By Scott Haller, director of the Translational Imaging Center, MPI Research
Everyone involved in drug discovery is seeking ways to lower costs and improve efficiencies. One process that may help pharma and bio firms achieve both goals is molecular imaging (MI). MI is a process which uses imaging platforms, similar in concept to the cameras used to detect white light, to detect the radioactive decay products of a specific radioisotope.
There are different types of imaging platforms which can be used in this process, the difference being the detection of decay/emission patterns of radioisotope(s). Imaging platforms will detect radioisotopes in animals but are also used on humans in clinical research and diagnostic evaluations. Application in both the preclinical and clinical domain gives researchers the ability to leverage preclinical data sets as a direct translational foundation upon which to develop a clinical program. As MI becomes more robust and its applications better understood, it will lead to improved program design and management. The technology has significantly progressed in informatics, which is our ability to evaluate and understand the information contained in the imaging data.
The process commonly starts with a sponsor sharing its chemical structure with the imaging lab. The lab determines the appropriate radioisotope to bind to the test material. This essentially places a homing beacon within the structure of the material so it can be followed through the animal or patient to whom it is administered. The treatment of cancer is a common use for the technology because it provides the ability to evaluate uptake in tumors and determine the size, growth, or reduction of the tumor. MI can be successfully applied to CNS, bone redevelopment, inflammation, and many other therapeutics.
The real power of MI is its flexibility to effectively address objectives across many development programs. MI can provide solutions to the sponsor or development group to answer various study objectives. This flexibility is achieved through modifications to study design, radioisotope (whether it is bound to the test material or to a surrogate biomarker), chemistry, and image acquisition parameters.
Speeding The Development Paradigm
Incorporating MI into drug development paradigms can cut the cost of drug development by getting answers to sponsors in a timely manner. In the traditional paradigm evaluating biodistribution, tissue is harvested from an animal at a particular time point (i.e., three days). The radioactivity is quantified against what was originally administered to the animal. This approach does not provide the opportunity to obtain multiple time points from a single subject. With MI, the same animal is imaged at multiple time points, which is less costly and less labor-intensive.
The amount of time saved on a study can vary widely and is dependent on the program design. A time reduction of only 1 to 2 percent could still be significant, especially in a large program. Savings of as much as 50 percent are possible if clear target engagement is demonstrated in early studies. Cost savings will also vary, but depending on the study could be millions of dollars.
The other improvement is the increase in resolution of activity within discrete segments of target tissues. With MI, the focal point can be a very finite position, allow for a three-dimensional analysis, and provide an understanding of the detailed distribution within a single organ. MI provides a robust data set which may not be attainable when performing a general tissue collection and counting methodology. This difference can be significant for many development efforts.
Have An Accurate Understanding
Although the MI process could be used in most therapeutic areas and with almost any molecule, the benefits can be overlooked by development teams. We find this commonly attributed to misconceptions about the cost, a lack of understanding on how best to apply it, or a lack of access to the technology or individuals who understand how to apply MI to the needs of their development efforts. These issues can be avoided via proper up-front discussions and collaborative approaches to program design.
Development of commercial imaging centers providing these services to drug development teams eliminates concerns with capital investment needed at the sponsor end and allows them access to the technology and expertise from collaborative, multidisciplinary teams. The time and cost savings are real, with MI providing needed medicines to patients in a more timely manner.