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Dive into the research topics where Laurence Chan is active.

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Featured researches published by Laurence Chan.


Transplantation | 2006

Patient-reported gastrointestinal symptom burden and health-related quality of life following conversion from mycophenolate mofetil to enteric-coated mycophenolate sodium.

Laurence Chan; Shamkant Mulgaonkar; Rowan G. Walker; Wolfgang Arns; Patrice M. Ambühl; Ruben Schiavelli

Background. The benefit of converting renal transplant recipients with gastrointestinal (GI) complaints from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) has not been evaluated using patient-reported outcomes. Methods. A multicenter, open-label, prospective study was undertaken in MMF-treated renal transplant patients. Patients experiencing GI complaints were converted to equimolar EC-MPS (Cohort A). Patients without GI complaints remained on MMF (Cohort B). At baseline and Visit 2 (4–6 weeks postbaseline), patients completed the Gastrointestinal Symptom Rating Scale (GSRS), Gastrointestinal Quality of Life Index (GIQLI) and Psychological General Well-being Index (PGWBI). At Visit 2, patients and physicians completed the Overall Treatment Effect (OTE) scale for GI symptoms. Additionally, patients completed the OTE for health-related quality of life (HRQoL). Minimal important difference (MID) was calculated for GSRS and GIQLI based on patients’ and physicians’ OTE evaluation. Results. Of 328 patients enrolled (i.e. the intent-to-treat and safety populations), 278 formed the per-protocol population (Cohort A, n=177; Cohort B, n=101). At baseline, Cohort A had significantly worse scores on all GSRS, GIQLI and PGWBI subscales compared to Cohort B (all P<0.0001). All GSRS, GIQLI and PGWBI subscale scores improved significantly in Cohort A between baseline and Visit 2 (all P<0.0001). Mean improvements in all GSRS subscales and most GIQLI subscores exceeded the calculated MID. GSRS, GIQLI and PGWBI subscales remained stable in Cohort B. Conclusion. This first exploratory study indicates that converting patients with mild, moderate or severe GI complaints from MMF to EC-MPS significantly reduces GI-related symptom burden and improves patient functioning and well-being.


Transplantation | 2008

Multicenter, randomized study of the use of everolimus with tacrolimus after renal transplantation demonstrates its effectiveness

Laurence Chan; Stuart M. Greenstein; Mark A. Hardy; Erica Hartmann; Suphamai Bunnapradist; Diane M. Cibrik; Leslie M. Shaw; Laura Munir; Bettina Ulbricht; Matthew Cooper

Background. Clinical data are lacking concerning concomitant administration of everolimus and tacrolimus in renal transplant recipients. Methods. In a prospective, multicenter, open-label, exploratory, randomized, 6-month study, 92 de novo renal transplant patients received everolimus, steroids, and basiliximab with low or standard tacrolimus exposure. The primary objective was to compare renal function at 6 months after transplant. Results. Mean 6-month serum creatinine (primary safety variable) was 112±31 &mgr;mol/L (1.26±0.35 mg/dL) and 127±50 &mgr;mol/L (1.44±0.57 mg/dL) in the low and standard tacrolimus groups, respectively, (n.s.); mean estimated GFR (Nankivell) was 75.3±16.6 mL/min and 72.5±15.2 mL/min (n.s.). Biopsy-proven acute rejection occurred in 13 patients: seven (14%) in the low tacrolimus group and six (14%) in the standard tacrolimus group, n.s. One graft was lost in the standard tacrolimus group. No patients died. Conclusions. Tacrolimus exposure reduction in the presence of everolimus, steroids and basiliximab induction results in good efficacy in de novo renal transplant recipients with very well-preserved renal function. Additional studies are warranted because between-group comparisons were limited by the relatively small differences in tacrolimus exposure in the 2 arms; trough levels were toward the upper end of the low-exposure ranges and toward the bottom of the standard-exposure ranges.


Transplantation | 2007

Improvement in 3-Month Patient-Reported Gastrointestinal Symptoms After Conversion From Mycophenolate Mofetil to Enteric-Coated Mycophenolate Sodium in Renal Transplant Patients

Paul Bolin; Bekir Tanriover; Gazi B. Zibari; Melissa L. Lynn; John D. Pirsch; Laurence Chan; Matthew Cooper; Anthony Langone; Stephen J. Tomlanovich

Background. The benefit of conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) in terms of gastrointestinal symptom burden has been evaluated previously using patient-reported outcomes. However, data are lacking concerning the sustained effect of conversion over time, and the potential impact of concomitant calcineurin inhibitor. Methods. In this 3-month, prospective, multicenter, longitudinal, open-label trial, MMF-treated renal transplant patients with gastrointestinal symptoms receiving cyclosporine or tacrolimus were converted to equimolar doses of EC-MPS. Change in gastrointestinal symptom burden was evaluated using a validated Gastrointestinal Symptom Rating Scale (GSRS). Results. A significant improvement in GSRS score was observed from baseline (2.61, 95% CI 2.54–2.68) to month 1 (1.87, 95% CI 1.81–1.93) after conversion to EC-MPS and was sustained to month 3 (1.81, 95% CI 1.74–188; both P<0.0001 versus baseline). The mean change in overall GSRS score from baseline to month 1 was −0.74 overall (cyclosporine: −0.73 and tacrolimus: −0.74; all P<0.0001 versus baseline), with a slight further improvement (−0.79) at month 3 (cyclosporine: −0.82 and tacrolimus: −0.78; all P<0.0001 versus baseline). A significant improvement in GSRS subscale scores was also observed in the total population regardless of calcineurin inhibitor at month 1, sustained to month 3 (all P<0.0001 versus baseline). The improvement in GSRS score postconversion was similar in African-American and non-African-American patients, and in diabetic and nondiabetic patients. Conclusions. This exploratory study in 728 patients demonstrates that following conversion from MMF to EC-MPS, regardless of concomitant calcineurin inhibitor, GSRS is improved and sustained over 3 months.


Transplantation | 2011

Enteric-coated mycophenolate sodium versus mycophenolate mofetil in renal transplant recipients experiencing gastrointestinal intolerance: a multicenter, double-blind, randomized study.

Anthony Langone; Laurence Chan; Paul Bolin; Matthew Cooper

Background. Two open-label studies demonstrated that conversion from mycophenolate mofetil (MMF) to enteric-coated mycophenolate sodium (EC-MPS) significantly reduces gastrointestinal (GI) symptom burden and improves GI-specific health-related quality of life. Using a randomized design, this study evaluated changes in GI symptoms and health-related quality of life in patients converted from MMF to EC-MPS versus patients who continued with MMF-based treatment. Methods. In this 4-week, multicenter, randomized, prospective, double-blind, parallel-group trial, renal transplant recipients with GI symptoms receiving MMF plus a calcineurin inhibitor±corticosteroids were randomized to an equimolar dose of EC-MPS+MMF placebo or continue on their MMF-based regimen+EC-MPS placebo. The primary efficacy outcome was a change from baseline in total Gastrointestinal Symptom Rating Scale score of a minimally important difference of more than or equal to 0.3. Results. Three hundred ninety-six patients (EC-MPS group: n=199; MMF group: n=197) were included. A greater proportion of EC-MPS patients (62%) reached the primary efficacy outcome compared with MMF patients (55%); however, the difference was not statistically significant (P=0.15). EC-MPS patients had a significantly greater decrease in the Gastrointestinal Symptom Rating Scale indigestion syndrome dimension versus MMF patients. Within the subgroups of patients with diabetes, patients transplanted 6 to 12 months of study enrollment, and patients on steroids, a statistically significant greater proportion of EC-MPS versus MMF patients reached the primary efficacy outcome. Conclusions. Conversion from MMF to EC-MPS may be associated with improvements in presence and severity of GI symptoms, particularly in patients with indigestion, diabetes, on steroids, and in patients converted between 6 and 12 months posttransplantation.


Transplantation | 2010

Optimal everolimus concentration is associated with risk reduction for acute rejection in de novo renal transplant recipients.

Laurence Chan; Erica Hartmann; Diane M. Cibrik; Matthew Cooper; Leslie M. Shaw

Background. Everolimus (Evl) plus tacrolimus (Tac) in de novo renal transplantation is effective and safe. Whether the concentration of Evl affects efficacy and safety in a Tac-based regimen has not been previously reported. Aim. To evaluate whether the concentration of Evl affects biopsy-proven acute rejection (BPAR), renal function, adverse events (AEs); and to assess for pharmacokinetic (PK) interactions. Methods. Data were from a prospective, multicenter, open-label, randomized, exploratory 6-month study of 92 renal transplant patients treated de novo with concentration-controlled Evl (target trough levels ≥3 ng/mL) plus low-dose Tac or Evl plus standard-dose Tac; both groups received basiliximab and corticosteroids. Data were pooled across study arms to examine BPAR rates in patients with Evl trough levels less than 3 (n=26), 3 to 8 (n=62), or more than 8 ng/mL (n=4). Groups were stratified by both Evl and Tac trough levels to evaluate glomerular filtration rate and AEs. Evl and Tac PK interactions were evaluated in a subset of 14 patients. Results. Evl trough level of more than or equal to 3 ng/mL was associated with significantly lower rates of BPAR as compared with a trough level of less than 3 ng/mL. Glomerular filtration rate was similar at 6 months for both the low and standard Tac groups. No apparent PK interactions were observed between Evl and Tac. AEs were infrequent and did not seem to be associated with the Evl or Tac level. Conclusions. Evl trough levels ≥3 ng/mL plus Tac are associated with low rates of BPAR without adversely affecting renal function. No evident PK interaction exists between Evl and Tac.


Clinical Transplantation | 2013

Association of clinical events with everolimus exposure in kidney transplant patients receiving reduced cyclosporine.

Fuad S. Shihab; Diane M. Cibrik; Laurence Chan; Yu Seun Kim; Mario Carmellini; Rowan G. Walker; Gazi B. Zibari; James Pattison; Catherine Cornu-Artis; Zailong Wang; Helio Tedesco-Silva

The association between clinical events and everolimus exposure in patients receiving reduced‐exposure calcineurin inhibitor therapy is poorly explored.


Transplantation | 2013

Outcomes in African American kidney transplant patients receiving tacrolimus and mycophenolic acid immunosuppression.

Mohanram Narayanan; O. Pankewycz; Mohamed El-Ghoroury; Fuad S. Shihab; Anne Wiland; Kevin McCague; Laurence Chan

Background Prospective data regarding immunosuppression and rejection in African American patients receiving modern immunosuppressive regimens are sparse. Methods One-year data were analyzed from 901 tacrolimus-treated de novo kidney transplant patients in the prospective Mycophenolic Acid Observational Renal Transplant registry. Results Mean tacrolimus dose was significantly higher in African Americans (n=217) versus non–African Americans (n=684), but mean tacrolimus trough concentrations were similar. The proportion of patients receiving mycophenolic acid dose equal to or more than 2000 mg per day (mycophenolate mofetil equivalents) was significantly higher with enteric-coated mycophenolate sodium versus mycophenolate mofetil at month 6 among African Americans and at month 3 in non–African Americans, but rates of acute rejection and adverse events (including gastrointestinal events) were similar. The 1-year incidence of biopsy-proven acute rejection (BPAR) was 14.1% in African Americans versus 7.5% in non–African Americans. On multivariate analysis, African American ethnicity was associated with a higher risk of BPAR (hazard ratio, 1.93; 95% confidence interval, 1.19–3.09; P=0.007). Mean (standard deviation) glomerular filtration rate at month 12 estimated by the Chronic Kidney Disease Epidemiology Collaboration formula was 59.2 (22.2) mL/min/1.73 m2 in African Americans versus 58.8 (19.9) mL/min/1.73 m2 in non–African Americans (confidence interval of the difference, −3.4 to 4.3; P=0.83). Conclusion This observational study confirms that African Americans require higher doses of tacrolimus to achieve target trough concentrations and are more likely to experience BPAR during the first year after kidney transplantation despite modern immunosuppression regimens. In our 1-year study, this was not associated with significantly inferior graft survival.


Clinical Transplantation | 2014

Long-term outcomes in African American kidney transplant recipients under contemporary immunosuppression: a four-yr analysis of the Mycophenolic acid Observational REnal transplant (MORE) study

Mohanram Narayanan; O. Pankewycz; Fuad S. Shihab; Anne Wiland; Kevin McCague; Laurence Chan

Mycophenolic acid Observational REnal transplant (MORE) was a prospective, observational study of de novo kidney transplant patients receiving mycophenolic acid (MPA). Four‐yr data on 904 patients receiving tacrolimus and enteric‐coated mycophenolate sodium (EC‐MPS) or mycophenolate mofetil (MMF) were analyzed to evaluate immunosuppression and graft outcomes in African American (AA, n = 218) vs. non‐AA (n = 686) patients. Mean tacrolimus dose was higher in AA vs. non‐AA patients but mean tacrolimus trough concentration was similar. Use of the recommended MPA dose in AA patients decreased from 78.9% at baseline to 33.1% at year 3. More AA patients received the recommended MPA dose with EC‐MPS than MMF at month 6 (56.2% vs. 35.7%, p = 0.016) and month 36 (46.6% vs. 16.7%, p = 0.029), with no safety penalty. Significantly, more AA patients received corticosteroids than non‐AA patients. Biopsy‐proven acute rejection was higher in AA vs. non‐AA patients (18.9% vs. 10.7%, p = 0.003), as was graft loss (10.9% vs. 4.4%, p = 0.003); differences were confirmed by Cox regression analysis. Patient survival was similar. Estimated GFR was comparable in AA vs. non‐AA patients. Kidney allograft survival remains lower for AA vs. non‐AA recipients even under the current standard of care.


Clinical Transplantation | 2013

Does reduction in mycophenolic acid dose compromise efficacy regardless of tacrolimus exposure level? An analysis of prospective data from the Mycophenolic Renal Transplant (MORE) Registry

Anthony Langone; Cataldo Doria; Stuart Greenstein; Mohanram Narayanan; Kimi Ueda; Bashir Sankari; O. Pankewycz; Fuad S. Shihab; Laurence Chan

Prospective data are lacking concerning the effect of reduced mycophenolic acid (MPA) dosing on efficacy and the influence of concomitant tacrolimus exposure. The Mycophenolic Renal Transplant (MORE) Registry is a prospective, observational study of de novo kidney transplant patients receiving MPA therapy under routine management. The effect of MPA dose reduction, interruption, or discontinuation (dose changes) was assessed in 870 tacrolimus‐treated patients: 375 (43.1%) reduced tacrolimus (≤7 ng/mL at baseline) and 495 (56.9%) standard tacrolimus (>7 ng/mL); enteric‐coated mycophenolate sodium 589 (67.7%) and mycophenolate mofetil 281 (32.3%). During baseline to month 1, months 1–3, months 3–6, and months 6–12, 9.3% (78/838), 16.6% (132/794), 20.7% (145/701), and 13.1% (70/535) patients, respectively, required MPA dose changes. These patients experienced an increased risk of biopsy‐proven acute rejection at one yr with tacrolimus exposure either included in the model (hazard ratio [HR] 2.60, 95% CI 1.28–5.29, p = 0.008) or excluded (HR 2.58, 95% CI 1.28–5.23, p = 0.008). MPA dose changes were significantly associated with one yr graft failure when tacrolimus exposure was included (HR 2.23; 95% CI 1.01–4.89, p = 0.047) but not when tacrolimus exposure was excluded (HR 2.16; 95% CI 0.99–4.79; p = 0.054). These results suggest that reducing or discontinuing MPA can adversely affect graft outcomes regardless of tacrolimus trough levels.


Annals of Transplantation | 2014

A longitudinal assessment of adherence with immunosuppressive therapy following kidney transplantation from the Mycophenolic Acid Observational REnal Transplant (MORE) study

Demetra Tsapepas; Anthony Langone; Laurence Chan; Anne Wiland; Kevin McCague; Marie A. Chisholm-Burns

BACKGROUND Nonadherence with immunosuppressive therapy after renal transplantation is a major clinical concern, but longitudinal data are sparse. Adherence data were recorded during the Mycophenolic Acid Observational REnal Transplant (MORE) study to help inform compliance management decisions. MATERIAL AND METHODS Prospective data were analyzed from the four-year, observational MORE study of de novo adult renal transplant recipients receiving mycophenolic acid (MPA) as enteric-coated mycophenolate sodium (EC-MPS) or mycophenolate mofetil (MMF) at 40 US sites under routine management. Adherence was assessed using the Immunosuppressant Therapy Adherence Scale (ITAS): total score 0-12 (12, adherence; <12, nonadherence). A logistic regression model was used to identify factors associated with nonadherence. RESULTS In total, 808/946 recipients (85.4%) provided ≥1 ITAS score. Nonadherence was reported by 24.8%, 31.5%, 33.0%, 39.8%, 35.4% and 26.4% at months 3, 6, 12, 24, 36 and 48, respectively. Mean ITAS score was higher with EC-MPS vs. MMF at months 24 (11.3[1.0] vs. 10.9[1.4], p=0.001) and 36 (11.4[1.0] vs. 11.1[11.3], p=0.024). The odds ratio for nonadherence was 1.60 (95% CI 1.17, 2.19; p=0.003) for African Americans vs. non-African Americans. The rate of biopsy-proven acute rejection was 12.7% (51/401) in nonadherent recipients vs. 11.3% (46/406) in adherent recipients (p=0.59); graft loss was 4.7% (19/402) vs. 3.0% (12/406) (p=0.20); death was 1.5% (6/402) vs. 4.7% (19/406) (p=0.013). CONCLUSIONS Adherence to the immunosuppressive regimen decreases over time, highlighting the need to monitor and encourage adherence even in long-term maintenance kidney transplant patients. Other than African American race, demographic factors may be of limited value in predicting nonadherence.

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Anthony Langone

Vanderbilt University Medical Center

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Cataldo Doria

Thomas Jefferson University

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Bashir Sankari

Charleston Area Medical Center

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