Citations

Background Kidney stones (nephrolithiasis) are an expensive and painful health problem with a complex etiology with ~70% of stones composed of calcium oxalate (CaOx). The Slc26 gene family contains several proteins that transport oxalate in the gut and kidney. Slc26a6 and its homologs exchange Cl − for oxalate (ox 2− ), as well as SO 4 2− , HCO 3 − and formate. Slc26a6 −/− mice have hyperoxaluria and CaOx stones illustrating a physiologic collaboration between the gut and kidney. We developed a Drosophila genetic model for CaOx stones (dPrestin, Slc26a5/6, manipulation) allowing rapid gut, renal and whole‐body physiological assessment (min/h v. mo/y). Methods (Tissue) First, Malpighian tubules (MT, renal tubule) were dissected from wild type and dPrestin knockdown mutants and soaked in ox 2− solutions. CaOx stones were visualized by DIC microscopy. Second, we generated Drosophila expressing eYFP in the MT, MT+gut or whole body. eYFP is a halide (Cl − ) sensor, allowing quantification of Cl − /ox 2− exchange by native dPrestin. (Whole body) Wild type and dPrestin knockdown flies were fed ox 2− enriched food, and flies imaged (CaOx quantified) by micro computed tomography (MicroCT). Results Exposing dPrestin‐knockdowns to bath ox 2− elicited almost no CaOx crystals. However, exposing wt‐MT to ox 2− elicited many CaOx crystals in 20 min. Increased CaOx crystal formation was also coupled with an eYFP intensity increase, matching dPrestin Cl − /ox 2− exchange characteristics. MicroCT showed more CaOx crystals in flies that fed on ox 2− longer. Conclusions Our observations indicate that Drosophila and dPrestin manipulation can be used for rapid, detailed studies of gut, renal and whole organism oxalate metabolism & CaOx stone formation. [DK83007]

Background Kidney stones are an expensive and painful health problem with calcium oxalate (CaOx) being 70% of cases. We developed a Drosophila model of CaOx stones [Hirata et al., AJP‐Renal Physiol, 2012]. This work showed that dPrestin (Slc26a5/a6) exchanges Cl − for oxalate (Ox). Thiosulfate (S 2 O 3 ) and tannic acid (TA) are implicated to inhibit CaOx crystals in supersaturated urine. Here, we report transporter, renal tubule and whole body effects of S 2 O 3 and TA on crystal formation. Methods S 2 O 3 and TA transport effects were examined by voltage clamping of dPrestin‐expressing Xenopus oocytes. Cis ‐inhibition of oxalate transport was also examined in (a) dissected Malpighian tubules (MT) or flies fed ox‐enriched food plus S 2 O 3 or TA. MT CaOx crystals were viewed by DIC, or whole flies by microCT. Results dPrestin transports S 2 O 3 but not TA, yet both inhibited Ox transport (K i (S 2 O 3 )~10mM; K i (TA)~100μM). S 2 O 3 competitively inhibits while TA blocks dPrestin. MT treated with S 2 O 3 or TA ↓ crystal formation compared to MT soaked in Ox only. Flies fed with S 2 O 3 or TA also showed ↓ CaOx in MTs. Conclusions S 2 O 3 and TA are both inhibitors of CaOx crystallization. These experiments show that these inhibitors have distinct mechanisms of action. Our Results indicate that (a) this Drosophila model can be used as a chemical screening assay for CaOx stone prevention and (b) TA, due to low Ki, might be a reasonable therapy for certain CaOx stones patients.[ DK83007, DK92408]

Background : Zn is implicated as having a role in the formation of calcium oxalate (CaOx) kidney stones. Our studies indicate that Slc39a10 (Zip10) may be important in this process. Zip10 has identifiable sequences in human, dog and fly ( Drosophila ). As we are interested in a translational model of kidney stones, we examined Zip10 from all 3 species. Methods: Zip10 cDNAs were cloned from human & dog (kidney) and fly (whole fly) using gene specific primers and RT‐PCR. Clones were put into a Xenopus oocyte expression vector so that Zip10 function could be measured. Three days post‐injection, oocytes were pre‐incubated in ND96, followed by 30 min in ND96 + 10 μM ZnCl + the PET isotope 63 Zn, with varying pHs and ion concentrations. 63 Zn uptake was measured in each oocyte using a gamma counter. Zip10 oocytes were also checked using electrophysiology (ion selective electrodes & voltage clamping). Results: Zip10 mRNA & protein are found in gut and kidney. In mouse kidney, Zip10 antibodies stained the apical membrane of proximal tubules. All clones transported 63 Zn (nmol/oocyte/hr): hZip10 = 70±8; cZip10= 44 ±7; dZip10= 64 ±8; water = 0.4 ±0.1. These clones seem to be most active at pH 7.5 as uptakes decreased at 5.5 and 8.5. Replacement of either all Cl ‐ (with HCO 3 舉 ) or all Na + (with choline) reduced Zn‐uptake. Electrophysiology revealed no evidence of I or V changes with addition of Zn (electroneutral). Conclusions: Our results indicated that all three Zip10 clones transport Zn 2+ . Understanding the detailed mechanisms of these Zn transporters in oocytes presents the opportunity to better use our Drosophila model in the study of CaOx stone formation and absorption. Grant Funding Source : Supported by DK83007, DK92408

Abstract Background and Aims Bowel urgency and abdominal pain are impactful, yet under-appreciated ulcerative colitis symptoms and not commonly assessed in clinical trials. We evaluated how these symptoms may improve with upadacitinib treatment and correlate with clinical and health-related quality of life [HRQOL] outcomes in the phase 2b U-ACHIEVE study. Methods Patients aged 18–75 years, with moderately to severely active ulcerative colitis, were randomised to receive placebo or upadacitinib (7.5, 15, 30, or 45 mg once daily [QD]). Bowel urgency and abdominal pain were evaluated at baseline and Weeks 2, 4, 6, and 8. Week 8 correlations were evaluated between bowel urgency/abdominal pain with clinical [Mayo subscores and high-sensitivity C-reactive protein and faecal calprotectin measurements] and HRQOL outcomes [Inflammatory Bowel Disease Questionnaire and 36-Item Short Form Health Survey scores]. Results A greater proportion of patients [n = 250] reported no bowel urgency and less abdominal pain with upadacitinib treatment compared with placebo, with improvements observed as early as 2 weeks. At Week 8, patients receiving the 45-mg QD dose had the greatest improvements versus placebo, with 46% reporting no bowel urgency [vs 9%; p ≤ 0.001] and 38% reporting no abdominal pain [vs 13%; p = 0.015]. At Week 8, moderate correlations were found between bowel urgency or abdominal pain and most clinical and HRQOL outcomes. Conclusions Induction treatment with upadacitinib demonstrated significant reductions in bowel urgency and abdominal pain compared with placebo. These symptoms also correlate to clinical and HRQOL outcomes, supporting their use to monitor disease severity and other treatment outcomes.

e21016 Background: BRAF mutations are grouped (class I, II or III) according to kinase activity, dependence on RAS, and dimerization. BRAF class I mutations are targeted with BRAF/MEK inhibitors. The management of class II/III mutations has not been fully elucidated. We aimed to further characterize BRAF-mutant NSCLC. Methods: Moffitt patients with BRAF-mutant NSCLC were identified through retrospective review of a clinical molecular database and electronic health record from 1/1/2012 - 03/31/2020. Demographics, PD-L1 expression, responses to chemotherapy/immunotherapy, and overall survival were collected. The correlation between BRAF mutation classes and these variables was determined using a pairwise comparison of p-values and corrected for testing using the Benjamini-Hochberg method. For survival analysis, we used the Kaplan-Meier method with log-rank test. Results: 153 patients were included. Table summarizes the demographic data. 14 evaluable patients with class I mutations received anti-BRAF therapy. The DCR was 79% (11/14) and 83% when PD-L1 ≥1% (5/6). 36 response-evaluable patients received immunotherapy. The DCR was 79% (11/14) for patients with class I, 69% (9/13) for class II, and 78% (7/9) for class III mutations (p=0.89). The DCR was 73% in those with PD-L1 ≥1% (22/30) and 44% in those with PD-L1 <1% (7/16; p= 0.02). 43 response-evaluable patients received chemotherapy. The DCR was 86% (18/21) for patients with class I, 69% (9/13) for class II, and 78% (7/9) for class III mutations (p=0.49). The mOS was 26.2 months for all patients. The mOS was 31.2 months for class I, 15.6 months for class II, 28.8 months for class III, 34.8 months for AMP, and 24 months for VUS (p=0.6). Conclusions: To our knowledge, this is the largest retrospective study of patients with BRAF-mutant NSCLC. BRAFmutations were more common in patients with adenocarcinoma and those with a smoking history. PD-L1 levels ≥1% were seen more frequently in all BRAF-mutant patients. Class I mutations were significantly more common than other mutations and responded well to BRAF-targeted therapy, particularly when PD-L1 ≥1%. All BRAF-mutant classes responded similarly to immunotherapy and better responses were seen among those with PD-L1 ≥1%. Responses to chemotherapy were similar across all classes. Improved OS in class I-mutant disease was seen. These findings were not statistically significant. Additional research is needed to better characterize these patients to individualize management and improve outcomes.[Table: see text]

e20554 Background: The paradigm for locally advanced non-small cell lung cancer has been markedly altered to include maintenance durvalumab (D) post completion of definitive chemoradiation (CRT) following the publication of the Pacific trial in 2018. The toxicity of this treatment has not been well evaluated in the real-world setting. Methods: We identified 42 patients (pts) with Stage IIB-IIIC NSCLC treated at Mayo Clinic Rochester between 6/1/2018 and 10/1/2020 who received definitive CRT followed by maintenance D. Data were abstracted by retrospective chart review under an IRB approved protocol. Results: Median age was 66 yrs (range 47-90) and 62% were women. Primary lung cancer histology included 19 adenocarcinoma, 20 squamous cell, and 3 adenosquamous. The distribution of stages was: IIB (4/42), IIIA (15/42), IIIB (19/42), IIIC (4/42). Approximately half of patients had PDL1 expression > 25% (20/42). With a median follow up of 12.2 months (calculated from first cycle of D; range 4.2-30.5 months), 14 had completed one year of maintenance D, 16 were receiving ongoing D, and 10 stopped D early with 6/12 discontinuing due to disease progression (4/6 local progression, 2/6 distant progression). Other reasons for discontinuation (5/10) included grade 3 colitis, grade 2 hepatitis, aspergillus lung infection, and flare of autoimmune disorders. One quarter of patients experienced grade 2 radiation pneumonitis (RP; 10/42) with median time to development of RP 78 days from end of CRT and 45 days from start of D. RP was determined by multidisciplinary review of imaging and treatment fields. 17/42 patients developed immune related adverse events (see Table for details). There was minimal overlap between the patients who experienced pneumonitis and immune related toxicity; 2/17 had both pneumonitis and immune related toxicity (hepatitis, thyroiditis). Conclusions: In our early experience with the Pacific regimen, 29% of patients did not complete D due to either toxicity or progression during D administration. Pneumonitis was common (10/42 patients) although there were no grade 3 events. Nearly half of the patients developed an immune-related adverse event. Further analysis is needed to evaluate the real-world toxicity of this treatment as well as oncologic outcomes.[Table: see text]

9093 Background: Treatment addressing non-small cell lung cancer (NSCLC) harboring EGFR or HER2 exon 20 insertion mutations remains an unmet need. These tumors are associated with a high incidence of CNS metastases and unfavorable survival rates. Poziotinib is a potent, irreversible, tyrosine kinase inhibitor (TKI) with a structure that can overcome the steric hindrance of the exon 20 limited binding pocket. Preclinical data suggest poziotinib CNS penetration, and here we show meaningful poziotinib CNS activity in patients with NSCLC harboring exon 20 insertion mutations in an ongoing multi-cohort, multi-center Phase 2 study (ZENITH20; NCT03318939). Methods: ZENITH20 enrolled previously treated and naïve patients with advanced/metastatic NSCLC and EGFR or HER2 exon 20 insertion mutations in several cohorts: Cohort 1 (C1) EGFR previously treated; Cohort 2 (C2) HER2 previously treated and Cohort 3 (C3) EGFR treatment-naïve. All patients with stable CNS metastases at baseline were included. Poziotinib (16 mg) was administered orally QD, with follow-up for up to 24 months. The primary endpoint was Objective Response Rate (ORR) evaluated centrally using RECIST v1.1 by an independent image review committee. Secondary endpoints included Disease Control Rate (DCR), Duration of Response (DOR), Progression-Free Survival (PFS) and safety. Primary efficacy results have been previously released. Intracranial response was determined based on the modified RECIST criteria. Results: A total of 284 patients across 3 cohorts (C1 n=115; and C2 n=90; and C3 n=79) with a median age of 60.5 years were enrolled. The median follow-up was 7.3, 8.3, and 9.2 months for all patients in C1, C2, and C3, respectively. In NSCLC patients that had baseline CNS lesions (N=36), the analysis showed a patient-based ORR of 22.2% (8/36) and a DCR of 88.9% (32/36). One patient in each cohort had a complete intracranial response and stable disease was 80.6% across 3 cohorts and 92.9% in C2. Two patients each in C1 and C3 had progressive disease (PD) and none had CNS progression in C2 (Table). Conclusions: Poziotinib exhibited clinically meaningful CNS activity in patients with EGFR or HER2 exon 20 mutations in ZENITH20 Cohorts 1-3. The majority of the patients had no CNS progression and 3/36 patients had intracranial complete responses. The preliminary data suggest that poziotinib may provide a meaningful treatment alternative for patients with NSCLC that harbor EGFR or HER2 exon 20 mutations and who present with CNS metastases that have poor prognosis. Clinical trial information: NCT03318939. [Table: see text]

Abstract Background Upadacitinib (UPA) is a selective and reversible Janus kinase inhibitor.U-ACCOMPLISH is one of two phase 3 induction trials that evaluated the safety and efficacy of UPA 45 mg once daily (QD) in adults with ulcerative colitis (UC). Methods U-ACCOMPLISH was a multicentre, randomized, double-blind, placebo-controlled trial (NCT03653026) that enrolled patients with moderate-to-severe UC (defined as adapted Mayo score 5–9 with centrally read endoscopic score 2–3) who had inadequate response, loss of response, or intolerance to aminosalicylates, immunosuppressants, corticosteroids and/or biologics. Patients were randomized 2:1 to UPA 45 mg QD or placebo (PBO) for 8 weeks. At week 8, responders entered the maintenance phase and non-responders entered the extended treatment period to receive open-label UPA 45 mg QD for additional 8 weeks.The primary endpoint (clinical remission per adapted Mayo Score) and ranked secondary endpoints including symptomatic, endoscopic– histologic evaluations from the 8-week PBO-controlled period are reported here. Non-responder imputation incorporating multiple imputation for missing data due to COVID-19 are reported. Results 522 patients were randomized (UPA, n=345; PBO, n=177); the intent-to-treat population included 341 patients in UPA and 174 patients in PBO group. Baseline demographics and disease characteristics were similar between groups; 50.7% and 51.1% were biologic inadequate responders in UPA and PBO groups, respectively (Table 1). A significantly higher proportion of patients receiving UPA 45 mg QD (33.5%) versus PBO (4.1%) achieved the primary endpoint (adjusted treatment difference: 29.0% [23.2, 34.7]; P&lt;0.001). A significantly higher proportion of patients receiving UPA versus PBO also achieved all ranked secondary endpoints (all P&lt;0.001; Figure 1).Serious adverse events were reported by 3.2% and 4.5% of patients in UPA and PBO groups, respectively (Table 2). Similar rates of serious infection were observed in both groups (0.6%); 2 events each of herpes zoster and opportunistic infection were reported in UPA group. No active tuberculosis, malignancy, adjudicated major adverse cardiovascular events, or deaths were reported in the study. One patient with venous thromboembolism (deep vein thrombosis and pulmonary embolism) and 1 patient with gastrointestinal perforation were reported in the placebo group. Conclusion In U-ACCOMPLISH, 8-week UPA 45 mg QD induction treatment led to statistically significant improvements in clinical, endoscopic, and combined endoscopic-histologic endpoints. The treatment was well tolerated, and the safety profile and AE prevalence was comparable with previous studies of UPA with no new safety signals identified.

Abstract Background Endoscopic healing has become a critical treatment target in Crohn’s disease (CD). Risankizumab (RZB), a humanized immunoglobulin G1 monoclonal antibody against the p19 subunit of interleukin 23, is being investigated as a treatment for moderate-to-severe CD. This analysis assessed different endoscopic endpoints in patients treated with RZB induction therapy in two double-blind, randomised, placebo (PBO)-controlled studies (ADVANCE [NCT03104413] and MOTIVATE [NCT03105128]). Methods Patients with moderate-to-severe CD (CD Activity Index [CDAI] of 220–450, Simple Endoscopic Score for CD [SES-CD] ≥ 6 [≥ 4 for isolated ileal disease] excluding the narrowing component, and average daily [liquid/very soft] stool frequency [SF] ≥ 4 and/or average daily abdominal pain [AP] score ≥ 2) who had demonstrated prior inadequate response or intolerance to conventional and/or biologic treatment (ADVANCE) or to biologic treatment (MOTIVATE) were randomised 2:2:1 (ADVANCE) or 1:1:1 (MOTIVATE) to receive intravenous (IV) RZB 600 mg, RZB 1200 mg, or PBO at weeks 0, 4, and 8. This analysis evaluated the proportion of patients who achieved endoscopic remission ulcer-free endoscopy (ie, absence of ulcers), and composite endpoints of CDAI clinical response and endoscopic response, and enhanced clinical response and endoscopic response at week 12 (endpoints defined in Figure 1 footnotes). All endoscopies were centrally read by a blinded reviewer. Safety was assessed throughout the studies. Results In ADVANCE and MOTIVATE, 850 and 569 patients, respectively, were randomised and included in the intent-to-treat population for this analysis. At week 12 greater proportions of RZB- vs PBO-treated patients in both studies achieved endoscopic remission (P ≤ .001), ulcer-free endoscopy (P ≤ .01), CDAI clinical response and endoscopic response (P ≤ .001), and enhanced clinical response and endoscopic response (P ≤ .001; Figure 1). Treatment with RZB 600 mg or 1200 mg was well tolerated, and no new safety risks were identified.1,2 Conclusion Induction therapy with IV RZB 600 mg or 1200 mg resulted in improved outcomes at week 12 compared with PBO as assessed by endoscopy and by composite endoscopic-clinical endpoints in patients with moderate-to-severe CD. References

AbstractBiallelic loss‐of‐function variants in the thrombospondin‐type laminin G domain and epilepsy‐associated repeats (TSPEAR) gene have recently been associated with ectodermal dysplasia and hearing loss. The first reports describing a TSPEAR disease association identified this gene is a cause of nonsyndromic hearing loss, but subsequent reports involving additional affected families have questioned this evidence and suggested a stronger association with ectodermal dysplasia. To clarify genotype–phenotype associations for TSPEAR variants, we characterized 13 individuals with biallelic TSPEAR variants. Individuals underwent either exome sequencing or panel‐based genetic testing. Nearly all of these newly reported individuals (11/13) have phenotypes that include tooth agenesis or ectodermal dysplasia, while three newly reported individuals have hearing loss. Of the individuals displaying hearing loss, all have additional variants in other hearing‐loss‐associated genes, specifically TMPRSS3, GJB2, and GJB6, that present competing candidates for their hearing loss phenotype. When presented alongside previous reports, the overall evidence supports the association of TSPEAR variants with ectodermal dysplasia and tooth agenesis features but creates significant doubt as to whether TSPEAR variants are a monogenic cause of hearing loss. Further functional evidence is needed to evaluate this phenotypic association.