Now here's a comparison that you don't get to see very often: how much do two large pharma compound collections overlap? There's a paper going into just that question in the wake of the 2006-2007 merger between Bayer and Schering AG. (By two coincidences, this paper is in the same feed as the one that I highlighted yesterday, and that merger is the one that closed my former research site out from under me).
Pre-merger, Bayer had over two million structures in its corporate collection, and Schering AG had just under 900,000. Both companies had undertaken recent library clean-up programs, clearing out undesirable compounds and adding both purchased and in-house diversity structures. Interestingly, it turns out that just under 50,000 structures were duplicated across both collections, about 1.5% of the total. Almost all of these duplicates were purchased compounds; only 2,000 of them had been synthesized in-house. And even most of those turned out to be from combichem programs or were synthetic intermediates - there was almost no overlap at all in submitted med-chem compounds.
Various measures of structural complexity and similarity backed up those numbers. The two collections were surprisingly different, which might well have something to do with the different therapeutic areas the two companies had focused on over the years. The Bayer compounds tended to run higher in molecular weight, rotatable bonds, and clogP, but then, a higher percentage of the Schering AG compounds were purchased with such filters already in place. As for undesirable structures, only about 2% of the Bayer collection and 1% of the Schering AG compounds were considered to be real offenders. I hope none of those were mine; I contributed quite a few compounds to the collection over the years, but they were, for the most part, relatively sane.
The paper's conclusion can be read in more than one way:
Furthermore, an argument that might support mergers and acquisitions (M&A) in the pharmaceutical sector can be harvested from this analysis. Currently, M&As in this industry are driven by product portfolios rather than by drug discovery competencies. With the current need for innovative drugs, R&D skills of pharmaceutical companies might again become more important. The technological complementarity of two companies is often quoted as an important factor for successful M&As in the long term. If compound libraries are regarded as a kind of company knowledge-base, then a high degree of complementarity is clearly desirable and would improve drug discovery skills. Based on our data, the libraries of BHC and SAG are structurally complementary and fit together well in terms of their physico-chemical properties. However, it remains to be proven if this leads to additional innovative products.
Not so sure about that, myself. I don't know how good a proxy the compound collections are, since the represent an historical record as much as they do the current state of a company. And that paragraph glosses over the effect of mergers on R&D itself - it's not like just adding pieces together, that's for sure. The track record for mergers generating "additional innovative products" is not good. We'll see how the Bayer-Schering one holds up. . .