Regulatory Challenges in Biomaterials: Focus on Medical Devices - Biomaterials Science: An Integrated Clinical and Engineering Approach - page 248

TABlE 10.3
Key Differences between Drug Trials and Device Trials

Medical Device
Development Drug Development References

FDA experience From 1906 From 1976 www.fda.gov [3]

Phases I, IIa, IIb, III, IV

(pharmacosurveillance)

I (feasibility
II (pivotal))
III post-marketing

FDA Handbook [16]
Kaplan et al. [14]

Number of patients
enrolled (average)

3000 (phase III) 500 (pivotal trial) Dhruva [27]

Time to the market
(from concept
design and
development to
regulatory
approval)

10-15 years 5-10 years Reed et al. [42]

Kaplan et al. [14]
Kaitin et al. [47]

Operator Clinical investigator Highly trained

operator

Sedrakyan et al. [37]

Clinical trial design Multicenter randomized

controlled trials
Control: placebo or
current best
management available

Not multicenter,
not randomized
historical Control

Dhruva [27],
Abded-Aleem [35]

Environment where
the clinical trial is
developed

Clinical investigator
office

Highly specialized
centers

Sedrakyan et al. [37]

FDA stringency Very high Variable Dhruva [27]

Control group Placebo or BMS Historical Dhruva [27]

Follow-up Compliance Tracking

(high-risk
devices)

Schoonmaker [48]

Average timeframes
in FDA approval
pathways (in days)

ANDA*: 510
NDA**: 231 (exceptions)
/ 357 (standard)

PMA: 151
510(k): 76

Schoonmaker [48]

* ANDA: Abbreviated New Drug Approval
** NDA: New Drug Approval

Technological Challenges

Engineering and Medical Science Integration

Engineering and medical sciences are two disciplines needed in medical
device development. For instance, in designing micro-electro-mechanical
system (MEMS)-based drug delivery devices, mechanical engineers must
consider mechanical parameters that could affect the diffusion of the drug or
release time from a reservoir once the system is activated. On the other hand,
physicians should advise engineers regarding the biological environment in
which the system will be implanted, as the local response to the implant
will affect drug diffusion because of the inflammatory response towards the