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Leigh Anderson Launches New Firm to Commercialize SISCAPA Technology

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By Adam Bonislawski

This article was originally posted on June 14.

Proteomics researcher Leigh Anderson has formed a new company to commercialize SISCAPA, the immunoaffinity-based mass spec assay he developed.

Launched last week at the American Society for Mass Spectrometry's annual meeting, the firm – SISCAPA Assay Technologies – is currently focused on selling assay development services to customers interested in using SISCAPA technology, Anderson told ProteoMonitor.

The company has also partnered with Burlingame, Calif.-based antibody company Epitomics to produce reagents for the system and sell SISCAPA assays as research kits and has licensed the technology to Pfizer for internal use and development.

SAT is also in negotiations with several "well-regarded" CROs interested in adding SISCAPA capabilities, Anderson said, as well as with several other large pharma firms, although those talks are still "in early-stage discussions at this point," he said.

SISCAPA — short for stable isotope standards and capture by anti-peptide antibodies — combines antibody-based peptide enrichment with mass spectrometry, increasing the sensitivity of mass spec instruments, which by themselves are often not sensitive enough to detect low-abundance proteins in complex samples. Mass spec is an attractive alternative to ELISAs for protein biomarker detection because its multiplexing capabilities make it potentially less expensive. Mass spec also allows for the use of true internal standards like stable isotope labeled peptides, allowing, in principle, for more precise assays.

Anderson and his SAT co-founder Terry Pearson – professor of microbiology and immunology at the University of Victoria – have been developing the technology for the last five years through the National Cancer Institute's Clinical Proteomic Technologies for Cancer initiative.

Recently, "it became clear that there was a lot of demand and need to have regular commercial distribution of the reagents to do the [SISCAPA] assays," he said. "The patent [for the technique] was issued 18 months ago, and so we've been moving deliberately towards real commercialization."

SAT consists of five employees at present, Anderson said, working in what he called "largely a virtual operation."

"We do the antibody generation through Epitomics. We contract out a lot of the mass spectrometry. And we basically do the screening and integration steps ourselves," he said.

The company will likely seek outside funding "in the not-too-distant future" in order to "accelerate the [growth] pace of the assay menu," Anderson said, but added that the principals "know enough about this business so that there's a pretty good cash flow coming out of the gate based on the commercial activities we've done before and the licensing activity."

One kit is currently available for sale through Epitomics, a five-protein kit containing reagents for protein C inhibitor, a potential prostate cancer marker; LPS-binding protein, a marker of acute phase response; the cancer biomarkers osteopontin and mesothelin; and soluble transferrin receptor. Pricing for the kit is still being determined, Anderson said, but, he added, "it's going to be in the same ballpark as a multiplex ELISA kit would be."

The product "is good way to measure these five proteins, and it also serves the function of being an introductory SISCAPA kit for people who want to begin to use the technology in general," he said.

While research kits will be sold through the company's licensing agreement with Epitomics, SAT's primary focus will be offering assay development services. In particular, it plans to target pharma and the CROs serving pharma companies, building SISCAPA assays to measure "biomarkers for disease diagnosis, target engagement, prognosis, and potentially companion diagnostics," Anderson said.

He added that as the firm's pharma work has progressed, unanticipated uses for the technique have arisen – quantitating levels of drug receptor proteins in tissue samples, for instance.

Pfizer associate research fellow Hendrik Neubert– who has been working with SAT as part of the two companies' license agreement – told ProteoMonitor that his team has been using SISCAPA in combination with an upfront protein immunocapture step to provide an additional level of sensitivity for their biomarker work.

"So we're running a combination of different [immunocapture] methods here," he said. "I actually view the SISCAPA approach as a module or tool we have on the shelf that we can almost plug and play with other modules to construct an assay."

At the Association for Mass Spectrometry's Applications to the Clinical Lab meeting in February, Neubert discussed the potential usefulness of immunoaffinity mass spec assays like SISCAPA in the drug development process (PM 02/18/2011).

In particular, he cited work his group did using immunoaffinity mass spec to measure serum levels of the protein nerve growth factor – the target of Pfizer's tanezumab, a biotherapeutic currently in Phase II and Phase III clinical trials for a variety of pain indications.

The researchers built an assay to measure total NGF levels in the presence of the drug, applying it to a 50-person Phase II patient-versus-placebo clinical trial examining the effect of a single dose of tanezumab over a three-month period, as well as a second study in normal healthy volunteers that generated more than 1,600 data points on subjects' NGF levels with particularly dense sampling done during the early days of treatment to better elucidate the kinetics of the drug's "on" phase.

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"The impact that this data is having in a clinical setting is tremendous," Neubert said, "because it enables the team to really link the pharmacokinetics of the drug to the occupancy of the target to the clinical outcomes. So you really have that triangular relationship with this kind of data."

From SAT's perspective, the Pfizer agreement provides not only license revenue, but also assay development insights. While the SISCAPA kits use magnetic beads for the peptide capture and elution, Neubert's team has refined a column-based approach that "is likely to be implemented by some of the CROs that serve pharmaceutical companies," Anderson said.

"You pump the [peptide] digest over the column, capture the peptides, and then wash and elute from the column," he said. "You get high performance and the ability to do very large numbers of samples."

Improving the technology's sample throughput is another front Anderson and SAT are working on, primarily through a collaboration with Agilent aimed at automating the workflow, something he has asserted is key to achieving the robustness and sample volume needed to bring proteomics into the clinic.

At MSACL he presented an automated SISCAPA workflow using an Agilent Bravo liquid handling system for sample prep attached to an Agilent 1200 series LC system and an Agilent 6490 triple quadrupole mass spec (PM 02/11/2011).

"We're actively in discussion about other ways to bring the [SISCAPA] technology both to a set of pharma clients as well as to the clinical vision [Anderson] has always talked about where this becomes a set of reagents for clinical diagnostics," Gus Salem, vice president and general manager of Agilent's Biological Systems division, told ProteoMonitor last week at ASMS.

"We're in the process of … putting together automated high-throughput sample prep for targeted protein quantitation assays," added Ken Miller, Agilent's director of marketing for LC/MS. "We believe that as people identify markers or marker panels and these things begin to translate into the clinic and people begin to consider larger sample cohorts and larger studies, this is going to be a necessary part of the technology that needs to come along with the ability to do the measurements and the mass spec."

Recent efforts have reduced the cycle time of the assay by eight-fold, from an original 40 minutes per samples to five minutes. Largely this is a function of the 6490's high sensitivity, Anderson said, which allows researchers to run the samples on a standard-flow HPLC system as opposed to a much slower nanoflow system.

"Now you can seriously look at analyzing hundreds of samples" with the technique, he said.

This sort of throughput is key to pharma work, Neubert noted. "When we run samples, we're not dealing with 10 samples or 100 samples; we're dealing with several thousand samples," he said.

In fact, he added, one of the great primary advantages of SISCAPA is the reduction in chromatography the additional immunocapture step allows.

"You can run an assay just using the anti-protein capture and actually omit the SISCAPA step," Neubert said. "But the SISCAPA component is sometimes [added] just to make the assay faster. If you do an additional peptide-capture step that allows you to get away with almost no chromatography or very little chromatography, you can have very fast run times, and that helps you with throughput."

"So our motivation to [use SISCAPA] is the sensitivity and specificity gain, but equally important if not more important is [gaining] throughput while maintaining really good sensitivity," he said.

Using the RapidFire technology Agilent obtained in its purchase of Biocius Life Sciences in March (PM 03/04/2011), it might be possible to eliminate LC from the workflow entirely and drop the cycle time down to seven seconds per sample, Anderson said. This, he noted, though, would "require further development."

Neubert said he hadn't yet seen SISCAPA run on the RapidFire system, but that the possibility was "on [his] radar."

While SISCAPA has been developed for use on a triple quad like Agilent's 6490, Anderson noted that last week's ASMS meeting introduced a number of instruments like Thermo Fisher's Q Exactive and Agilent's 6550 iFunnel Q-TOF that might also offer good peptide quantitation.

"The performance of triple quads continues to improve, so that helps extend the sensitivity of [SISCAPA] assays going forward," he said. "But there are a whole range of instrument types that work very well for peptide quantitation at this point. So it's turning out to be a fairly broad field of instruments than can be used for this purpose."


Have topics you'd like to see covered in ProteoMonitor? Contact the editor at abonislawski [at] genomeweb [.] com.

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