Brant Inman

Molecular profiling studies have shown that 85% of canine urothelial carcinomas (UC) harbor an activating BRAF V595E mutation, which is orthologous to the V600E variant found in several human cancer subtypes. In dogs, this mutation provides both a powerful diagnostic marker and a potential therapeutic target; however, due to their relative infrequency, the remaining 15% of cases remain understudied at the molecular level. We performed whole exome sequencing analysis of 28 canine urine sediments exhibiting the characteristic DNA copy number signatures of canine UC, in which the BRAF V595E mutation was undetected (UDV595E specimens). Among these we identified 13 specimens (46%) harboring short in-frame deletions within either BRAF exon 12 (7/28 cases) or MAP2K1 exons 2 or 3 (6/28 cases). Orthologous variants occur in several human cancer subtypes and confer structural changes to the protein product that are predictive of response to different classes of small molecule MAPK pathway inhibitors. DNA damage response and repair genes, and chromatin modifiers were also recurrently mutated in UDV595E specimens, as were genes that are positive predictors of immunotherapy response in human cancers. Our findings suggest that short in-frame deletions within BRAF exon 12 and MAP2K1 exons 2 and 3 in UDV595E cases are alternative MAPK-pathway activating events that may have significant therapeutic implications for selecting first-line treatment for canine UC. We developed a simple, cost-effective capillary electrophoresis genotyping assay for detection of these deletions in parallel with the BRAF V595E mutation. The identification of these deletion events in dogs offers a compelling cross-species platform in which to study the relationship between somatic alteration, protein conformation, and therapeutic sensitivity.

BACKGROUND: Bacille Calmette-Guérin (BCG) is the standard therapy after transurethral resection of bladder tumour for high-risk non-muscle-invasive bladder cancer (NMIBC). However, post-BCG recurrence/progression occurs frequently, and noncystectomy options are limited. OBJECTIVE: To evaluate the safety and clinical activity of atezolizumab ± BCG in high-risk BCG-unresponsive NMIBC. DESIGN, SETTING, AND PARTICIPANTS: This phase 1b/2 GU-123 study (NCT02792192) treated patients with BCG-unresponsive NMIBC who had carcinoma in situ with atezolizumab ± BCG. INTERVENTION: Patients in cohorts 1A and 1B received atezolizumab 1200 mg IV q3w for ≤96 wk. Those in cohort 1B also received standard BCG induction (six weekly doses) and maintenance courses (three doses weekly starting at month 3) with optional maintenance at 6, 12, 18, 24, and 30 mo. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Coprimary endpoints were safety and 6-mo complete response (CR) rate. Secondary endpoints included 3-mo CR rate and duration of CR; 95% confidence intervals were calculated using the Clopper-Pearson method. RESULTS AND LIMITATIONS: At data cut-off (September 29, 2020), 24 patients were enrolled (cohort 1A, n = 12; cohort 1B, n = 12), and the recommended BCG dose was 50 mg in cohort 1B. Four patients (33%) had adverse events (AEs) leading to BCG dose modification/interruption. Three patients (25%) in cohort 1A reported atezolizumab-related grade 3 AEs; cohort 1B had no atezolizumab- or BCG-related grade ≥3 AEs. No grade 4/5 AEs were reported. The 6-mo CR rate was 33% in cohort 1A (median duration of CR, 6.8 mo) and 42% in cohort 1B (median duration of CR, not reached [≥12 mo]). These results are limited by the small sample size of GU-123. CONCLUSIONS: In this first report of the atezolizumab-BCG combination in NMIBC, atezolizumab ± BCG was well tolerated, with no new safety signals or treatment-related deaths. Preliminary results suggested clinically meaningful activity; the combination favoured a longer duration of response. PATIENT SUMMARY: We studied atezolizumab with and without bacille Calmette-Guérin (BCG) to determine whether this combination was safe and had clinical activity in patients with high-risk noninvasive bladder cancer (high-grade bladder tumours that affect the outermost lining of the bladder wall) that has previously been treated with BCG and is still present or occurred again. Our results suggest that atezolizumab with or without BCG was generally safe and could be used to treat patients unresponsive to BCG.

PURPOSE: Renal function outcomes between radical nephroureterectomy (RNU) and nephron-sparing surgery (NSS) for upper tract urothelial carcinoma (UTUC) patients are not well established. We sought to compare the incidence and factors associated with development of advanced chronic kidney disease (CKD) between RNU and NSS and examine the role of acute kidney injury (AKI) on renal function outcomes. METHODS: We retrospectively analyzed an institutional database for patients who underwent either RNU or NSS for UTUC. Cumulative incidence of postoperative advanced CKD, defined as eGFR < 30 ml/min/1.73 m2, was compared between groups. Fine-Gray competing risk regression was used to identify predictors of advanced CKD. Locally weight scatterplot smoothing was used to assess postoperative eGFR trends. AKI events were counted, staged, and assessed for influence of progression to advanced CKD. RESULTS: Four hundred and twenty-six patients were included in analysis, with a median follow up of 6.68 years (IQR 3.4-12.2). Median preoperative eGFR was similar between the groups (NSS: 68 ml/min/1.73 m2, RNU: 65 ml/min/1.73 m2,P = 0.220). Cumulative incidence of advanced CKD was significantly lower in the NSS cohort (P = 0.009). Factors associated with advanced CKD included age, diabetes, recurrent AKI and RNU. Percent of patients with an AKI event differed between the groups (51.5% NSS, 72.7% RNU, P = <0.001), there was no between group difference in percentage of patients with recurrent AKI (25.6% NSS, 25.9% RNU, P =1). CONCLUSION: NSS provides a renal function benefit in UTUC. AKI is common among UTUC patients and recurrent AKI is a risk factor for development of advanced CKD.