Delayed-entry models using PROC PHREG in Survival Analysis

Statistical Consultancy Team

Time-to-event data often arise in clinical research, and in many cases represent the primary outcome of interest. These data generally represent the elapsed time between a reference time-point (e.g., treatment randomization) and an event of interest (e.g. death, relapse, etc.).

Whereas right censoring is a feature that is easily accommodated by most existing software, the same doesn’t strictly hold for another feature of survival data, left-truncation. In this post we’ll describe what left-truncation is, when it can arise and provide some SAS code that can be used to derive survival estimates and curves. 

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Topics: Survival Analysis, Statistical Programming, SAS Programming, SAS, PROC PHREG

Electronic Data Capture Systems In Clinical Data Management: The myths and the reality

Clear Clinica

This post is a guest blog written by David Tashjian from Clear Clinica. The views and opinions in this post are not representative of Quanticate. By publishing Guest blog posts it does not imply Quanticate has a working relationship with any companies associated with a post and we are happy to receive guest blogs from any industry related company.

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Topics: Clinical Data Storage, Case Report Form (CRF), Electronic Data Capture, Phase 3 Studies, Clinical Data Management, Paper-Based Studies

The Rise of Risk Based Monitoring [Infographic]

Thomas Underwood

Risk Based Monitoring is a term that is not new to the pharmaceutical industry. With increasing demand for budget reduction and reduced time to submission in drug development, both sponsors and vendors are seeking ways to reduce costs whilst still maintaining and potentially improving the quality of the data collected in clinical trials. Study costs can rise considerably for clinical trials with a large number of sites, especially across multiple countries. Risk Based Monitoring can reduce study costs considerably as there is a reduction in the need for CRAs to travel to sites, especially when coupled with a remote monitoring component. Also a reduction in the need to monitor all clinical trial sites and 100% of trial data, as those which are identified as more risk prone are visited more frequently according to targeted or triggered formulas. Even the FDA understands and encourages the desire to move away from 100% source data verification. Why therefore is the general mind-set in clinical operations exhibiting a degree of inertia to change with regard to RBM techniques? 

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Topics: Clinical Trials, Remote Monitoring, Electronic Data Capture, e-Clinical, Source Data Verification (SDV), Adverse Events (AEs), On-Site Monitoring, Serious Adverse Events (SAEs), Clinical Trial Phases, Additional Monitoring, Phase 2 Studies, Technology Trends, CRAs, Risk Based Monitoring

Assessing Equivalence in Rheumatoid Arthritis in Clinical Trials

Statistical Consultancy Team

In Rheumatoid Arthritis (RA) clinical trials, treatment response is often assessed via the American College of Rhematology (ACR) composite responder score ACR20. This is a binary criterion that incorporates several indices of treatment activity in terms of symptoms reduction and is equal to 1 if at least 20% of improvement between a baseline and post-baseline measurement is observed in tender and swollen joint counts, in at least three out of five other indicators (C-Reactive Protein, patient global assessment of disease activity, physician global assessment of disease activity, patient pain scale, Health Assessment Questionnaire Disability Index), and 0 otherwise.

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Topics: Statistical Programming, Biostatistics Consulting, Rheumatoid Arthritis (RA), PROC NLMIXED

mHealth Apps and Wearables in Clinical Trials to Consider

Nick Burch

Today, mHealth, Mobile Health, Mobile Apps and Wearables are hot topics with consumers and regulators alike. We're also starting to see consumer-grade wearables and mHealth technologies creeping into clinical trials. We've written this blog for those looking to use this area more.

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Topics: Regulatory Requirements, FDA, European Medicines Agency, Quality Assurance, Mobile Device, Technology Trends, Wearables in Clinical Trials, Wearables, mHealth

Is Lack of Data the Biggest Challenge for Early Phase Pharmacovigilance?

Pharmacovigilance Team

We recently hosted a webinar on the challenges of Pharmacovigilance in early phase clinical trials. During the registration process we had the chance to survey members of the industry, 70% of the respondents were from pharmaceutical, biotechnology or medical device companies. We wanted to present the data from the 150 respondents in this blog.

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Topics: Regulatory Requirements, FDA, Phase I Studies, Adverse Events (AEs), Pharmacovigilance, Serious Adverse Events (SAEs), Clinical Trial Phases, Oncology

Understanding the Proportional Odds Assumption in Clinical Trials

Statistical Consultancy Team


Ordinal scales are commonly used to assess clinical outcomes; however, the choice of analysis is often sub-optimal.  In 2007, the Optimising Analysis of Stroke Trials (OAST) collaboration showed that ordinal-appropriate analyses of ordinal stroke outcome scales were preferable over binary analysis of a chosen ‘favourable’ outcome[1] but uptake of ordinal methods between 2007 and 2014 has been low [2].

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Topics: Randomization, SAS Programming, Biostatistics Consulting, Statistics, Ordinal Logistic Regression, Proportional Odds Assumption, PROC Logistic, Neurology

Celebrating International Clinical Trials Day

Marketing Quanticate

Happy International Clinical Trials Day! For those of you who do not know, International Clinical Trials Day is celebrated each year on 20th May. The event was created to commemorate the day James Lind started the first ever clinical trial to try and cure the deadly disease scurvy.

The clinical trial James Lind conducted consisted of using citrus fruit to cure scurvy. At the time the concept of vitamins were unknown, today we know scurvy is a result of vitamin C deficiency. James Lind was the first to study the effects of citrus fruits by conducting a systematic experiment on sailors in 1747 which is now regarded as one of the first clinical experiments in the history of medicine. 

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Topics: Clinical Trials, Ethics, Clinical Data Services, Statistics, International Clinical Trial Day

The Rise of Risk Based Monitoring in Clinical Trials

Thomas Underwood

During drug development the cost of clinical trials can rise significantly for studies that require several monitoring visits across multiple sites. Traditional monitoring techniques account for a large portion of these costs. Pharmaceutical companies absorb the costs of travel when their own Clinical Research Associates (CRAs) visit sites, while CROs normally charge clients these travel costs as pass through charges. It is estimated that remote monitoring in clinical trials could reduce travel costs (including unproductive time spent travelling) by up to 30%, and in theory the practice should be scalable across small to large clinical studies over several clinical trial phases[1]. The unproductive travel time saved also means CRAs have more time available for monitoring activities, aiding with the current CRA shortages[2].

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Topics: Clinical Trials, Remote Monitoring, Electronic Data Capture, e-Clinical, Source Data Verification (SDV), Adverse Events (AEs), On-Site Monitoring, Serious Adverse Events (SAEs), Clinical Trial Phases, Additional Monitoring, Phase 2 Studies, Technology Trends, CRAs, Risk Based Monitoring

Celebrating Women in Science, Medicine and Mathematics

Marketing Quanticate

Happy International Women's Day! On this day, we wanted to celebrate the success of women within science, mathematics and medicine, and how they have helped shape the pharmaceutical industry in which we work. Without the hard work and success of these individuals, we may not be providing the level of healthcare available today. Today, half of medical graduates are female, as well as doctors and top researchers, it is reported that the number of statisticians equals the number of men. Therefore please read on to learn about some of the most influential women to celebrate international women’s day.

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Topics: Statistical Programming, Medical Writing, Clinical Programming, Drug Development, Nobel Prize, Women in Science

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