Hans R. Hendriks

BI-847325 is an ATP-competitive inhibitor of MEK/Aurora kinases with the potential to treat a wide range of cancers. In a panel of 294 human tumor cell lines in vitro, BI-847325 was found to be a highly selective inhibitor that was active in the submicromolar range. The most sensitive cancer types were acute lymphocytic and myelocytic leukemia, melanomas, bladder, colorectal, and mammary cancers. BI-847325 showed a broader range of activity than the MEK inhibitor GDC-0623. The high efficacy of BI-847325 was associated with but not limited to cell lines with oncogenic mutations in NRAS, BRAF, and MAP2K1.The high antiproliferative activity of BI-847325 was validated in vivo using subcutaneous xenograft models. After oral administration of 80 and 40 mg/kg once weekly for 3 or 4 weeks, BI-847325 was highly active in four of five colorectal, two of two gastric, two of two mammary, and one of one pancreatic cancer models (test/control < 25%), and tumor regressions were observed in five of 11 cancer models. The treatment was well tolerated with no relevant lethality or body weight changes. In combination with capecitabine, BI-847325 displayed synergism over single-agent therapies, leading to complete remission in the triple-negative mammary model MAXFTN 401, partial regression in the colon model CXF 1103, and stasis in the gastric models GXA 3011 and GXA 3023. In conclusion, dual MEK/Aurora kinase inhibition shows remarkable potential for treating multiple types of hematologic and solid tumors. The combination with capecitabine was synergistic in colorectal, gastric, and mammary cancer.Significance:We report the preclinical evaluation of BI-847325, a MEK/Aurora kinase inhibitor. Our data demonstrate that BI-847325 has potent antitumor activity in a broad range of human solid and hematologic cancer models in vitro and in vivo and is well tolerated in animal models. It also shows synergistic effect when combined with capecitabine. These findings provide a strong rationale for further development of BI-847325 as a potential therapeutic for patients with cancer.

BI-847325 is an ATP-competitive inhibitor of MEK/Aurora kinases with the potential to treat a wide range of cancers. In a panel of 294 human tumor cell lines in vitro, BI-847325 was found to be a highly selective inhibitor that was active in the submicromolar range. The most sensitive cancer types were acute lymphocytic and myelocytic leukemia, melanomas, bladder, colorectal, and mammary cancers. BI-847325 showed a broader range of activity than the MEK inhibitor GDC-0623. The high efficacy of BI-847325 was associated with but not limited to cell lines with oncogenic mutations in NRAS, BRAF, and MAP2K1.The high antiproliferative activity of BI-847325 was validated in vivo using subcutaneous xenograft models. After oral administration of 80 and 40 mg/kg once weekly for 3 or 4 weeks, BI-847325 was highly active in four of five colorectal, two of two gastric, two of two mammary, and one of one pancreatic cancer models (test/control < 25%), and tumor regressions were observed in five of 11 cancer models. The treatment was well tolerated with no relevant lethality or body weight changes. In combination with capecitabine, BI-847325 displayed synergism over single-agent therapies, leading to complete remission in the triple-negative mammary model MAXFTN 401, partial regression in the colon model CXF 1103, and stasis in the gastric models GXA 3011 and GXA 3023. In conclusion, dual MEK/Aurora kinase inhibition shows remarkable potential for treating multiple types of hematologic and solid tumors. The combination with capecitabine was synergistic in colorectal, gastric, and mammary cancer.Significance:We report the preclinical evaluation of BI-847325, a MEK/Aurora kinase inhibitor. Our data demonstrate that BI-847325 has potent antitumor activity in a broad range of human solid and hematologic cancer models in vitro and in vivo and is well tolerated in animal models. It also shows synergistic effect when combined with capecitabine. These findings provide a strong rationale for further development of BI-847325 as a potential therapeutic for patients with cancer.

BI-847325 is an ATP-competitive inhibitor of MEK/Aurora kinases with the potential to treat a wide range of cancers. In a panel of 294 human tumor cell lines in vitro, BI-847325 was found to be a highly selective inhibitor that was active in the submicromolar range. The most sensitive cancer types were acute lymphocytic and myelocytic leukemia, melanomas, bladder, colorectal, and mammary cancers. BI-847325 showed a broader range of activity than the MEK inhibitor GDC-0623. The high efficacy of BI-847325 was associated with but not limited to cell lines with oncogenic mutations in NRAS, BRAF, and MAP2K1. The high antiproliferative activity of BI-847325 was validated in vivo using subcutaneous xenograft models. After oral administration of 80 and 40 mg/kg once weekly for 3 or 4 weeks, BI-847325 was highly active in four of five colorectal, two of two gastric, two of two mammary, and one of one pancreatic cancer models (test/control < 25%), and tumor regressions were observed in five of 11 cancer models. The treatment was well tolerated with no relevant lethality or body weight changes. In combination with capecitabine, BI-847325 displayed synergism over single-agent therapies, leading to complete remission in the triple-negative mammary model MAXFTN 401, partial regression in the colon model CXF 1103, and stasis in the gastric models GXA 3011 and GXA 3023. In conclusion, dual MEK/Aurora kinase inhibition shows remarkable potential for treating multiple types of hematologic and solid tumors. The combination with capecitabine was synergistic in colorectal, gastric, and mammary cancer. Significance: We report the preclinical evaluation of BI-847325, a MEK/Aurora kinase inhibitor. Our data demonstrate that BI-847325 has potent antitumor activity in a broad range of human solid and hematologic cancer models in vitro and in vivo and is well tolerated in animal models. It also shows synergistic effect when combined with capecitabine. These findings provide a strong rationale for further development of BI-847325 as a potential therapeutic for patients with cancer.

MI-773 is a recently developed small-molecule inhibitor of the mouse double minute 2 (MDM2) proto-oncogene. Preclinical data on the anti-tumour activity of MI-773 are limited and indicate that tumour cell lines (CLs) with mutatedTP53are more resistant to MI-773 than wild typeTP53. Here, we explored the compound’s therapeutic potential in vitro using a panel of 274 annotated CLs derived from a diversity of tumours. MI-773 exhibited a pronounced selectivity and moderate potency, with anti-tumour activity in the sub-micromolar range in about 15% of the CLs. The most sensitive tumour types were melanoma, sarcoma, renal and gastric cancers, leukaemia, and lymphoma. A COMPARE analysis showed that the profile of MI-773 was similar to that of Nutlin-3a, the first potent inhibitor of p53–MDM2 interactions, and, in addition, had a superior potency. In contrast, it poorly correlates with profiles of compounds targeting the p53 pathway with another mechanism of action. OMICS analyses confirmed that MI-773 was primarily active in CLs with wild typeTP53. In silico biomarker investigations revealed that theTP53mutation status plus the aggregated expression levels of 11 genes involved in the p53 signalling pathway predicted sensitivity or resistance of CLs to inhibitors of p53–MDM2 interactions reliably. The results obtained for MI-773 could help to refine the selection of cancer patients for therapy.

The BET family of bromodomain proteins (BRD2, BRD3, BRD4, and BRDT) has emerged as a promising new cancer target for small-molecule drug discovery. GSK 1324726A (I-BET726) is a highly selective inhibitor of BET family proteins that binds BRD2, BRD3 and BRD4 with IC50 of 41 nM, 31 nM, and 22 nM, respectively. In the present study, we aimed to identify sensitive tumor types for GSK 1324726A and predictive biomarkers for response or resistance. GSK 1324726A was tested in vitro in a 2D monolayer assay in 274 human tumor cell lines of 36 tumor types (50 liquid and 224 solid cancer cell lines). Antitumor activity was then tested in vivo in 5 of the most sensitive tumor cell lines transplanted sc in nude mice. Drug sensitivity results in vitro were correlated with molecular data of the tumor models, including whole exome mutations, gene copy number variations and gene expression profiles. GSK 1324726A showed a moderate anti-tumor potency (median IC70 6,6 µM, range 0.03 - >30 µM) and a pronounced selectivity in a wide range of blood and solid cancer cell lines. AML, ALL, multiple myelomas and B-cell lymphomas were 1 log more sensitive than the most sensitive solid tumors. Taking 10% of the median IC70 of all tumors as cut off (0.66 µM) 5/11 AML, 4/9 ALL, 5/11 MM and 7/13 B-NHL were sensitive. Among the solid tumor panel cervix uterus and prostate models were sensitive (2/5) followed by breast, soft tissue, CRC, ovarian cancers and melanomas (between 17 and 40%). In-vivo experiments of the most sensitive tumors are under way. The MTD of GSK 1324726A (po for 15 days) was 15 mg/kg/day as it effected a slight body weight loss of 4% and no lethality. Evaluation of tumor cell lines for molecular parameters associated with response was carried out separately for hematologic and solid cell lines. For the leukemias, lymphomas and myelomas about 100 genes were significantly associated with response to GSK 1324726A at the transcriptome level (intersection of Spearman and Limma tests, adjusted p values . Extending evaluation of the compound in vivo and continuing investigation of predictors of response are underway. Citation Format: Heinz-Herbert Fiebig, Gerhard Kelter, Hans R Hendriks, Vincent Vuaroqueaux. Broad spectrum activity of the BET inhibitor GSK 1324726A in hematologic and solid cancer cell lines in-vitro and determination of associated predictive biomarkers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3074.

Drug development consists of many sequential and parallel steps; failure in one of the steps can lead to discontinuation of the process. The process is time-consuming and very expensive, especially the clinical phase. In order to enhance cancer drug development in the 1980s, the National Cancer Institute (NCI) adopted a new screening system using 60 different tumour cell lines from various histologies. All standard drugs were tested in this panel and it is still open for testing of new chemical entities (NCE) of potential interest. The European NCI compounds initiative, a collaborative programme of the NCI, the Cancer Research Campaign (CRC; now CRUK) and the Pharmacology and Molecular Mechanism Group (PAMM) of the EORTC (European Organization on Research and Treatment of Cancer), was initiated in 1993. The programme aimed to help the NCI reducing its backlog of in vivo testing by further evaluation of interesting European compounds using a pharmacologically directed approach. Considerable multidisciplinary expertise in drug development was combined by the CRC and EORTC-PAMM: chemists, pharmacists, biologists, pharmacologists, oncologists. Selection criteria for European NCI compounds included novelty of the NCE, in vitro activity, if available in vivo and hollow fibre activity, and COMPARE negativity. Over a period of more than 20 years 95 out of approximately 2,000 reviewed compounds were selected. These compounds were put through a series of stepwise pharmacological tests comprising solubility (suitable formulation to administer the NCE to mice), feasibility to develop a simple analytical assay (usually HPLC), limited toxicology and angiogenic properties. This paper provides examples to illustrate the rigorousness of the elimination process of the compounds and discusses the way to improve the process by inclusion of more physico-chemical parameters.

Apaziquone (also known as EO9 and QapzolaTM) is a prodrug that is activated to DNA damaging species by oxidoreductases (particularly NQO1) and has the ability to kill aerobic and/or hypoxic cancer cells. Areas covered: Whilst its poor pharmacokinetic properties contributed to its failure in phase II clinical trials when administered intravenously, these properties were ideal for loco-regional therapies. Apaziquone demonstrated good anti-cancer activity against non-muscle invasive bladder cancer (NMIBC) when administered intravesically to marker lesions and was well tolerated with no systemic side effects. However, phase III clinical trials did not reach statistical significance for the primary endpoint of 2-year recurrence in apaziquone over placebo although improvements were observed. Post-hoc analysis of the combined study data did indicate a significant benefit for patients treated with apaziquone, especially when the instillation of apaziquone was given 30 min or more after surgery. A further phase III study is ongoing to test the hypotheses generated in the unsuccessful phase III studies conducted to date. Expert opinion: Because of its specific pharmacological properties, Apaziquone is excellently suited for local therapy such as NMIBC. Future studies should include proper biomarkers.

The European NCI compounds programme, a joint initiative of the EORTC Research Branch, Cancer Research Campaign and the US National Cancer Institute, was initiated in 1993. The objective was to help the NCI in reducing the backlog of in vivo testing of potential anticancer compounds, synthesised in Europe that emerged from the NCI in vitro 60-cell screen. Over a period of more than twenty years the EORTC—Cancer Research Campaign panel reviewed ∼ 2000 compounds of which 95 were selected for further evaluation. Selected compounds were stepwise developed with clear go/no go decision points using a pharmacologically directed programme. This approach eliminated quickly compounds with unsuitable pharmacological properties. A few compounds went into Phase I clinical evaluation. The lessons learned and many of the principles outlined in the paper can easily be applied to current and future drug discovery and development programmes. Changes in the review panel, restrictions regarding numbers and types of compounds tested in the NCI in vitro screen and the appearance of targeted agents led to the discontinuation of the European NCI programme in 2017 and its transformation into an academic platform of excellence for anticancer drug discovery and development within the EORTC-PAMM group. This group remains open for advice and collaboration with interested parties in the field of cancer pharmacology.