Combination Of Temsirolimus Research Articles

Temsirolimus inhibits FSP1 enzyme activity to induce ferroptosis and restrain liver cancer progression.

Ferroptosis is a non-apoptotic mode of cell death characterized by iron-dependent accumulation of lipid peroxidation. While lipid radical elimination reaction catalyzed by glutathione peroxidase 4 (GPX4) is a major anti-ferroptosis mechanism, inhibiting this pathway pharmaceutically shows promise as an anti-tumor strategy. However, certain tumor cells exhibit redundancy in lipid radical elimination pathways, rendering them unresponsive to GPX4 inhibitors. In this study, we conducted screens across different cancer cell lines and FDA-approved drugs, leading to the identification of temsirolimus in combination with the GPX4 inhibitor RSL3 as a potent inducer of ferroptosis in liver cancer cells. Mechanistically, temsirolimus sensitized liver cancer cells to ferroptosis by directly binding to and inhibiting ferroptosis suppressor protein 1 (FSP1) enzyme. Notably, while temsirolimus is recognized as a potent mTOR inhibitor, its ferroptosis-inducing effect is primarily attributed to its inhibition of FSP1 rather than mTOR activity. By performing in vitro colony formation assays and in vivo tumor xenograft models, we demonstrated that the combination of temsirolimus and RSL3 effectively suppressed liver tumor progression. This tumoricidal effect was associated with increased lipid peroxidation and induction of ferroptosis. In conclusion, our findings underscore the potential of combining multi-target ferroptosis-inducing agents to circumvent resistance to ferroptosis in liver cancer cells and highlight temsirolimus as a promising FSP1 inhibitor and ferroptosis inducer, which also deserves further investigation in translational medicine.

Abstract A121: Temsirolimus in combination with metformin in patients with advanced or recurrent endometrial cancer

Abstract Background: Molecular alterations in the PI3K/AKT and Ras/Raf/MAPK are frequently seen in endometrial cancers and mTOR is a downstream target activated by both pathways. Blocking mTOR with temsirolimus produced modest response. Studies have shown that metformin, in addition to producing metabolic changes, also causes activation of AMPK, which in turn inhibits the mTOR pathway. Therefore, we enrolled patients with advanced or recurrent endometrial cancer in the expansion cohort of a phase I study of temsirolimus in combination with metformin. Methods: Patients received intravenous (IV) temsirolimus 25 mg weekly and oral metformin 2000 mg daily in 28-day cycles. The objective of this study was to evaluate the efficacy of this combination and assessment of correlatives of target inhibition in tumor biopsies from patients with known mutations. Response was assessed every 2 cycles by clinical evaluation, tumor markers, and imaging per RECIST 1.1. All toxicities were graded using NCI CTCAE, version 4.0. TIL (tumor infiltrating lymphocyte) percentage was assessed in tumor tissue samples collected at baseline and on treatment. Results: A total of 40 patients were included in this study. Among the 33 patients evaluable for response, 2 patients had partial response (PR) and 13 had stable disease (SD), including 11 with SD ≥4 months. The objective response rate was 6% and clinical benefit rate 39%. Molecular alteration in the PI3K and/or RAS pathway was seen in 25 of 33 patients. Eleven of the 25 patients (44%) had either PR or SD ≥4 months. Interestingly, all 3 patients with molecular alteration in both the pathways had SD ≥4 months. The most common treatment-related adverse events included hypertriglyceridemia (n=14), diarrhea (n=13), mucositis (n=13), anorexia (n=12) and anemia (n=10). The grade 3 AEs were anemia and thrombocytopenia (n=2 each) and mucositis, fatigue, weight loss, hypokalemia, hypophosphatemia, and increase in aspartate aminotransferase and alanine transaminase (n=1 each). Although baseline TIL scores did not distinguish responder from non-responder (p=0.25), on-treatment increase in TIL score was significantly higher among responders compared to non-responders (p-value 0.034). Metabolomics portion of the study is ongoing. Conclusions: In conclusion, the combination of temsirolimus with metformin had modest anti-tumor activity in patients with advanced or recurrent endometrial cancer without added safety concerns. Correlative studies may provide further insight about this combination. Citation Format: Jibran Ahmed, Bettzy Stephen, Samir Beyaz, Charlie Chung, Ece Kilic, Muhammad R Khawaja, Yali Yang, Alpa M Nick, Maria G Raso, Elizve B Toro, Daniel D Karp, Sarina A Piha-Paul, Anil Sood, Chaan Ng, Amber M Johnson, Pamela T Soliman, Funda Meric-Bernstam, Karen H Lu, Aung Naing. Temsirolimus in combination with metformin in patients with advanced or recurrent endometrial cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A121.

Combination of temsirolimus with cisplatin as anti-cancer agents through inducing apoptosis and altering cell cycle distribution in Hela cell line

Combination treatment is the most effective therapy strategy on cancer by dramatically reducing drug toxicity and enhancing efficacy. In this study, we assessed whether temsirolimus, an mTOR inhibitor enhanced anti-cancer effects of cisplatin on human cervical Hela cell line or not. The combination of temsirolimus and cisplatin, to a large extent, reduced proliferation rate of cervical Hela cells in comparision with single chemotherapeutics cisplatin in vitro and resulted in synergistic effects (CI<1). Flow cytometry results indicated that temsirolimus markedly increased cisplatin-induced apoptosis. Thus, the combination chemotherapy using cisplatin and temsirolimus could be a novel strategy for synergistic effects against human cervical cancer.

Therapeutic targeting of LCK tyrosine kinase and mTOR signaling in T-cell acute lymphoblastic leukemia

AbstractRelapse and refractory T-cell acute lymphoblastic leukemia (T-ALL) has a poor prognosis, and new combination therapies are sorely needed. Here, we used an ex vivo high-throughput screening platform to identify drug combinations that kill zebrafish T-ALL and then validated top drug combinations for preclinical efficacy in human disease. This work uncovered potent drug synergies between AKT/mTORC1 (mammalian target of rapamycin complex 1) inhibitors and the general tyrosine kinase inhibitor dasatinib. Importantly, these same drug combinations effectively killed a subset of relapse and dexamethasone-resistant zebrafish T-ALL. Clinical trials are currently underway using the combination of mTORC1 inhibitor temsirolimus and dasatinib in other pediatric cancer indications, leading us to prioritize this therapy for preclinical testing. This combination effectively curbed T-ALL growth in human cell lines and primary human T-ALL and was well tolerated and effective in suppressing leukemia growth in patient-derived xenografts (PDX) grown in mice. Mechanistically, dasatinib inhibited phosphorylation and activation of the lymphocyte-specific protein tyrosine kinase (LCK) to blunt the T-cell receptor (TCR) signaling pathway, and when complexed with mTORC1 inhibition, induced potent T-ALL cell killing through reducing MCL-1 protein expression. In total, our work uncovered unexpected roles for the LCK kinase and its regulation of downstream TCR signaling in suppressing apoptosis and driving continued leukemia growth. Analysis of a wide array of primary human T-ALLs and PDXs grown in mice suggest that combination of temsirolimus and dasatinib treatment will be efficacious for a large fraction of human T-ALLs.

Phase II Trial of the Combination of Temsirolimus and Sorafenib in Advanced Hepatocellular Carcinoma with Tumor Mutation Profiling

Background: The mammalian target of rapamycin (mTOR) pathway is upregulated in nearly half of hepatocellular carcinoma (HCC) tumors and is associated with poor prognosis. In preclinical models of HCC, the combination of mTOR pathway inhibition with the multikinase inhibitor sorafenib improves treatment efficacy. A prior phase I study of the allosteric mTOR inhibitor temsirolimus combined with sorafenib demonstrated acceptable safety at the recommended phase II dose. Methods: We conducted a single-arm, multicenter phase II trial of the combination of temsirolimus 10 mg intravenously weekly plus sorafenib 200 mg b.i.d. The primary endpoint was time to progression (TTP) with efficacy target of median TTP of at least 6 months; secondary endpoints included overall survival (OS), objective response rate, safety, and alpha-fetoprotein (AFP) tumor marker response. Next-generation tumor sequencing was performed as an exploratory endpoint. Results: Twenty-nine patients were enrolled, including 48% with hepatitis C virus infection and 28% with hepatitis B virus; 86% had Barcelona clinic liver cancer stage C disease. Among 28 patients evaluable for efficacy, the median TTP was 3.7 (95% confidence interval [CI]: 2.2, 5.3) months, with 14% of patients achieving TTP of at least 6 months. The median OS was 8.8 (95% CI: 6.8, 14.8) months. There were no complete or partial responses; 75% of patients had stable disease as best response. AFP decline by at least 50% was associated with prolonged TTP and OS. Serious adverse events occurred in 21%; the most common treatment-related adverse events of CTCAE grade 3 or higher were hypophosphatemia (36%), thrombocytopenia (14%), and rash (11%). There were no grade 5 events attributed to sorafenib or temsirolimus. Tumor next-generation sequencing (NGS) was performed in a subgroup of 24 patients with adequate tumor samples. Tumor mTOR pathway mutations were identified in 42%. There was no association between tumor mutation profile and OS or TTP. Conclusions: The combination of temsirolimus and sorafenib demonstrated acceptable safety but did not achieve the target threshold for efficacy in this phase II study. Tumor NGS including the presence of mTOR pathway mutations was not associated with treatment response in an exploratory subgroup analysis.

Abstract CT163: Temsirolimus in combinaton with metformin in patients with advanced or refractory endometrial cancers

Abstract Purpose: There is limited success with chemotherapeutic agents in women with advanced or recurrent endometrial cancer. Dysregulation of the PI3K/RAS signaling pathways in endometrial cancer have been well documented. However, responses with mTOR inhibitor such as temsirolimus have been modest. Previously we have shown that metformin prevents temsirolimus-induced AKT activation. Therefore, we enrolled patients with advanced endometrial carcinoma in the expansion cohort of a phase I study of temsirolimus in combination with metformin. Methods: Patients with advanced endometrial cancer refractory to or relapse after standard therapies, ECOG performance status 0 or 1, and with significant organ function reserve were enrolled. Patients were administered intravenous temsirolimus 25mg weekly and oral metformin 2000 mg daily in 28-day cycles. Response was assessed every 2 cycles by clinical evaluation, tumor markers, and imaging per RECIST 1.1. All toxicities were graded using NCI CTCAE, version 4.0. Results: Forty patients were treated. Median age is 67 years (range, 33-78). Drug-related adverse events of any grade were reported in 34 patients. The most common toxicities were mucositis (n=13), AST increase (n=13), anorexia (n=12), diarrhea (n=12) and anemia (n=10). Eleven grade 3 drug-related adverse events were reported. They were anemia (n=2), thrombocytopenia (n=2), mucositis, fatigue, weight loss, hypokalemia, hypophosphatemia, AST increase and ALT increase (n=1 each). Of the 33 patients evaluable for response, objective response was seen in 2 (6%) patients. Both had partial response (PR) and were on the study for 8.7 and 18.2 months respectively. In addition, 13 (39%) patients had stable disease (SD), including 11 with SD ≥4 months, representing a clinical benefit rate of 39%. Molecular characterization of tumor was available for 35 patients. Thirty of 35 patients had molecular alterations in the PI3K and/or RAS pathway. Of the 30 patients, 1 had benign PI3K mutation and 4 were not evaluable for response. Of the remaining 25 patients with PI3K and/or KRAS pathway, 11 (44%) had either objective response or SD ≥4 months. Eighteen of them had molecular alteration only in the PI3K pathway. Seven of 18 (39%) had objective response or SD ≥4 months. Importantly, all 3 patients who had molecular alterations in both the PI3K and RAS pathway achieved SD ≥4 months, while 3 of the 4 patients with exclusive resistant KRAS mutation had progressive disease. Collectively, of the 13 patients with either objective response or SD ≥4 months, 11 (85%) patients had molecular alteration in the PI3K and/or RAS pathway. Conclusion: Temsirolimus in combination with metformin was well tolerated. Anti-tumor activity was seen in patients with advanced/refractory endometrial cancer, particularly in patients with molecular alterations in the PI3K and/or RAS pathway that warrants further study. Citation Format: Aung Naing, Daniel Karp, Sarina A. Piha-Paul, Shubham Pant, Vivek Subbiah, Diane C. Bodurka, Siqing Fu, Amir A. Jazaeri, Shumei Kato, Kathleen Schmeler, Alpa Nick, Yali Yang, Fechukwu O. Akhmedzhanov, Senait Fessahaye, Jing Gong, Bettzy Stephen, Amber M. Johnson, Pamela T. Soliman, Anil K. Sood, Funda Meric-Bernstam, Karen H. Lu. Temsirolimus in combinaton with metformin in patients with advanced or refractory endometrial cancers [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr CT163.

Final Results of a Phase I/II Trial of the Combination Bendamustine and Rituximab With Temsirolimus (BeRT) in Relapsed Mantle Cell Lymphoma and Follicular Lymphoma.

In this phase I/II study, we explored the combination of Temsirolimus with Bendamustine and Rituximab (BeRT) in patients with relapsed or refractory (r/r) follicular lymphoma (FL) or mantle cell lymphoma (MCL). Patients with 1 to 3 previous therapies received Bendamustine (90 mg/m2, day 1 + 2) and Rituximab (375 mg/m2, day 1) with Temsirolimus in doses from 25 to 75 mg in phase I and 50 mg Temsirolimus in phase II, added on day 1, 8, 15 of a 28 days cycle. The primary endpoint of the phase II was ORR at the end of treatment. Overall, 39 (29 MCL, 10 FL) patients were included. Median age was 71 years and median pretreatment number was 2. Grade 3/4 non-hematologic adverse events were rare and included hyperglycemia in 3 patients (7%) and angioedema in 2 patients (5%). Infectious complications grade 3/4 were observed in 9 patients (23%). Hematologic grade 3/4 events included leukopenia in 22 (56%), neutropenia in 18 (46%), lymphopenia in 16 (41%) and thrombocytopenia in 14 patients (36%). An objective response (best response) was observed in 33/39 patients (89%; 24 MCL (89%) and 9 FL (90%)), including 14 CR (38%; 12 MCL (36%) and 2 FL (20%)). Median PFS is 1.5y for MCL and 1.82 years for FL, and median OS has not been reached for either entity. This data demonstrates promising efficacy of Temsirolimus in r/r MCL and FL with acceptable toxicity. The BeRT regimen may be used as a treatment option for both entities.

Tumor regression and potentiation of polymeric vascular disrupting therapy through reprogramming of a hypoxia microenvironment with temsirolimus.

Although the polymeric vascular disrupting agent (poly(l-glutamic acid)-graft-methoxy poly(ethylene glycol)/combretastatin A4) nanoparticles (CA4-NPs) has great potential to inhibit cancer growth, it is still a challenge to avert tumor recurrence and metastasis after treatment. It is mainly tightly associated with hypoxia induced by CA4-NPs, which can activate many downstream genes regulating tumor growth and metastasis. Herein, to relieve a tumor hypoxia microenvironment, the mTOR inhibitor temsirolimus was employed to modulate the tumor microenvironment when treated with CA4-NPs. In vitro MTT experiments strongly verified that the combination of temsirolimus with polymeric CA4-NPs exhibited an additive toxicity to 4T1 cells. An in vivo study with the 4T1 mammary adenocarcinoma model revealed that consistent with the proposed scenario, combination therapy with CA4-NPs plus temsirolimus suppressed tumor growth significantly more strongly compared to either CA4-NPs or temsirolimus monotherapy, and the inhibition rate to 4T1 tumor with a volume of 300 mm3 was 71%. The mechanism underling combination treatment was confirmed by western blotting and immunofluorescence staining, and the results demonstrated that temsirolimus could inhibit HIF1α expression. Thus, this work provides a mechanistic rationale for the use of VDAs in combination with the mTOR inhibitor to enhance anticancer efficacy, delaying tumor recurrence and inhibiting tumor metastasis.

Low-dose Docetaxel Enhanced the Anticancer Effect of Temsirolimus by Overcoming Autophagy in Prostate Cancer Cells.

Chemotherapy with docetaxel (DTX) is used for castration-resistant prostate cancer (CRPC), but it is inadequate. We evaluated the effect of the combination treatment DTX and the mTOR inhibitor temsirolimus (TEM) in the PC3 prostate cancer cell line, by focusing on the induction of autophagy and apoptosis. TEM induced autophagy but not apoptosis even at a high dose, whereas DTX induced apoptosis. The combination of low-dose DTX and TEM caused a 34% suppression in cell proliferation compared to monotherapy with a higher dose of DTX. The induction of apoptosis was increased by their combination. The combination with DTX overcame the induction of autophagy by TEM. The combination treatment suppressed tumor growth 72% less than the control group after 14 days of treatment in vivo. The combination of TEM and DTX induced apoptosis by overcoming autophagy and enhanced the anticancer effect compared to monotherapy.

Abstract CT113: A Phase I study of Suberoylanilide Hydroxamic Acid (SAHA) with Temsirolimus in children with newly diagnosed or progressive diffuse intrinsic pontine glioma (DIPG)

Abstract Background/rationale: Diffuse intrinsic pontine glioma (DIPG) in children remains essentially incurable with a median survival of 12 months. Radiation therapy is currently the standard treatment modality. To date chemotherapy or biologic agents have had no meaningful increase in survival, making it imperative to profile novel therapeutic combinations. Data from biopsied DIPG showed the PI3K/AKT/mTOR pathway as a major oncogenic player. At the gene level high PDGFR amplification (most commonly seen) and overexpression of the PI3K-Akt-mTOR pathway were noted in these tumors. Focal amplifications of genes within the receptor tyrosine kinase-Ras-phosphoinositol 3-kinase signaling pathway were found in 47% of DIPG. Thus targeting this pathways with mTOR inhibitors could hold therapeutic promise. Elevated expression of DNA repair proteins in the NHEJ and HRR pathway are known to induce resistance to radiation. Preclinical data shows inhibition of these pathways potentiates the sensitivity of these tumors to radiation. SAHA a pan HDAC inhibitor, has been associated with decreased expression of key DNA repair proteins in both the NHEJ and HRR pathways. Both temsirolimus (an mTOR inhibitor) and SAHA are well described in pediatric clinical trials with an established maximum tolerated dose (MTD). The efficacy of the combination of temsirolimus and SAHA has been well-established in other malignancies including prostate cancer, mantle lymphoma, and renal carcinoma. This is the first multi-targeted therapeutic trial in pediatric DIPG, using SAHA and temsirolimus in a combinatorial approach, targeting the key oncogenic pathway and molecules along with enhancing the radiation sensitivity. Correlative study: Stratum I (chemoradiotherapy phase): Histone acetylation will be quantified from peripheral blood mononuclear cell (PBMC) collected prior to the first dose of vorinostat and radiation and at the end of radiation. Stratum I and II (maintenance phase): Evaluation of histone acetylation, phosphorylated 70S6K and Akt on day 1 and 8 (prior to chemotherapy with temsirolimus) during cycle 1 and cycle 2. Methods Patients with a performance score of 50 or greater with newly diagnosed (Stratum 1) or progressive DIPG (stratum II) as confirmed by gadolinium enhanced MRI are eligible. Biopsy is not mandatory. Stratum I: Patients will receive radiation therapy concurrently with vorinostat on the days of radiation at a dose of 230mg/m2/dose, followed by adjuvant therapy with vorinostat and temsirolimus for 10 cycles if patients do not have progressive disease. Stratum II: Patients will receive vorinostat and temsirolimus for 12 cycles (28 day cycle), if patient does not have progressive disease. SAHA will be given once daily at 230 mg/m2 orally from day 1 to day 8, along with temsirolimus at 25mg/m2 intravenously on day 1 and day 8. This will be the dose level 1 and 2 dose escalations and 1 dose de-escalation will be allowed. A standard 3+3 design will be used and a minimum of 9 patients and a maximum of 18 patients will be enrolled. Trial is ongoing (30% of planned patients enrolled), with patients now in the second dose level (enrollment of this cohort started on September 2018). No dose limiting toxicity (DLT) were noted at the first dose level. Trial: NCT02420613 (currently recruiting). Note: This abstract was not presented at the meeting. Citation Format: Soumen Khatua, Joya Chandra, Miriam M. Morrell, Heather B. Meador, David I. Sandberg, Jeffrey Weinberg, Greg Fuller, Leena Ketonen, Jason M. Johnson, Kenneth R. Hess, Wafik Zaky. A Phase I study of Suberoylanilide Hydroxamic Acid (SAHA) with Temsirolimus in children with newly diagnosed or progressive diffuse intrinsic pontine glioma (DIPG) [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 CT113.

The combination of temsirolimus and chloroquine increases radiosensitivity in colorectal cancer cells.

The PI3K/AKT/mTOR pathway and autophagy are known to play important roles in cancer radioresistance. The aim of the present study was to investigate whether the combination of temsirolimus (TEM), an mTOR inhibitor, and chloroquine(CQ), an autophagy inhibitor, can increase radiosensitivity in colorectal cancer(CRC) cells. The efficacies of TEM and/or CQ as radiosensitizers were examined using clonogenic assays in CRC cell lines SW480 and HT‑29. The expression levels of the phosphorylated isoforms of S6 and 4E‑BP1, downstream proteins of mTOR, as well as the expression levels of p62 and LC3, autophagy‑related proteins, were assessed by western blot analysis. The formation of acidic organelles was detected in acridine orange‑stained cells. Apoptosis and caspase activity were assessed using flow cytometry. The results revealed that ionizing radiation(IR) activated the downstream proteins of mTOR and induced autophagy. In the clonogenic assays, neither TEM nor CQ influenced the efficacy of IR, whereas their combination significantly increased the dose‑dependent efficacy of IR. TEM inhibited phosphorylation of the downstream proteins of mTOR and induced autophagy. CQ inhibited autophagy in the late phase and did not influence the downstream proteins of mTOR. TEM and CQ inhibited both the phosphorylation of downstream proteins of mTOR and autophagy. Cell death analysis revealed that the combination of TEM and CQ strongly induced apoptosis in cells exposed to IR. In conclusion, the combination of TEM and CQ increased radiosensitivity in CRC cells through co‑inhibition of mTOR and autophagy.

Targeted therapy in head neck tumours

Targeted therapy in head neck tumours

Role of Angiogenesis and Anti-Angiogenic Treatment Strategies in Mantle Cell Lymphoma

Introduction: Role of angiogenesis in growth, spread and survival of malignant lymphomas remains largely unexplored. Bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), has been approved for treatment of several types of solid tumors including colorectal carcinoma or breast carcinoma, in all cases in combination with chemotherapy. Mantle cell lymphoma (MCL) is a type of B-cell non-Hodgkin lymphoma characterized by frequent extranodal involvement. Two agents approved for the therapy of MCL including lenalidomide and temsirolimus exert their anti-lymphoma activity at least partially by inhibition of angiogenesis. Our aim was to investigate role of VEGF-dependent angiogenesis on growth and spread of MCL in vivo using different murine models of MCL including patient-derived xenografts (PDXs). We also analyzed a potential anti-lymphoma synergy of a multi-level inhibition of angiogenesis achieved by bevacizumab and temsirolimus.Methods: Experimental therapies were implemented using NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice purchased from Jackson Laboratory (Bar Harbor, Maine, USA). Therapies were initiated three to five days after subcutaneous (SC) or intravenous (IV) injection of MCL cells (= day 1, D1). Therapies were terminated when SC tumor reached 2 cm, or when mice developed signs of terminal disease. Mice were xenografted either with MCL cell lines (JEKO-1, HBL2) or with PDX cells (VFN-M1, VFN-M2) derived in our laboratory from patients with relapsed MCL. Both PDXs were confirmed by NGS to keep majority of somatic mutations with the primary MCL cells. Growth curves of calculated tumor volumes and overall survivals were compared in case of SC and IV-xenografted animals, respectiverly, in the treated mice compared to untreated controls. VEGF levels were analyzed in different tissues (blood, tumor lysate, spleen lysate) by commercially available ELISA kit. TaqMan Angiogenesis Array was used to compare gene expression changes associated with bevacizumab failure.Results: Bevacizumab significantly inhibited growth of SC MCL tumors all tested models (Figure 1) (JEKO-1: 0.71g ±0.24g vs 3.22g ±0.65g, p=0.0061; HBL-2: 0.95g ±0.11g vs 4.2g ±0.28g, p<0.0001; VFN-M1: 0.49g ±0.04g vs 2.18g ±0.13g, p<0.0001; VFN-M2: 0.77g ±0.07g vs 1.15g ±0.18g, p=0.0012). Unexpectedly, bevacizumab failed to prolong overall survival of IV-xenografted mice in three out of four murine models (HBL-2, JEKO-1, VFN-M1) compared to controls (p=0.89, 0.87 and 0.09, respectively), and only prolonged survival of bevacizumab-treated mice in VFN-M2-xenografted mice by as few as 3 days (Figure 2). Analysis of VEGF levels in lysates of SC tumors revealed a positive correlation between the tumor size and the VEGF level. In contrast, analysis of murine blood and spleen did not detect measureable amounts of VEGF in any case. We hypothesize that SC growth of MCL cells (in form of a lymphoma mass) is associated with hypoxia, which induces secretion of VEGF that stimulates angiogenesis and functions as a paracrine growth factor for MCL cells. SC tumor growth is therefore VEGF-stimulated and sensitive to inhibition by bevacizumab. Indeed, murine (but not human) vessels were detected by immunohistochemistry in SC tumors in all MCL models including both PDX models. In sharp contrast, systemic engraftment and spread of MCL cells (e.g. infiltration of the bone marrow or involvement of the spleen) are not associated with hypoxia, which would explain why bevacizumab failed to prolong overall survival of IV-xenografted mice. Combination of temsirolimus and bevacizumab did not lead to anti-lymphoma synergy, but was associated with additive effect only. Failure of bevacizumab monotherapy was associated with higher expression of several proangiogenic genes including angiogenin, transcription factor FOXC2 or interferon-beta I suggesting activation of alternate pro-angiogenic pathways after blockage of VEGF.Conclusions: Our data clearly indicate that all anti-angiogenic treatment approaches in malignant lymphomas have to be validated in vivo not only using SC xenografts, but also using systemic (IV) models. Our data also indicate that anti-angiogenic therapies might have auxiliary role (in combination with chemotherapy or targeted agents) in the treatment of malignant lymphomas. The gene expression data after failure of bevacizumab suggest activation of alternate pro-angiogenic pathways. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Rapalog combined with CCR4 antagonist improves anticancer vaccines efficacy.

mTOR pathway inhibitors such as rapalogs represent a promising tool to induce functional memory CD8 T cells. In our study, we investigated the combination of temsirolimus with anticancer vaccines. Using various designs of cancer vaccines (short and long peptides or the B subunit of Shiga toxin as an antigen delivery vector) and tumor models (melanoma, lung and colon cancer), we showed that the administration of temsirolimus efficiently decreased tumor growth and enhanced tumor-specific CD8 T-cell responses induced by vaccination. Furthermore, tumor-specific CD8 T cells induced by the bi-therapy (vaccine + temsirolimus) exhibit phenotypic characteristics of central memory (CD127+ CD62L+ ) CD8 T cells compared to vaccination alone. We demonstrated that regulatory CD4 T cells (Tregs ) expansion in vivo limits the efficacy of the bi-therapy by altering the antitumor CD8 T-cell responses. Finally, the use of a small molecule CCR4 antagonist to prevent Tregs induction considerably improved the efficacy of the bi-therapy by enhancing CD8 T cells-mediated antitumor immunity. Taken together, our study highlights the potential interest of combining cancer vaccines with drugs that promote memory CD8 T cells and inhibit Tregs .

Therapeutic Effect of Repurposed Temsirolimus in Lung Adenocarcinoma Model.

Lung cancer is one of the major cause of cancer-related deaths worldwide. The poor prognosis and resistance to both radiation and chemotherapy urged the development of potential targets for lung cancer treatment. In this study, using a network-based cellular signature bioinformatics approach, we repurposed a clinically approved mTOR inhibitor for renal cell carcinomans, temsirolimus, as the potential therapeutic candidate for lung adenocarcinoma. The PI3K-AKT-mTOR pathway is known as one of the most frequently dysregulated pathway in cancers, including non-small-cell lung cancer. By using a well-documented lung adenocarcinoma mouse model of human pathophysiology, we examined the effect of temsirolimus on the growth of lung adenocarcinoma in vitro and in vivo. In addition, temsirolimus combined with reduced doses of cisplatin and gemcitabine significantly inhibited the lung tumor growth in the lung adenocarcinoma mouse model compared with the temsirolimus alone or the conventional cisplatin–gemcitabine combination. Functional imaging techniques and microscopic analyses were used to reveal the response mechanisms. Extensive immunohistochemical analyses were used to demonstrate the apparent effects of combined treatments on tumor architecture, vasculature, apoptosis, and the mTOR-pathway. The present findings urge the further exploration of temsirolimus in combination with chemotherapy for treating lung adenocarcinoma.

Chemotherapy in Pancreatic Cancer: A Systematic Review.

Background and Aim: Pancreatic cancer is one of the most fatal cancers. Cytotoxic chemotherapy remains the mainstream treatment for unresectable pancreatic cancer. This systematic review evaluated and compared the overall survival (OS) and progression-free survival (PFS) outcomes obtained from recent phase 2 and 3 clinical trials of pancreatic cancer chemotherapy. Materials and methods: Thirty-two studies were included and compared based on chemotherapy agents or combinations used. Additionally, outcomes of first-line versus second-line chemotherapy in pancreatic cancer were compared. Results: In studies that investigated the treatments in adjuvant settings, the highest OS reported was for S-1 in patients, who received prior surgical resection (46.5 months). In neoadjuvant settings, the combination of gemcitabine, docetaxel, and capecitabine prior to the surgical resection had promising outcomes (OS of 32.5 months). In non-adjuvant settings, the highest OS reported was for the combination of temsirolimus plus bevacizumab (34.0 months). Amongst studies that investigated second-line treatment, the highest OS reported was for the combination of gemcitabine plus cisplatin (35.5 months), then temsirolimus plus bevacizumab (34.0 months). Conclusions: There is a need to develop further strategies besides chemotherapy to improve the outcomes in pancreatic cancer treatment. Future studies should consider surgical interventions, combination chemotherapy, and individualized second-line treatment based on the prior chemotherapy.

Combined activity of temozolomide and the mTOR inhibitor temsirolimus in metastatic melanoma involves DKK1.

The BRAFV600E inhibitor vemurafenib achieves remarkable clinical responses in patients with BRAF-mutant melanoma, but its effects are limited by the onset of drug resistance. In the case of resistance, chemotherapy can still be applied as second line therapy. However, it yields low response rates and strategies are urgently needed to potentiate its effects. In a previous study, we showed that the inhibition of the PI3K-AKT-mTOR pathway significantly increases sensitivity of melanoma cells to chemotherapeutic drugs (J. Invest. Dermatol. 2009, 129, 1500). In this study, the combination of the mTOR inhibitor temsirolimus with the chemotherapeutic agent temozolomide significantly increases growth inhibition and apoptosis in melanoma cells compared to temsirolimus or temozolomide alone. The combination of temozolomide with temsirolimus is not only effective in established but also in newly isolated and vemurafenib-resistant metastatic melanoma cell lines. These effects are associated with the downregulation of the anti-apoptotic protein Mcl-1 and the upregulation of the Wnt antagonist Dickkopf homologue 1 (DKK1). Knock-down of DKK1 suppresses apoptosis induction by the combination of temsirolimus and temozolomide. These data suggest that the inhibition of the mTOR pathway increases sensitivity of melanoma cells towards temozolomide. Chemosensitisation is associated with enhanced expression of the Wnt antagonist DKK1.

Abstract CT029: A phase I study of vorinostat and temsirolimus in children with newly diagnosed or progressive diffuse intrinsic pontine glioma (DIPG)

Abstract Background/rationale: Diffuse intrinsic pontine glioma (DIPG) in children remains essentially incurable with a median survival of 12 months. Radiation therapy is currently the standard treatment modality. To date chemotherapy or biologic agents have had no meaningful increase in survival, making it imperative to profile novel therapeutic combinations. Data from biopsied DIPG showed the PI3K/AKT/mTOR pathway as a major oncogenic player. At the gene level high PDGFR amplification and overexpression of the PI3K-Akt-mTOR pathway were noted in these tumors. Focal amplifications of genes within the PI3K-Akt-mTOR signaling pathway were found in 47% of DIPG. Thus targeting these pathways with mTOR inhibitors could hold promise. Elevated expression of DNA repair proteins in the NHEJ and HRR pathway are known to induce resistance to radiation. Preclinical data shows inhibition of these pathways potentiates the sensitivity of these tumors to radiation. Recent genomic and epigenetic insights demonstrates the role of histone deacetylase (HDAC) in these tumors. Vorinostat a pan HDAC inhibitor has been associated with decreased expression of key DNA repair proteins in both the NHEJ and HRR pathways and have been tested in clinical trial for children with DIPG. Both temsirolimus (an mTOR inhibitor) and vorinostat are well described in pediatric clinical trials with a determined maximum tolerated dose (MTD). The efficacy of the combination of temsirolimus and vorinostat has been well-established in other malignancies including prostate cancer, mantle lymphoma, and renal carcinoma. This is the first multi-targeted therapeutic trial in pediatric DIPG, using vorinostat and temsirolimus in a combinatorial approach, targeting the key oncogenic pathway and molecules along with enhancing the radiation sensitivity. Correlative study: Stratum I (chemoradiotherapy phase): Histone acetylation will be quantified from peripheral blood mononuclear cell (PBMC) collected prior to the first dose of vorinostat and radiation and at the end of radiation. Stratum I and II (maintenance phase): Evaluation of histone acetylation, phosphorylated 70S6K and Akt on day 1 and 8 (prior to chemotherapy with temsirolimus) during cycle 1 and cycle 2 will be performed. Methods: Patients with a performance score of 50 or greater with newly diagnosed (Stratum 1) or progressive DIPG (stratum II) as confirmed by gadolinium enhanced MRI, will be eligible. Biopsy is not mandatory. Stratum I: Patients will receive radiation therapy concurrently with vorinostat on the days of radiation at a dose of 230 mg/m2/dose orally, followed by maintenance phase with vorinostat and temsirolimus for 12 cycles if patients do not have progressive disease. Stratum I and Stratum II (maintenance phase): Patients will receive vorinostat and temsirolimus for 12 cycles (28 day cycle), if patient do not have progressive disease. Vorinostat will be given once daily orally at 230 mg/m2/dose orally from day 1 to day 8, along with temsirolimus at 25mg/m2 intravenously on day 1 and day 8. This will be dose level 1 with provisions for 2 higher dose levels and 1 lower dose level if needed. A standard 3+3 design will be used and a minimum of 9 patients and a maximum of 18 patients will be enrolled. Trial is continuing as planned and patient are on dose level 1. Trial: NCT02420613 (currently recruiting). Citation Format: Soumen Khatua, Vidya Gopalakrishnan, Joya Chandra, Leena Ketonen, David I. Sandberg, Jeffrey Weinberg, Fuller Gregory, Kenneth R. Hess, Natalie Slone, Heather Meador, Mirriam Morrell, Wafik Zaky. A phase I study of vorinostat and temsirolimus in children with newly diagnosed or progressive diffuse intrinsic pontine glioma (DIPG) [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 CT029. doi:10.1158/1538-7445.AM2017-CT029

Phase I study of temsirolimus in combination with cetuximab in patients with advanced solid tumours

BackgroundPreclinical studies suggest synergistic antitumour effects of mammalian target of rapamycin (mTOR) inhibitor such as temsirolimus combined with anti-EGFR monoclonal antibody such as cetuximab. MethodsTemsirolimus (T) and cetuximab (C) were combined and escalated in cohorts of patients with advanced or metastatic solid tumours, respectively from 15 to 25 mg and 150–250 mg/m2, until the maximum tolerated dose (MTD) was determined. Effort was made in the expansion cohort to enrol patients harbouring a molecular aberration in the human epidermal growth factor receptor (EGFR) and/or phosphoinositide 3-kinase (PI3K) pathways. Paired biopsies were optional to evaluate pathway modulation. ResultsAmong 39 patients enrolled, three experienced dose-limiting toxicities (DLTs): pulmonary embolism (C200 + T20), stomatitis (C250 + T20) and acneiform rash (C250 + T25). The weekly C 250 mg/m2 and T 25 mg dose level was selected as the MTD. The most common treatment-related adverse events were: acneiform rash (97%), oral mucositis (82%), fatigue (59%), nausea (41%) and diarrhoea (36%). The median progression-free survival (PFS) and overall survival (OS) were respectively 2.0 months [95% CI: 1.8, 3.5] and 7.5 months [95% CI: 5.5, 11.9]. Among all patients, partial responses (PRs) and stable diseases (SDs) were observed in 2 (5.1%) and 18 patients (46.2%), respectively. The objective response rate (ORR) in patients with a molecular aberration was 2/14 (14%), versus 0/24 in those without molecular aberration. ConclusionsCombination of T + C showed significant but manageable toxicities. Due to modest clinical activity, further evaluation is not recommended. Molecular selection could potentially increase the objective response rate and should be implemented during drug development.

Temsirolimus in Combination with Bendamustine and Rituximab (BeRT) for the Treatment of Relapsed Mantle Cell and Follicular Lymphoma: Final Phase I/II Results

Background: mTOR inhibition has been shown to be effective in various subtypes of malignant lymphomas (Smith et al, JCO 2010). Furthermore, in relapsed MCL a phase III trial demonstrated superiority of Temsirolimus to chemotherapy. Although novel treatment options as Ibrutinib have changed the treatment landscape for MCL, no curative potential could be shown for this approach and novel concepts continue to be needed. Several trials provided promising results when Temsirolimus is combined with agents like Rituximab (Ansell et al, Lancet Oncology 2011) or chemoimmunotherapy, as shown in part I (phase I) of the reported trial (Hess, Leukemia, 2015). We now report the final analysis of phase I and II results.Methods: This is a multicenter, national, prospective trial. Inclusion criteria: Patients were eligible with histologically proven FL or MCL, 1-3 prior treatment lines, no curative option available, no refractoriness to Bendamustine, measurable disease, ECOG < 3, sufficient bone marrow reserve, no severe concomitant diseases and given informed consent. Treatment consisted of Bendamustine 90mg/m² day 1-2, Rituximab 375mg/m² day 1 and Temsirolimus 50 mg day 2, 8, 15 of a 28d cycle. A total of 4 cycles was planned with interim staging after 2 cycles.Results: Overall, 39 patients (pts) have been included (15 pts phase I, 24pts phase II): median age was 71 years, with 29 MCL and 10 FL, and a median number of 2 pretreatments (1-3). Overall the treatment was well tolerated, and toxicity was predominantly hematologic. In 133 evaluable cycles of chemotherapy the following hematologic grade 3 / 4 toxicities were noted: leukopenia (17pts, 45%), lymphopenia (14 pts, 37%), neutropenia (12 pts, 32%), and thrombocytopenia (10 pts, 27%). Non-hematologic grade 3 / 4 side effects observed in at least two patients were angioedema, hyperglycaemia and stomatitis. AE's of special interest: pulmonary: rate of cough (4; 10%) and pneumonitis (1; 3%); gastrointestinal: diarrhea (11; 28%), nausea (19, 49%); general: fatigue (18; 46%), mucositis (17, 44%); bleeding: epistaxis (5; 13%), which all were predominantly grade 1 or 2. Response: currently, best responses were 13 CR (38%), 18 PR (53%) and 3 SD (9%) in 34 patients evaluable so far. Updated results will be presented at the meeting. Overall responses were 92% in MCL (11 CR, 11 PR, 2 SD) and 90% in FL (2 CR, 7 PR, 1 SD). After a median follow up of 24 months (mean: 26 months) median PFS is 22 months for the entire cohort, with 33 months for MCL and 22 months in FL. Median OS has not been reached for FL and is 3,55 years (95% CI: 2,7-4,4) for MCL.Summary: The BeRT-combination of 50mg Temsirolimus (day 1,8,15) in combination with Bendamustine and Rituximab is a safe and feasible regimen with substantial activity. As mTOR inhibitors display a noticeable side effect profile especially with long term use, combination with chemoimmunotherapy demonstrates a clinically meaningful balance between efficacy and tolerability, thereby widening the therapeutic portfolio. DisclosuresHess:Roche: Honoraria; Roche, CTI, Pfizer, Celgene: Research Funding; Janssen: Honoraria; Novartis: Honoraria; Celgene: Honoraria; Pfizer: Honoraria. LaRosee:Pfizer: Honoraria. Keller:Spectrum Pharmaceutical: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pfizer: Consultancy, Honoraria; Roche: Consultancy, Honoraria. Witzens-Harig:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Dreyling:Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau.