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result(s) for
"Sajeev, Gautam"
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Prognostic factors for changes in the timed 4-stair climb in patients with Duchenne muscular dystrophy, and implications for measuring drug efficacy: A multi-institutional collaboration
by
Landry, John
,
Ward, Susan J.
,
Dieye, Ibrahima
in
Biology and Life Sciences
,
Clinical trials
,
Collaboration
2020
The timed 4-stair climb (4SC) assessment has been used to measure function in Duchenne muscular dystrophy (DMD) practice and research. We sought to identify prognostic factors for changes in 4SC, assess their consistency across data sources, and the extent to which prognostic scores could be useful in DMD clinical trial design and analysis. Data from patients with DMD in the placebo arm of a phase 3 trial (Tadalafil DMD trial) and two real-world sources (Universitaire Ziekenhuizen, Leuven, Belgium [Leuven] and Cincinnati Children's Hospital Medical Center [CCHMC]) were analyzed. One-year changes in 4SC completion time and velocity (stairs/second) were analyzed. Prognostic models included age, height, weight, steroid use, and multiple timed function tests and were developed using multivariable regression, separately in each data source. Simulations were used to quantify impacts on trial sample size requirements. Data on 1-year changes in 4SC were available from the Tadalafil DMD trial (n = 92) Leuven (n = 67), and CCHMC (n = 212). Models incorporating multiple timed function tests, height, and weight significantly improved prognostic accuracy for 1-year change in 4SC (R.sup.2 : 29%-36% for 4SC velocity, and 29%-34% for 4SC time) compared to models including only age, baseline 4SC and steroid duration (R.sup.2 :8%-17% for 4SC velocity and 2%-13% for 4SC time). Measures of walking and rising ability contributed important prognostic information for changes in 4SC. In a randomized trial with equal allocation to treatment and placebo, adjustment for such a prognostic score would enable detection (at 80% power) of a treatment effect of 0.25 stairs/second with 100-120 patients, compared to 170-190 patients without prognostic score adjustment. Combining measures of ambulatory function doubled prognostic accuracy for 1-year changes in 4SC completion time and velocity. Randomized clinical trials incorporating a validated prognostic score could reduce sample size requirements by approximately 40%. Knowledge of important prognostic factors can also inform adjusted comparisons to external controls.
Journal Article
Categorising trajectories and individual item changes of the North Star Ambulatory Assessment in patients with Duchenne muscular dystrophy
by
Ward, Susan J.
,
Mayhew, Anna
,
Domingos, Joana
in
Adolescent
,
Ambulatory assessment
,
Biological Variation, Individual
2019
Functional variability among boys with Duchenne muscular dystrophy (DMD) is well recognised and complicates interpretation of clinical studies. We hypothesised that boys with DMD could be clustered into groups sharing similar trajectories of ambulatory function over time, as measured by the North Star Ambulatory Assessment (NSAA) total score. We also explored associations with other variables such as age, functional abilities, and genotype. Using the NorthStar Clinical Network database, 395 patients with >1 NSAA assessment were identified. We utilised latent class trajectory analysis of longitudinal NSAA scores, which produced evidence for at least four clusters of boys sharing similar trajectories versus age in decreasing order of clinical severity: 25% of the boys were in cluster 1 (NSAA falling to ≤ 5 at age ~10y), 35% were in cluster 2 (NSAA ≤ 5 ~12y), 21% in were cluster 3 (NSAA≤ 5 ~14y), and 19% in cluster 4 (NSAA > 5 up to 15y). Mean ages at diagnosis of DMD were similar across clusters (4.2, 3.9, 4.3, and 4.8y, respectively). However, at the first NSAA assessment, a significant (p<0.05) association was observed between earlier declining clusters and younger age, worse NSAA, slower rise from supine, slower 10 metre walk/run times, and younger age of steroid initiation. In order to assess the probability of observing complete loss of function for individual NSAA items, we examined the proportion of patients who shifted from a score of 1 or 2 at baseline to a score of 0. We also assessed the probability of gain of function using the inverse assessment and stratified the probability of deterioration, improvement-or static behavior-by age ranges and using baseline functional status. Using this tool, our study provides a comprehensive assessment of the NSAA in a large population of patients with DMD and, for the first time, describes discrete clusters of disease progression; this will be invaluable for future DMD clinical trial design and interpretation of findings.
Journal Article
Functional trajectories before and after loss of ambulation in Duchenne muscular dystrophy and implications for clinical trials
2024
This study examined functional trajectories of subjects during the transition phase between ambulatory and non-ambulatory Duchenne muscular dystrophy (DMD) to inform clinical trial designs for new therapeutics. Ambulatory, pulmonary, and upper limb function leading up to loss of ambulation (LoA) and non-ambulatory measures following LoA were quantified; time ordering of pulmonary and upper limb milestones relative to LoA were determined; and the 10-second time threshold for 10-meter walk/run (10MWR) as a marker of approaching LOA was explored. Included in this analysis were 51 subjects aged between 7 and 18 years who experienced LoA during follow-up in the PRO-DMD-01 natural history study. Mean age at LoA was 12.7 (7.1–18.6) years. Mean annual rates of decline in forced vital capacity (FVC) <80%-predicted and performance of upper limb (PUL) 1.2 total score were smaller before than after LoA, but not significantly (FVC %-predicted: 5.6% vs. 10.1%, p = 0.21; PUL 1.2 total score: 2.3 vs. 3.8 units, p = 0.20). More than half of patients experienced clinically significant deficits in FVC %-predicted and PUL 1.2 before experiencing LoA. Among subjects with baseline 10MWR >10 s, those with <1 year to LoA had similar mean ages but significantly worse mean ambulatory function at baseline compared to those with ≥1 year to LoA. Enriching DMD clinical trials for patients with declining pulmonary or upper limb function is achievable without restricting enrollment to non-ambulatory patients. The sequencing of LoA and initial deficits in pulmonary and upper limb function varied across patients and highlights the potential for composite outcomes or multi-outcome trial designs to assess disease-modifying therapies more comprehensively.
Journal Article
Meaningful changes in motor function in Duchenne muscular dystrophy (DMD): A multi-center study
by
Dieye, Ibrahima
,
Done, Nicolae
,
McDonald, Craig
in
Adolescent
,
Benchmarks
,
Biology and Life Sciences
2024
Evaluations of treatment efficacy in Duchenne muscular dystrophy (DMD), a rare genetic disease that results in progressive muscle wasting, require an understanding of the ‘meaningfulness’ of changes in functional measures. We estimated the minimal detectable change (MDC) for selected motor function measures in ambulatory DMD, i.e., the minimal degree of measured change needed to be confident that true underlying change has occurred rather than transient variation or measurement error. MDC estimates were compared across multiple data sources, representing >1000 DMD patients in clinical trials and real-world clinical practice settings. Included patients were ambulatory, aged ≥4 to <18 years and receiving steroids. Minimal clinically important differences (MCIDs) for worsening were also estimated. Estimated MDC thresholds for >80% confidence in true change were 2.8 units for the North Star Ambulatory Assessment (NSAA) total score, 1.3 seconds for the 4-stair climb (4SC) completion time, 0.36 stairs/second for 4SC velocity and 36.3 meters for the 6-minute walk distance (6MWD). MDC estimates were similar across clinical trial and real-world data sources, and tended to be slightly larger than MCIDs for these measures. The identified thresholds can be used to inform endpoint definitions, or as benchmarks for monitoring individual changes in motor function in ambulatory DMD.
Journal Article
Predicting trajectories of the north star ambulatory assessment total score in Duchenne muscular dystrophy
by
Servais, Laurant
,
Li, Jiayang
,
Done, Nicolae
in
Adolescent
,
Adrenal Cortex Hormones - therapeutic use
,
Ambulatory assessment
2025
The North Star Ambulatory Assessment (NSAA) is a widely used functional endpoint in drug development for ambulatory patients with Duchenne muscular dystrophy (DMD). Accurately predicting NSAA total score trajectories is important for designing randomized trials for novel therapies in DMD and for contextualizing outcomes, especially over longer-term follow-up (>18 months) when placebo-controlled studies are infeasible. We developed a prognostic model for NSAA total score trajectories over at most 5 years of follow-up for patients with DMD aged 4 to <16 years who were initially ambulatory and receiving corticosteroids but no other disease-modifying therapies. The model was based on longitudinal data from four natural history databases: UZ Leuven, PRO-DMD-01 (provided by CureDuchenne), the North Star Clinical Network, and iMDEX. Candidate predictors included age, height, weight, body mass index, steroid type and regime, NSAA total score, rise from floor velocity, and 10-meter walk/run velocity, as well as DMD genotype class, index year, and data source. Among N = 416 patients at baseline, mean age was 8.2 years, mean NSAA total score was 24, and 61% were receiving prednisone and 39% deflazacort, with the majority having been treated with daily corticosteroid regimens (69%) relative to other regimens (31%). Patients had an average of four NSAA assessments post-baseline during a median follow-up of 2.6 years (inter-quartile range 1.9 to 3.6 years). The best-fitting model in the full study sample explained 39% of the variation in NSAA total score changes, with prediction errors of ±3.6, 5.1, 5.9, 7.5, 9.5 NSAA units during follow-up years 1–5, respectively. The most important predictors were baseline age, NSAA, rise from floor velocity, and 10-meter walk/run velocity. In conclusion, trajectories of ambulatory motor function in DMD, as measured by the NSAA total score, can be well-predicted using readily available baseline characteristics. We discuss applications of these predictions to DMD drug development.
Journal Article
Primary Hyperoxaluria Type 1 Disease Manifestations and Healthcare Utilization: A Multi-Country, Online, Chart Review Study
by
Wang, Yao
,
Danese, David
,
Baldwin, Jessica
in
Caregivers
,
chart review
,
chronic kidney disease
2021
Background: Primary hyperoxaluria type 1 (PH1) is a rare genetic disease that can result in irreversible damage to the kidneys and, eventually, extrarenal organs. While kidney failure is a known consequence of PH1, few studies to date have characterized clinical consequences of PH1 prior to kidney failure, and data on healthcare resource use outcomes across different stages of disease severity in PH1 are also limited. To help fill this knowledge gap, this study characterized the clinical and healthcare resource use (HRU) burden in patients with PH1 with varying stages of kidney disease. Methods: Nephrologists in the United States, Canada, United Kingdom, France, Germany, and Italy abstracted chart data from patients with PH1 under their care via an online questionnaire. Eligible patients had confirmed PH1 and ≥2 office visits from 2016 to 2019. Results: A total of 120 patients were analyzed (median age at diagnosis, 17.4 years old, median age at index 19.5 years old, median eGFR at index 45 ml/min/1.73 m 2 ; median follow-up 1.7 years). During follow-up, the most common PH1 manifestations were kidney stones and urinary tract infections (UTIs, both 56.8%), and the most common symptoms were fatigue/weakness (71.7%) and pain (64.6%). With regard to HRU during follow-up, 37.4% required lithotripsy, 31.3% required ureteroscopy, and 9.6% required nephrolithotomy. PH1-related hospitalizations and emergency/urgent care visits were noted for 84.0 and 81.6% of patients, respectively. Conclusions: The current study demonstrated that patients with PH1 across various stages of kidney disease exhibited a substantial clinical burden, including kidney stones, UTIs, fatigue/weakness, and pain, and required frequent HRU, including kidney stone procedures, hospitalizations, and emergency visits. These findings highlight the significant morbidity and HRU burden in patients with PH1.
Journal Article
Efficacy outcomes between tarlatamab and real-world physicians’ choice of therapies for previously treated extensive stage small cell lung cancer
2025
Abstract
Background
Tarlatamab, a bispecific T-cell engager immunotherapy, showed durable response with promising survival outcomes in patients with previously treated small cell lung cancer (SCLC) in the phase 2 DeLLphi-301 study. Given the lack of a comparator in DeLLphi-301, this analysis aimed to evaluate the relative efficacy of tarlatamab against physicians’ choice of therapies in real-world practice.
Patients and Methods
This analysis compared the outcomes of patients in DeLLphi-301 who received tarlatamab 10 mg (n = 97) with patients in real-world cancer clinics captured in the Flatiron Health database who received third or later-line comparator therapies for SCLC (n = 184). Propensity score weighting was used to adjust for differences in key prognostic factors between cohorts. Overall survival (OS), progression-free survival (PFS), time to treatment discontinuation (TTD), time to next treatment or death (TTNTD), and objective response rate (ORR) were compared after weighting.
Results
Tarlatamab was associated with significantly longer OS, PFS, TTD, and TTNTD, and higher ORR vs comparator therapies. After weighting, the hazard ratios (95% confidence interval [CI]) of tarlatamab vs comparator therapies were 0.45 (0.30, 0.68) for OS, 0.61 (0.43, 0.90) for PFS, 0.57 (0.39, 0.84) for TTD, and 0.45 (0.30, 0.66) for TTNTD. The odds ratio for ORR was 2.80 (95% CI, 1.44, 5.83).
Conclusion
The study findings suggest that tarlatamab offers potential clinical benefits relative to comparator treatments. This analysis underscores the potential of tarlatamab to become a new therapeutic option for previously treated SCLC, a disease that has historically been associated with extremely poor outcomes and limited treatment options.
Journal Article
Treatment patterns and healthcare resource utilization in ruxolitinib-treated patients with myelofibrosis with and without anemia: a real-world analysis
2025
Anemia affects many patients with myelofibrosis and is associated with poor prognosis. The Janus kinase inhibitor ruxolitinib is often used in myelofibrosis but may cause or worsen anemia. Using healthcare claims data from the IQVIA PharMetrics Plus database, this retrospective analysis evaluated healthcare resource utilization (HCRU), healthcare costs, and treatment patterns in ruxolitinib-treated patients with myelofibrosis stratified by anemia diagnosis prior to ruxolitinib initiation. Of 11,499 patients diagnosed with myelofibrosis between January 2011 and December 2022, 481 had ≥ 1 ruxolitinib claim on or after the myelofibrosis diagnosis date and were included in this analysis. Mean follow-up was 2.0 years. At baseline, anemic patients (
n
= 257) were older (mean age, 60.2 vs. 56.8 years;
P
< 0.001) and had a higher mean Charlson Comorbidity Index (1.0 vs. 0.5;
P
< 0.001) than nonanemic patients (
n
= 224). During follow-up, anemic patients exhibited higher median annual all-cause HCRU (inpatient admissions, 0.3 vs. 0.0 [
P
< 0.001]; outpatient visits, 40.0 vs. 20.0 [
P
< 0.001]; emergency department visits, 0.4 vs. 0.0 [
P
< 0.010]) and also had numerically higher median annual all-cause total healthcare costs ($198,491 vs. $170,419;
P
= 0.549) and medical costs ($44,830 vs. $12,017;
P
= 0.638) but significantly lower median annual total pharmacy costs ($129,381 vs. $136,686;
P
< 0.050), compared with nonanemic patients. Ruxolitinib discontinuation rates were higher and median time to discontinuation was approximately 1 year earlier in anemic patients (14.1 vs. 23.8 months;
P
< 0.010). In conclusion, patients with myelofibrosis and baseline anemia who are treated with ruxolitinib may be an HCRU-intensive population, suggesting a potential need for alternative treatments that reduce their medical resource burden.
Journal Article
Late-life Cognitive Activity and Dementia
by
Weuve, Jennifer
,
Jackson, John W.
,
VanderWeele, Tyler J.
in
Aging
,
Alzheimer Disease - epidemiology
,
Bias
2016
BACKGROUND:Engaging in late-life cognitive activity is often proposed as a strategy to delay or prevent Alzheimer’s disease (AD) and other dementias. However, it is unclear to what extent the available evidence supports a causal effect of cognitive activity in dementia prevention.
METHODS:We systematically searched PubMed and EMBASE through June 2014 to identify peer-reviewed epidemiologic studies of cognitive activity and incidence of AD or all-cause dementia. Eligible articles analyzed data from cohort or nested case–control studies, explicitly defined cognitive activity, evaluated participants for AD or all-cause dementia using clearly defined criteria, and provided effect estimates adjusted for at least age and sex. We describe methodologic issues and biases relevant to interpretation of these studies, and quantify the degree of bias due to confounding and reverse causation required to nullify typically observed associations.
RESULTS:We reviewed 12 studies involving 13,939 participants and 1,663 dementia cases, of which 565 were specifically evaluated as AD. Most studies found associations between late-life cognitive activity and lower AD and/or all-cause dementia incidence. Differences in cognitive activity operationalization across studies precluded meta-analysis of effect estimates. Our bias analysis indicated that the observed inverse associations are probably robust to unmeasured confounding, and likely only partially explained by reverse causation.
CONCLUSION:Our systematic review and bias analyses provide support for the hypothesis that late-life cognitive activity offers some reduction in AD and all-cause dementia risk. However, more data are needed to confirm this relationship and on the optimal type, duration, intensity, and timing of that activity.
Journal Article
Interpretation of epidemiologic studies very often lacked adequate consideration of confounding
by
Ladanie, Aviv
,
Shaw, Jonathan G.
,
Hemkens, Lars G.
in
Bias
,
Bibliometrics
,
Confidence intervals
2018
Confounding bias is a most pervasive threat to validity of observational epidemiologic research. We assessed whether authors of observational epidemiologic studies consider confounding bias when interpreting the findings.
We randomly selected 120 cohort or case–control studies published in 2011 and 2012 by the general medical, epidemiologic, and specialty journals with the highest impact factors. We used Web of Science to assess citation metrics through January 2017.
Sixty-eight studies (56.7%, 95% confidence interval: 47.8–65.5%) mentioned “confounding” in the Abstract or Discussion sections, another 20 (16.7%; 10.0–23.3%) alluded to it, and there was no mention or allusion at all in 32 studies (26.7%; 18.8–34.6%). Authors often acknowledged that for specific confounders, there was no adjustment (34 studies; 28.3%) or deem it possible or likely that confounding affected their main findings (29 studies; 24.2%). However, only two studies (1.7%; 0–4.0%) specifically used the words “caution” or “cautious” for the interpretation because of confounding-related reasons and eventually only four studies (3.3%; 0.1–6.5%) had limitations related to confounding or any other bias in their Conclusions. Studies mentioning that the findings were possibly or likely affected by confounding were more frequently cited than studies with a statement that findings were unlikely affected (median 6.3 vs. 4.0 citations per year, P = 0.04).
Many observational studies lack satisfactory discussion of confounding bias. Even when confounding bias is mentioned, authors are typically confident that it is rather irrelevant to their findings and they rarely call for cautious interpretation. More careful acknowledgment of possible impact of confounding is not associated with lower citation impact.
Journal Article