Regulatory Challenges in Biomaterials: Focus on Medical Devices - Biomaterials Science: An Integrated Clinical and Engineering Approach - page 244

group receives the treatment under study. In cross-over trials,
the same individuals receives the standard treatment and the
treatment under study at different times, and the clinically rel-
evant outcomes (end points) are assessed in the same subjects.
In factorial trials, more than one treatment is evaluated in the
same trial by assigning different groups to receive different
treatments that are assessed against the standard treatment or
placebo.
5. Number of patients taking part of the study : The trial may involve
either only one patient, a fixed number of patients (from
smaller trials up to multicenter trials), or a sequential num-
ber of patients (the number of patients increases as the trial is
being run).
d) Trial development: During the trial development, patients start
to take the study medication or are subject to a procedure such as
device implantation, and they are followed up to see the effect of
the new intervention. Data regarding their medical status along the
study are collected and their quality confirmed before the final data
analysis is performed.
e) Analysis of the results: Statistical analysis of the results should be
carried out in order to know whether the differences found between
the experimental device and its comparator are statistically signifi-
cant (and therefore could be attributed to the new intervention) or
are a random difference [35, 36].
Drug Trials vs. Medical Device Trials
We will now describe briefly the differences between trials performed to
assess a drug's effectiveness and safety, and trials performed to assess bio-
material-based devices' effectiveness and safety, because biomaterials are
being used in both areas. Examples range from a drug delivery system that
uses biopolymers surrounding a core where the drug (payload) is embedded
to a less sophisticated titanium femoral head for hip replacement. Therefore,
it could be useful for those interested in the biomaterial field to become
familiar with both regulatory pathways.
As we have previously stated, drug regulation is older than device regula-
tion. Drugs have been regulated since 1906 (Food and Drug Act), whereas
medical devices started to be regulated more recently (after the 1976
Amendment Act). There are some differences in the phases of the trial, the
number of patients being enrolled in each phase, the time to the market for
each product, and the training of the investigator.
1) Phases: Drug development and device development are conducted in
several stages or phases, each designed with a specific aim.