Citations

Tubulin, one of the most abundant cytoskeletal building blocks, has numerous isotypes in metazoans encoded by different conserved genes. Whether these distinct isotypes form cell type– and context-specific microtubule structures is poorly understood. Based on a cohort of 12 patients with primary ciliary dyskinesia as well as mouse mutants, we identified and characterized variants in the TUBB4B isotype that specifically perturbed centriole and cilium biogenesis. Distinct TUBB4B variants differentially affected microtubule dynamics and cilia formation in a dominant-negative manner. Structure-function studies revealed that different TUBB4B variants disrupted distinct tubulin interfaces, thereby enabling stratification of patients into three classes of ciliopathic diseases. These findings show that specific tubulin isotypes have distinct and nonredundant subcellular functions and establish a link between tubulinopathies and ciliopathies.

Abstract Adagrasib, an irreversible, selective KRASG12C inhibitor, may be an effective treatment in KRASG12C-mutated colorectal cancer, particularly when combined with an anti-EGFR antibody. In this analysis of the KRYSTAL-1 trial, patients with previously treated KRASG12C-mutated unresectable or metastatic colorectal cancer received adagrasib (600 mg twice daily) plus cetuximab. The primary endpoint was objective response rate (ORR) by blinded independent central review. Ninety-four patients received adagrasib plus cetuximab. With a median follow-up of 11.9 months, ORR was 34.0%, disease control rate was 85.1%, and median duration of response was 5.8 months (95% confidence interval [CI], 4.2–7.6). Median progression-free survival was 6.9 months (95% CI, 5.7–7.4) and median overall survival was 15.9 months (95% CI, 11.8–18.8). Treatment-related adverse events (TRAEs) occurred in all patients; grade 3–4 in 27.7% and no grade 5. No TRAEs led to adagrasib discontinuation. Exploratory analyses suggest circulating tumor DNA may identify features of response and acquired resistance. Significance: Adagrasib plus cetuximab demonstrates promising clinical activity and tolerable safety in heavily pretreated patients with unresectable or metastatic KRASG12C-mutated colorectal cancer. These data support a potential new standard of care and highlight the significance of testing and identification of KRASG12C mutations in patients with colorectal cancer. This article is featured in Selected Articles from This Issue, p. 897 See co-corresponding author Rona Yaeger discuss this research article, published simultaneously at the AACR Annual Meeting 2024: https://vimeo.com/932606282/f27a6e46f4

Background and importance Neurointervention is a very competitive specialty in the United States due to the limited number of training spots and the larger pool of applicants. The training standards are continuously updated to ensure solid training experiences. Factors affecting candidate(s) selection have not been fully established yet. Our study aims to investigate the factors influencing the selection process. Methods A 52-question survey was distributed to 93 program directors (PDs). The survey consisted of six categories: (a) Program characteristics, (b) Candidate demographics, (c) Educational credentials, (d) Personal traits, (e) Research and extracurricular activities, and (f) Overall final set of characteristics. The response rate was 59.1%. As per the programs’ characteristics, neurosurgery was the most involved specialty in running the training programs (69%). Regarding demographics, the need for visa sponsorship held the greatest prominence with a mean score of 5.9 [standard deviation (SD) 2.9]. For the educational credentials, being a graduate from a neurosurgical residency and the institution where the candidate's residency training is/was scored the highest [5.4 (SD = 2.9), 5.4 (SD = 2.5), respectively]. Regarding the personal traits, assessment by faculty members achieved the highest score [8.9 (SD = 1)]. In terms of research/extracurricular activities, fluency in English had the highest score [7.2 (SD = 1.9)] followed by peer-reviewed/PubMed-indexed publications [6.4 (SD = 2.2)]. Conclusion Our survey investigated the factors influencing the final decision when choosing the future neurointerventional trainee, including demographic, educational, research, and extracurricular activities, which might serve as valuable guidance for both applicants and programs to refine the selection process.

Background: Baseline concussion testing can be helpful to perform when providing concussion care for young athletes. To appropriately interpret these data, it is important to understand how certain factors may affect concussion testing. Purpose: To examine the relationship of sociodemographic and health variables with baseline concussion testing in young athletes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: High school and middle school athletes competing in sports or positions at high risk for concussion (football, soccer, ice hockey, wrestling, lacrosse, and pitchers/catchers in baseball/softball) during the 2020-2021 or 2021-2022 academic years completed annual baseline concussion testing and were included in the study. Baseline data included self-reported demographic and medical information, a graded symptom checklist, the Standardized Assessment of Concussion, and the King-Devick test. A validated measure, HOUSES (HOUsing-based index of SocioEconomic Status), was used to determine participants’ socioeconomic status (SES) by linking personal address information to publicly available property data. Multivariable linear regression models were fit to analyze the relationship of concussion baseline testing to sociodemographic and health variables. Results: Among the eligible 2747 athletes (mean age, 15.4 ± 1.5 years; 73.6% male), the mean Standardized Assessment of Concussion score was 26.7 ± 2.0 and the mean best King-Devick test time was 50.3 ± 10.1 seconds. Higher baseline symptom severity scores were related to lower SES ( P = .002). A lower (ie, poorer) mean Standardized Assessment of Concussion score was significantly associated with the following in the multivariable model: male sex ( P < .001), younger age ( P < .001), Black/African American race ( P = .029), Hispanic ethnicity ( P = .016), previous diagnosis of learning disorder or attention-deficit hyperactivity disorder ( P < .001), and lower SES ( P = .003). A higher (ie, poorer) mean King-Devick test time was related to younger age, previous diagnosis of a learning disorder or attention-deficit hyperactivity disorder, and lower SES (all P < .001). Conclusion: Baseline concussion testing was found to be associated with certain sociodemographic variables and underlying health conditions in high school and middle school athletes.

Abstract Background Urinary tract infections (UTIs) caused by multidrug-resistant Gram-negative bacilli (MDR-GNB) have become increasingly challenging to manage due to the limited number of available effective oral agents. Minocycline, a second-generation tetracycline with a broad antimicrobial spectrum and reasonable urinary concentration, has recently gained attention as a potential treatment option for MDR-GNB UTIs. In this study, we aim to review the in vitro minocycline susceptibility against a wide spectrum of urinary GNB isolates performed at our reference lab. Methods We conducted a retrospective review of all minocycline susceptibility testing performed on urinary GNB isolates performed at the Mayo Clinic reference lab between 2013-2022. We stratified our results for different species based on phenotypic resistance profiles as well as known species-specific resistance association. Results During the study timeframe, we identified 28,388 GNB isolates that underwent minocycline susceptibility testing. Among the Escherichia coli (E.Coli) isolates resistant to ceftriaxone, ciprofloxacin, or meropenem, minocycline susceptibility was noted to be 78%, 46%, 76%, respectively (Fig 1). Among the Klebsiella pneumonia (KP) isolate resistant to ceftriaxone, ciprofloxacin, or meropenem, minocycline susceptibilities were 47%, 40%, and 53% respectively (Fig 1). Among the high risk Amp-C group Citrobacter freundii, Enterobacter Cloacae and Klebsiella aerogenes, minocycline susceptibility rate was noted to be 87%, 77%, and 89%, respectively (Fig 2). Finally, among the isolate group of non-fermenters including Achromobacter spp, Acinetobacter spp & Stenotrophomonas spp, susceptibility rates were noted to be 65%, 94%, and 100%, respectively (Fig 3). Conclusion Minocycline showed in vitro activity against many hard to treat GNB urinary isolates, including ceftriaxone and meropenem resistant E.coli & KP isolates. High-risk Amp-C producing GN species & some of the less common GN including Stenotrophomonas, Acinetobacter, and Achromobacter. Disclosures All Authors: No reported disclosures

Abstract Background Perianal fistulas and abscesses occur commonly as complications of pediatric Crohn’s disease (CD). A validated imaging assessment tool for quantification of perianal disease severity and activity is needed to evaluate treatment response. We aimed to identify magnetic resonance imaging (MRI)-based measures of perianal fistulizing disease activity and study design features appropriate for pediatric patients. Methods Seventy-nine statements relevant to MRI-based assessment of pediatric perianal fistulizing CD activity and clinical trial design were generated from literature review and expert opinion. Statement appropriateness was rated by a panel (N = 15) of gastroenterologists, radiologists, and surgeons using modified RAND/University of California Los Angeles appropriateness methodology. Results The modified Van Assche Index (mVAI) and the Magnetic Resonance Novel Index for Fistula Imaging in CD (MAGNIFI-CD) were considered appropriate instruments for use in pediatric perianal fistulizing disease clinical trials. Although there was concern regarding the use of intravascular contrast material in pediatric patients, its use in clinical trials was considered appropriate. A clinically evident fistula tract and radiologic disease defined as at least 1 fistula or abscess on pelvic MRI were considered appropriate trial inclusion criteria. A coprimary clinical and radiologic end point and inclusion of a patient-reported outcome were also considered appropriate. Conclusion Outcomes of treatment of perianal fistulizing disease in children must include MRI. Existing multi-item measures, specifically the mVAI and MAGNIFI-CD, can be adapted and used for children. Further research to assess the operating properties of the indices when used in a pediatric patient population is ongoing.

PURPOSEThere are numerous barriers to enrollment in oncology biomarker-driven studies.METHODSThe ELAINE 2 study (ClinicalTrials.gov identifier: NCT04432454 ) is an open-label phase 2 study of lasofoxifene combined with abemaciclib in patients with advanced or metastatic estrogen receptor–positive/human epidermal growth factor receptor 2–negative breast cancer with an ESR1 mutation. ELAINE 2 opened clinical sites by using a Traditional approach, which activated a site before patient identification, and the Tempus TIME Trial network, which opened a site only after identifying an eligible patient. This manuscript presents the operational metrics comparing the Traditional and TIME Trial site data.RESULTSThe study enrolled patients over 34 weeks and 16 sites (six Traditional and 10 TIME Trial) participated. Duration for full clinical trial agreement execution for Traditional sites and TIME Trial sites averaged 200.5 (range, 142-257) and 7.6 days (range, 2-14), respectively. Institutional review board approval time for Traditional sites and TIME Trial sites was 27.5 (range, 12-71) and 3.0 days (range, 1-12), respectively. Duration from study activation to first consent was 33.3 (range, 18-58) and 8.8 days (range, 1-35) for Traditional and TIME Trial sites, respectively. The first patient on study was at a TIME Trial site 115 days before a Traditional site and the first seven patients enrolled were at TIME Trial sites. Traditional sites consented 23 and enrolled 16 patients, while TIME Trial sites consented 16 and enrolled 13. The trial enrolled 29 patients in 8.5 months with the anticipated enrollment duration being 12-18 months.CONCLUSIONThe TIME Trial network opened earlier and enrolled the first study patients. These results demonstrate that the Just-in-TIME model, along with a Traditional model, can improve enrollment in biomarker-driven studies.

TPS3159 Background: ELU001 is a novel first-in-class nanoparticle drug conjugate that consists of ~13 folic acid targeting moieties and a payload of ~22 molecules of the topoisomerase-1 inhibitor, exatecan. Folic acid and exatecan are covalently bound by non-cleavable and cathepsin-B cleavable linkers, respectively, to short polyethylene glycol chains which surround the C’Dot’s silica core. CDCs are very small (~6 nm), allowing for more efficient penetration into solid tumors compared to ADCs and a rapid elimination by the kidneys, which is expected to lead to less toxicity than ADCs that have a longer half-life in circulation. ELU001’s high avidity is designed to promote binding to FRα on the surface of cancer cells that express any level of antigen (low to high). ELU001 then internalizes into the tumor cell and traffics to the lysosome where enzymatic cleavage releases the exatecan payload. ELU001 has demonstrated efficacy in preclinical models with low, moderate and high levels of FRα. The first-in-human trial, ELU-FRα-1, is currently recruiting patients with ovarian, endometrial, colorectal, gastric, gastroesophageal junction, triple negative breast, or non-small cell lung cancers, or cholangiocarcinoma cancers, and, in the opinion of the Investigator, have no meaningful life-prolonging therapy option available. Methods: This is a Phase 1 / 2 multicenter, open label clinical trial with two parts: Part 1 Dose Escalation and Part 2 Tumor Group Expansion Cohort(s). In Part 1, patients with cancer types with a high likelihood of having FRα overexpressing tumors, (ovarian, endometrial, colorectal, gastric, gastroesophageal junction, triple negative breast, or non-small cell lung cancers, or cholangiocarcinoma) will be enrolled. FRα expression is determined retrospectively. ELU001 is administered either weekly (QW) (once a week for 3 weeks, 1 week rest), every other week (Q2W, with no rest between cycles), or every three weeks (Q3W). Initial Part 2 expansion cohorts are planned in ovarian cancer with high FRα expression, ovarian cancer with moderate or low FRα expression, and endometrial cancer with any positive FRα expression. Here, FRα will be prospectively determined. Other cancer types may be assessed in the future. The primary objective for Part 1 is to identify the MTD/RP2D. The primary objective for Part 2 is to determine the ORR. Secondary objectives include DOR, PFS, TFST, PFS2, OS, frequency, severity and tolerability of adverse events, PK, ADA, and FRα expression assessments. Part 1 Dose Escalation will recruit about 2-5 patients at each dose for each regimen (QW; Q2W; Q3W). Part 2 Stage 1 will recruit about 15 patients per tumor group expansion cohort and is expected to begin recruitment in the second half of 2023. The study is enrolling in Part 1 Q2W Cohort 301 and Q3W Cohort A in the US. Clinical trial information: NCT05001282 .

PURPOSE Adagrasib, a KRAS G12C inhibitor, has demonstrated clinical activity in patients with KRAS G12C -mutated non–small-cell lung cancer (NSCLC) and colorectal cancer (CRC). KRAS G12C mutations occur rarely in other solid tumor types. We report evaluation of the clinical activity and safety of adagrasib in patients with other solid tumors harboring a KRAS G12C mutation. METHODS In this phase II cohort of the KRYSTAL-1 study (ClinicalTrials.gov identifier: NCT03785249 ; phase Ib cohort), we evaluated adagrasib (600 mg orally twice daily) in patients with KRAS G12C -mutated advanced solid tumors (excluding NSCLC and CRC). The primary end point was objective response rate. Secondary end points included duration of response, progression-free survival (PFS), overall survival, and safety. RESULTS As of October 1, 2022, 64 patients with KRAS G12C -mutated solid tumors were enrolled and 63 patients treated (median follow-up, 16.8 months). The median number of prior lines of systemic therapy was 2. Among 57 patients with measurable disease at baseline, objective responses were observed in 20 (35.1%) patients (all partial responses), including 7/21 (33.3%) responses in pancreatic and 5/12 (41.7%) in biliary tract cancers. The median duration of response was 5.3 months (95% CI, 2.8 to 7.3) and median PFS was 7.4 months (95% CI, 5.3 to 8.6). Treatment-related adverse events (TRAEs) of any grade were observed in 96.8% of patients and grade 3-4 in 27.0%; there were no grade 5 TRAEs. TRAEs did not lead to treatment discontinuation in any patients. CONCLUSION Adagrasib demonstrates encouraging clinical activity and is well tolerated in this rare cohort of pretreated patients with KRAS G12C -mutated solid tumors.