The gut wall's potential as a partner for precision oncology in immune checkpoint treatment

The gut wall is the largest immune organ and forms a barrier through which gut microbiota interact with the immune system in the rest of the body. Gut microbiota composition plays a role in the strength and timing of the anticancer immune response on immune checkpoint inhibitors (ICI). Surprisingly, the effects of gut wall characteristics, such as physical barrier integrity, permeability, and activity and composition of the intestinal immune system, on response to ICI has received little attention. Here, we provide an overview of markers to characterize the gut wall and interventions that can modulate these gut wall characteristics. Finally, we present a future perspective on how these gut wall markers and interventions might be utilized and studied to improve ICI treatment strategies

Treatment costs and quality of life with granulocyte-macrophage colony-stimulating factor in patients with antineoplastic therapy-related febrile neutropenia:Results of a randomised placebo-controlled trial

This study examined the costs of treatment of, and quality of life in, patients with antineoplastic therapy-induced neutropenic fever who were treated with antibacterials, with or without granulocyte-macrophage colony-stimulating factor (GM-CSF). Patients with haematological malignancies (n = 47) or solid tumours (n = 87) who had severe neutropenia (neutrophil count &lt;0.5 x 109/L) and fever (&gt;38.5°C once, or &gt;38°C twice, in a 12-hour observation period) were randomised to receive subcutaneous GM-CSF 5 μg/kg/day (n = 65) or placebo (n = 69) in conjunction with broad-spectrum antibacterials. GM-CSF enhanced neutrophil recovery compared with placebo. Median neutrophil counts at day 4 were 2.9 (range 0 to 25) x 109/L in the GM-CSF arm and 1.3 (range 0 to 9) x 109/L in the placebo group (p &lt; 0.001). No significant difference was observed with regard to median days with neutrophil count ≤1.0 x 109/L or in time to resolution of fever. Quality-of-life scores in 90 patients demonstrated significant differences in favour of the placebo group. The results for the oncology and haematology patients were similar to the results for the total group. patients in the GM-CSF and placebo groups had a mean hospital stay of 7.25 and 8.33 days, respectively. Hospital costs were higher for the GM-CSF-treated patients when GM-CSF was included in the price [mean costs: GM-CSF arm $US5177 vs placebo arm$US4178 (p &lt; 0.05; 1992 values)l. The haematology patients stayed longer in hospital than the oncology patients, resulting in higher total costs for the former group. These results indicate that GM-CSF does not affect the number of days required for resolution of fever or the hospitalisation period for this patient group, and does not provide a cost-effective contribution to the treatment of these patients. Sensitivity analyses indicate that GM-CSF would produce savings if the duration of hospitalisation with GM-CSF was ≤76.5% of that in the placebo group.</p

Combining Simvastatin with the Farnesyltransferase Inhibitor Tipifarnib Results in an Enhanced Cytotoxic Effect in a Subset of Primary CD34 +

Purpose: To show whether the inhibitory effects of the cholesterol synthesis inhibitor simvastatin on human CD34(+) acute myeloid leukemia (AML) cells can be further promoted by combining it with the farnesyltransferase inhibitor tipifarnib. Experimental Design: Normal CD34(+), AML CD34(+), and CD34(-) sorted subfractions, and AML cell lines (TF-1 and KG1A) were exposed to simvastatin and tipifarnib. Results: Both simvastatin and tipifarnib showed a cytotoxic effect on AML cell lines, which was additive when used in combination. In primary sorted CD34(+) AML cells, a heterogeneous response pattern was observed upon treatment with simvastatin when analyzing cell survival. A group of normal (n = 12) and abnormal (n = 10) responders were identified within the AML CD34(+) subfraction when compared with normal CD34(+) cells. This distinction was not observed within the AML CD34(-) cell fraction. When the CD34(+) AML cells were exposed to simvastatin and tipifarnib, a significant enhanced inhibitory effect was shown exclusively in the normal AML responder group, whereas the AML CD34(-) cell fractions all showed an enhanced inhibitory effect. The observed heterogeneity in AML responsiveness could not be explained by differences in effects on cholesterol metabolism genes or extracellular signal-regulated kinase phosphorylation in response to simvastatin and tipifarnib treatment. Conclusion: The results suggest that combined treatment with statins and farnesyltransferase inhibitors may be beneficial for a subset of AML patients that can be defined by studying the AML CD34(+) fraction

Assessing the role of tumour-associated macrophage subsets in breast cancer subtypes using digital image analysis

Purpose: The number of M1-like and M2-like tumour-associated macrophages (TAMs) and their ratio can play a role in breast cancer development and progression. Early clinical trials using macrophage targeting compounds are currently ongoing. However, the most optimal detection method of M1-like and M2-like macrophage subsets and their clinical relevance in breast cancer is still unclear. We aimed to optimize the assessment of TAM subsets in different breast cancer subtypes, and therefore related TAM subset numbers and ratio to clinicopathological characteristics and clinical outcome. Methods: Tissue microarrays of 347 consecutive primary Luminal-A, Luminal-B, HER2-positive and triple-negative tumours of patients with early-stage breast cancer were serially sectioned and immunohistochemically stained for the pan-macrophage marker CD68 and the M2-like macrophage markers CD163, CSF-1R and CD206. TAM numbers were quantified using a digital image analysis algorithm. M1-like macrophage numbers were calculated by subtracting M2-like TAM numbers from the total TAM number. Results: M2-like markers CD163 and CSF-1R showed a moderate positive association with each other and with CD68 (r ≥ 0.47), but only weakly with CD206 (r ≤ 0.06). CD68 + , CD163 + and CSF-1R + macrophages correlated with tumour grade in Luminal-B tumours (P < 0.001). Total or subset TAM numbers did not correlate with disease outcome in any breast cancer subtype. Conclusion: In conclusion, macrophages and their subsets can be detected by means of a panel of TAM markers and are related to unfavourable clinicopathological characteristics in Luminal-B breast cancer. However, their impact on outcome remains unclear. Preferably, this should be determined in prospective series

Radiolabeled Monoclonal Antibody Against Colony-Stimulating Factor 1 Receptor Specifically Distributes to the Spleen and Liver in Immunocompetent Mice

Macrophages can promote tumor development. Preclinically, targeting macrophages by colony-stimulating factor 1 (CSF1)/CSF1 receptor (CSF1R) monoclonal antibodies (mAbs) enhances conventional therapeutics in combination treatments. The physiological distribution and tumor uptake of CSF1R mAbs are unknown. Therefore, we radiolabeled a murine CSF1R mAb and preclinically visualized its biodistribution by PET. CSF1R mAb was conjugated to N-succinyl-desferrioxamine (N-suc-DFO) and subsequently radiolabeled with zirconium-89 ((89)Zr). Optimal protein antibody dose was first determined in non-tumor-bearing mice to assess physiological distribution. Next, biodistribution of optimal protein dose and (89)Zr-labeled isotype control was compared with PET and ex vivo biodistribution after 24 and 72 h in mammary tumor-bearing mice. Tissue autoradiography and immunohistochemistry determined radioactivity distribution and tissue macrophage presence, respectively. [(89)Zr]Zr-DFO-N-suc-CSF1R-mAb optimal protein dose was 10 mg/kg, with blood pool levels of 10 ± 2% injected dose per gram tissue (ID/g) and spleen and liver uptake of 17 ± 4 and 11 ± 4%ID/g at 72 h. In contrast, 0.4 mg/kg of [(89)Zr]Zr-DFO-N-suc-CSF1R mAb was eliminated from circulation within 24 h; spleen and liver uptake was 126 ± 44% and 34 ± 7%ID/g, respectively. Tumor-bearing mice showed higher uptake of [(89)Zr]Zr-DFO-N-suc-CSF1R-mAb in the liver, lymphoid tissues, duodenum, and ileum, but not in the tumor than did (89)Zr-labeled control at 72 h. Immunohistochemistry and autoradiography showed that (89)Zr was localized to macrophages within lymphoid tissues. Following [(89)Zr]Zr-DFO-N-suc-CSF1R-mAb administration, tumor macrophages were almost absent, whereas isotype-group tumors contained over 500 cells/mm(2). We hypothesize that intratumoral macrophage depletion by [(89)Zr]Zr-DFO-N-suc-CSF1R-mAb precluded tumor uptake higher than (89)Zr-labeled control. Translation of molecular imaging of macrophage-targeting therapeutics to humans may support macrophage-directed therapeutic development

Phase II study (KAMELEON) of single-agent T-DM1 in patients with HER2-positive advanced urothelial bladder cancer or pancreatic cancer/cholangiocarcinoma

The antibody-drug conjugate trastuzumab emtansine (T-DM1) is approved for human epidermal growth factor receptor 2 (HER2/ERBB2)-positive breast cancer. We aimed to study tumor HER2 expression and its effects on T-DM1 responses in patients with HER2-positive urothelial bladder cancer (UBC) or pancreatic cancer (PC)/cholangiocarcinoma (CC). In the phase II KAMELEON study (NCT02999672), HER2 status was centrally assessed by immunohistochemistry, with positivity defined as non-focal homogeneous or heterogeneous overexpression of HER2 in ≥30% of stained cells. We also performed exploratory biomarker analyses (e.g., gene-protein assay) on tissue samples collected from study participants and consenting patients who failed screening. Of the 284 patients successfully screened for HER2 status (UBC, n = 69; PC/CC, n = 215), 13 with UBC, four with PC, and three with CC fulfilled eligibility criteria. Due to recruitment difficulty, the sponsor terminated KAMELEON prematurely. Of the five responders in the UBC cohort (overall response rate, 38.5%), HER2 expression was heterogeneous in two and homogeneous in three. The one responder in the PC/CC cohort had PC, and the tumor displayed homogeneous expression. In the biomarker-evaluable population, composed of screen-failed and enrolled patients, 24.3% (9/37), 1.5% (1/66), and 8.2% (4/49) of those with UBC, PC, or CC, respectively, had HER2-positive tumors. In a gene-protein assay combining in situ hybridization with immunohistochemistry, greater HER2 homogeneity was associated with increased ERBB2 amplification ratio. In conclusion, KAMELEON showed that some patients with HER2-positive UBC or PC can respond to T-DM1 and provided insight into the prevalence of HER2 positivity and expression patterns in three non-breast tumor types.</p

First-in-human study of the biodistribution and pharmacokinetics of ⁸⁹Zr-CX-072, a novel immunopet tracer based on an anti–PD-L1 probody

Purpose: CX-072, a PD-L1–targeting Probody therapeutic, is engineered to be activated by tumor proteases that remove a masking peptide. To study effects on biodistribution and pharmacokinetics, we performed 89Zr-CX-072 positron emission tomography (PET) imaging. Experimental Design: Patients received 1 mg, 37 MBq 89Zr-CX-072 plus 0, 4, or 9 mg unlabeled CX-072 and PET scans at days 2, 4, and 7. After that, treatment comprised 10 mg/kg CX-072 q2 weeks (n ¼ 7) þ 3 mg/kg ipilimumab q3w 4 (n ¼ 1). Normal organ tracer uptake was expressed as standardized uptake value (SUV)mean and tumor uptake as SUVmax. PD-L1 expression was measured immunohistochemically in archival tumor tissue. Results: Three of the eight patients included received 10-mg protein dose resulting in a blood pool mean SUVmean SD of 4.27 0.45 on day 4, indicating sufficient available tracer. Tumor uptake was highest at day 7, with a geometric mean SUVmax 5.89 (n ¼ 113) and present in all patients. The median follow-up was 12 weeks (4–76þ). One patient experienced stable disease and two patients a partial response. PD-L1 tumor expression was 90% in one patient and ≤1% in the other patients. Mean SUVmean SD day 4 at 10 mg in the spleen was 8.56 1.04, bone marrow 2.21 0.46, and liver 4.97 0.97. Four patients out of seven showed uptake in normal lymph nodes and Waldeyer’s ring. The tracer was intact in the serum or plasma. Conclusions: 89Zr-CX-072 showed tumor uptake, even in lesions with ≤1% PD-L1 expression, and modest uptake in normal lymphoid organs, with no unexpected uptake in other healthy tissues

CX-072 (pacmilimab), a Probody® PD-L1 inhibitor, in advanced or recurrent solid tumors (PROCLAIM-CX-072): an open-label dose-finding and first-in-human study

Background: Probody® therapeutics are antibody prodrugs that are activated in the tumor microenvironment by tumor-associated proteases, thereby restricting the activity to the tumor microenvironment and minimizing 'off-tumor' toxicity. We report dose-escalation and single-agent expansion phase data from the first-in-human study of CX-072 (pacmilimab), a Probody checkpoint inhibitor directed against programmed death-ligand 1 (PD-L1). Methods: In the dose-escalation phase of this multicenter, open-label study (NCT03013491), adults with advanced solid tumors (naive to programmed-death-1/PD-L1 or cytotoxic T-lymphocyte-associated antigen 4 inhibitors) were enrolled into one of seven dose-escalation cohorts, with pacmilimab administered intravenously every 14 days. The primary endpoints were safety and determination of the maximum tolerated dose (MTD). In the expansion phase, patients with one of six prespecified malignancies (triple-negative breast cancer [TNBC]; anal squamous cell carcinoma [aSCC]; cutaneous SCC [cSCC]; undifferentiated pleomorphic sarcoma [UPS]; small bowel adenocarcinoma [SBA]; and thymic epithelial tumor [TET]); or high tumor mutational burden (hTMB) tumors were enrolled. The primary endpoint was objective response (Response Evaluation Criteria In Solid Tumors v.1.1). Results: An MTD was not reached with doses up to 30 mg/kg. A recommended phase 2 dose (RP2D) of 10 mg/kg was chosen based on pharmacokinetic and pharmacodynamic findings in the expansion phase. Ninety-eight patients enrolled in the expansion phase: TNBC (n=14), aSCC (n=14), cSCC (n=14), UPS (n=20), SBA (n=14), TET (n=8), and hTMB tumors (n=14). Of 114 patients receiving pacmilimab at the RP2D, grade ≥3 treatment-related adverse events (TRAEs) were reported in 10 patients (9%), serious TRAEs in six patients (5%), and treatment discontinuation due to TRAEs in two patients (2%). Grade ≥3 immune-related AEs occurred in two patients (rash, myocarditis). High PD-L1 expression (ie, >50% Tumor Proportion Score) was observed in 22/144 (19%) patients. Confirmed objective responses were observed in patients with cSCC (n=5, including one complete response), hTMB (n=4, including one complete response), aSCC (n=2), TNBC (n=1), UPS (n=1), and anaplastic thyroid cancer (n=1). Conclusions: Pacmilimab can be administered safely at the RP2D of 10 mg/kg every 14 days. At this dose, pacmilimab had a low rate of immune-mediated toxicity and showed signs of antitumor activity in patients not selected for high PD-L1 expression