Integrated Diagnostics this week said it has launched a new operating division called InDi Imaging to commercialize PET imaging probes based on its protein catalyzed capture agent, or PCC, technology.
The company announced that it has appointed Norman Hardman president of the new division and appointed University of California, Los Angeles professor Michael Phelps, the inventor of PET, to the division as an advisor. It also said that it planned to start the first human studies of the PCC-based PET imaging reagents over the next 12 to 18 months.
InDi chose to create the new division due to the distinct natures of the in vivo imaging business and the in vitro diagnostic space on which the company has traditionally focused, CEO Albert Luderer told ProteoMonitor.
"We've known from the get-go that you have very dissimilar commercialization and regulatory underlayment between the in vitro diagnostics sphere and the in vivo imaging sphere," he said. "In the clinic and from a medical usage standpoint these things complement each other beautifully, but from a business package standpoint they're quite different."
These differences could lead to difficulties in obtaining investment if the two businesses were kept together, Luderer suggested, noting that "unless you're a massively large company, it's hard to manage the financing" of such disparate units.
He said that the InDi Imaging would most likely remain a part of the overall firm until the middle of 2012 after which it will probably be spun off as an independent company.
InDi's PCC reagents use click chemistry combined with pairs of random peptide libraries – one containing acetylene functionalities and the other containing azide groups – to create affinity reagents to given proteins. Target proteins are screened against these libraries to find peptides that bind them, and when these peptides bind, the protein epitope acts as a catalytic point for the acetylene- and azide-containing peptides, which then link together via click chemistry, forming multi-peptide, protein-binding constructs that can then be pulled down and identified.
InDi has licensed the PCC technology from the California Institute of Technology where it was developed by CalTech professor and InDi co-founder Jim Heath (PM 10/28/2011). In a 2011 paper in the Journal of the American Chemistry Society, a team led by Heath demonstrated the use of the technology to develop a capture agent for the protein Akt1. InDi introduced the reagents last October as a product in development.
The company has achieved levels of performance with its PCCs that are "essentially indistinguishable" from a high-level monoclonal antibody, Luderer said. "In areas where you can compare apples to apples – like in strength of binding and specificity — I think we can say we're virtually identical to antibodies."
The reagents also have potential advantages compared to antibodies where imaging applications are concerned, he said.
In particular, Luderer said, the fact that they are produced synthetically means they could prove useful for in vivo imaging of protein targets that are difficult to tag via antibodies.
"As we move into the animal study phase, now we're starting to look at all the different chemical parameters associated with these constructs, to make subtle changes to them to influence how quickly they transit the body and exit, how long they stay on a target," he said. "We can make all sorts of structural changes outside the binding region to incorporate any kind of chemistry you'd like to attach."
The reagents' small size relative to antibodies could also make them well suited for imaging purposes, particularly by speeding up the process, Luderer added.
"When they're small they get in fast and they don't hang around too long," he said. "So from the standpoint of physician and patient logistics this can be a half-a-day procedure… [whereas] with an antibody you have to load [the patient] up, send them home, and then have them come back and be imaged later, because it can take a long time to equilibrate [with antibodies]."
"We're thinking that we could take a giant step over the next few years towards building up a whole new branch of radiologic-based anatomic pathology, which takes you from what you see now – basically a structural image of organs – to showing the molecular content of the surfaces of these structures," Luderer said. "This would really open up a whole new area of earlier and more specific molecular diagnostics."
He pointed to Eli Lilly's $800 million acquisition of imaging reagent firm Avid Radiopharmaceuticals in 2010 as a sign of the field's potential. In April the company's florbetapir F 18 reagent for the detection of brain amyloid deposits via PET received US Food and Drug Administration approval as a diagnostic aid for Alzheimer's disease.
"With Alzheimer's you have a real issue of establishing a true and accurate early diagnosis, so if you have an image that demonstrates several of the hallmarks – tau protein and beta-amyloid plaque, for instance – that goes a long way toward cementing a diagnosis," he said. "There's strong interest from pharmaceutical companies in this tailored imaging capability."
InDi isn't alone in exploring the potential of in vivo protein biomarkers. Last year a team of researchers led by Stanford oncologist Dean Felsher published a paper in Science Translational Medicine on an algorithm they devised to predict response to cancer therapies based on cellular signaling protein dynamics and changes in tumor size (PM 10/14/2011).
In an interview following the release of the paper, Felsher told ProteoMonitor that he and Stanford colleague David Paik were investigating techniques for measuring protein signaling in vivo using PET imaging. He noted as well that InDi's PCCs could "be very useful" to this line of work.
In October 2011, Janet Woodcock, FDA drug division head, said at a conference hosted in Bethesda, Md., by the FDA and the Drug Information Association that while much diagnostic development has focused on in vitro tests, imaging could also prove a key technology.
"We think there will be a lot of business now [in this area.] We think [in vivo] imaging, being so dynamic and so forth, may be better in some ways than [in vitro] tests," she said, noting that in March 2011, the FDA had moved medical imaging into its own drug center division due in part to anticipation of an increased demand for this technology in personalized medicine.
InDi has not chosen a specific target or disease to focus on for its first PCC-based PET probes, Luderer said, but it has several potential targets and is working with collaborators at UCLA "to find one that has the most bang for the buck and the highest potential to translate into an immediate product."
The company isn't working with any PET imaging firms to develop the reagents, he said, noting that the aim is to develop probes that can "run on everybody's installed base" of PET instruments. "The value proposition here is the uniqueness of our content, so if you have a Siemens [instrument], that's great; if you have a GE, that's great."