patients (NCT04975308).

Table 1. Preliminary efficacy in combination therapies in EMBER

Citation Format: Komal Jhaveri, Hwei-Chung Wang, Cynthia Ma, Elgene Lim, Jessica J. Tao, Luis Manso, Jean-Yves Pierga, Ritesh Parajuli, Yolanda Jerez Gilarranz, Yen-Shen Lu, Muralidhar Beeram, Tim Larson, Ajay Dhakal, Roohi Ismail-Khan, Claudia Karacsonyi, Shanshan Cao, Cynthia Osborne, Shawn T. Estrem, Bastien Nguyen, Yujia Li, Eunice Yuen. PD13-12 Imlunestrant, an oral selective estrogen receptor degrader, in combination with abemaciclib with or without an aromatase inhibitor, in estrogen receptor-positive advanced breast cancer: Results from the phase 1a/b EMBER study [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD13-12.

A178 BIOLOGIC THERAPY DURING PREGNANCY AS PER GUIDELINE RECOMMENDATIONS REDUCES ADVERSE PREGNANCY RELATED OUTCOMES

Background

Inflammatory bowel disease (IBD) disease activity during pregnancy is associated with adverse neonatal and pregnancy-related outcomes. Biologics are used to suppress disease activity but crosses the placenta in the third trimester. Conflicting studies and guidelines on the timing of biologic dosing in pregnancy persist as we try to balance the risk of disease flare and possible adverse drug effects. The American Gastroenterology Association (AGA) recommends timing the final dose according to the half-life and dosing regimen of each biologic agent.

Aims

To compare neonatal and pregnancy-related outcomes in early versus late dosing of biologics.

Methods

This was a single-center retrospective cohort study conducted at Mount Sinai Hospital from 2016–2021. We included patients with an established diagnosis of IBD before pregnancy who were at least 18 years of age at the time of conception. All patients must have been treated with an IBD-specific biologic agent and had a documented final dose during the pregnancy. The early group received their last biologic dose earlier than the AGA recommendations and the late group received it within the recommended interval. A patient was considered to have a flare based on the overall clinical impression of their gastroenterologist informed by reported symptoms, investigations (fecal calprotectin, endoscopy), and response to treatment. Neonatal and pregnancy-related outcomes were compared amongst the two groups using the student’s t-test (for continuous variables) and Fischer’s exact test (for categorical variables) using SPSS Version 27.

Results

Of 322 patients who had a completed pregnancy at Mount Sinai Hospital, 107 were included in this study. 67 (62.6%) were in the early and 40 (37.4%) were in the late groups. Baseline characteristics including age, comorbidities, IBD phenotype and disease activity were similar between the two groups. The late group had significantly later gestational ages (37.4 vs 38.7 weeks, p=0.006), higher 5-minute Apgar scores (8.7 vs. 9.0, p=0.042), fewer NICU admissions (25.4% vs 5.0%, p=0.036), and fewer IBD flares (28.3% vs 11.1%, p=0.039) in the 6-month post-partum period. There were no significant differences in the rates of premature birth, caesarian sections, infections, and congenital abnormalities. Results are displayed in figure 1.

Conclusions

Our study suggests that late dosing of biologics according to the AGA guidelines was associated with favourable outcomes. However, this is an unadjusted analysis based on retrospective data and findings should be confirmed in a prospective manner to account for confounders.

Funding Agencies

None

A177 INADEQUATE OR EXCESSIVE GESTATIONAL WEIGHT GAIN IN INFLAMMATORY BOWEL DISEASE AND IMPACT ON PREGNANCY AND NEONATAL OUTCOMES

Background

Patients with inflammatory bowel disease (IBD) are at a risk of adverse pregnancy outcomes. Prior studies have suggested that inadequate gestational weight gain is associated with preterm birth and intrauterine growth restriction.

Aims

We sought to characterize the proportion of people with IBD who gain inadequate or excessive weight during pregnancy and how this affects pregnancy and neonatal outcomes.

Methods

Pregnant patients with ulcerative colitis (UC), Crohn’s disease (CD), and inflammatory bowel disease unclassified (IBD-U) were identified retrospectively at Mount Sinai Hospital from 2016 to 2020. Total gestational weight gain (GWG) was calculated as the difference of the weight recorded at time of labor and pre-pregnancy weight. GWG was categorized as inadequate GWG, adequate GWG, and excessive GWG based on the pre-pregnancy body-mass index and standards set by the U.S. Institute of Medicine. Neonatal-related outcomes were also recorded for each patient and included preterm delivery, small for gestational age (SGA) and large for gestational age (LGA). Multiple logistic regression was used to assess the association between gestational weight gain and outcomes while controlling for maternal age, history of gestational diabetes, and preconception disease activity.

Results

225 pregnancies were included (106 UC, 115 CD, 4 IBD-U). Forty-eight patients (21.3%) had inadequate, 91 (40.4%) adequate, and 86 (38.2%) excessive GWG. People of East Asian, African, and Hispanic ethnicity were more likely to have inadequate GWG. People with inadequate GWG were more likely than those with excessive GWG to have lower preconception BMI (21.7 vs 25.5 kg/m2, P=0.001). IBD type was not associated with inadequate GWG or excessive GWG, though people with inadequate GWG were 2-fold less likely to be on anti-TNF therapy. People with excessive GWG were more likely than those with adequate GWG to have babies with higher birth weight (3,364g vs 3,132g, P=0.003). People with inadequate GWG were not at increased risk of SGA compared to those with adequate GWG (adjusted odds ratio (aOR), 1.01; 95% CI: 0.37 – 2.71, P=0.99). Those with excessive GWG were substantially less likely to have an infant with SGA (aOR, 0.23; 95% CI: 0.07 – 0.72, P=0.01). On multivariable logistic regression analysis, excessive GWG was not associated with increased odds of delivering infants with LGA (aOR, 1.46; 95% CI: 0.54 – 3.95, P=0.46). There was no association between non-adequate gestational weight gain and preterm delivery or Caesarean delivery.

Conclusions

Less than half of persons with IBD have adequate GWG during pregnancy. Inadequate GWG was not associated with poor neonatal outcomes, and excessive GWG appeared to protect against delivering infants born SGA.

Funding Agencies

None

A151 COMPARABLE NEONATAL AND PREGNANCY-RELATED OUTCOMES BETWEEN EARLY AND LATE DISCONTINUATION OF BIOLOGICS IN PREGNANT WOMEN WITH INFLAMMATORY BOWEL DISEASE

Background

Inflammatory bowel disease (IBD) disease activity during pregnancy is related to adverse neonatal and pregnancy-related outcomes. Biologics are used to suppress disease activity, however, since there is known transplacental passage, the American Gastroenterology Association (AGA) recommends timing the final dose with drug-specific half-lives although there is little evidence demonstrating adverse outcomes.

Aims

We aim to assess the safety of early versus late discontinuation of biologics according to drug-specific half-lives by comparing various neonatal and pregnancy-related outcomes.

Methods

This is a REB approved single-center retrospective cohort study on all patients with IBD ≥18 years of age on a biologic agent prior to conception, have a documented final dose during pregnancy, and were seen at Mount Sinai Hospital from 2016–2019. Neonate and pregnancy-related outcomes were compared amongst the two groups (Table 1) using the student’s t-test (birthweight, gestational age, Apgar scores) and Fischer’s exact test (NICU admission, congenital anomalies, GBS, chorioamnionitis) analyzed in SPSS Version 27. The level of significance was set at p<0.05.

Results

We identified 53 patients on biologics pre-conception. 26 patients had a documented final dose (19 early cohort, 7 late cohort) and were included in the analysis. Aside from mean birthweight (3014 vs 3561 g, p=0.036), there were no statistically significant differences between the early and late cohorts for gestational age (37.4 vs 39.0 weeks, p=0.20), 1- and 5-min Apgar scores (7.8 vs 8.8, p=0.37 and 8.5 vs 9.0, p=0.49), NICU admissions (p=0.54), congenital anomalies (p=1.00), GBS (p=0.55), and chorioamnionitis (p=1.00).

Conclusions

Overall, our study suggests that early and late discontinuation of biologics have comparable safety profiles based on various neonatal and pregnancy-related outcomes. In fact, we see significantly higher birthweights in the late cohort along with a consistent (non-statistically significant) trend of later gestational ages, and higher Apgar scores. Further, no cases involving NICU admissions, congenital abnormalities, GBS, or chorioamnionitis were seen in the late cohort. Next, we hope to verify our findings by conducting a prospective cohort study with a larger study population and more comprehensive data collection. This will provide higher statistical power and allow for additional subgroup analyses based on objective disease activity (FCP levels) and therapeutic drug monitoring (serum drug levels).

Funding Agencies

None

Three-dimensional viscous Rayleigh-Taylor instability at the cylindrical interface

In this paper, the rotational part of the disturbance flow field caused by viscous Rayleigh-Taylor instability (RTI) at the cylindrical interface is considered, and the most unstable mode is revealed to be three-dimensional for interfaces of small radii R. With an increase in R, the azimuthal wave number of the most unstable mode increases step by step, and the corresponding axial wave number increases as well at each step of the azimuthal wave number. When the amplitude of the wave-number vector is much larger or much smaller than 1/R, the cylindrical RTI is close to the semi-infinite planar viscous RTI limit or the finite-thickness creeping-flow RTI limit, respectively. The effect of the viscosity ratio is double-edged; it may enhance or suppress the cylindrical RTI, depending on R and the amplitude range of the wave-number vector.

Management of Breast Cancer During the COVID-19 Pandemic: A Stage- and Subtype-Specific Approach

The COVID-19 pandemic has rapidly changed delivery of cancer care. Many nonurgent surgeries are delayed to preserve hospital resources, and patient visits to health care settings are limited to reduce exposure to SARS-CoV-2. Providers must carefully weigh risks and benefits of delivering immunosuppressive therapy during the pandemic. For breast cancer, a key difference is increased use of neoadjuvant systemic therapy due to deferral of many breast surgeries during the pandemic. In some cases, this necessitates increased use of genomic tumor profiling on core biopsy specimens to guide neoadjuvant therapy decisions. Breast cancer treatment during the pandemic requires multidisciplinary input and varies according to stage, tumor biology, comorbidities, age, patient preferences, and available hospital resources. We present here the Johns Hopkins Women's Malignancies Program approach to breast cancer management during the COVID-19 pandemic. We include algorithms based on tumor biology and extent of disease that guide management decisions during the pandemic. These algorithms emphasize medical oncology treatment decisions and demonstrate how we have operationalized the general treatment recommendations during the pandemic proposed by national groups, such as the COVID-19 Pandemic Breast Cancer Consortium. Our recommendations can be adapted by other institutions and medical oncology practices in accordance with local conditions and resources. Guidelines such as these will be important as we continue to balance treatment of breast cancer against risk of SARS-CoV-2 exposure and infection until approval of a vaccine.

Origin of lobe and cleft at the gravity current front

In this Rapid Communication, the Rayleigh-Taylor instability (RTI) along the density interfaces of gravity current fronts is analyzed. Both the location and the spanwise wave number of the most unstable mode determined by the local dispersion relation agree with those of the strongest perturbation obtained from numerical simulations, suggesting that the original formation mechanism of lobes and clefts at the current front is RTI. Furthermore, the predictions of the semi-infinite RTI model, i.e., the original dominating spanwise wave number of the Boussinesq current substantially depends on the Prandtl number and has a 1/3 scaling law with the Grashof number, are confirmed by the three-dimensional numerical simulations.

Real-World Outcomes of an Automated Physician Support System for Genome-Driven Oncology

PURPOSE

Matching patients to investigational therapies requires new tools to support physician decision making. We designed and implemented Precision Insight Support Engine (PRECISE), an automated, just-in-time, clinical-grade informatics platform to identify and dynamically track patients on the basis of molecular and clinical criteria. Real-world use of this tool was analyzed to determine whether PRECISE facilitated enrollment to early-phase, genome-driven trials.

MATERIALS AND METHODS

We analyzed patients who were enrolled in genome-driven, early-phase trials using PRECISE at Memorial Sloan Kettering Cancer Center between April 2014 and January 2018. Primary end point was the proportion of enrolled patients who were successfully identified using PRECISE before enrollment. Secondary end points included time from sequencing and PRECISE identification to enrollment. Reasons for a failure to identify genomically matched patients were also explored.

RESULTS

Data were analyzed from 41 therapeutic trials led by 19 principal investigators. In total, 755 patients were accrued to these studies during the period that PRECISE was used. PRECISE successfully identified 327 patients (43%) before enrollment. Patients were diagnosed with 29 tumor types and harbored alterations in 43 oncogenes, most commonly ERBB2 (21.3%), PIK3CA (14.1%), and BRAF (8.7%). Median time from sequencing to enrollment was 163 days (interquartile range, 66 to 357 days), and from PRECISE identification to enrollment 87 days (interquartile range, 37 to 180 days). Common reasons for failing to identify patients before enrollment included accrual on the basis of molecular alterations that did not match pre-established PRECISE genomic eligibility (140 [33%] of 428) and external sequencing not available for parsing (127 [30%] of 428).

CONCLUSION

PRECISE identified 43% of all patients accrued to a diverse cohort of early-phase, genome-matched studies. Purpose-built informatics platforms represent a novel and potentially effective method for matching patients to molecularly selected studies.

Demonstrating the impact of POLST forms on hospital care requires information not contained in state registries

Background

Physician Orders for Life-Sustaining Treatment (POLST) programs have expanded rapidly, but evaluating their impact on hospital care is challenging.

Objectives

To demonstrate how careful study design can reveal POLST’s impact at hospital admission and why analyses of state registry data are unlikely to capture POLST’s effects.

Design

Prospective cohort study.

Setting and participants

Adult in-patients with Do Not Intubate and/or Do Not Resuscitate (DNR/I) orders in the electronic medical record at the time of discharge from Johns Hopkins Hospital over 18 months. For patients with unplanned readmissions within 30 days, records were reviewed to determine if a Maryland Medical Order for Life-Sustaining Treatment (MOLST) form was presented and for the time from readmission to a DNR/I order in the EMR. Analyses were stratified by whether patients could communicate or were accompanied by a proxy at readmission.

Results

Among 1,507 patients with DNR/I orders at discharge, 124 (8%) had unplanned readmissions, 112 (90%) could communicate or were accompanied by a proxy at readmission, and 12 (10%) could not communicate and were unaccompanied. For patients who were unaccompanied and could not communicate, MOLST significantly decreased the median time from readmission to DNR/I order (1.2 vs 27.1 hours, P = .001), but this association was greatly attenuated among patients who could communicate or were accompanied by a proxy (16.4 vs 25.4 hours P = .10).

Conclusion

Among patients who wanted to avoid intubation and/or CPR, MOLST forms were protective when the patient was unaccompanied by a healthcare proxy at admission and could not communicate. Fewer than 10% of patients met these criteria during unplanned readmissions, and state registry data does not allow this sub-population to be identified.

First-in-Human Phase I Study of the Activin A Inhibitor, STM 434, in Patients with Granulosa Cell Ovarian Cancer and Other Advanced Solid Tumors

PURPOSE

STM 434 is a soluble receptor ligand trap targeting activin A, a protein in the TGFβ family that plays important roles in growth, differentiation, and cancer cachexia. This study evaluated the safety, antitumor activity, and metabolic effects of STM 434 in a first-in-human, multicenter, phase I clinical trial (NCT02262455).

PATIENTS AND METHODS

Patients with advanced solid tumors were enrolled in 8 dose cohorts ranging from 0.25 mg/kg every 4 weeks to 8 mg/kg every 2 weeks via a 3 + 3 dose-escalation design. The primary endpoint was maximum tolerated dose (MTD). Secondary endpoints included safety, pharmacokinetics, and response. As activin A is implicated in metabolism and muscle function, changes in key metabolic parameters, including lean body mass and 6-minute walk test, were serially measured.

RESULTS

Thirty-two patients were treated on study. The most common treatment-related adverse events were fatigue (41%) and mucocutaneous bleeding complications including epistaxis (34%) and gingival bleeding (22%), likely related to off-target inhibition of bone morphogenetic protein 9 (BMP9). STM 434 treatment resulted in the expected follicle-stimulating hormone level decreases in most patients and in metabolic parameter changes, including an increase in total lean body mass and 6-minute walk test distance. No responses were observed in the 30 evaluable patients, but the stable disease rate in patients with granulosa cell ovarian cancer was 10 of 12 (80%).

CONCLUSIONS

Although no direct antitumor efficacy was documented, potentially clinically meaningful dose-related metabolic effects, including treatment of cancer cachexia, were observed that support further exploration of activin A inhibitors that limit BMP9 blockade.See related commentary by Bonilla and Oza, p. 5432.

Unified decomposition method to study Rayleigh-Taylor instability in liquids and solids

In the previous studies of Rayleigh-Taylor instability, different methods were used to consider the effects of elasticity, viscosity, and magnetic fields. In this paper, a unified method, which was first used for fluids, is validated for different physical models, where the unstable mode is decomposed into an irrotational part and a rotational part, and the latter one includes the effects of nonconservative forces and constitutive relations. Previous results of solid and liquid with or without the effects of magnetic fields and finite thickness can be easily recovered after applying the corresponding interface boundary conditions. In addition, new approximate but analytical solutions of the growth rates for a semi-infinite solid-solid interface and solid-fluid interface are obtained with substantially improved accuracy in comparison with the previous ones.

Abstract CT011: First in human study of activin-A inhibitor, STM434, in patients with granulosa cell ovarian cancer and other advanced solid tumors

Background: STM434 is a soluble receptor ligand trap targeting activin A, a protein in the TGF-beta family that plays important roles in growth, differentiation, and cancer cachexia. Activin A overexpression is a common feature in many gynecologic cancers. Granulosa cell tumors also harbor pathognomonic mutations in FOXL2, which specifically promotes dysregulated activin signaling. The role of inhibiting activin A signaling in human cancers has not been previously explored.

Methods: Primary endpoint was to establish to maximum tolerated dose of STM434. Dose was initially escalated by accelerated titration and then 3+3 design. Secondary endpoints included safety per CTCAE v4, pharmacokinetics, and response by RECIST v1.1. As Activin A is also implicated in metabolism and muscle function, changes in key metabolic parameters including lean body and fat mass established by DXA scan and 6 minute walk test (6MWT), were serially measured.

Results: 32 patients were treated at doses ranging from 0.25 - 8 mg/kg IV every 2-4 weeks. Tumor types included ovarian granulosa cell (n=13), epithelial ovarian (n=7), colon (n=3), pancreatic (n=2), and other solid tumors (n=7). A total of 5 DLTs were observed in 3 pts (all grade 3): hemorrhagic ascites (0.5 mg/kg Q4W) and stomatitis, gastritis, epistaxis, and alkaline phosphatase increase (all 8 mg/kg Q2W). The most common treatment-related AEs were fatigue (n=12), epistaxis (n=11), and gingival bleeding (n=6). Other observed hematologic related-AEs included telangiectasia (n=3), hemorrhagic ascites (n=2), and petechiae (n=2). No treatment-related grade 4 or 5 AEs occurred. STM434 resulted in the expected FSH level decreases in most patients. STM434 also resulted in metabolic parameter changes, including an increase in total lean body mass (1%-20%, 0.5 mg/kg Q2W to 4 mg/kg Q2W cohorts) and 6-minute walk test (25-150 meters in the 0.5 mg/kg Q2W-2 mg/kg Q2W cohort) and decrease in total fat mass (-3% to -18% in the 0.5 mg/kg Q4W- 4 mg/kg Q2W cohorts). One patient with fatty liver on baseline imaging had complete resolution of this finding after 2 cycles of therapy. No responses were observed in the 28 evaluable patients. In granulosa cell patients, the stable disease rate was 9/12 (75%) although the significance of this finding is uncertain.

Conclusions: The MTD of STM434 was 4 mg/kg Q2W. STM434 use resulted in mucocutaneous bleeding complications likely related to off-target inhibition of bone morphogenic protein 9 (BMP9). BMP9 bears substantial homology to activin A and inherited inactivation of BMP9 can result in hereditary hemorrhagic telangiectasia which shares a phenotype similar to the AE profile observed here. While no direct antitumor efficacy was documented, potentially clinically meaningful dose-related metabolic effects were observed that support further exploration of Activin A inhibitors that avoid BMP9 blockade in cancer.

Citation Format: Jessica J. Tao, Joyce F. Liu, Drew W. Rasco, Willis Navarro, Christopher M. Haqq, David M. Hyman. First in human study of activin-A inhibitor, STM434, in patients with granulosa cell ovarian cancer and other advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT011.

Basket Studies: Redefining Clinical Trials in the Era of Genome-Driven Oncology

Understanding a tumor's detailed molecular profile has become increasingly necessary to deliver the standard of care for patients with advanced cancer. Innovations in both tumor genomic sequencing technology and the development of drugs that target molecular alterations have fueled recent gains in genome-driven oncology care. "Basket studies," or histology-agnostic clinical trials in genomically selected patients, represent one important research tool to continue making progress in this field. We review key aspects of genome-driven oncology care, including the purpose and utility of basket studies, biostatistical considerations in trial design, genomic knowledgebase development, and patient matching and enrollment models, which are critical for translating our genomic knowledge into clinically meaningful outcomes.

Retarding viscous Rayleigh-Taylor mixing by an optimized additional mode

The Rayleigh-Taylor (RT) mixing induced by random interface disturbances between two incompressible viscous fluids is simulated numerically. The ensemble averaged spike velocity is found to be remarkably retarded when the random interface disturbances are superimposed with an optimized additional mode. The mode's wavenumber is selected to be large enough to avoid enhancing the dominance of long-wavelength modes, but not so large that its saturated spike and bubble velocities are too small to stimulate a growing effective density-gradient layer suppressing the long-wavelength modes. Such an optimized suppressing mode is expected to be found in the RT mixing including other diffusion processes, e.g., concentration diffusion and thermal diffusion.

PI3K inhibition results in enhanced estrogen receptor function and dependence in hormone receptor-positive breast cancer

Activating mutations of PIK3CA are the most frequent genomic alterations in estrogen receptor (ER)-positive breast tumors, and selective phosphatidylinositol 3-kinase α (PI3Kα) inhibitors are in clinical development. The activity of these agents, however, is not homogeneous, and only a fraction of patients bearing PIK3CA-mutant ER-positive tumors benefit from single-agent administration. Searching for mechanisms of resistance, we observed that suppression of PI3K signaling results in induction of ER-dependent transcriptional activity, as demonstrated by changes in expression of genes containing ER-binding sites and increased occupancy by the ER of promoter regions of up-regulated genes. Furthermore, expression of ESR1 mRNA and ER protein were also increased upon PI3K inhibition. These changes in gene expression were confirmed in vivo in xenografts and patient-derived models and in tumors from patients undergoing treatment with the PI3Kα inhibitor BYL719. The observed effects on transcription were enhanced by the addition of estradiol and suppressed by the anti-ER therapies fulvestrant and tamoxifen. Fulvestrant markedly sensitized ER-positive tumors to PI3Kα inhibition, resulting in major tumor regressions in vivo. We propose that increased ER transcriptional activity may be a reactive mechanism that limits the activity of PI3K inhibitors and that combined PI3K and ER inhibition is a rational approach to target these tumors.

Long term side effects of adjuvant chemotherapy in patients with early breast cancer

Adjuvant systemic therapy along with screening has been key to the observed improvements in disease-free and overall survival (DFS/OS) in breast cancer. Improvements in overall survival already take into account therapy related toxicities that can result in death. However, this measure alone does not adequately capture the impact on health-related quality of life. Therefore, it is important to examine the prevalence, frequency and short/long-term impact of therapy-related toxicities, identify patients who might be at greatest risk. Ultimately decisions regarding expected therapy benefits (relative and absolute percentage improvements in DFS/OS) must be made against a background of known potential harms. For many patients with early breast cancer (EBC), their risk of recurrence is not zero but is small. At the same time, for many therapies for early stage breast cancer, the risk of serious side effects is small but is not zero. As we better understand the long-term side effects of adjuvant chemotherapy and targeted therapy, it becomes critical to integrate our growing understanding of breast cancer biology with standard high-quality histopathologic measures to better identify the patients most likely to benefit from the various options for combined multimodality therapy. Hence, we must strive against the notion of recommending adjuvant systemic chemotherapy "just in case." This article focuses on the long-term side effects of adjuvant chemotherapy in patients with EBC.

Antagonism of EGFR and HER3 enhances the response to inhibitors of the PI3K-Akt pathway in triple-negative breast cancer

Both abundant epidermal growth factor receptor (EGFR or ErbB1) and high activity of the phosphatidylinositol 3-kinase (PI3K)-Akt pathway are common and therapeutically targeted in triple-negative breast cancer (TNBC). However, activation of another EGFR family member [human epidermal growth factor receptor 3 (HER3) (or ErbB3)] may limit the antitumor effects of these drugs. We found that TNBC cell lines cultured with the EGFR or HER3 ligand EGF or heregulin, respectively, and treated with either an Akt inhibitor (GDC-0068) or a PI3K inhibitor (GDC-0941) had increased abundance and phosphorylation of HER3. The phosphorylation of HER3 and EGFR in response to these treatments was reduced by the addition of a dual EGFR and HER3 inhibitor (MEHD7945A). MEHD7945A also decreased the phosphorylation (and activation) of EGFR and HER3 and the phosphorylation of downstream targets that occurred in response to the combination of EGFR ligands and PI3K-Akt pathway inhibitors. In culture, inhibition of the PI3K-Akt pathway combined with either MEHD7945A or knockdown of HER3 decreased cell proliferation compared with inhibition of the PI3K-Akt pathway alone. Combining either GDC-0068 or GDC-0941 with MEHD7945A inhibited the growth of xenografts derived from TNBC cell lines or from TNBC patient tumors, and this combination treatment was also more effective than combining either GDC-0068 or GDC-0941 with cetuximab, an EGFR-targeted antibody. After therapy with EGFR-targeted antibodies, some patients had residual tumors with increased HER3 abundance and EGFR/HER3 dimerization (an activating interaction). Thus, we propose that concomitant blockade of EGFR, HER3, and the PI3K-Akt pathway in TNBC should be investigated in the clinical setting.

PI3K pathway inhibitors: better not left alone

The PI3K/Akt/mTOR signaling pathway plays a key role in diverse physiologic processes. It is also central to many aspects of the malignant process. Genetic phenomena that lead to constitutive pathway activation are common in human cancer; the most relevant are mutations affecting the catalytic subunit of PI3K and loss of function of the PTEN tumor suppressor. These factors have made this important cascade attractive as a potential target for cancer therapeutics. A host of inhibitors are now in various stages of development that target key nodes within the PI3K pathway. To date, however, the efficacy of these agents has fallen short of expectation, with at least one possible explanation being the presence of feedback loops and cross-talk that exists within and between PI3K and other signaling pathways. Accordingly, enthusiasm is again high as strategies employing therapeutic combinations are gaining pace, with encouraging results documented in both preclinical studies and emerging clinical trials. Here, we review the agents that have reached evaluation in early phase clinical studies of human subjects with cancer, and discuss the rationale for and use of novel drug combinations.

Nonlinear Rayleigh-Taylor instability of rotating inviscid fluids

It is demonstrated theoretically that the nonlinear stage of the Rayleigh-Taylor instability can be retarded at arbitrary Atwood numbers in a rotating system with the axis of rotation normal to the acceleration of the interface between two uniform inviscid fluids. The Coriolis force provides an effective restoring force on the perturbed interface, and the uniform rotation will always decrease the nonlinear saturation amplitude of the interface at any disturbance wavelength.

High frequency of SDHB germline mutations in patients with malignant catecholamine-producing paragangliomas: implications for genetic testing

CONTEXT

Adrenal and extraadrenal paragangliomas are tumors of chromaffin cells that are usually benign but that may also develop into malignant disease. Mutations of the gene for succinate dehydrogenase subunit B (SDHB) are associated with a high risk of malignancy, but establishing the precise contribution requires relatively large numbers of patients with well-defined malignancy.

OBJECTIVE

We assessed the prevalence of SDHB mutations in a series of patients with malignant paraganglioma.

DESIGN

SDHB mutation testing was carried out in 44 consecutive patients with malignant paraganglioma. Clinical characteristics of patients with malignant disease due to SDHB mutations were compared with those without mutations.

RESULTS

Pathogenic SDHB mutations were found in 13 of the 44 patients (30%). Close to one third of patients had metastases originating from an adrenal primary tumor, compared with a little over two thirds from an extraadrenal tumor. Among the latter patients, the frequency of SDHB mutations was 48%.

CONCLUSION

This study establishes that missense, nonsense, frameshift, and splice site mutations of the SDHB gene are associated with about half of all malignancies originating from extraadrenal paragangliomas. The high frequency of SDHB germline mutations among patients with malignant disease, particularly when originating from an extraadrenal paraganglioma, may justify a high priority for SDHB germline mutation testing in these patients.