Sirolimus enhances remission induction in patients with high risk acute myeloid leukemia and mTORC1 target inhibition
Background Mammalian Target of Rapamycin Complex 1 (mTORC1) inhibitors enhance chemotherapy response in acute myelogenous leukemia (AML) cells in vitro. However whether inhibiting mTORC1 enhances clinical response to AML chemotherapy remains controversial. We previously optimized measurement of mTORC1’s kinase activity in AML blasts during clinical trials using serial phospho-specific flow cytometry of formaldehyde-fixed whole blood or marrow specimens. To validate mTORC1 as a therapeutic target in AML, we performed two clinical trials combining an mTORC1 inhibitor (sirolimus) and MEC (mitoxantrone, etoposide, cytarabine) in patients with relapsed, refractory, or untreated high-risk AML. Methods Flow cytometric measurements of ribosomal protein S6 phosphorylation (pS6) were performed before and during sirolimus treatment to determine whether mTORC1 inhibition enriched for chemotherapy response. Results In 51 evaluable subjects, the overall response rate (ORR) to the combination regimen was 47% (95% confidence interval 33–61%, 33% CR, 2% CRi, 12% PR) and similar toxicity to historic experience with MEC alone. 37 subjects had baseline pS6 measured pre-sirolimus, of whom 27 (73%) exhibited mTORC1 activity. ORR was not significantly different between subjects with and without baseline mTORC1 activity (52% vs 40%, respectively, p = 0.20). The ORR among subjects with baseline target activation and mTORC1 inhibition during therapy was 71% (12/17) compared to 20% (2/10) in subjects without target inhibition. Conclusions Fixed, whole blood pS6 by flow cytometry may be a predictive biomarker for clinical response to mTORC1 inhibitor-based regimens. These data provide clinical confirmation that mTORC1 activation mediates chemotherapy resistance in patients with AML.
KeywordsAcute myeloid leukemia mTOR mTORC1 Biomarker Phospho-flow cytometry
The authors wish to acknowledge contributions of Joy Cannon, Amanda Cloud, Kristin Coffan, Martina DiMeglio, Cesary Swider, and Doris Shank for their contribution to this research. We also wish to thank the nurses involved for their excellent care of enrolled subjects.
Compliance with ethical standards
Conflict of interest
All authors declare no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This article does not contain any studies with animals performed by any of the authors.
Informed consent was obtained from all individual participants included in the study.
- 1.Roboz GJ, Rosenblat T, Arellano M, Gobbi M, Altman JK, Montesinos P, O’Connell C, Solomon SR, Pigneux A, Vey N, Hills R et al. (2014) International randomized phase III study of elacytarabine versus investigator choice in patients with relapsed/refractory acute myeloid leukemia. J Clin Oncol 32(18):1919–1926CrossRefPubMedGoogle Scholar
- 6.Yee KW, Zeng Z, Konopleva M, Verstovsek S, Ravandi F, Ferrajoli A, Thomas D, Wierda W, Apostolidou E, Albitar M, O'Brien S et al (2006) Phase i/ii study of the mammalian target of rapamycin inhibitor everolimus (rad001) in patients with relapsed or refractory hematologic malignancies. Clin Cancer Res 12(17):5165–5173CrossRefPubMedGoogle Scholar
- 7.Yee KWL, Garcia-Manero G, Thomas D, Ravandi-Kashani F, Verstovsek S, Andreeff M, Dancey JE, Giles FJ (2004) A phase ii study of temsirolimus (cci-779) in patients with advanced leukemias. Blood 104(11):4523aGoogle Scholar
- 8.Perl AE, Kasner MT, Tsai DE, Vogl DT, Loren AW, Schuster SJ, Porter DL, Stadtmauer EA, Goldstein SC, Frey NV, Nasta SD et al (2009) A phase i study of the mammalian target of rapamycin inhibitor sirolimus and mec chemotherapy in relapsed and refractory acute myelogenous leukemia. Clin Cancer Res 15(21):6732–6739CrossRefPubMedGoogle Scholar
- 9.Park S, Chapuis N, Saint Marcoux F, Recher C, Prebet T, Chevallier P, Cahn JY, Leguay T, Bories P, Witz F, Lamy T et al. (2013) A phase Ib GOELAMS study of the mTOR inhibitor RAD001 in association with chemotherapy for AML patients in first relapse. Leukemia 27(7):1479–1486CrossRefPubMedGoogle Scholar
- 10.Amadori S, Stasi R, Martelli AM, Venditti A, Meloni G, Pane F, Martinelli G, Lunghi M, Pagano L, Cilloni D, Rossetti E et al (2012) Temsirolimus, an mtor inhibitor, in combination with lower-dose clofarabine as salvage therapy for older patients with acute myeloid leukaemia: Results of a phase ii gimema study (aml-1107). Br J Haematol 156(2):205–212CrossRefPubMedGoogle Scholar
- 11.Perl AE, Kasner MT, Shank D, Luger SM, Carroll M (2012) Single-cell pharmacodynamic monitoring of s6 ribosomal protein phosphorylation in aml blasts during a clinical trial combining the mtor inhibitor sirolimus and intensive chemotherapy. Clin Cancer Res: an official journal of the American Association for Cancer Research 18(6):1716–1725CrossRefGoogle Scholar
- 12.Loi S, Michiels S, Baselga J, Bartlett JM, Singhal SK, Sabine VS, Sims AH, Sahmoud T, Dixon JM, Piccart MJ, Sotiriou C (2013) Pik3ca genotype and a pik3ca mutation-related gene signature and response to everolimus and letrozole in estrogen receptor positive breast cancer. PLoS One 8(1):e53292CrossRefPubMedPubMedCentralGoogle Scholar
- 15.Cheson BD, Bennett JM, Kopecky KJ, Buchner T, Willman CL, Estey EH, Schiffer CA, Doehner H, Tallman MS, Lister TA, Lo-Coco F et al (2003) Revised recommendations of the international working group for diagnosis, standardization of response criteria, treatment outcomes, and reporting standards for therapeutic trials in acute myeloid leukemia. J Clin Oncol 21(24):4642–4649CrossRefPubMedGoogle Scholar
- 17.Greenberg PL, Lee SJ, Advani R, Tallman MS, Sikic BI, Letendre L, Dugan K, Lum B, Chin DL, Dewald G, Paietta E et al (2004) Mitoxantrone, etoposide, and cytarabine with or without valspodar in patients with relapsed or refractory acute myeloid leukemia and high-risk myelodysplastic syndrome: A phase iii trial (e2995). J Clin Oncol 22(6):1078–1086CrossRefPubMedPubMedCentralGoogle Scholar
- 19.Litzow MR, Wang XV, Carroll MP, Karp JE, Ketterling R, Kaufmann SH, Lazarus HM, Luger SM, Paietta EM, Rowe JM, Altman JK et al (2014) A randomized phase ii trial of three novel regimens for relapsed/ refractory acute myeloid leukemia (aml) demonstrates encouraging results with a flavopiridol-based regimen: Results of eastern cooperative oncology group (ecog) trial e1906. Blood 124:3742–3742Google Scholar