Faculty Bibliography

BACKGROUND:Cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors radically changed the treatment paradigm for breast cancer. Similar to estrogen receptor in breast cancer, androgen receptor signaling activates cyclin D-CDK4/6, driving proliferation and resistance to hormonal manipulation in prostate cancer. This study was designed to detect signals of clinical activity for abemaciclib in treatment-refractory metastatic castration-resistant prostate cancer (mCRPC). METHODS:Eligible patients had progressive mCRPC, measurable disease, and previously received ≥1 novel hormonal agent(s) and 2 lines of taxane chemotherapy. Abemaciclib 200 mg BID was administered on a continuous dosing schedule. Primary endpoint was objective response rate (ORR) without concurrent bone progression. This study was designed to detect a minimum ORR of 12.5%. RESULTS:At trial entry, forty (90.9%) of 44 patients had objective radiographic disease progression, four (9.1%) had prostate-specific antigen (PSA)-only progression, and 20 (46.5%) had visceral metastases (of these, 60% had liver metastases). Efficacy analyses are as follows: ORR without concurrent bone progression: 6.8%; disease control rate: 45.5%; median time to PSA progression: 6.5 months (95% CI: 3.2, NA); median radiographic PFS; 2.7 months (95% CI: 1.9, 3.7); and median OS: 8.4 months (95% CI: 5.6, 12.7). Most frequent grade ≥3 TEAEs were neutropenia (25.0%), anemia, and fatigue (11.4% each). No grade 4 or 5 AEs were related to abemaciclib. CONCLUSION/CONCLUSIONS:Abemaciclib monotherapy was well tolerated and showed clinical activity in this heavily pretreated population, nearly half with visceral metastases. This study is considered preliminary proof-of-concept and designates CDK4/6 as a valid therapeutic target in prostate cancer.

BACKGROUND:Dickkopf-related protein 1 (DKK1) is a Wingless-related integrate site (Wnt) signaling modulator that is upregulated in prostate cancers (PCa) with low androgen receptor expression. DKN-01, an IgG4 that neutralizes DKK1, delays PCa growth in pre-clinical DKK1-expressing models. These data provided the rationale for a clinical trial testing DKN-01 in patients with metastatic castration-resistant PCa (mCRPC). METHODS:(combination) for men with mCRPC who progressed on ≥1 AR signaling inhibitors. DKK1 status was determined by RNA in-situ expression. The primary endpoint of the phase 1 dose escalation cohorts was the determination of the recommended phase 2 dose (RP2D). The primary endpoint of the phase 2 expansion cohorts was objective response rate by iRECIST criteria in patients treated with the combination. RESULTS:18 pts were enrolled into the study-10 patients in the monotherapy cohorts and 8 patients in the combination cohorts. No DLTs were observed and DKN-01 600 mg was determined as the RP2D. A best overall response of stable disease occurred in two out of seven (29%) evaluable patients in the monotherapy cohort. In the combination cohort, five out of seven (71%) evaluable patients had a partial response (PR). A median rPFS of 5.7 months was observed in the combination cohort. In the combination cohort, the median tumoral DKK1 expression H-score was 0.75 and the rPFS observed was similar between patients with DKK1 H-score ≥1 versus H-score = 0. CONCLUSION/CONCLUSIONS:DKN-01 600 mg was well tolerated. DKK1 blockade has modest anti-tumor activity as a monotherapy for mCRPC. Anti-tumor activity was observed in the combination cohorts, but the response duration was limited. DKK1 expression in the majority of mCRPC is low and did not clearly correlate with anti-tumor activity of DKN-01 plus docetaxel.

Protein-losing enteropathy (PLE) is a well described entity, typically associated with autoimmune disorders such as Systemic Lupus Erythematosus (SLE). However, there is only one prior case reported on the association between PLE and the use of immune checkpoint inhibitors. We describe a case of PLE presenting in a patient in their 70"™s with muscle-invasive urothelial bladder cancer that developed while on treatment with pembrolizumab, radiation and gemcitabine for her cancer. The patient presented initially with progressive edema and hypoalbuminemia, and diffuse small bowel thickening on CT imaging without associated upper or lower gastrointestinal symptoms. Endoscopy with biopsy was performed demonstrating normal gastric and small bowel epithelium. A stool test for alpha-1-antitrypsin demonstrated increased clearance consistent with fecal protein loss and a diagnosis of PLE, presumed immune-related. She was promptly initiated on systemic corticosteroids with brisk resolution in her symptoms and normalization of serum albumin levels. Insights: This case highlights a rare immune-related adverse event, PLE, that should be considered in patients who develop hypoalbuminemia and its clinical sequelae after immune checkpoint inhibition therapy without evidence of colitis.

BACKGROUND:Evading immune surveillance is a hallmark for the development of multiple cancer types. Whether immune evasion contributes to the pathogenesis of high-grade prostate cancer (HGPCa) remains an area of active inquiry. METHODS:Through single-cell RNA sequencing and multicolor flow cytometry of freshly isolated prostatectomy specimens and matched peripheral blood, we aimed to characterize the tumor immune microenvironment (TME) of localized prostate cancer (PCa), including HGPCa and low-grade prostate cancer (LGPCa). RESULTS: TILs. The PCa TME was infiltrated by macrophages but these did not clearly cluster by M1 and M2 markers. CONCLUSIONS:T cell exhaustion in localized PCa, a finding enriched in HGPCa relative to LGPCa. These studies suggest a possible link between the clinical-pathologic risk of PCa and the associated TME. Our results have implications for our understanding of the immunologic mechanisms of PCa pathogenesis and the implementation of immunotherapy for localized PCa.

BACKGROUND:Progression-free survival was significantly longer in patients who received avelumab plus axitinib versus sunitinib as first-line treatment for advanced renal cell carcinoma (aRCC) in a randomized phase III trial. We report long-term safety and efficacy of avelumab plus axitinib as first-line treatment for patients with aRCC from the JAVELIN Renal 100 phase Ib trial (NCT02493751). MATERIALS AND METHODS/METHODS:In this open-label, multicenter, phase Ib study, patients with untreated aRCC received avelumab 10 mg/kg every 2 weeks plus axitinib 5 mg twice daily or with axitinib for 7 days followed by avelumab plus axitinib. Safety and efficacy were assessed in all patients receiving at least one dose of avelumab or axitinib. RESULTS:Overall, 55 patients were enrolled and treated. Median follow-up was 55.7 months (95% CI, 54.5-58.7). Treatment-related adverse events of any grade or grade ≥3 occurred in 54 (98.2%) and 34 (61.8%) patients, respectively. The confirmed objective response rate was 60.0% (95% CI, 45.9-73.0), including complete response in 10.9% of patients. Median duration of response was 35.9 months (95% CI, 12.7-52.9); the probability of response was 65.8% (95% CI, 46.7-79.4) at 2 years. Median progression-free survival was 8.3 months (95% CI, 5.3-32.0). Median overall survival was not reached (95% CI, 40.8-not estimable); the 5-year overall survival rate was 57.3% (95% CI, 41.2-70.5). CONCLUSION/CONCLUSIONS:Five-year follow-up for combination treatment with avelumab plus axitinib in previously untreated patients with aRCC showed long-term clinical activity with no new safety signals, supporting use of this regimen within its approved indication in clinical practice (Clinicaltrials.gov NCT02493751).

BACKGROUND:Immune checkpoint inhibitors are a standard therapy in metastatic urothelial carcinoma (UC). Long-term follow-up is necessary to confirm durability of response and identify further safety concerns. PATIENTS AND METHODS/METHODS:In KEYNOTE-045, patients with metastatic UC that progressed on platinum-containing chemotherapy were randomly assigned 1:1 to receive pembrolizumab or investigator's choice of paclitaxel, docetaxel, or vinflunine. Primary end points were progression-free survival (PFS) per RECIST v1.1 by blinded independent central review (BICR) and overall survival (OS). In KEYNOTE-052, cisplatin-ineligible patients with metastatic UC received first-line pembrolizumab. The primary end point was objective response rate (ORR) per RECIST v1.1 by BICR. RESULTS:A total of 542 patients (pembrolizumab, n = 270; chemotherapy, n = 272) were randomly assigned in KEYNOTE-045. Median follow-up was 62.9 months (range, 58.6-70.9; data cutoff October 1, 2020). At 48 months, OS rates were 16.7% for pembrolizumab and 10.1% for chemotherapy; PFS rates were 9.5% and 2.7%, respectively. Median duration of response (DOR) was 29.7 months (range, 1.6+ to 60.5+) for pembrolizumab and 4.4 months (range, 1.4+ to 63.1+) for chemotherapy; 36-month DOR rates were 44.4% and 28.3%, respectively. A total of 370 patients were enrolled in KEYNOTE-052. Median follow-up was 56.3 months (range, 51.2-65.3; data cutoff September 26, 2020). Confirmed ORR was 28.9% (95% CI, 24.3-33.8), and median DOR was 33.4 months (range, 1.4+ to 60.7+); 36-month DOR rate was 44.8%. Most treatment-related adverse events for pembrolizumab in either study were grade 1 or 2 and manageable, which is consistent with prior reports. CONCLUSION/CONCLUSIONS:With approximately 5 years of follow-up, pembrolizumab monotherapy continued to demonstrate durable efficacy with no new safety signals in patients with platinum-resistant metastatic UC and as first-line therapy in cisplatin-ineligible patients. Clinical trial registry and ID: ClinicalTrials.gov, NCT02256436 (KEYNOTE-045) and NCT02335424 (KEYNOTE-052).

Erdheim-Chester disease (ECD) is a rare clonal histiocytic process that is characterized by a foamy (xanthomatous) proliferation often associated with Touton giant cells. The diagnosis is often challenging and not exclusively a histologic diagnosis, as it requires correlation with unique clinical, radiographic and recently described molecular findings. Activating mutations involving the MAPK pathway including BRAF, ARAF, N/KRAS and MEK are recurrent in the disease. However, it is increasingly being described that mutations associated with clonal hematopoiesis are also found in bone marrow specimens of patients with Erdheim-Chester disease (ECD), as well as higher frequency of overt concomitant myeloid malignancy including acute myeloid leukemia, myeloproliferative neoplasms, myelodysplastic syndromes, and mixed myeloproliferative neoplasms/myelodysplastic syndromes. Herein, we report a unique case of a patient presenting with BRAF-V600E-positive ECD with with peripheral blood findings consistent with a concurrent myeloid malignancy featuring co-occurrence of NRAS and IDH-2 mutations.

PURPOSE/OBJECTIVE:In an exploratory analysis, we investigated the association between PD-L1, TMB, T-cell-inflamed gene expression profile (TcellinfGEP), and stromal signature with outcomes of pembrolizumab in urothelial carcinoma (UC). EXPERIMENTAL DESIGN/METHODS:Patients with advanced UC received first-line pembrolizumab 200mg Q3W in the single-arm phase 2 KEYNOTE-052 trial (NCT02335424) and salvage pembrolizumab 200mg Q3W or chemotherapy (paclitaxel/docetaxel/vinflunine) in the randomized phase 3 KEYNOTE-045 trial (NCT02256436). The association of each biomarker (continuous variable) with ORR, PFS, and OS was evaluated using logistic regression (ORR) and Cox PH (PFS, OS), adjusted for ECOG PS; nominal P values were calculated without multiplicity adjustment (one-sided, pembrolizumab; two-sided, chemotherapy). Significance was prespecified at α=0.05. RESULTS:In KEYNOTE-052, PD-L1, TMB, and TcellinfGEP were significantly associated with improved outcomes; stromal signature was significantly associated with worse outcomes. In KEYNOTE-045, although findings for TMB and TcellinfGEP with pembrolizumab were consistent with those of KEYNOTE-052, PD-L1 was not significantly associated with improved outcomes nor was stromal signature associated with worse outcomes with pembrolizumab; chemotherapy was not associated with outcomes in a consistent manner for any of the biomarkers. HR estimates at prespecified cutoffs showed an advantage for pembrolizumab versus chemotherapy regardless of PD-L1 or TMB, with a trend toward lower HRs in the CPS{greater than or equal to}10 and the TMB{greater than or equal to}175 mutation/exome subgroup. For TcellinfGEP, PFS and OS HRs were lower in the TcellinfGEP-nonlow subgroup regardless of treatment. CONCLUSION/CONCLUSIONS:Multiple biomarkers characterizing the tumor microenvironment may help predict response to pembrolizumab monotherapy in UC and potential clinical utility of these biomarkers may be context-dependent.

BACKGROUND:The EV-201 trial (NCT03219333) demonstrated a clinically meaningful and durable response rate and a tolerable safety profile with enfortumab vedotin (EV) in patients with locally advanced/metastatic urothelial carcinoma (LA/mUC) treated with prior PD-1/PD-L1 inhibitor therapy and platinum-containing chemotherapy (cohort 1). Patient-reported outcome (PRO) measures were included in EV-201 as exploratory endpoints. OBJECTIVE:To evaluate PRO data for cohort 1 of EV-201 to better understand the relationship between EV therapy and health-related quality of life (HRQoL). DESIGN, SETTING, AND PARTICIPANTS/METHODS:Enrolled patients with LA/mUC who received EV were invited to electronically complete two HRQoL instruments (EORTC QLQ-C30 and EQ-5D-3L) at baseline and day 1 of each cycle until treatment discontinuation. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS/UNASSIGNED:Patient demographics, completion and compliance rates, and PRO scores were analysed using descriptive statistics. Selected EORTC QLQ-C30 scores were analysed post hoc using a repeated-measures mixed model. RESULTS AND LIMITATIONS/CONCLUSIONS:Among treated patients (n = 125), 95% completed both baseline questionnaires. Compliance rates were ≥86% throughout the study. Descriptive analyses showed that global health status, physical functioning, and symptom scores remained stable over time, with average scores similar at each cycle. Lower pain and fatigue scores were observed in responders at cycles following an objective response. Pain was lower at cycle 3 than at baseline in patients with bone metastases. Mean EQ-5D-3L utility score (0.80 at baseline; range from 0.77 at cycle 2 to 0.91 at cycle 10) and visual analogue scale scores (66.9 at baseline; range from 65.5 at cycle 2 to 78.4 at cycle 10) remained similar over time. Variability and the small sample size limited definitive conclusions. CONCLUSIONS:PRO scores remained stable throughout EV treatment, further supporting the overall value of EV in the treatment of patients with LA/mUC. The potential benefit of EV therapy on overall HRQoL and symptoms such as pain and fatigue is currently being explored. PATIENT SUMMARY/UNASSIGNED:In this study of adult patients with advanced cancer of the urinary tract that progressed after previous medications, quality of life, ability to function, and symptoms did not worsen on treatment with enfortumab vedotin, which is an antibody + drug combination. Some improvements in pain and fatigue were reported by patients, but further research needs to be conducted. These data complement the efficacy and safety data from the EV-201 trial.

PURPOSE/OBJECTIVE:Neoadjuvant gemcitabine and cisplatin (GC) followed by radical cystectomy (RC) is standard for patients with muscle-invasive bladder cancer (MIBC). On the basis of the activity of atezolizumab (A) in metastatic BC, we tested neoadjuvant GC plus A for MIBC. METHODS:Eligible patients with MIBC (cT2-T4aN0M0) received a dose of A, followed 2 weeks later by GC plus A every 21 days for four cycles followed 3 weeks later by a dose of A before RC. The primary end point was non-muscle-invasive downstaging to < pT2N0. RESULTS:= .3 for association between PD-L1 and < pT2N0). CONCLUSION/CONCLUSIONS:Neoadjuvant GC plus A is a promising regimen for MIBC and warrants further study. Patients with < pT2N0 experienced improved relapse-free survival. The PD-L1 positivity rate was low compared with published data, which limits conclusions regarding PD-L1 as a predictive biomarker.