Leukemia cell proliferation and death in chronic lymphocytic leukemia patients on therapy with the BTK inhibitor ibrutinib

• Text
• PDF

Abstract

BACKGROUND. Ibrutinib is an effective targeted therapy for patients with chronic lymphocytic leukemia (CLL) that inhibits Bruton’s tyrosine kinase (BTK), a kinase involved in B cell receptor signaling.

METHODS. We used stable isotopic labeling with deuterated water (²H₂O) to measure directly the effects of ibrutinib on leukemia cell proliferation and death in 30 patients with CLL.

RESULTS. The measured average CLL cell proliferation (“birth”) rate before ibrutinib therapy was 0.39% of the clone per day (range 0.17%–1.04%); this decreased to 0.05% per day (range 0%–0.36%) with treatment. Death rates of blood CLL cells increased from 0.18% per day (average, range 0%–0.7%) prior to treatment to 1.5% per day (range 0%–3.0%) during ibrutinib therapy, and they were even higher in tissue compartments.

CONCLUSIONS. This study provides the first direct in vivo measurements to our knowledge of ibrutinib’s antileukemia actions, demonstrating profound and immediate inhibition of CLL cell proliferation and promotion of high rates of CLL cell death.

TRIAL REGISTRATION. This trial was registered at clinicaltrials.gov (NCT01752426).

FUNDING. This study was supported by a Cancer Center Support Grant (National Cancer Institute grant P30 CA016672), an NIH grant (CA081554) from the National Cancer Institute, MD Anderson’s Moon Shots Program in CLL, and Pharmacyclics, an AbbVie company.

Authors

Jan A. Burger, Kelvin W. Li, Michael J. Keating, Mariela Sivina, Ahmed M. Amer, Naveen Garg, Alessandra Ferrajoli, Xuelin Huang, Hagop Kantarjian, William G. Wierda, Susan O’Brien, Marc K. Hellerstein, Scott M. Turner, Claire L. Emson, Shih-Shih Chen, Xiao-Jie Yan, Dominik Wodarz, Nicholas Chiorazzi

Protection against Plasmodium falciparum malaria by PfSPZ Vaccine

• Text
• PDF

Abstract

BACKGROUND: A radiation-attenuated Plasmodium falciparum (Pf) sporozoite (SPZ) malaria vaccine, PfSPZ Vaccine, protected 6 of 6 subjects (100%) against homologous Pf (same strain as in the vaccine) controlled human malaria infection (CHMI) 3 weeks after 5 doses administered intravenously. The next step was to assess protective efficacy against heterologous Pf (different from Pf in the vaccine), after fewer doses, and at 24 weeks.

METHODS: The trial assessed tolerability, safety, immunogenicity, and protective efficacy of direct venous inoculation (DVI) of 3 or 5 doses of PfSPZ Vaccine in non-immune subjects.

RESULTS: Three weeks after final immunization, 5 doses of 2.7 × 10⁵ PfSPZ protected 12 of 13 recipients (92.3% [95% CI: 48.0, 99.8]) against homologous CHMI and 4 of 5 (80.0% [10.4, 99.5]) against heterologous CHMI; 3 doses of 4.5 × 10⁵ PfSPZ protected 13 of 15 (86.7% [35.9, 98.3]) against homologous CHMI. Twenty-four weeks after final immunization, the 5-dose regimen protected 7 of 10 (70.0% [17.3, 93.3]) against homologous and 1 of 10 (10.0% [–35.8, 45.6]) against heterologous CHMI; the 3-dose regimen protected 8 of 14 (57.1% [21.5, 76.6]) against homologous CHMI. All 22 controls developed Pf parasitemia. PfSPZ Vaccine was well tolerated, safe, and easy to administer. No antibody or T cell responses correlated with protection.

CONCLUSIONS: We have demonstrated for the first time to our knowledge that PfSPZ Vaccine can protect against a 3-week heterologous CHMI in a limited group of malaria-naive adult subjects. A 3-dose regimen protected against both 3-week and 24-week homologous CHMI (87% and 57%, respectively) in this population. These results provide a foundation for developing an optimized immunization regimen for preventing malaria.

TRIAL REGISTRATION: ClinicalTrials.gov NCT02215707.

FUNDING: Support was provided through the US Army Medical Research and Development Command, Military Infectious Diseases Research Program, and the Naval Medical Research Center’s Advanced Medical Development Program.

Authors

Judith E. Epstein, Kristopher M. Paolino, Thomas L. Richie, Martha Sedegah, Alexandra Singer, Adam J. Ruben, Sumana Chakravarty, April Stafford, Richard C. Ruck, Abraham G. Eappen, Tao Li, Peter F. Billingsley, Anita Manoj, Joana C. Silva, Kara Moser, Robin Nielsen, Donna Tosh, Susan Cicatelli, Harini Ganeshan, Jessica Case, Debbie Padilla, Silas Davidson, Lindsey Garver, Elizabeth Saverino, Tooba Murshedkar, Anusha Gunasekera, Patrick S. Twomey, Sharina Reyes, James E. Moon, Eric R. James, Natasha KC, Minglin Li, Esteban Abot, Arnel Belmonte, Kevin Hauns, Maria Belmonte, Jun Huang, Carlos Vasquez, Shon Remich, Mary Carrington, Yonas Abebe, Amy Tillman, Bradley Hickey, Jason Regules, Eileen Villasante, B. Kim Lee Sim, Stephen L. Hoffman

Chorioretinal thinning in chronic kidney disease links to inflammation and endothelial dysfunction

• Text
• PDF

Abstract

BACKGROUND. Chronic kidney disease (CKD) is strongly associated with cardiovascular disease and there is an established association between vasculopathy affecting the kidney and eye. Optical coherence tomography (OCT) is a novel, rapid method for high-definition imaging of the retina and choroid. Its use in patients at high cardiovascular disease risk remains unexplored.

METHODS. We used the new SPECTRALIS OCT machine to examine retinal and retinal nerve fiber layer (RNFL) thickness, macular volume, and choroidal thickness in a prospective cross-sectional study in 150 subjects: 50 patients with hypertension (defined as a documented clinic BP greater than or equal to 140/90 mmHg (prior to starting any treatment) with no underlying cause identified); 50 with CKD (estimated glomerular filtration rate (eGFR) 8–125 ml/min/1.73 m²); and 50 matched healthy controls. We excluded those with diabetes. The same, masked ophthalmologist carried out each study. Plasma IL-6, TNF-α , asymmetric dimethylarginine (ADMA), and endothelin-1 (ET-1), as measures of inflammation and endothelial function, were also assessed.

RESULTS. Retinal thickness, macular volume, and choroidal thickness were all reduced in CKD compared with hypertensive and healthy subjects (for retinal thickness and macular volume P < 0.0001 for CKD vs. healthy and for CKD vs. hypertensive subjects; for choroidal thickness P < 0.001 for CKD vs. healthy and for CKD vs. hypertensive subjects). RNFL thickness did not differ between groups. Interestingly, a thinner choroid was associated with a lower eGFR (r = 0.35, P <0.0001) and, in CKD, with proteinuria (r = –0.58, P < 0.001) as well as increased circulating C-reactive protein (r = –0.57, P = 0.0002), IL-6 (r = –0.40, P < 0.01), ADMA (r = –0.37, P = 0.02), and ET-1 (r = –0.44, P < 0.01). Finally, choroidal thinning was associated with renal histological inflammation and arterial stiffness. In a model of hypertension, choroidal thinning was seen only in the presence of renal injury.

CONCLUSIONS. Chorioretinal thinning in CKD is associated with lower eGFR and greater proteinuria, but not BP. Larger studies, in more targeted groups of patients, are now needed to clarify whether these eye changes reflect the natural history of CKD. Similarly, the associations with arterial stiffness, inflammation, and endothelial dysfunction warrant further examination.

TRIAL REGISTRATION. Registration number at www.clinicalTrials.gov: NCT02132741.

SOURCE OF FUNDING. TR was supported by a bursary from the Erasmus Medical Centre, Rotterdam. JJMHvB was supported by a bursary from the Utrecht University. JRC is supported by a Rowling Scholarship. SB was supported by a Wellcome Trust funded clinical research fellowship from the Scottish Translational Medicine and Therapeutics Initiative, and by a Rowling Scholarship, at the time of this work. ND is supported by a British Heart Foundation Intermediate Clinical Research Fellowship (FS/13/30/29994).

Authors

Craig Balmforth, Job J.M.H. van Bragt, Titia Ruijs, James R. Cameron, Robert Kimmitt, Rebecca Moorhouse, Alicja Czopek, May Khei Hu, Peter J. Gallacher, James W. Dear, Shyamanga Borooah, Iain M. MacIntyre, Tom M.C. Pearson, Laura Willox, Dinesh Talwar, Muriel Tafflet, Christophe Roubeix, Florian Sennlaub, Siddharthan Chandran, Baljean Dhillon, David J. Webb, Neeraj Dhaun