19 research outputs found
Distinct molecular profiles and immunotherapy treatment outcomes of V600E and V600K BRAF-mutant melanoma
Purpose: BRAF V600E and V600K melanomas have distinct clinicopathologic features, and V600K appear to be less responsive to BRAFi±MEKi. We investigated mechanisms for this and explored whether genotype affects response to immunotherapy.
Experimental Design: Pretreatment formalin-fixed paraffin-embedded tumors from patients treated with BRAFi±MEKi underwent gene expression profiling and DNA sequencing. Molecular results were validated using The Cancer Genome Atlas (TCGA) data. An independent cohort of V600E/K patients treated with anti–PD-1 immunotherapy was examined.
Results: Baseline tissue and clinical outcome with BRAFi±MEKi were studied in 93 patients (78 V600E, 15 V600K). V600K patients had numerically less tumor regression (median, −31% vs. −52%, P = 0.154) and shorter progression-free survival (PFS; median, 5.7 vs. 7.1 months, P = 0.15) compared with V600E. V600K melanomas had lower expression of the ERK pathway feedback regulator dual-specificity phosphatase 6, confirmed with TCGA data (116 V600E, 17 V600K). Pathway analysis showed V600K had lower expression of ERK and higher expression of PI3K-AKT genes than V600E. Higher mutational load was observed in V600K, with a higher proportion of mutations in PIK3R1 and tumor-suppressor genes. In patients treated with anti–PD-1, V600K (n = 19) had superior outcomes than V600E (n = 84), including response rate (53% vs. 29%, P = 0.059), PFS (median, 19 vs. 2.7 months, P = 0.049), and overall survival (20.4 vs. 11.7 months, P = 0.081).
Conclusions: BRAF V600K melanomas appear to benefit less from BRAFi±MEKi than V600E, potentially due to less reliance on ERK pathway activation and greater use of alternative pathways. In contrast, these melanomas have higher mutational load and respond better to immunotherapy.J.S. Wilmott is supported by an NHMRC Research Fellowship. J.L. McQuade is supported by an ASCO/CCF Career Development Award, a Melanoma SPORE Developmental Research Program Award, and an NIH T32 Training Grant CA009666. R.A. Scolyer is supported by an NHMRC Practitioner Fellowship. J.Y.H. Yang is supported by NHMRC CDF and ARC Discovery Project grant (DP170100654). G.V. Long is supported by an NHMRC Practitioner Fellowship and the University of Sydney Medical Foundation. A.M. Menzies is supported by a Cancer Institute NSW Fellowship. This work was supported by a Pfizer Australia grant (WS2345795 to A.M. Menzies), and a Cancer Council NSW grant (RG17-04 to J. Holst, J.S. Wilmott, and A.M. Menzies). This research was also supported by an Australian National Health and Medical Research Council program grant
IPATunity130: A pivotal randomized phase III trial evaluating ipatasertib (IPAT) + paclitaxel (PAC) for PIK3CA/AKT1/PTEN
Final results of the double-blind placebo-controlled randomized phase 2 LOTUS trial of first-line ipatasertib plus paclitaxel for inoperable locally advanced/metastatic triple-negative breast cancer
Purpose In LOTUS (NCT02162719), adding the oral AKT inhibitor ipatasertib to first-line paclitaxel for locally advanced/metastatic triple-negative breast cancer (aTNBC) improved progression-free survival (PFS; primary endpoint), with an enhanced effect in patients with PIK3CA/AKT1/PTEN-altered tumors (FoundationOne next-generation sequencing [NGS] assay). We report final overall survival (OS) results. Methods Eligible patients had measurable previously untreated aTNBC. Patients were stratified by prior (neo)adjuvant therapy, chemotherapy-free interval, and tumor immunohistochemistry PTEN status, and were randomized 1:1 to paclitaxel 80 mg/m(2) (days 1, 8, 15) plus ipatasertib 400 mg or placebo (days 1-21) every 28 days until disease progression or unacceptable toxicity. OS (intent-to-treat [ITT], immunohistochemistry PTEN-low, and PI3K/AKT pathway-activated [NGS PIK3CA/AKT1/PTEN-altered] populations) was a secondary endpoint. Results Median follow-up was 19.0 versus 16.0 months in the ipatasertib-paclitaxel versus placebo-paclitaxel arms, respectively. In the ITT population (n = 124), median OS was numerically longer with ipatasertib-paclitaxel than placebo-paclitaxel (hazard ratio 0.80, 95% CI 0.50-1.28; median 25.8 vs 16.9 months, respectively; 1-year OS 83% vs 68%). Likewise, median OS favored ipatasertib-paclitaxel in the PTEN-low (n = 48; 23.1 vs 15.8 months; hazard ratio 0.83) and PIK3CA/AKT1/PTEN-altered (n = 42; 25.8 vs 22.1 months; hazard ratio 1.13) subgroups. The ipatasertib-paclitaxel safety profile was unchanged. Conclusions Final OS results show a numerical trend favoring ipatasertib-paclitaxel and median OS exceeding 2 years with ipatasertib-paclitaxel. Overall, results are consistent with the reported PFS benefit; interpretation within biomarker-defined subgroups is complicated by small sample sizes and TNBC heterogeneity
Ipatasertib plus paclitaxel versus placebo plus paclitaxel as first-line therapy for metastatic triple-negative breast cancer (LOTUS): a multicentre, randomised, double-blind, placebo-controlled, phase 2 trial
The oral AKT inhibitor ipatasertib is being investigated in cancers with a high prevalence of PI3K/AKT pathway activation, including triple-negative breast cancer. The LOTUS trial investigated the addition of ipatasertib to paclitaxel as first-line therapy for triple-negative breast cancer
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Genomic Features of Exceptional Response in Vemurafenib ± Cobimetinib–treated Patients with BRAFV600-mutated Metastatic Melanoma
PurposePrevious investigations identified transcriptional signatures associated with innate resistance to anti-programmed cell death protein 1 therapy in melanoma. This analysis aimed to increase understanding of the role of baseline genetic features in the variability of response to BRAF and MEK inhibitor therapy for BRAF V600-mutated metastatic melanoma.Patients and methodsThis exploratory analysis compared genomic features, using whole-exome and RNA sequencing, of baseline tumors from patients who had complete response versus rapid progression (disease progression at first postbaseline assessment) on treatment with cobimetinib combined with vemurafenib or vemurafenib alone. Associations of gene expression with progression-free survival or overall survival were assessed by Cox proportional hazards modeling.ResultsWhole-exome sequencing showed that MITF and TP53 alterations were more frequent in tumors from patients with rapid progression, while NF1 alterations were more frequent in tumors from patients with complete response. However, the low frequency of alterations in any one gene precluded their characterization as drivers of response/resistance. Analysis of RNA profiles showed that expression of immune response-related genes was enriched in tumors from patients with complete response, while expression of keratinization-related genes was enriched in tumors from patients who experienced rapid progression.ConclusionsThese findings suggest that enriched immune infiltration might be a shared feature favoring response to both targeted and immune therapies, while features of innate resistance to targeted and immune therapies were distinct
Overall survival (OS) update of the double-blind placebo (PBO)-controlled randomized phase 2 LOTUS trial of first-line ipatasertib (IPAT) + paclitaxel (PAC) for locally advanced/metastatic triple-negative breast cancer (mTNBC).
Transcriptional Subtypes Resolve Tumor Heterogeneity and Identify Vulnerabilities to MEK Inhibition in Lung Adenocarcinoma
Tumor-intrinsic expression of the autophagy gene Atg16l1 suppresses anti-tumor immunity in colorectal cancer
Abstract Microsatellite-stable colorectal cancer (MSS-CRC) is highly refractory to immunotherapy. Understanding tumor-intrinsic determinants of immunotherapy resistance is critical to improve MSS-CRC patient outcomes. Here, we demonstrate that high tumor expression of the core autophagy gene ATG16L1 is associated with poor clinical response to anti-PD-L1 therapy in KRAS-mutant tumors from IMblaze370 (NCT02788279), a large phase III clinical trial of atezolizumab (anti-PD-L1) in advanced metastatic MSS-CRC. Deletion of Atg16l1 in engineered murine colon cancer organoids inhibits tumor growth in primary (colon) and metastatic (liver and lung) niches in syngeneic female hosts, primarily due to increased sensitivity to IFN-γ-mediated immune pressure. ATG16L1 deficiency enhances programmed cell death of colon cancer organoids induced by IFN-γ and TNF, thus increasing their sensitivity to host immunity. In parallel, ATG16L1 deficiency reduces tumor stem-like populations in vivo independently of adaptive immune pressure. This work reveals autophagy as a clinically relevant mechanism of immune evasion and tumor fitness in MSS-CRC and provides a rationale for autophagy inhibition to boost immunotherapy responses in the clinic