Biomedical Engineering Reference
In-Depth Information
9.7
Phasing (timing) of non-clinical testing
of medical devices
Device development and the phasing of non-clinical safety evaluation
performed are very different than the corresponding processes employed
in drug development. First, clinical trials may or may not be required for
device approval. If clinical trials are required, it is because proof of effi cacy
is needed for the device. If the 510(k) route to approval is being employed,
then clinical evaluation (of the device's effi cacy) will generally not be
required if the similarity to the predicate is suffi cient to provide confi dence
that no concern as to the device working in a clinical setting exists. If, how-
ever, such a concern exists or the route to approval is via a PMA, then one
or more clinical trials will be required. While an IDE must be submitted
for review prior to any such trial, there is great asymmetry in the potential
patient risks (and therefore in the scope of required pre-IDE non-clinical
safety testing) in such trials based primarily on whether the device is to be
implanted in the body or not.
The reason is simple - once in place, an implanted device (heart valve,
orthopedic, pacemaker, or coronary vascular stent, for example) cannot
simply be turned off or taken off if there is a safety problem. Rather, a
surgical procedure (with its inherent risks) is required. It is thus consid-
ered that the patient exposure component of the risk consideration must
be prolonged to permanent. In such cases, subchronic animal studies of
suitable length (and perhaps even carcinogenicity and reproductive tox-
icity studies) may be required prior to initiation of a clinical study. Also,
because of this duration of the exposure component of the risk consider-
ation for implanted devices, true phase I trials in normal volunteers are not
justifi able. Instead, the fi rst clinical trials are done only in patients. Another
implication of this paradigm is that for most devices where a clinical trial
and IDE are required, all the non-clinical safety testing required for mar-
keting approval is both required and performed as part of the IDE devel-
opment program.
9.8 Sources of further information and advice
Strategies for development
Armon , B. , 'Bringing your medical device to the marketplace',
Physician's News
Digest
, 2002 .
Meinert , Lawrence , 'Pointing Us in the Right Direction',
Applied Clinical Trials
,
2005 .
