The painting above is an early Van Gogh from Paris. You can see the basis for the talent that was to follow but it is also easy to see why this painting did not sell. Commercializing a new product is implicitly a conflict between adding value to what existing before while still maintaining comfort with previous understanding. This is definitely the case with aptamer-based products. In this blog I will continue with the story of what we learned with the commercialization of the first aptamer based diagnostic application.
In the last blog we described the challenge of identifying aptamers that could be commercialized, we ended with publications on the best aptamers identified for small molecules to that point. The next thing we did was attempt to truncate the aptamer down to it’s minimal binding sequence. Our ochratoxin aptamer was subsequently demonstrated by others through crystallization analysis that it formed a G-quartet. This was clear in our truncation analysis with the need to maintain the contiguous four G sections. G-quartets can take more than 24 hours to stabilize after solubilization, but once they have formed, they are very stable. We learned that it was important to test aptamer performance early after solubilization and a week later. This is still a rule that we use with every aptamer we qualify at NeoVentures.
Fortunately, ochratoxin is a fluorescent molecule. For diagnosis we needed to develop methods to purify it from various matrices and measure its fluorescence. Sounds simple, right? Ochratoxin is deposited by fungi growing on grapes and grain. This means that we had to purify the target molecule from red wine. We found the most challenging wines to deal with were Primitivo’s and Negromaro’s. All wines have low pH (~3.1 to 3.3) and a lot of fluorescent polyphenols. These two wines were packed with the polyphenols. We also imposed a rule early in our commercial development process that any wine brought into the lab could not be consumed thereafter. A tough rule… We can say now though that developing aptamer that will work in bodily fluids like serum, urine or interstitial fluid are trivial compared to our experience with wine.
We also discovered that our aptamers stopped working after about a week in buffer when immobilized on streptavidin resin. We learned that by storing the aptamers in 20% DMSO they would retain activity indefinitely. We performed tests on our aptamer based affinity columns and demonstrated 98% efficacy after storage at room temperature for a year.
The key factors that we learned in our commercial development process were the following:
- Developing an effective standard operating procedure for the development of a commercial product is essential and much harder than it would seem.
It is necessary to identify every possible source of variation, develop methods to control for the variation, and document your process with excruciating detail. Finding problems is a good thing because it enables you to understand what you need to control.
- It is absolutely necessary to develop operating instructions (product inserts) with a user other than your own laboratory.
It never ceases to amaze me what we think is obvious and clear is not obvious and clear to others. You simply cannot develop operating instructions for a commercial kit without transferring the technology to another party.
- End users will run into problems that you have never imagined.
In one case, an end-user of our ochratoxin test was clearly not obtaining satisfactory results. After intensive investigation we suggested that they switch their water. They were not replacing filters on their Millipore system and they had high levels of calcium in the water. With the water we supplied them with, they had excellent results. This type of detective work requires skilled staff and constructive conversations with end-users.
I do not mean to compare our aptamer development with the genius of Van Gogh paintings. The point that I was trying to make is that the market can only handle so much innovation at a time. The idea that a diagnostic test is based on a aptamer is a key innovation. The performance and use of the aptamer must fit the comfort level of how the end-user presently performs diagnostics with antibody based tests. The introduction of new measurement equipment is a high barrier for commercial success. Just like Van Gogh in the early years, the eyes of the market were not ready for the product.