A Phase Ib/II study of IGF-neutralising antibody xentuzumab with enzalutamide in metastatic castration-resistant prostate cancer

BACKGROUND

This multicentre, open-label, Phase Ib/II trial evaluated the insulin-like growth factor (IGF) 1/2 neutralising antibody xentuzumab plus enzalutamide in metastatic castrate-resistant prostate cancer (mCRPC).

METHODS

The trial included Phase Ib escalation and expansion parts and a randomised Phase II part versus enzalutamide alone. Primary endpoints in the Phase Ib escalation, Phase Ib expansion and Phase II parts were maximum tolerated dose (MTD), prostate-specific antigen response and investigator-assessed progression-free survival (PFS), respectively. Patients in the Phase Ib escalation and Phase II parts had progressed on/after docetaxel/abiraterone.

RESULTS

In the Phase Ib escalation (n = 10), no dose-limiting toxicities were reported, and xentuzumab 1000 mg weekly plus enzalutamide 160 mg daily (Xe1000 + En160) was defined as the MTD and recommended Phase 2 dose. In the Phase Ib expansion (n = 24), median PFS was 8.2 months, and one patient had a confirmed, long-term response. In Phase II (n = 86), median PFS for the Xe1000 + En160 and En160 arms was 7.4 and 6.2 months, respectively. Subgroup analysis suggested trends towards benefit with Xe1000 + En160 in patients whose tumours had high levels of IGF1 mRNA or PTEN protein. Overall, the combination was well tolerated.

CONCLUSIONS

Xentuzumab plus enzalutamide was tolerable but lacked antitumour activity in unselected patients with mCRPC.

CLINICAL TRIAL REGISTRATION

EudraCT number 2013-004011-41.

Abstract CT507: ATP128 vaccine with ezabenlimab promotes antigen-specific immune responses in stage IV colorectal cancer in the KISIMA-01 phase 1b trial

Background: KISIMA࣪ is a vaccine platform based on a single chimeric fusion protein, containing a proprietary cell-penetrating peptide (CPP) for antigen delivery, a proprietary Toll-like receptor (TLR)-peptide agonist with self-adjuvant properties and a modulable multi-antigenic domain (Mad). ATP128 vaccine targets 3 antigens: carcinoembryonic antigen (CEA), Survivin and Achaete-scute complex homolog 2 (ASCL2); it is used in combination with a PD-1 inhibitor in the treatment of MSS/MMR proficient stage IV colorectal cancer (CRC) patients, after first line of standard of care therapy or as perioperative administration in patients with resectable liver metastases.

Method: KISIMA-01 (NCT04046445) is an open-label, multi-center Phase 1b trial to investigate the safety, tolerability and immunogenicity of AT128 alone or in combination with the anti-PD-1 antibody ezabenlimab in patients with stage IV CRC. ATP128 is given SC q2w for the first 3 immunizations (prime) and q4w for the last 3 immunizations (boost). Ezabenlimab is administered q3w starting with the first ATP128 administration. Blood and tissue samples are collected before, during and after ATP128 treatment to monitor the induction of a tumor associated antigen-specific immune response (ELISpot) and immune-related changes in the peripheral blood and in the tumor microenvironment by immunohistochemistry (IHC) and flow cytometry.

Results: In more than 50% of evaluated patients treated with ATP128 alone or with ezabenlimab, a cellular immune response against at least one out of three antigens was observed as determined by IFN-γ ELISpot analyses of patient PBMCs after the 3rd vaccination. Analysis of liver metastases by IHC indicated that evaluated patients were positive for all 3 antigens in ATP128. Furthermore, for the patients with paired biopsies, a significant increase in CD8 T cells infiltration into the tumor parenchyma was observed after 3 vaccine administrations, along with a significantly higher proportion of CD45RO expressing memory cells within the CD4 population as compared to baseline. Tumor infiltrating lymphocytes (TILs) flow cytometry analysis comparing untreated (historical controls) and ATP128/ezabenlimab-treated patients showed a similar quantity of the different infiltrated subsets but an improved quality of infiltrated T cells, indicated by an increase (more than 2-fold) in proportion of central memory T cells and an impressive decrease of the proportion of cells positive for exhaustion markers expression in KISIMA-01 patients.

Conclusions: Analyses indicate induction of ATP128-specific immune response in the peripheral circulation and increased infiltration of TILs into liver metastases with an improved quality of T cells.

Citation Format: Heinz-Josef Lenz, Hanz Prenen, Eric Van Cutsem, Thibaud Kössler, Jean-François Mayol, Francesca Trapani, Matthieu Tihy, Laura Rubbia-Brandt, Christian Toso, Thomas Bogenrieder, Elodie Belnoue, Madiha Derouazi, Scott Kopetz. ATP128 vaccine with ezabenlimab promotes antigen-specific immune responses in stage IV colorectal cancer in the KISIMA-01 phase 1b trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT507.

Abstract CT570: KISIMA-01: A first-in-human trial of the heterologous prime-boost vaccine ATP128/VSV-GP128 with ezabenlimab (BI 754091) in patients with stage IV colorectal cancer

Background: Most microsatellite stable/mismatch repair proficient (MSS/MMRp) stage IV colorectal cancers (CRC) do not respond to PD-1 inhibition. ATP128, based on the KISIMA platform, is a single chimeric fusion protein, composed of 3 elements essential to generate potent antitumoral cellular immunity: a proprietary cell-penetrating peptide (CPP) for antigen delivery, a proprietary Toll-like receptor (TLR)-peptide agonist with self-adjuvant properties and a modulable multi-antigenic domain (Mad), where the Mad for CRC includes 3 antigens: carcinoembryonic antigen (CEA), Survivin, Achaete-scute complex homolog 2 (ASCL2). VSV-GP128 is a recombinant vesicular stomatitis virus (VSV) carrying the glycoprotein (GP) of a non-neurotropic strain of lymphocytic choriomeningitis virus (LCMV) instead of the native VSV-GP. The GP of the LCMV abrogates neurotoxicity. As viral vector, VSV-GP128 expresses a Mad with identical sequence to ATP128 integrated in a linear, negative-sense, single-stranded RNA genome. Preclinical data have shown that priming with KISIMA vaccine followed by VSV-GP boost induced a large pool of polyfunctional and persistent antigen-specific cytotoxic T cells in the periphery as well as within the tumor in several tumor models. Combining heterologous vaccination with a PD-1 inhibitor further improved its therapeutic efficacy (Das et al., Nature Communication 2021).

Methods: KISIMA-01 (NCT04046445) is an open-label, multi-center Phase 1b umbrella trial to investigate the safety, tolerability and immunogenicity of the heterologous prime-boost vaccine AT128/VSV-GP128 in combination with the anti-PD1 ezabenlimab in patients with stage IV MSS CRC. Two different patient cohorts are investigated: 1) maintenance setting (during a chemotherapy free period) after a minimum of 4 months of 1st line standard chemotherapy with clinical benefit (defined as PR or SD) (n=30); 2) resectable liver-limited disease (n=15). ATP128 is given subcutaneously on day 1 (prime); VSV-GP128 is administered intravenously on day 15 as the heterologous boost. ATP128 is again administered on day 29 (injection 3) and then every 4 weeks for the last 3 immunizations. Ezabenlimab is administered every 3 weeks starting with the first ATP128 administration. Blood and tissue samples are collected before, during and after ATP128/VSV-GP128 treatment to monitor the induction of a tumor associated antigen-specific immune response and immune-related changes. Immunogenicity will be analyzed in the peripheral blood using ELISpot, and in the tumor microenvironment by immunohistochemical assessment of tumor-infiltrating lymphocytes (TILs). Clearance of ctDNA is analyzed as an exploratory endpoint. The heterologous prime-boost cohorts (ATP128/VSV-GP128) of the KISIMA-01 trial are recruiting in the US, Switzerland and Belgium.

Citation Format: Heinz-Josef Lenz, Thibaud Koessler, Paul Oberstein, Eric Van Cutsem, Sunnie Kim, Ralph Fritsch, Hans Prenen, Michael Morse, Delphine Gani, Madiha Derouazi, Thomas Bogenrieder, Scott Kopetz. KISIMA-01: A first-in-human trial of the heterologous prime-boost vaccine ATP128/VSV-GP128 with ezabenlimab (BI 754091) in patients with stage IV colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT570.

CHK1 inhibition exacerbates replication stress induced by IGF blockade

We recently reported that genetic or pharmacological inhibition of insulin-like growth factor receptor (IGF-1R) slows DNA replication and induces replication stress by downregulating the regulatory subunit RRM2 of ribonucleotide reductase, perturbing deoxynucleotide triphosphate (dNTP) supply. Aiming to exploit this effect in therapy we performed a compound screen in five breast cancer cell lines with IGF neutralising antibody xentuzumab. Inhibitor of checkpoint kinase CHK1 was identified as a top screen hit. Co-inhibition of IGF and CHK1 caused synergistic suppression of cell viability, cell survival and tumour growth in 2D cell culture, 3D spheroid cultures and in vivo. Investigating the mechanism of synthetic lethality, we reveal that CHK1 inhibition in IGF-1R depleted or inhibited cells further downregulated RRM2, reduced dNTP supply and profoundly delayed replication fork progression. These effects resulted in significant accumulation of unreplicated single-stranded DNA and increased cell death, indicative of replication catastrophe. Similar phenotypes were induced by IGF:WEE1 co-inhibition, also via exacerbation of RRM2 downregulation. Exogenous RRM2 expression rescued hallmarks of replication stress induced by co-inhibiting IGF with CHK1 or WEE1, identifying RRM2 as a critical target of the functional IGF:CHK1 and IGF:WEE1 interactions. These data identify novel therapeutic vulnerabilities and may inform future trials of IGF inhibitory drugs.

Phase 1b Open-Label Trial of Afatinib Plus Xentuzumab (BI 836845) in Patients With EGFR Mutation-Positive NSCLC After Progression on EGFR Tyrosine Kinase Inhibitors

Introduction

Insulin-like growth factor signaling has been implicated in acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) in NSCLC. This phase 1 trial (NCT02191891) investigated the combination of xentuzumab (an insulin-like growth factor-ligand neutralizing monoclonal antibody) and afatinib (an EGFR TKI) in patients with previously treated EGFR mutation-positive NSCLC.

Methods

The trial comprised dose escalation (part A) and expansion (part B). Patients had advanced or metastatic NSCLC that had progressed on EGFR TKI monotherapy or platinum-based chemotherapy (nonadenocarcinoma only, part A) or irreversible EGFR TKI monotherapy (part B). Absence of EGFR T790M mutation was required in part B. Part A used a 3 + 3 design, with a starting dose of xentuzumab 1000 mg/wk (intravenous) and afatinib 30 mg/d (oral). Primary endpoints were the maximum tolerated dose of the combination (part A) and objective response (part B).

Results

A total of 16 patients each were treated in parts A and B. Maximum tolerated dose was xentuzumab 1000 mg/wk plus afatinib 40 mg/d. No patients in part B had an objective response, but 10 had stable disease (median [range] duration of disease control: 2.3 [0.8–10.9] mo). The most common drug-related adverse events were diarrhea (75 %), paronychia (69 %), and rash (69 %) in part A and diarrhea (31 %), rash (19 %), paronychia (19 %), and fatigue (19 %) in part B.

Conclusions

There were no new safety issues; xentuzumab and afatinib could be safely coadministered. Nevertheless, the combination revealed only modest activity in patients with EGFR mutation-positive, T790M-negative NSCLC after progression on afatinib.

Targeting IGF Perturbs Global Replication through Ribonucleotide Reductase Dysfunction

Inhibition of IGF receptor (IGF1R) delays repair of radiation-induced DNA double-strand breaks (DSB), prompting us to investigate whether IGF1R influences endogenous DNA damage. Here we demonstrate that IGF1R inhibition generates endogenous DNA lesions protected by 53BP1 bodies, indicating under-replicated DNA. In cancer cells, inhibition or depletion of IGF1R delayed replication fork progression accompanied by activation of ATR-CHK1 signaling and the intra-S-phase checkpoint. This phenotype reflected unanticipated regulation of global replication by IGF1 mediated via AKT, MEK/ERK, and JUN to influence expression of ribonucleotide reductase (RNR) subunit RRM2. Consequently, inhibition or depletion of IGF1R downregulated RRM2, compromising RNR function and perturbing dNTP supply. The resulting delay in fork progression and hallmarks of replication stress were rescued by RRM2 overexpression, confirming RRM2 as the critical factor through which IGF1 regulates replication. Suspecting existence of a backup pathway protecting from toxic sequelae of replication stress, targeted compound screens in breast cancer cells identified synergy between IGF inhibition and ATM loss. Reciprocal screens of ATM-proficient/deficient fibroblasts identified an IGF1R inhibitor as the top hit. IGF inhibition selectively compromised growth of ATM-null cells and spheroids and caused regression of ATM-null xenografts. This synthetic-lethal effect reflected conversion of single-stranded lesions in IGF-inhibited cells into toxic DSBs upon ATM inhibition. Overall, these data implicate IGF1R in alleviating replication stress, and the reciprocal IGF:ATM codependence we identify provides an approach to exploit this effect in ATM-deficient cancers. SIGNIFICANCE: This study identifies regulation of ribonucleotide reductase function and dNTP supply by IGFs and demonstrates that IGF axis blockade induces replication stress and reciprocal codependence on ATM. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/81/8/2128/F1.large.jpg.

A phase Ib/II study of xentuzumab, an IGF-neutralising antibody, combined with exemestane and everolimus in hormone receptor-positive, HER2-negative locally advanced/metastatic breast cancer

Background

Xentuzumab—a humanised IgG1 monoclonal antibody—binds IGF-1 and IGF-2, inhibiting their growth-promoting signalling and suppressing AKT activation by everolimus. This phase Ib/II exploratory trial evaluated xentuzumab plus everolimus and exemestane in hormone receptor-positive, locally advanced and/or metastatic breast cancer (LA/MBC).

Methods

Patients with hormone receptor-positive/HER2-negative LA/MBC resistant to non-steroidal aromatase inhibitors were enrolled. Maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of xentuzumab/everolimus/exemestane were determined in phase I (single-arm, dose-escalation). In phase II (open-label), patients were randomised 1:1 to the RP2D of xentuzumab/everolimus/exemestane or everolimus/exemestane alone. Randomisation was stratified by the presence of visceral metastases. Primary endpoint was progression-free survival (PFS).

Results

MTD was determined as xentuzumab 1000 mg weekly plus everolimus 10 mg/day and exemestane 25 mg/day. A total of 140 patients were enrolled in phase II (70 to each arm). Further recruitment was stopped following an unfavourable benefit-risk assessment by the internal Data Monitoring Committee appointed by the sponsor. Xentuzumab was discontinued; patients could receive everolimus/exemestane if clinically indicated. Median PFS was 7.3 months (95% CI 3.3–not calculable) in the xentuzumab/everolimus/exemestane group and 5.6 months (3.7–9.1) in the everolimus/exemestane group (hazard ratio 0.97, 95% CI 0.57–1.65; P = 0.9057). In a pre-specified subgroup of patients without visceral metastases at screening, xentuzumab/everolimus/exemestane showed evidence of PFS benefit versus everolimus/exemestane (hazard ratio 0.21 [0.05–0.98]; P = 0.0293). Most common any-cause adverse events in phase II were diarrhoea (29 [41.4%] in the xentuzumab/everolimus/exemestane group versus 20 [29.0%] in the everolimus/exemestane group), mucosal inflammation (27 [38.6%] versus 21 [30.4%]), stomatitis (24 [34.3%] versus 24 [34.8%]), and asthenia (21 [30.0%] versus 24 [34.8%]).

Conclusions

Addition of xentuzumab to everolimus/exemestane did not improve PFS in the overall population, leading to early discontinuation of the trial. Evidence of PFS benefit was observed in patients without visceral metastases when treated with xentuzumab/everolimus/exemestane, leading to initiation of the phase II XENERA™-1 trial (NCT03659136).

Trial registration

ClinicalTrials.gov, NCT02123823. Prospectively registered, 8 March 2013.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-020-01382-8.

Two first-in-human studies of xentuzumab, a humanised insulin-like growth factor (IGF)-neutralising antibody, in patients with advanced solid tumours

BACKGROUND

Xentuzumab, an insulin-like growth factor (IGF)-1/IGF-2-neutralising antibody, binds IGF-1 and IGF-2, inhibiting their growth-promoting signalling. Two first-in-human trials assessed the maximum-tolerated/relevant biological dose (MTD/RBD), safety, pharmacokinetics, pharmacodynamics, and activity of xentuzumab in advanced/metastatic solid cancers.

METHODS

These phase 1, open-label trials comprised dose-finding (part I; 3 + 3 design) and expansion cohorts (part II; selected tumours; RBD [weekly dosing]). Primary endpoints were MTD/RBD.

RESULTS

Study 1280.1 involved 61 patients (part I: xentuzumab 10-1800 mg weekly, n = 48; part II: 1000 mg weekly, n = 13); study 1280.2, 64 patients (part I: 10-3600 mg three-weekly, n = 33; part II: 1000 mg weekly, n = 31). One dose-limiting toxicity occurred; the MTD was not reached for either schedule. Adverse events were generally grade 1/2, mostly gastrointestinal. Xentuzumab showed dose-proportional pharmacokinetics. Total plasma IGF-1 increased dose dependently, plateauing at ~1000 mg/week; at ≥450 mg/week, IGF bioactivity was almost undetectable. Two partial responses occurred (poorly differentiated nasopharyngeal carcinoma and peripheral primitive neuroectodermal tumour). Integration of biomarker and response data by Bayesian Logistic Regression Modeling (BLRM) confirmed the RBD.

CONCLUSIONS

Xentuzumab was well tolerated; MTD was not reached. RBD was 1000 mg weekly, confirmed by BLRM. Xentuzumab showed preliminary anti-tumour activity.

CLINICAL TRIAL REGISTRATION

NCT01403974; NCT01317420.

Antitumor Activity of the IGF-1/IGF-2-Neutralizing Antibody Xentuzumab (BI 836845) in Combination with Enzalutamide in Prostate Cancer Models

Androgen deprivation therapy and second-generation androgen receptor signaling inhibitors such as enzalutamide are standard treatments for advanced/metastatic prostate cancer. Unfortunately, most men develop resistance and relapse; signaling via insulin-like growth factor (IGF) has been implicated in castration-resistant prostate cancer. We evaluated the antitumor activity of xentuzumab (IGF ligand-neutralizing antibody), alone and in combination with enzalutamide, in prostate cancer cell lines (VCaP, DuCaP, MDA PCa 2b, LNCaP, and PC-3) using established in vitro assays, and in vivo, using LuCaP 96CR, a prostate cancer patient-derived xenograft (PDX) model. Xentuzumab + enzalutamide reduced the viability of phosphatase and tensin homolog (PTEN)-expressing VCaP, DuCaP, and MDA PCa 2b cells more than either single agent, and increased antiproliferative activity and apoptosis induction in VCaP. Xentuzumab or xentuzumab + enzalutamide inhibited IGF type 1 receptor and AKT serine/threonine kinase (AKT) phosphorylation in VCaP, DuCaP, and MDA PCa 2b cells; xentuzumab had no effect on AKT phosphorylation and proliferation in PTEN-null LNCaP or PC-3 cells. Knockdown of PTEN led to loss of antiproliferative activity of xentuzumab and reduced activity of xentuzumab + enzalutamide in VCaP cells. Xentuzumab + enzalutamide inhibited the growth of castration-resistant LuCaP 96CR PDX with acquired resistance to enzalutamide, and improved survival in vivo The data suggest that xentuzumab + enzalutamide combination therapy may overcome castration resistance and could be effective in patients who are resistant to enzalutamide alone. PTEN status as a biomarker of responsiveness to combination therapy needs further investigation.

Targeting IGF-1/2 with xentuzumab (Xe) plus enzalutamide (En) in metastatic castration-resistant prostate cancer (mCRPC) after progression on docetaxel chemotherapy (DCt) and abiraterone (Abi): Randomized phase II trial results

5030

Background: Insulin-like growth factor receptor-1 (IGF-1R) signaling activates the PI3K/AKT pathway and may lead to androgen receptor (AR) transactivation and progression to endocrine treatment resistance. Xe, an IGF-ligand-neutralizing antibody, binds to IGF-1 and IGF-2 and inhibits IGF-1R signaling. This multi-center randomized phase II trial (NCT02204072) evaluated anti-tumor activity of Xe plus En in mCRPC. Methods: Men with histologically/cytologically confirmed mCRPC and progression after DCt+Abi were randomized to receive Xe 1000mg IV QW + En 160mg/day oral, or En alone (28-day cycles until progression or intolerable adverse events [AEs]). Primary endpoint: progression-free survival by investigator assessment (PFS-IA); secondary: PFS by central review (PFS-CR), overall survival (OS), AEs. Results: Overall, 43 patients were randomized per arm; 70% Caucasian and 29% Asian (median age 70 y; range 46–88). At baseline (BL) the two arms were generally well balanced, although 33% v 47% were ECOG PS O, and 72% v 56% had a Gleason total score ≥8. By data cut-off (23 October 2017), 39/43 (Xe+En) and 38/43 patients (En) had discontinued, most due to disease progression. The median PFS-IA was 7.4 m for Xe+En (95% CI: 3.5–8.7) and 6.2 m for En (3.5–11.1) [HR = 0.99 (0.56–1.73); p = 0.96]. The results were similar after adjusting for BL ECOG PS and Gleason score. The median PFS-CR was 3.6 m for Xe+En (3.5–8.1) and 6.2 m for En (3.6–8.3) (HR = 1.22 [0.70–2.13]; p = 0.48). OS data are immature. For the two arms, prostate-specific antigen (PSA) response rates were 21% and 19%; maximum decline in PSA: -20 v -9 μg/L; PSA change at week 12: 19% v 18%; maximum decline in circulating tumor cells (CTC): -52% v -35%; and CTC response: 16% v 11%. The most frequently reported AEs were: fatigue 67% v 49%; decreased appetite 56% v 54%; weight reduction 37% v 12%; anemia 33% v 44%; back pain 30% v 37%. Nine patients discontinued Xe due to AEs. Conclusions: Addition of Xe to En did not prolong PFS in mCRPC compared with En alone. There were no notable differences in PSA-related endpoints and CTC between arms. Clinical trial information: NCT02204072.

Abstract P6-21-01: Xentuzumab (BI 836845), an insulin-like growth factor (IGF)-neutralizing antibody (Ab), combined with exemestane and everolimus in hormone receptor-positive (HR+) locally advanced/metastatic breast cancer (LA/mBC): Randomized phase 2 results

Background:

Xentuzumab (Xen), an IGF-1/-2-neutralizing Ab, binds IGF-1 and IGF-2, inhibits their growth-promoting signaling, and suppresses AKT activation by everolimus (Ev). This Phase 1b/2 trial evaluates Xen in combination with Ev and exemestane (Ex) in HR+/HER2− LA/mBC.

Methods:

The two-arm, open-label, randomized Phase 2 part enrolled female patients (pts) with HR+/HER2− LA/mBC not amenable to curative therapy and refractory to nonsteroidal aromatase inhibitors. Pts were randomized (1:1) to: oral Ev (10 mg/d) + Ex (25 mg/d); or Xen (1000 mg/wk iv) + Ev (10 mg/d) + Ex (25 mg/d). Randomization was stratified by visceral metastases (VM; Y vs N). Treatment continued in 28-day cycles until progression, intolerable adverse events (AEs) or other reasons for discontinuation. Primary endpoint was progression-free survival (PFS), with an interim futility analysis incorporated in the study design.

Results:

Following the results of the interim analysis, the Data Monitoring Committee (DMC) advised early termination of the trial and discontinuation of Xen treatment. Thus, Xen treatment exposure time and time-to-event data for the Xen+Ev+Ex arm are limited. Of the 139 women treated (Xen+Ev+Ex 70; Ev+Ex 69), 77% had VM. Median PFS was not significantly different between arms (Xen+Ev+Ex vs Ev+Ex, 7.3 vs 5.6 months; HR [95% CI] 0.97 [0.57–1.65]; p=0.91). In a pre-specified subgroup of pts without VM, Xen+Ev+Ex showed favorable PFS vs Ev+Ex (HR 0.21 [0.05–0.98]; Pint=0.0141). Pint values <0.05 were also observed for ad hoc subgroups: measurable disease at baseline; bone-only metastases. Rates of total AEs/grade ≥3 AEs/drug-related AEs were similar between arms (Xen+Ev+Ex, 100/60/96%; Ev+Ex, 99/58/96%). The most common AEs overall were diarrhea (44 vs 33%), mucosal inflammation (39 vs 32%), rash (34 vs 33%) and stomatitis (34 vs 38%); most were grade 1/2. 6% of pts in the Xen+Ev+Ex arm discontinued Xen due to AEs. Ev/Ex discontinuations (Xen+Ev+Ex vs Ev+Ex) occurred in 13/6% vs 23/6%; 1 pt each in the Xen+Ev+Ex arm died from pneumonitis and liver injury and 1 pt each in the Ev+Ex arm died from Burkitt's lymphoma, acute kidney injury and metastases to the peritoneum.

Conclusion:

In the overall population, PFS did not improve with the addition of Xen to Ev+Ex and the trial was therefore discontinued early. Nevertheless, a favorable signal was observed in the pre-specified subgroup of pts without VM when treated with Xen+Ev+Ex, which warrants additional investigation. The safety profile was comparable between arms.

Citation Format: Crown J, Sablin M-P, Cortés J, Bergh J, Im S-A, Lu Y-S, Martínez N, Neven P, Lee KS, Morales S, Pérez-Fidalgo JA, Adamson D, Goncalves A, Prat A, Jerusalem G, Schlieker L, Espadero R-M, Bogenrieder T, Chin-Lun Huang D, Schmid P. Xentuzumab (BI 836845), an insulin-like growth factor (IGF)-neutralizing antibody (Ab), combined with exemestane and everolimus in hormone receptor-positive (HR+) locally advanced/metastatic breast cancer (LA/mBC): Randomized phase 2 results [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-21-01.

Bad to the Bone: The Role of the Insulin-Like Growth Factor Axis in Osseous Metastasis

Bone metastases are a frequent complication of cancer that are associated with considerable morbidity. Current treatments may temporarily palliate the symptoms of bone metastases but often fail to delay their progression. Bones provide a permissive environment because they are characterized by dynamic turnover, secreting factors required for bone maintenance but also stimulating the establishment and growth of metastases. Insulin-like growth factors (IGF) are the most abundant growth factors in bone and are required for normal skeletal development and function. Via activation of the IGF-1 receptors (IGF-1R) and variant insulin receptors, IGFs promote cancer progression, aggressiveness, and treatment resistance. Of specific relevance to bone biology, IGFs contribute to the homing, dormancy, colonization, and expansion of bone metastases. Furthermore, preclinical evidence suggests that tumor cells can be primed to metastasize to bone by a high IGF-1 environment in the primary tumor, suggesting that bone metastases may reflect IGF dependency. Therapeutic targeting of the IGF axis may therefore provide an effective method for treating bone metastases. Indeed, anti-IGF-1R antibodies, IGF-1R tyrosine kinase inhibitors, and anti-IGF-1/2 antibodies have demonstrated antitumor activity in preclinical models of prostate and breast cancer metastases, either alone or in combination with other agents. Several studies suggest that such treatments can inhibit bone metastases without affecting growth of the primary tumor. Although previous trials of anti-IGF-1R drugs have generated negative results in unselected patients, these considerations suggest that future clinical trials of IGF-targeted agents may be warranted in patients with bone metastases.

Regulation of proliferation and invasion by the IGF signalling pathway in Epstein-Barr virus-positive gastric cancer

Several carcinomas including gastric cancer have been reported to contain Epstein-Barr virus (EBV) infection. EBV-associated gastric cancer (EBVaGC) is classified as one of four molecular subtypes of gastric cancer by The Cancer Genome Atlas (TCGA) group with increased immune-related signatures. Identification of EBV-dependent pathways with significant biological roles is needed for EBVaGC. To compare the biological changes between AGS gastric epithelial cells and EBV-infected AGS (AGS-EBV) cells, proliferation assay, CCK-8 assay, invasion assay, cell cycle analysis, RT-PCR, Western blot and ELISA were performed. BI836845, a humanized insulin-like growth factor (IGF) ligand-neutralizing antibody, was used for IGF-related signalling pathway inhibition. AGS-EBV cells showed slower proliferating rate and higher sensitivity to BI836845 compared to AGS cells. Moreover, invasiveness of AGS-EBV was increased than that of AGS, and BI836845 treatment significantly decreased the invasiveness of AGS-EBV. Although no apoptosis was detected, entry into the S phase of the cell cycle was delayed in BI836845-treated AGS-EBV cells. In conclusion, AGS-EBV cells seem to modulate their proliferation and invasion through the IGF signalling pathway. Inhibition of the IGF signalling pathway therefore could be a potential therapeutic strategy for EBVaGC.

Abstract 1852: Combination of the CDK4/6 inhibitor abemaciclib with xentuzumab, a humanized IGF-1 and IGF-2 ligand co-neutralizing monoclonal antibody, results in synergistic antineoplastic effects in human breast cancer cell lines

Background: The proliferative and pro-survival signals driven by the insulin-like growth factor (IGF) ligands, IGF-1 and IGF-2, are transmitted through their binding to the IGF-1 receptor (IGF-1R). In addition, IGF-2 promotes proliferation through activation of the insulin receptor variant A (IR-A) that is expressed during embryonic development as well as in many cancers. IGF survival signaling has been implicated in driving resistance to cancer therapies with diverse mechanisms of action, due to cross-talk between cellular signaling networks. Recent studies[1][2] suggest that the combination of IGF-1R signaling inhibitors with CDK4/6 inhibitors can result in enhanced anti-tumor activity. The aim of this study was to explore the potential of the IGF-1/-2 ligand blocking antibody, xentuzumab (BI 836845[3]), to enhance the anti-tumor activity of the CDK4/6 inhibitor abemaciclib, alone or in combination with fulvestrant, in human breast cancer (BC) cell lines.

Methods: The anti-proliferative activity of the xentuzumab/abemaciclib combination was evaluated using CellTiter-Glo and propidium iodide staining in a panel of 51 and 20 BC cell lines, respectively. Detailed studies of abemaciclib (+/- fulvestrant), xentuzumab and combinations thereof were performed in MCF7 cells. Cell cycle analysis was done by FACS and BrdU ELISA, cellular signaling was assessed by Western blotting, proliferation was evaluated by Incucyte, CellTiter-Glo and alamarBlue assay. Apoptosis was measured by detection of cleaved PARP and caspase 3.

Results:

Among a panel of BC cell lines, enhanced anti-proliferative activity of xentuzumab+abemaciclib vs. abemaciclib alone was observed specifically in hormone receptor positive (HR+) cell lines. Combined treatment resulted in more pronounced cell cycle arrest in MCF7 cells, associated with synergistic blockade of IGF survival signaling and suppression of cell cycle genes downstream of CDK4/6. The triple combination with fulvestrant more effectively inhibited tumor cell proliferation than the doublet abemaciclib+fulvestrant, and led to induction of apoptosis.

Conclusion: The study results show that addition of the IGF-1/-2 neutralizing antibody xentuzumab to abemaciclib, in the absence or presence of fulvestrant, leads to improved anti-proliferative activity and, in the triple combination, results in cellular death in MCF7 HR+ breast cancer cells. A phase Ib trial evaluating the abemaciclib+xentuzumab combination, including triplets with endocrine therapy in HR+BC patients, is currently ongoing.

References:

[1] Miller ML et al. (2013). Sci Signal 6;ra85

[2] Heilmann AM et al. (2014). Cancer Res 74:3947-58

[3] Friedbichler K et al. (2014). Mol Cancer Ther 13(2):399-409

Citation Format: Ulrike Weyer-Czernilofsky, Rosa Baumgartinger, Susanne Schmittner, Xueqian Gong, Sean Buchanan, Richard P. Beckmann, Carlos Marugan, Raquel Torres, Karsten Boehnke, Maria Jose Lallena, Flavio Solca, Norbert Kraut, Thomas Bogenrieder. Combination of the CDK4/6 inhibitor abemaciclib with xentuzumab, a humanized IGF-1 and IGF-2 ligand co-neutralizing monoclonal antibody, results in synergistic antineoplastic effects in human breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1852.

Nuclear IGF1R Interacts with Regulatory Regions of Chromatin to Promote RNA Polymerase II Recruitment and Gene Expression Associated with Advanced Tumor Stage

Internalization of ligand-activated type I IGF receptor (IGF1R) is followed by recycling to the plasma membrane, degradation or nuclear translocation. Nuclear IGF1R reportedly associates with clinical response to IGF1R inhibitory drugs, yet its role in the nucleus is poorly characterized. Here, we investigated the significance of nuclear IGF1R in clinical cancers and cell line models. In prostate cancers, IGF1R was predominantly membrane localized in benign glands, while malignant epithelium contained prominent internalized (nuclear/cytoplasmic) IGF1R, and nuclear IGF1R associated significantly with advanced tumor stage. Using ChIP-seq to assess global chromatin occupancy, we identified IGF1R-binding sites at or near transcription start sites of genes including JUN and FAM21, most sites coinciding with occupancy by RNA polymerase II (RNAPol2) and histone marks of active enhancers/promoters. IGF1R was inducibly recruited to chromatin, directly binding DNA and interacting with RNAPol2 to upregulate expression of JUN and FAM21, shown to mediate tumor cell survival and IGF-induced migration. IGF1 also enriched RNAPol2 on promoters containing IGF1R-binding sites. These functions were inhibited by IGF1/II-neutralizing antibody xentuzumab (BI 836845), or by blocking receptor internalization. We detected IGF1R on JUN and FAM21 promoters in fresh prostate cancers that contained abundant nuclear IGF1R, with evidence of correlation between nuclear IGF1R content and JUN expression in malignant prostatic epithelium. Taken together, these data reveal previously unrecognized molecular mechanisms through which IGFs promote tumorigenesis, with implications for therapeutic evaluation of anti-IGF drugs.Significance: These findings reveal a noncanonical nuclear role for IGF1R in tumorigenesis, with implications for therapeutic evaluation of IGF inhibitory drugs. Cancer Res; 78(13); 3497-509. ©2018 AACR.

Abstract OT3-06-02: A phase Ib trial of xentuzumab and abemaciclib in patients with locally advanced or metastatic solid tumors, including hormone receptor-positive, HER2-negative breast cancer (plus endocrine therapy)

Background: Resistance to endocrine therapy remains an important clinical problem in hormone receptor-positive (HR+), HER2-negative (HER2-) breast cancer (BC), necessitating alternative treatment options. The insulin-like growth factor (IGF) axis and cyclin D-cyclin-dependent kinase (CDK) 4/6-retinoblastoma pathway have been implicated in the pathogenesis and resistance mechanisms of a variety of cancers, including BC. Binding of IGF-I and -II to the IGF receptor results in upregulation of cyclin D1, and subsequent progression through the cell cycle, thus providing rationale for the simultaneous inhibition of IGF-I and -II and CDK4/6. This Phase Ib trial assesses the maximum-tolerated dose (MTD)/recommended phase II dose (RP2D), safety and preliminary efficacy of the IGF-ligand-neutralizing antibody, xentuzumab, in combination with abemaciclib, a selective, small-molecule inhibitor of both CDK4 and 6, in patients (pts) with solid tumors. The trial includes four dose finding cohorts followed by two expansion cohorts. Only those cohorts that will include pts with postmenopausal HR+, HER2- BC will be presented here.

Trial design: In this phase Ib multicenter, non-randomized, open-label, dose escalation trial (BI 1280.18 [NCT03099174]), the key aims in the BC cohorts (Cohorts B–D, F) are to define the MTD or recommended phase 2 dose (RP2D), and to evaluate the preliminary efficacy, safety and tolerability of xentuzumab plus abemaciclib in combination with endocrine therapies. Eligible pts include adults ≥18 yrs (≥20 for Japan), with measurable or evaluable disease, adequate organ function, ECOG PS ≤1, and postmenopausal locally advanced or metastatic HR+, HER2- BC (Cohorts B–D, F). CDK4/6 inhibitor-naïve pts (Cohorts B–D) and pts who have received prior CDK4/6 inhibitors (palbociclib or ribociclib) plus aromatase inhibitors (Cohort F) are included. The MTD/RP2D of xentuzumab plus abemaciclib to be used in Cohorts B–D will be established in pts with solid tumors (Cohort A) who will receive xentuzumab (starting dose 1000mg weekly iv) plus abemaciclib (starting dose 150mg every 12 hours). CDK4/6 inhibitor-naïve pts with BC will receive xentuzumab plus abemaciclib at the RP2D determined in Cohort A in combination with letrozole (2.5mg/day; Cohort B), anastrozole (1mg/day; Cohort C), or fulvestrant (500mg/month; Cohort D). CDK4/6 inhibitor pre-treated pts with BC (Cohort F) will receive xentuzumab plus abemaciclib and fulvestrant at the RP2D determined in Cohort D. Primary endpoints in the BC cohorts are the MTD and/or RP2D of xentuzumab plus abemaciclib in combination with endocrine therapies, and the objective response (OR) in CDK4/6 inhibitor pre-treated pts with advanced BC (Cohort F); disease control (DC), duration of DC, time to OR, duration of OR, and progression-free survival (PFS) in Cohort F are secondary endpoints. Additionally, PK outcomes, safety and tolerability will be assessed in all cohorts. This study will be conducted in the US, Europe and Japan. Pt screening started in May 2017. Target enrolment is ˜88 pts, including ˜56 pts with advanced HR+, HER2- BC, of whom ˜20 had previously been treated with CDK 4/6 inhibitors.

Citation Format: Yee D, Sablin MP, Iwata H, Johnston EL, Bogenrieder T, Serra J, Hua H, Lo Russo P, Prat A. A phase Ib trial of xentuzumab and abemaciclib in patients with locally advanced or metastatic solid tumors, including hormone receptor-positive, HER2-negative breast cancer (plus endocrine therapy) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-06-02.

Blockade of insulin-like growth factors increases efficacy of paclitaxel in metastatic breast cancer

Breast cancer remains the leading cause of cancer death in women owing to metastasis and the development of resistance to established therapies. Macrophages are the most abundant immune cells in the breast tumor microenvironment and can both inhibit and support cancer progression. Thus, gaining a better understanding of how macrophages support cancer could lead to the development of more effective therapies. In this study, we find that breast cancer-associated macrophages express high levels of insulin-like growth factors 1 and 2 (IGFs) and are the main source of IGFs within both primary and metastatic tumors. In total, 75% of breast cancer patients show activation of insulin/IGF-1 receptor signaling and this correlates with increased macrophage infiltration and advanced tumor stage. In patients with invasive breast cancer, activation of Insulin/IGF-1 receptors increased to 87%. Blocking IGF in combination with paclitaxel, a chemotherapeutic agent commonly used to treat breast cancer, showed a significant reduction in tumor cell proliferation and lung metastasis in pre-clinical breast cancer models compared to paclitaxel monotherapy. Our findings provide the rationale for further developing the combination of paclitaxel with IGF blockers for the treatment of invasive breast cancer, and Insulin/IGF1R activation and IGF+ stroma cells as potential biomarker candidates for further evaluation.

Insulin-Like Growth Factor (IGF) Pathway Targeting in Cancer: Role of the IGF Axis and Opportunities for Future Combination Studies

Despite a strong preclinical rationale for targeting the insulin-like growth factor (IGF) axis in cancer, clinical studies of IGF-1 receptor (IGF-1R)-targeted monotherapies have been largely disappointing, and any potential success has been limited by the lack of validated predictive biomarkers for patient enrichment. A large body of preclinical evidence suggests that the key role of the IGF axis in cancer is in driving treatment resistance, via general proliferative/survival mechanisms, interactions with other mitogenic signaling networks, and class-specific mechanisms such as DNA damage repair. Consequently, combining IGF-targeted agents with standard cytotoxic agents, other targeted agents, endocrine therapies, or immunotherapies represents an attractive therapeutic approach. Anti-IGF-1R monoclonal antibodies (mAbs) do not inhibit IGF ligand 2 (IGF-2) activation of the insulin receptor isoform-A (INSR-A), which may limit their anti-proliferative activity. In addition, due to their lack of specificity, IGF-1R tyrosine kinase inhibitors are associated with hyperglycemia as a result of interference with signaling through the classical metabolic INSR-B isoform; this may preclude their use at clinically effective doses. Conversely, IGF-1/IGF-2 ligand-neutralizing mAbs inhibit proliferative/anti-apoptotic signaling via IGF-1R and INSR-A, without compromising the metabolic function of INSR-B. Therefore, combination regimens that include these agents may be more efficacious and tolerable versus IGF-1R-targeted combinations. Herein, we review the preclinical and clinical experience with IGF-targeted therapies to-date, and discuss the rationale for future combination approaches as a means to overcome treatment resistance.

Abstract 20: Xentuzumab, a humanized IGF-1 and IGF-2 ligand neutralizing antibody, improves the antitumor efficacy of enzalutamide in preclinical models of prostate cancer

Background: The proliferative and pro-survival signals driven by the insulin-like growth factor (IGF) ligands, IGF-1 and IGF-2, are transmitted through their binding to the IGF-1 receptor (IGF-1R). In addition, IGF-2 activates the insulin receptor variant A (IR-A) that is expressed during embryonic development as well as in many cancers. A large body of preclinical evidence suggests that IGF signaling plays a key role in cancer by driving therapy resistance, due to cross-talk with other signaling networks such as androgen receptor signaling. The aim of this study was to explore the potential of the IGF-1/-2 ligand blocking antibody, xentuzumab (BI 836845[1]), to enhance the anti-tumor activity of enzalutamide in prostate cancer cell lines and in a patient-derived prostate cancer xenograft model.

Methods: Effects of enzalutamide, xentuzumab and combinations thereof on in vitro proliferation, survival, cell cycle and signaling were evaluated using the prostate cancer cell lines VCaP, DuCaP, MDA PCa 2b, and LNCaP. The in vivo efficacy of enzalutamide, alone and in combination with xentuzumab was investigated using LuCaP 96CR, a patient-derived xenograft model of castration-resistant prostate cancer. Tumors were implanted s.c. into castrate SCID mice. When tumors exceeded 150mm3 animals were randomized into groups: 1) Control; 2) enzalutamide (50 mg/kg QD po), 3) xentuzumab (BI 836845[1], 200 mg/kg QW ip) in combination with enzalutamide.

Results: Cell viability was more effectively reduced by the combination of enzalutamide and xentuzumab than either drug alone in three of four cell lines expressing the IGF-1R and the androgen receptor (AR). In VCaP cells, prolonged inhibition of IGF pathway signaling and enhanced blockade of proliferation as well as induction of apoptosis was observed after combination treatment. In vivo, enzalutamide monotherapy did not show significant antitumor efficacy in the LuCaP 96CR model, however, combined treatment with xentuzumab significantly inhibited progression of LuCaP 96CR tumor growth (p<0.001 vs. enzalutamide alone). Reduced serum PSA levels were observed after enzalutamide and combination treatment. Enzalutamide plus xentuzumab inhibited tumor growth at tolerated doses and resulted in significant improvements in survival.

Conclusions: These studies demonstrated that addition of the IGF-1/-2 neutralizing antibody xentuzumab to enzalutamide results in improved anti-neoplastic activity in a subset of prostate cancer cell lines in vitro, and to re-sensitization to enzalutamide in a patient-derived xenograft model of CRPC.

Reference:

[1] Friedbichler K et al. (2014). Mol Cancer Ther 13(2):399-409.

Citation Format: Ulrike Weyer-Czernilofsky, Marco H. Hofmann, Paul J. Adam, Flavio Solca, Katrin Friedbichler, Norbert Kraut, Eva Corey, Thomas Bogenrieder. Xentuzumab, a humanized IGF-1 and IGF-2 ligand neutralizing antibody, improves the antitumor efficacy of enzalutamide in preclinical models of prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 20. doi:10.1158/1538-7445.AM2017-20

Chemoresistance in Pancreatic Cancer Is Driven by Stroma-Derived Insulin-Like Growth Factors

Tumor-associated macrophages (TAM) and myofibroblasts are key drivers in cancer that are associated with drug resistance in many cancers, including pancreatic ductal adenocarcinoma (PDAC). However, our understanding of the molecular mechanisms by which TAM and fibroblasts contribute to chemoresistance is unclear. In this study, we found that TAM and myofibroblasts directly support chemoresistance of pancreatic cancer cells by secreting insulin-like growth factors (IGF) 1 and 2, which activate insulin/IGF receptors on pancreatic cancer cells. Immunohistochemical analysis of biopsies from patients with pancreatic cancer revealed that 72% of the patients expressed activated insulin/IGF receptors on tumor cells, and this positively correlates with increased CD163⁺ TAM infiltration. In vivo, we found that TAM and myofibroblasts were the main sources of IGF production, and pharmacologic blockade of IGF sensitized pancreatic tumors to gemcitabine. These findings suggest that inhibition of IGF in combination with chemotherapy could benefit patients with PDAC, and that insulin/IGF1R activation may be used as a biomarker to identify patients for such therapeutic intervention. Cancer Res; 76(23); 6851-63. ©2016 AACR.

Reversal of the low-affinity neurotrophin receptor stromal-epithelial expression pattern between benign and malignant human prostate

Reduced expression of the low-affinity p75 neurotrophin receptor (p75(NTR)) occurs in prostate epithelial cells during malignant transformation. Recent studies indicating that the p75(NTR) can transduce signals that induce apoptosis suggest that diminished p75(NTR) in transformed prostate cells may contribute to immortalization. Mutations in the transmembrane domain of the p75(NTR) gene have been associated with decreased p75(NTR) protein expression and may block the ability of the p75(NTR) to induce apoptosis. Therefore, we used Western blot to analyze prostate cancer (PC) cell lines for p75(NTR) protein expression and gene single strand conformation polymorphism (SSCP) analysis and direct DNA sequencing to analyze mutations in the transmembrane domain of the p75(NTR). p75(NTR) Protein was present in all cell lines, and mutations in the p75(NTR) gene were not detected in cDNA derived from any cell line. To define the expression pattern of p75(NTR) in PCs in vivo, we used immunohistochemical techniques to examine tissue specimens from 20 benign, 19 malignant primary, and 14 metastatic prostate specimens. In benign prostate tissues, expression of p75(NTR) was universally detected in basal cells but not in secretory epithelial or stromal cells. In both primary and metastatic PC tissues, p75(NTR) immunoreactivity could not be detected in malignant prostate epithelial cells. However, in contrast to the benign prostate, p75(NTR) protein was expressed in stromal cells surrounding malignant epithelial cells. Stromal p75(NTR) expression was present in 84% (16 of 19) primary and in 86% (12 of 14) metastatic specimens. These data show that in the benign prostate p75(NTR) protein is expressed by basal cells and not stromal cells whereas in malignant prostate p75(NTR) protein is expressed by stromal cells but not prostatic carcinoma cells. Reversal of the p75(NTR) stromal-epithelial pattern of expression between benign and malignant prostate suggests that p75(NTR) may contribute to the development and maintenance of prostate cancer.

BI 836845, a fully human IGF ligand neutralizing antibody, to improve the efficacy of rapamycin by blocking rapamycin-induced AKT activation

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Background: Analogs of rapamycin (rapalogs) targeting mammalian target of rapamycin complex 1 (mTORC1) have shown clinical activity in several cancers. Nonetheless, preclinical and clinical data suggest that there may be intrinsic resistance to rapalogs through a feedback loop which activates upstream signaling when mTORC1 is blocked. BI 836845 is a fully human antibody, currently in phase I clinical trials, which potently neutralizes both IGF-1 and IGF-2. We tested whether BI 836845 is able to improve the efficacy of rapamycin by inhibiting upstream signaling in preclinical models. Methods: Cancer cell lines were profiled in vitro and in vivo for sensitivity to BI 836845 and rapamycin, alone or in combination. Mitogenic signaling was examined by measuring levels of phosphorylated AKT (pAKT) using Western blot analysis. IGF bioactivity was determined using a cellular IGF-1R phosphorylation ELISA. Results: The combination of BI 836845 and rapamycin was more effective than either agent alone at inhibiting the proliferation of Ewing’s sarcoma cells cultured in vitro as well as in a nude mouse xenograft model in vivo. Analysis of cell signaling upstream of mTOR demonstrated that treatment with rapamycin alone resulted in elevated pAKT, indicating feedback loop activation. BI 836845 treatment alone or in combination with rapamycin inhibited AKT phosphorylation, demonstrating that the rapamycin-induced increase in pAKT was due to elevated IGF bioactivity. Consistent with this we demonstrated that rapamycin increased IGF bioactivity in mice and that this could be inhibited by BI 836845. We extended these studies to include other cancer cell lines and profiled the correlation between improved efficacy of the combination with BI 836845 inhibition of rapamycin-induced feedback. A correlation has been observed for cancer cells derived from several indications. Conclusions: Rapamycin treatment increases AKT activation via elevated IGF ligand bioactivity. This effect can be inhibited by BI 836845, thus explaining the improved pre-clinical efficacy seen when both agents are combined. These data provide a rationale for the clinical combination of rapalogs and BI 836845.

Spontaneous adverse event reports of Stevens-Johnson syndrome/toxic epidermal necrolysis: detecting associations with medications

PURPOSE

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are medically serious skin reactions that are often drug induced. The mainstay of therapy and future prevention is to discontinue and avoid the use of the suspected inducing drug. However, many cases of SJS/TEN occur in patients who are taking multiple medications, and it is often difficult to determine which drug to stop. This analysis was conducted to identify drugs that were most associated with SJS/TEN in the US Food and Drug Administration (FDA) Adverse Event Reporting System (AERS) database and to identify medications that were likely innocent bystanders.

METHODS

A Multi-item Gamma Poisson Shrinker value with an EB05 ≥ 2 was considered a disproportional increase in reporting frequency (at least two times higher than expected). The identified drugs with reporting frequency of SJS/TEN in the US FDA AERS database were then compared to the EuroSCAR (European case-control surveillance of severe cutaneous adverse reactions) study results as a reference to define signals. The EB05s were calculated as a cumulative relative reporting frequency from 1968 to 3Q2009.

RESULTS

Fifty drugs were identified as being associated with SJS/TEN. This included 12 "highly suspect" drugs and 36 "suspect" drugs. Meloxicam was the only drug that appeared on the "highly suspect" list from EuroSCAR that did not show a disproportional increase in relative reporting frequency (EB05 = 0.734). In addition, several drugs did not have an association with SJS/TEN (EB05 < 2).

CONCLUSIONS

There was good concordance between the reporting frequencies observed in the FDA AERS database and the published risk estimation of medications implicated in SJS/TEN.

Topotecan Weekly Versus Conventional 5-Day Schedule in Patients With Platinum-Resistant Ovarian Cancer: a randomized multicenter phase II trial of the North-Eastern German Society of Gynecological Oncology Ovarian Cancer Study Group

PURPOSE

Weekly administration of topotecan (Tw) is less toxic and widely considered a better treatment option than conventional 5-day therapy (Tc) in women with platinum-resistant recurrent ovarian cancer. We conducted a randomized phase II trial (TOWER [Topotecan Weekly Versus Conventional 5-Day Schedule in Patients With Platinum-Resistant Ovarian Cancer]) to better define the ratio between benefits and risks with either treatment approach.

PATIENTS AND METHODS

Patients were randomly assigned to two independent two-stage protocols of Tw (4 mg/m(2)/wk administered on days 1, 8, and 15) or Tc (1.25 mg/m(2)/d on days 1 to 5). We evaluated risk ratios (RRs) for the primary end point of clinical benefit (complete response, partial response, and stable disease), the duration of progression-free survival (PFS) and overall survival (OS), associated hazard ratios (HRs), and RRs of toxicity with 95% CIs.

RESULTS

In total, 194 patients were randomly assigned at 54 centers to Tw (n = 97) or Tc (n = 97). Clinical benefit was observed in 36 of 76 (47%; 95% CI, 36% to 59%) Tw and 46 of 80 (58%; 95% CI, 46% to 68%) Tc patients (RR, 1.21; 95% CI, 0.90 to 1.64; P = .205). Patients in the Tw group had a slightly shorter PFS (HR, 1.29; 95% CI, 0.96 to 1.76) but similar OS (HR, 1.04; 95% CI, 0.74 to 1.45) compared with Tc. Tw was associated with significantly lower risks of anemia (RR, 0.35; 95% CI, 0.16 to 0.79), neutropenia (RR, 0.38; 95% CI, 0.23 to 0.65), and thrombocytopenia (RR, 0.23; 95% CI, 0.09 to 0.57).

CONCLUSION

With regard to effectiveness in terms of response and PFS, Tc remains the standard of care in patients with platinum-resistant recurrent ovarian cancer. However, comparable OS rates and a favorable toxicity profile make Tw another viable treatment option in this setting.

Topotecan in cervical cancer

Recurrent and advanced cervical cancers are associated with high mortality and a lack of effective treatment options, especially for women who are poor candidates for surgery or radiation therapy. The broad clinical effectiveness and manageable toxicity of topotecan in other human malignancies as well as promising recent study results suggest that it is highly effective in treating cervical tumors. We therefore conducted a systematic review on the studies using topotecan in cervical cancer. Seven phase I-III clinical trials using topotecan, both as a single agent and in combination with cisplatin or paclitaxel, in patients with recurrent or advanced carcinoma of the cervix were reviewed. Data from two studies in which topotecan was used in combination with radiotherapy for induction therapy were also evaluated. Although single-agent cisplatin-based chemoradiotherapy is the standard of care for high-risk or locally advanced cervical cancer, topotecan, when used concurrently with cisplatin and/or radiation therapy, produces high objective response rates and prolonged survival. Gynecologic Oncology Group (GOG) Protocol 179 for the first time showed significantly improved overall survival and progression-free survival in a combination therapy for advanced cervical cancer compared to cisplatin alone. Recent data suggest that topotecan, when used concurrently with cisplatin, may be the new standard of care for the management of recurrent or advanced cervical cancer. Ongoing phase III studies (GOG-204, AGO-Zervix-1) will compare this combination with other cisplatin-containing and cisplatin-free combinations. Moreover, further evaluation of topotecan appears to be warranted in conjunction with radiotherapy and in the neoadjuvant setting as well as in combination with novel biologic agents.

[Detection of lymph node metastases of malignant melanoma by palpation and ultrasound]

BACKGROUND AND PURPOSE

Early detection of metastases of malignant melanoma has therapeutic implications. The aim of this study was to evaluate palpation and ultrasound examination in the diagnostics of lymph node metastases in locally advanced melanoma.

PATIENTS AND METHODS

83 patients suffering from melanoma (Clark level IV or V) were examined for lymph node metastases by palpation and sonography. Findings were compared to histopathologic results after lymph node extirpation if available or the findings at the next follow-up visit.

RESULTS

Lymph node metastases were confirmed histopathologically in 14 patients at the first study visit, in three others at the control visit. Sensitivity, specificity, positive and negative predictive values of palpation for the detection of metastases or suspicious nodes with increasing volume at follow-up in this population were 65%, 81%, 48%, and 89%, and of ultrasound 100%, 66%, 45%, and 100%, respectively.

CONCLUSION

Sonography of lymph nodes should be included as a standard procedure in the detection of metastases of locally advanced malignant melanoma.

Axis of evil: molecular mechanisms of cancer metastasis

Although the genetic basis of tumorigenesis may vary greatly between different cancer types, the cellular and molecular steps required for metastasis are similar for all cancer cells. Not surprisingly, the molecular mechanisms that propel invasive growth and metastasis are also found in embryonic development, and to a less perpetual extent, in adult tissue repair processes. It is increasingly apparent that the stromal microenvironment, in which neoplastic cells develop, profoundly influences many steps of cancer progression, including the ability of tumor cells to metastasize. In carcinomas, the influences of the microenvironment are mediated, in large part, by bidirectional interactions (adhesion, survival, proteolysis, migration, immune escape mechanisms lymph-/angiogenesis, and homing on target organs) between epithelial tumor cells and neighboring stromal cells, such as fibroblasts as well as endothelial and immune cells. In this review, we summarize recent advances in understanding the molecular mechanisms that govern this frequently lethal metastatic progression along an axis from primary tumor to regional lymph nodes to distant organ sites. Affected proteins include growth factor signaling molecules, chemokines, cell-cell adhesion molecules (cadherins, integrins) as well as extracellular proteases (matrix metalloproteinases). We then discuss promising new therapeutic approaches targeting the microenvironment. We note, however, that there is still too little knowledge of how the many events are coordinated and integrated by the cancer cell, with conspiratorial help by the stromal component of the host. Before drug development can proceed with a legitimate chance of success, significant gaps in basic knowledge need to be filled.

Reciprocal regulation of MelCAM and AKT in human melanoma

Alteration in the expression of invasion/metastasis-related melanoma cell adhesion molecule (MelCAM) is strongly associated with the acquisition of malignancy by human melanoma. However, little is known about the molecular and biochemical mechanisms that regulate the expression and function of MelCAM, or its downstream signaling transduction. In this study, we show that there is a reciprocal regulation loop between AKT and MelCAM. Pharmacological inhibition of AKT in human melanoma cell lines substantially reduced the expression of MelCAM. Overexpression of constitutively active AKT upregulated the levels of MelCAM in melanoma cell lines, whereas expression of a dominant-negative PI-3 kinase downregulated MelCAM. On the other hand, overexpression of MelCAM activated endogenous AKT and inhibited proapoptotic protein BAD in melanoma cells, leading to increased survival under stress conditions. Constitutive activation of AKT was observed in most melanoma cell lines and tumor samples of different progression stages. These data link AKT activation with MelCAM expression, and implicate that intervention of MelCAM-AKT signaling axis in melanoma is a potential therapeutical approach.

Treatment of Old World cutaneous leishmaniasis with intralesionally injected meglumine antimoniate using a Dermojet device

Pentavalent antimonial compounds, the mainstay in the treatment of the various forms of leishmaniasis, have considerable toxicity, are difficult to administer and expensive. We describe a safe and efficient therapeutic modality using a spring-loaded and air-powered device for the intralesional injection of a high-velocity meglumine antimoniate microspray in a patient with cutaneous leishmaniasis.

Orofacial granulomatosis as the initial presentation of Crohn's disease in an adolescent

Orofacial granulomatosis (OFG) is a rare and heterogeneous clinical condition that presents with chronic swelling of the oral or facial tissues due to granulomatous inflammation. It is histologically characterized by noncaseating giant cell granulomata and epithelioid histiocytes. OFG includes the previously recognized clinical entities of Melkersson-Rosenthal syndrome and cheilitis granulomatosa (Miescher's cheilitis). A consistently effective medical treatment is not currently available. We describe an adolescent patient with a history of recurrent orofacial swelling preceding gastrointestinal symptoms by several years. He exhibited clinical and histological changes consistent with the diagnosis of OFG. It was resistant to standard therapies such as topical corticosteroids. Thorough history taking and clinical examination suggested Crohn's disease (CD), and further tests confirmed the diagnosis. The patient improved promptly after initiating oral treatment for CD with mesalazine and prednisolone. We conclude that OFG may be under- or misdiagnosed since the clinical manifestation may be misleading and its course is independent of or even preceding CD. Thus, patients with OFG should be asked about gastrointestinal symptoms consistent with CD. Those with suspicious symptoms should undergo a careful gastrointestinal evaluation, possibly including enteroclysis and complete gastrointestinal endoscopic examination, especially when the patient's history is conspicuous.

Function and regulation of melanoma-stromal fibroblast interactions: when seeds meet soil

Melanoma development and progression not only involve genetic and epigenetic changes that take place within the melanocytic cells, but also involve processes that are determined collectively by contextual factors including intercellular adhesions and communications. In this review, we focus on melanoma-stromal fibroblast crosstalk by direct cell-cell contact and by growth factors/cytokines/chemokines interacting with their respective receptors. The interactions between melanoma cells and stromal fibroblasts create a context that promotes tumor growth, migration/invasion, and angiogenesis. An understanding of this process and developing new experimental and screening models are of great importance for the development of effective therapeutical strategies to treat melanoma.

Benign Degos' disease developing during pregnancy and followed for 10 years

Degos' disease, or malignant atrophic papulosis, is a rare and often fatal multisystem vasculopathy of unknown etiology. The cutaneous manifestations comprise erythematous papules, which heal to leave scars with a pathognomonic central porcelain-white atrophic area and a peripheral telangiectatic rim. Involvement of the gastrointestinal tract is observed in 50% of cases, with intestinal perforation being the most common cause of death. Other organ systems can also be affected; 20% of cases involve the central nervous system. Systemic manifestations usually develop from weeks to years after onset of skin lesions or, in rare instances, may precede skin lesions. In the patient with Degos' disease reported in this article, the characteristic skin lesions developed during pregnancy, a precipitating event not previously reported. She has survived an unusually long time (10 years) without visceral or neurological involvement, despite florid cutaneous lesions. Moreover, we could detect the presence of antiphospholipid antibodies, the significance of which are currently unclear. These observations therefore confirm that there may be a strictly cutaneous form of Degos' disease with a favourable prognosis.

Stroma formation and angiogenesis by overexpression of growth factors, cytokines, and proteolytic enzymes in human skin grafted to SCID mice

Reorganization of skin during wound healing, inflammatory disorders, or cancer growth is the result of expression changes of multiple genes associated with tissue morphogenesis. We wanted to identify proteins involved in skin remodeling and select those that may be targeted for agonistic or antagonist therapeutic approaches in various disease processes. Full-thickness human skin was grafted to severe combined immunodeficient mice and injected intradermally with 38 different adenoviral vectors inserted with 37 different genes coding for growth factors, cytokines, proteolytic enzymes and their inhibitors, adhesion receptors, oncogenes, and tumor suppressor genes. Responses were characterized for infiltration of inflammatory cells, vascular density, matrix formation, fibroblast-like cell proliferation, and epidermal hyperplasia. Of the 17 growth factor vectors, 16 induced histological changes in human skin. Members of the VEGF and angiopoietin families induced neovascularization. PDGFs and TGF-betas stimulated connective tissue formation, and the chemokines IL-8 and MCP-1 attracted inflammatory neutrophils and monocytes, respectively. The serine protease uPA induced a vascular response similar to that of VEGF. Vectors with adhesion receptors, oncogenes and tumor suppressor genes had, with few exceptions, little effects on skin architecture. The overall results suggest that adenoviral vectors can effectively remodel the architecture of human skin for studies in morphogenesis, inflammatory skin disorders, wound healing, and cancer development.

[From the New World. Louis A. Duhring and dermatitis herpetiformis]

Louis Adolphus Duhring (born December 23, 1845) died in Philadelphia, the city of his birth and life work, on May 8, 1913. After medical school, he studied for two years in dermatology departments in London, Paris and Vienna. As a student in Vienna, he was under the tutelage of Ferdinand von Hebra, when the brilliant clinician and teacher was at the zenith of his fame. Duhring's series of 18 papers--published between 1884 and 1891--gave him an important and recognized position as one of the leading dermatological thinkers of the world. These publications described the skin disease which he named "dermatitis herpetiformis" (Duhring's disease). His assertion that dermatitis herpetiformis was a distinct dermatological disease process aroused at first considerable opposition. Moriz Kaposi, at that time the doyen of the Vienna school of dermatology, attacked his views with vigor and tenacity. Louis A. Duhring--this modest, unassuming, quiet-working, gentlemanly physician--made monumental contributions to American dermatology and played a significant role in establishing Philadelphia as one of the great centers of dermatologic activity.

Differential response of primary and metastatic melanomas to neutrophils attracted by IL-8

IL-8 is a strong chemoattractant for neutrophils, and it is constitutively produced by many tumors, including human melanomas. To determine the biologic importance of IL-8 for melanoma cells from primary and metastatic lesions, we transduced selected cell lines constitutively producing low levels of IL-8 with IL-8 cDNA using a replication-deficient adenoviral vector. Nontumorigenic SBcl2 primary melanoma cells formed tumors when transduced with increasing plaque-forming units of IL-8 per cell. However, at high IL-8 transduction levels (100 ng/ml/10(5) cells in 48 hr), tumor growth was impaired due to massive neutrophil infiltration. A similar biphasic response was observed in WM115 primary melanomas, which are tumorigenic but not metastatic. Depletion of neutrophils with an antibody that blocks the accumulation of granulocytes at the site of inflammation enabled transduced primary melanomas secreting high levels of IL-8 to survive and grow. In contrast, highly tumorigenic and metastatic 451Lu cells showed marked increases in tumor growth and number of metastatic foci in the lungs depending on the expression levels of IL-8. Cytotoxicity assays with isolated neutrophils confirmed the preferential killing of primary over metastatic melanoma cells. SBcl2 cells stimulated by IL-8 to form tumors in immunodeficient mice were induced to produce VEGF, suggesting that the angiogenic response is enhanced due to increased growth factor production. Our results demonstrate that nontumorigenic primary melanomas depend on IL-8 stimulation in vivo for growth and that tumor growth depends on the level of neutrophil infiltration. Metastatic melanomas proliferate in vivo independently of infiltrating neutrophils.

Eruptive multiple lentigo-maligna-like lesions in a patient undergoing chemotherapy with an oral 5-fluorouracil prodrug for metastasizing colorectal carcinoma: a lesson for the pathogenesis of malignant melanoma?

Induction of multiple eruptive dermal and atypical melanocytic naevi has frequently been reported in children with malignant haematological diseases and chemotherapy-induced immunosuppression. This is the first report of an adult patient to develop multiple eruptive melanocytic skin lesions while undergoing chemotherapy with an oral 5-fluorouracil prodrug for metastasizing cancer. Our observation adds further evidence to the link between systemic (iatrogenic or intrinsic) immunosuppression and the induction of melanocyte proliferation and transformation.

Cell-surface proteolysis, growth factor activation and intercellular communication in the progression of melanoma

Normal skin architecture and melanocyte function is maintained by a dynamic interplay between the melanocytes themselves, the epithelial cells between which they are interspersed, and their microenvironment. The microenvironment consists of the extracellular matrix, fibroblasts, migratory immune cells, and neural elements supported by a vascular network, all within a milieu of cytokines, growth factors, and bioactive peptides as well as proteolytic enzymes. Cells interact with the microenvironment via complex autocrine and paracrine mechanisms. Proteolytic enzymes in melanoma may activate or release growth factors from the microenvironment or act directly on the microenvironment itself, thereby facilitating angiogenesis or tumor cell migration. This review summarizes recent findings regarding the expression, structure and function of proteolytic enzymes at or near the cell surface in cell-cell and cell-stroma interactions during melanoma progression. Cell-surface (membrane) peptidases are a multi-functional group of ectoenzymes that have been implicated in the control of growth and differentiation of many cellular systems. The potential, but yet speculative, role of other membrane-bound molecules, such as multifunctional surface proteins with adhesion and protease activity (ADAM gene family) or the ephrin/Eph receptor protein kinases in the pathogenesis of melanoma are discussed.

Multiple, bilateral and painful ear nodules of the anthelices: a variant of chondrodermatitis nodularis?

A case of a distinctive clinicopathologic condition of the ear cartilage is presented, characterized by multiple, bilateral and painful nodules of the anthelices without epidermal involvement. Histologically, there was a peri-chondrial lymphohistiocytic infiltrate and a small focus of degenerate, basophilic cartilage as well as cystic chondromalacia containing an amorphous mass. This condition is both clinically and histopathologically distinct from other causes of ear nodules, although the lesions seen in our patient exhibit features of chondrodermatitis nodularis helices and therefore could well be a variant of the latter.