Deciphering radiological stable disease to immune checkpoint inhibitors.

BACKGROUND: 'Stable disease (SD)' as per RECIST is a common but ambiguous outcome in patients receiving immune checkpoint inhibitors (ICIs). This study aimed to characterize SD and identify the subset of patients with SD who are benefiting from treatment. Understanding SD would facilitate drug development and improve precision in correlative research. PATIENTS AND METHODS: A systematic review was carried out to characterize SD in ICI trials. SD and objective response were compared to proliferation index using The Cancer Genome Atlas gene expression data. To identify a subgroup of SD with outcomes mirroring responders, we examined a discovery cohort of non-small-cell lung cancer (NSCLC). Serial cutpoints of two variables, % best overall response and progression-free survival (PFS), were tested to define a subgroup of patients with SD with similar survival as responders. Results were then tested in external validation cohorts. RESULTS: Among trials of ICIs (59 studies, 14 280 patients), SD ranged from 16% to 42% in different tumor types and was associated with disease-specific proliferation index (ρ = -0.75, P = 0.03), a proxy of tumor kinetics, rather than relative response to ICIs. In a discovery cohort of NSCLC [1220 patients, 313 (26%) with SD to ICIs], PFS ranged widely in SD (0.2-49 months, median 4.9 months). The subset with PFS >6 months and no tumor growth mirrored partial response (PR) minor (overall survival hazard ratio 1.0) and was proposed as the definition of SD responder. This definition was confirmed in two validation cohorts from trials of NSCLC treated with durvalumab and found to apply in tumor types treated with immunotherapy in which depth and duration of benefit were correlated. CONCLUSIONS: RECIST-defined SD to immunotherapy is common, heterogeneous, and may largely reflect tumor growth rate rather than ICI response. In patients with NSCLC and SD to ICIs, PFS >6 months and no tumor growth may be considered 'SD responders'. This definition may improve the efficiency of and insight derivable from clinical and translational research.

IgE blockade with omalizumab reduces pruritus related to immune checkpoint inhibitors and anti-HER2 therapies.

BACKGROUND: Immunoglobulin E (IgE) blockade with omalizumab has demonstrated clinical benefit in pruritus-associated dermatoses (e.g. atopic dermatitis, bullous pemphigoid, urticaria). In oncology, pruritus-associated cutaneous adverse events (paCAEs) are frequent with immune checkpoint inhibitors (CPIs) and targeted anti-human epidermal growth factor receptor 2 (HER2) therapies. Thus, we sought to evaluate the efficacy and safety of IgE blockade with omalizumab in cancer patients with refractory paCAEs related to CPIs and anti-HER2 agents. PATIENTS AND METHODS: Patients included in this multicenter retrospective analysis received monthly subcutaneous injections of omalizumab for CPI or anti-HER2 therapy-related grade 2/3 pruritus that was refractory to topical corticosteroids plus at least one additional systemic intervention. To assess clinical response to omalizumab, we used the Common Terminology Criteria for Adverse Events version 5.0. The primary endpoint was defined as reduction in the severity of paCAEs to grade 1/0. RESULTS: A total of 34 patients (50% female, median age 67.5 years) received omalizumab for cancer therapy-related paCAEs (71% CPIs; 29% anti-HER2). All had solid tumors (29% breast, 29% genitourinary, 15% lung, 26% other), and most (n = 18, 64%) presented with an urticarial phenotype. In total 28 of 34 (82%) patients responded to omalizumab. The proportion of patients receiving oral corticosteroids as supportive treatment for management of paCAEs decreased with IgE blockade, from 50% to 9% (P < 0.001). Ten of 32 (31%) patients had interruption of oncologic therapy due to skin toxicity; four of six (67%) were successfully rechallenged following omalizumab. There were no reports of anaphylaxis or hypersensitivity reactions related to omalizumab. CONCLUSIONS: IgE blockade with omalizumab demonstrated clinical efficacy and was well tolerated in cancer patients with pruritus related to CPIs and anti-HER2 therapies.

Outcomes of patients with metastatic clear-cell renal cell carcinoma treated with second-line VEGFR-TKI after first-line immune checkpoint inhibitors.

BACKGROUND: Immune checkpoint inhibitors (ICIs) are being increasingly utilised in the front-line (1L) setting of metastatic clear-cell renal cell carcinoma (mccRCC). Limited data exist on responses and survival on second-line (2L) vascular endothelial growth factor-receptor tyrosine kinase inhibitor (VEGFR-TKI) therapy after 1L ICI therapy. PATIENTS AND METHODS: This is a retrospective study of mccRCC patients treated with 2L VEGFR-TKI after progressive disease (PD) with 1L ICI. Patients were treated at MD Anderson Cancer Center or Memorial Sloan Kettering Cancer Center between December 2015 and February 2018. Objective response was assessed by blinded radiologists' review using Response Evaluation Criteria in Solid Tumours v1.1. Descriptive statistics and Kaplan-Meier method were used. RESULTS: Seventy patients were included in the analysis. Median age at mccRCC diagnosis was 59 years; 8 patients (11%) had international metastatic database consortium favourable-risk disease, 48 (69%) had intermediate-risk disease and 14 (20%) had poor-risk disease. As 1L therapy, 12 patients (17%) received anti-programmed death ligand-1 (PD-(L)1) monotherapy with nivolumab or atezolizumab, 33 (47%) received nivolumab plus ipilimumab and 25 (36%) received combination anti-PD-(L)1 plus bevacizumab. 2L TKI therapies included pazopanib, sunitinib, axitinib and cabozantinib. On 2L TKI therapy, one patient (1.5%) achieved a complete response, 27 patients (39.7%) a partial response and 36 patients (52.9%) stable disease. Median progression-free survival (mPFS) was 13.2 months (95% confidence interval: 10.1, NA). Forty-five percent of subjects required a dose reduction, and twenty-seven percent of patients discontinued treatment because of toxicity. CONCLUSIONS: In this retrospective study of patients with mccRCC receiving 2L TKI monotherapy after 1L ICI, we observed 2L antitumour activity and tolerance comparable to historical data for 1L TKI.

Immune checkpoint inhibitors in MITF family translocation renal cell carcinomas and genetic correlates of exceptional responders.

BACKGROUND: Microphthalmia Transcription Factor (MITF)family translocation renal cell carcinoma (tRCC) is a rare RCC subtype harboring TFE3/TFEB translocations. The prognosis in the metastatic (m) setting is poor. Programmed death ligand-1 expression was reported in 90% of cases, prompting us to analyze the benefit of immune checkpoint inhibitors (ICI) in this population. PATIENTS AND METHODS: This multicenter retrospective study identified patients with MITF family mtRCC who had received an ICI in any of 12 referral centers in France or the USA. Response rate according to RECIST criteria, progression-free survival (PFS), and overall survival (OS) were analyzed. Genomic alterations associated with response were determined for 8 patients. RESULTS: Overall, 24 patients with metastatic disease who received an ICI as second or later line of treatment were identified. Nineteen (82.6%) of these patients had received a VEGFR inhibitor as first-line treatment, with a median PFS of 3 months (range, 1-22 months). The median PFS for patients during first ICI treatment was 2.5 months (range, 1-40 months); 4 patients experienced partial response (16,7%) and 3 (12,5%) had stable disease. Of the patients whose genomic alterations were analyzed, two patients with mutations in bromodomain-containing genes (PBRM1 and BRD8) had a clinical benefit. Resistant clones in a patient with exceptional response to ipilimumab showed loss of BRD8 mutations and increased mutational load driven by parallel evolution affecting 17 genes (median mutations per gene, 3), which were enriched mainly for O-glycan processing (29.4%, FDR = 9.7 × 10- 6). CONCLUSIONS: MITF family tRCC is an aggressive disease with similar responses to ICIs as clear-cell RCC. Mutations in bromodomain-containing genes might be associated with clinical benefit. The unexpected observation about parallel evolution of genes involved in O-glycosylation as a mechanism of resistance to ICI warrants exploration.

A randomized phase II trial of CRLX101 in combination with bevacizumab versus standard of care in patients with advanced renal cell carcinoma.

BACKGROUND: Nanoparticle-drug conjugates enhance drug delivery to tumors. Gradual payload release inside cancer cells augments antitumor activity while reducing toxicity. CRLX101 is a novel nanoparticle-drug conjugate containing camptothecin, a potent inhibitor of topoisomerase I and the hypoxia-inducible factors 1α and 2α. In a phase Ib/2 trial, CRLX101 + bevacizumab was well tolerated with encouraging activity in metastatic renal cell carcinoma (mRCC). We conducted a randomized phase II trial comparing CRLX101 + bevacizumab versus standard of care (SOC) in refractory mRCC. PATIENTS AND METHODS: Patients with mRCC and 2-3 prior lines of therapy were randomized 1 : 1 to CRLX101 + bevacizumab versus SOC, defined as investigator's choice of any approved regimen not previously received. The primary end point was progression-free survival (PFS) by blinded independent radiological review in patients with clear cell mRCC. Secondary end points included overall survival, objective response rate and safety. RESULTS: In total, 111 patients were randomized and received ≥1 dose of drug (CRLX101 + bevacizumab, 55; SOC, 56). Within the SOC arm, patients received single-agent bevacizumab (19), axitinib (18), everolimus (7), pazopanib (4), sorafenib (4), sunitinib (2), or temsirolimus (2). In the clear cell population, the median PFS on the CRLX101 + bevacizumab and SOC arms was 3.7 months (95% confidence interval, 2.0-4.3) and 3.9 months (95% confidence interval 2.2-5.4), respectively (stratified log-rank P = 0.831). The objective response rate by IRR was 5% with CRLX101 + bevacizumab versus 14% with SOC (Mantel-Haenszel test, P = 0.836). Consistent with previous studies, the CRLX101 + bevacizumab combination was generally well tolerated, and no new safety signal was identified. CONCLUSIONS: Despite promising efficacy data on the earlier phase Ib/2 trial of mRCC, this randomized trial did not demonstrate improvement in PFS for the CRLX101 + bevacizumab combination when compared with approved agents in patients with heavily pretreated clear cell mRCC. Further development in this disease is not planned. CLINICAL TRIAL IDENTIFICATION: NCT02187302 (NIH).

Genomic Alterations and Outcomes with VEGF-Targeted Therapy in Patients with Clear Cell Renal Cell Carcinoma.

Background: Mutations in VHL, PBRM1, SETD2, BAP1, and KDM5C are common in clear cell renal cell carcinoma (ccRCC), and presence of certain mutations has been associated with outcomes in patients with non-metastatic disease. Limited information is available regarding the correlation between genomic alterations and outcomes in patients with metastatic disease, including response to VEGF-targeted therapy. Objective: To explore correlations between mutational profiles and cancer-specific outcomes, including response to standard VEGF-targeted agents, in patients with metastatic cc RCC. Methods: A retrospective review of 105 patients with metastatic ccRCC who had received systemic therapy and had targeted next-generation sequencing of tumors was conducted. Genomic alterations were correlated to outcomes, including overall survival and time to treatment failure to VEGF-targeted therapy. Results: The most frequent mutations were detected in VHL (83%), PBRM1 (51%), SETD2 (35%), BAP1 (24%), KDM5C (16%), and TERT (14%). Time to treatment failure with VEGF-targeted therapy differed significantly by PBRM1 mutation status (p = 0.01, median 12.0 months for MT versus 6.9 months for WT) and BAP1 mutation status (p = 0.01, median 6.4 months for MT versus 11.0 months for WT). Shorter overall survival was associated with TERT mutations (p = 0.03, median 29.6 months for MT versus 52.6 months for WT) or BAP1 mutations (p = 0.02, median 28.7 months for MT versus not reached for WT). Conclusions: Genomic alterations in ccRCC tumors have prognostic implications in patients with metastatic disease. BAP1 and TERT promoter mutations may be present in higher frequency than previously thought, and based on this data, deserve further study for their association with poor prognosis.

Safety and clinical activity of vascular endothelial growth factor receptor (VEGFR)-tyrosine kinase inhibitors after programmed cell death 1 inhibitor treatment in patients with metastatic clear cell renal cell carcinoma.

BACKGROUND: Emerging agents blocking the programmed cell death 1 (PD-1) pathway show activity in metastatic clear cell renal cell carcinoma (mRCC). The aim of this study was to evaluate the efficacy and safety of vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR)-tyrosine kinase inhibitor (TKI) therapy after PD-1 inhibition. PATIENTS AND METHODS: Patients with mRCC treated with anti-PD-1 antibody (aPD-1) monotherapy or in combination (with VEGFR-TKI or ipilimumab) that subsequently received VEGFR-TKI were retrospectively reviewed. The efficacy end points were objective response rate (ORR) and progression-free survival (PFS) stratified by the type of prior PD-1 regimen. Safety by the type and PD-1 exposure was also evaluated. RESULTS: Seventy patients were included. Forty-nine patients received prior therapy with immune checkpoint inhibitors (CPIs) alone and 21 had combination therapy of aPD-1 and VEGFR-TKI. Overall, ORR to VEGFR-TKI after PD-1 inhibition was 28% (19/68) and the median PFS was 6.4 months (mo) (4.3-9.5). ORR to VEGFR-TKI after aPD-1 in combination with VEGFR-TKI was lower than that in patients treated with VEGFR-TKI after CPI alone (ORR 10% versus 36%, P = 0.039). In the multivariable analysis, patients treated with prior CPI alone were more likely to achieve an objective response than those treated with aPD-1 in combination with VEGFR-TKI (OR = 5.38; 95% CI 1.12-26.0, P = 0.03). There was a trend toward numerically longer median PFS in the VEGFR-TKI after the CPI alone group, 8.4 mo (3.2-12.4) compared with 5.5 mo (2.9-8.3) for those who had VEGFR-TKI after aPD-1 in combination with VEGFR-TKI (P = 0.15). The most common adverse events (AEs) were asthenia, hypertension, and diarrhea. CONCLUSIONS: The efficacy and safety of VEGFR-TKIs after PD-1 inhibition were demonstrated in this retrospective study. The response rate was lower and the median progression-free survival was shorter in those patients who received prior PD-1 in combination with VEGFR-TKI. PD-1 exposure does not seem to significantly influence the safety of subsequent VEGFR-TKI treatment.

Treatment outcome with mTOR inhibitors for metastatic renal cell carcinoma with nonclear and sarcomatoid histologies.

BACKGROUND: The clinical trials that reported benefit of the rapalogs temsirolimus and everolimus in advanced renal cell carcinoma (RCC) were primarily conducted in patients with clear-cell histology (ccRCC). We assessed outcome with these mammalian target of rapamicin (mTOR) inhibitors in two subsets of kidney cancer: sarcomatoid variant ccRCC and nonclear-cell RCC. PATIENTS AND METHODS: Baseline clinical features, information on prior treatment, and histologic subtypes were collected for patients previously treated with rapalogs for metastatic RCC of either nonclear phenotype or ccRCC with sarcomatoid features. Outcome was assessed centrally by a dedicated research radiologist for determination of tumor response, progression-free survival (PFS), and overall survival (OS). RESULTS: Eighty-five patients received temsirolimus (n = 59) or everolimus (n = 26). Nonclear-cell phenotypes included papillary (n = 14), chromophobe (n = 9), collecting duct (n = 4), translocation-associated (n = 3), and unclassified (n = 32) RCC. Twenty-three patients had clear-cell histology with sarcomatoid features. The response rate in assessable patients (n = 82) was 7% (all partial responses); 49% of patients achieved stable disease, and 44% had progressive disease as their best response. Tumor shrinkage was observed in 26 patients (32%). Median PFS and OS were 2.9 and 8.7 months, respectively. Nine patients (11%) were treated for ≥1 year, including cases of papillary (n = 3), chromophobe (n = 2), unclassified (n = 3) RCC, and ccRCC with sarcomatoid features (n = 1). No tumor shrinkages were observed for patients with collecting duct or translocation-associated RCC. CONCLUSIONS: A subset of patients with nonclear-cell and sarcomatoid variant ccRCC subtypes benefit from mTOR inhibitors, but most have poor outcome. Histologic subtype does not appear to be helpful in selecting patients for rapalog therapy. Future efforts should include the identification of predictive tissue biomarkers.

Importance of day 21 BM chimerism in sustained neutrophil engraftment following double-unit cord blood transplantation.

Delayed or failed engraftment remains a concern after cord blood transplantation (CBT) even when using double-unit grafts. Therefore, we analyzed the association between BM assessment performed approximately 21 days after transplantation, and the speed and success of sustained donor-derived neutrophil engraftment in 56 myeloablative double-unit CBT (DCBT) recipients. Overall, the cumulative incidence of sustained neutrophil engraftment was 95% (95% confidence intervals (CI): 89-100). Of the percentage of myeloid precursors, the BM cellularity and the total donor chimerism the total donor chimerism percentage had the most critical association with the speed and success of engraftment. DCBT recipients who were 100% donor achieved a 98% engraftment rate at a median of 22 days. This compared with 100% engraftment in patients who were 90-99% donor, but at a delayed median of 29 days and only 68% engraftment in patients <90% donor at a median of 37 days (P=0.001). Multivariate analysis was performed in the subgroup of patients who had not engrafted at the time the BM analysis was performed, the subgroup of most clinical concern. This confirmed donor chimerism was predictive of subsequent neutrophil recovery (P=0.004). These findings demonstrate the importance of the day 21 BM chimerism determinations after DCBT.