Citations 2
The effect of burosumab on intact and C‐terminal FGF23 measurements
Ashrafzadeh‐Kian, Susan , Ito, Nobuaki , Sethna, Christine B. , Garg, Uttam, Katô, Hajime , Bornhorst, Joshua A. , Ashrafzadeh-Kian, Susan Louise , Srivastava, Tarak , Bornhorst, Joshua , Algeciras‐Schimnich, Alicia
Clinical Endocrinology | October 20, 2022 | Volume: 99 | Issue: 2 | Pages: 152-157
AbstractObjectiveTo investigate the effect of CRYSVITA® (burosumab‐twza) on FGF23 measurements in an intact and a C‐terminal immunoassay.MethodsAn intact serum FGF23 (MedFrontier) and a C‐terminal plasma FGF23 assay (Immutopics) were used. Serum/plasma pools were spiked to span the burosumab therapeutic range (1.4–11.3 μg/ml) and FGF23 recovery was assessed. Patient serum and plasma samples obtained pre and post‐burosumab treatment were evaluated on both assays and compared with corresponding phosphorus measurementsResultsSpiking burosumab (1.4–11.3 μg/ml) into sample pools resulted in a dose‐dependent negative analytical interference on intact FGF23 measurements and no significant interference for C‐terminal FGF23 measurements. However, more than a 500‐fold median increase (post‐ vs. pre‐burosumab administration) in in vivo FGF23 concentrations were observed by both assays.ConclusionsTherapeutic concentrations of burosumab result in a negative analytical interference of the intact, but not the C‐terminal FGF23 immunoassay. Despite this in vitro analytical interference in the intact assay, relatively large elevations of both intact FGF23 and C‐terminal FGF23 measurements were observed in vivo following burosumab administration. Following burosumab administration, FGF23 measurements must be interpreted within the clinical context of the patient and other relevant biomarker results.SummaryThis article describes a negative analytical interference by burosumab in an intact FGF23 immunoassay. The recovery of C‐terminal FGF23 is not significantly affected by the presence of burosumab. In vivo, both assays demonstrate extreme FGF23 elevations in the presence of the drug. Furthermore, the measurement of FGF23 blocked by burosumab is not clinically useful regarding hypophosphataemia.
The longitudinal relationship between patient-reported outcomes and clinical characteristics among patients with focal segmental glomerulosclerosis in the Nephrotic Syndrome Study Network
Troost, Jonathan P. , Waldo, Anne, Carlozzi, Noelle E. , Murphy, Shannon L., Modersitzki, Frank , Trachtman, Howard , Nachman, Patrick H. , Reidy, Kimberly J. , Selewski, David T. , Herreshoff, Emily, Srivastava, Tarak, Gibson, Keisha L. , Derebail, Vimal K. , Lin, Jen Jar, Hingorani, Sangeeta, Sambandam, Kamalanathan K. , Athavale, Ambarish M., Reich, Heather N. , Adler, Sharon G. , Dell, Katherine M., Appel, Gerald B., Wang, Chia-shi , Kaskel, Frederick J. , Lafayette, Richard , Atkinson, Meredith A. , Kretzler, Matthias , Lemley, Kevin V. , Brown, Elizabeth , Meyers, Kevin , Gadegbeku, Crystal A., Holzman, Lawrence B. , Jefferson, Jonathan Ashley, Tuttle, Katherine R, Singer, Pamela, Hogan, Marie C. , Cattran, Daniel C., Network, the Nephrotic Syndrome Study, Dell, K, Schachere, M., Lemley, K, Whitted, L, Haney, Connie J, Gurusinghe, Sayuri , Toledo, Michelly Louise Sartório Altoé, Greenbaum, L, Wang, C, Lee, B, Nast, Cynthia C. , Page, J La, Stroger, John H, Itteera, M. , Neu, Alicia M. , Boynton, Sara Ashley, Chernitskiy, Vladimir, Reidy, K, Kopp, J, Castro-Rubio, E, Brede, E, Blake, J. Thomas, Modersitzki, F, Lafayette, R, Mehta, K. , Johnstone, Duncan B., Pfeffer, Zoe, Cattran, D, Hladunewich, M, Reich, H, Ling, P., Romano, M, Barisoni, L, Bidot, Carlos, Kretzler, M, Williams, A, Pitter, R, Gibson, K, Grubbs, S, Froment, Anne, Holzman, L, Kallem, K., Cerecino, F J, Johnson, N, Jefferson, A, Tuttle, Katherine R. , Klepach, K, Kelton, M, Cooper, Ann , Lin, J J, Spainhour, Mitzie, Gray, S, Barisoni, L, Gillespie, B, Gipson, D, Holzman, L, Mariani, Laura , Song, Peter X.‐K. , Kincaid, Colleen, Lienczewski, Chrysta, Mainieri, T, Williams, Anna , Ávila-Casado, Carmen , Bagnasco, Serena M. , Gaut, Joseph P. , Hewitt, Stephen M. , Palmer, M, Rosenberg, A, Royal, Virginie , Barisoni, L, Nast, C, Roy, Cindy N., Urv, T, Dell, K, Greenbaum, L, Lee, B, Page, J La, Stroger, John H, Reidy, K, Kopp, J, Brede, E, Modersitzki, F, Lafayette, R, Gadegbeku, C, Cattran, D, Hladunewich, M, Reich, H, Romano, M, Pitter, R, Gibson, K, Cerecino, F J, Jefferson, A, Lin, J J, Gray, S, Kretzler, M, Gillespie, B, Gipson, D, Mariani, L, Mainieri, T, Williams, A, Mariani, L, Palmer, M, Rosenberg, A, Barisoni, L, Urv, T, Wang, Chia-Shi , Tuttle, Katherine R , Hogan, Marie C , Fornoni, Alessia , Fervenza, Fernando C. , Kopp, Jeffrey B. , Greenbaum, Larry A. , Sedor, John R. , Lieske, John C. , Srivastava, Tarak , Hladunewich, Michelle , Tuttle, Katherine R, Singer, Pamela S. , Barisoni, Laura , Gipson, Debbie S , Network, the Nephrotic Syndrome Study, Dell, K, Lemley, K, Greenbaum, L, Lee, B, Page, J La, Stroger, John H, Reidy, K, Kopp, J, Brede, E, Zhdanova, Olga A. , Modersitzki, F, Vento, Sandro , Lafayette, R, Cattran, D, Hladunewich, M, Reich, H, Romano, M, Barisoni, L, Bidot, C, Kretzler, M, Williams, A, Pitter, R, Gibson, K, Holzman, L, Cerecino, F J, Jefferson, A, Freedman, Barry I. , Lin, J J, Gray, S, Barisoni, L, Gillespie, B, Gipson, D, Holzman, L, Sampson, Matthew Gordon , Zee, Jarcy , Mainieri, T, Hodgin, Jeffrey B. , Palmer, M, Rosenberg, A, Thomas, D, Barisoni, L, Nast, C, Abbott, Kevin C. , Roy, C, Urv, T, Brooks, Philip John , Dell, K, Greenbaum, L, Lee, B, Page, J La, Stroger, John H, Reidy, K, Kopp, J, Brede, E, Modersitzki, F, Lafayette, R, Gadegbeku, C, Cattran, D, Hladunewich, M, Reich, H, Romano, M, Bidot, C, Pitter, R, Gibson, K, Cerecino, F J, Jefferson, A, Lin, J J, Gray, S, Kretzler, M, Gillespie, B, Gipson, D, Mariani, L, Mainieri, T, Williams, A, Mariani, L, Palmer, M, Rosenberg, A, Thomas, D, Barisoni, L, Roy, C, Urv, T, Troost, Jonathan P.
Clinical Kidney Journal | July 3, 2019 | Volume: 13 | Issue: 4 | Pages: 597-606
Abstract Background Understanding the relationship between clinical and patient-reported outcomes (PROs) will help support clinical care and future clinical trial design of novel therapies for focal segmental glomerulosclerosis (FSGS). Methods FSGS patients ≥8 years of age enrolled in the Nephrotic Syndrome Study Network completed Patient-Reported Outcomes Measurement Information System PRO measures of health-related quality of life (HRQoL) (children: global health, mobility, fatigue, pain interference, depression, anxiety, stress and peer relationships; adults: physical functioning, fatigue, pain interference, sleep impairment, mental health, depression, anxiety and social satisfaction) at baseline and during longitudinal follow-up for a maximum of 5 years. Linear mixed-effects models were used to determine which demographic, clinical and laboratory features were associated with PROs for each of the eight children and eight adults studied. Results There were 45 children and 114 adult FSGS patients enrolled that had at least one PRO assessment and 519 patient visits. Multivariable analyses among children found that edema was associated with global health (−7.6 points, P = 0.02) and mobility (−4.2, P = 0.02), the number of reported symptoms was associated with worse depression (−2.7 per symptom, P = 0.009) and anxiety (−2.3, P = 0.02) and the number of emergency room (ER) visits in the prior 6 months was associated with worse mobility (−2.8 per visit, P < 0.001) and fatigue (−2.4, P = 0.03). Multivariable analyses among adults found the number of reported symptoms was associated with worse function in all eight PROMIS measures and the number of ER visits was associated with worse fatigue, pain interference, sleep impairment, depression, anxiety and social satisfaction. Laboratory markers of disease severity (i.e. proteinuria, estimated glomerular filtration rate and serum albumin) did not predict PRO in multivariable analyses, with the single exception of complete remission and better pain interference scores among children (+9.3, P = 0.03). Conclusions PROs provide important information about HRQoL for persons with FSGS that is not captured solely by the examination of laboratory-based markers of disease. However, it is critical that instruments capture the patient experience and FSGS clinical trials may benefit from a disease-specific instrument more sensitive to within-patient changes.