On 2016 Jan 25, Dimitrios Tzalis commented:

The European Public Compound Collection (PCC) is a very unique collection of compounds that are already synthesized and available for screening within ELF Screening Campaign. The goal of the paper was to compare PCC with other compounds that are available for biological screening or that were actually screened. That is why, with a full awareness, we have analyzed it against part of the PubChem collection called MLP of NIH, commercially available Maybridge and already tested compounds represented by ChEMBL. It might be interesting to collate the PCC and the 15 millions of patent-extracted compounds, in respect to broadly understood novelty, but we wanted to avoid the contamination of our comparison with theoretical compounds. In such a way the work is much more consistent. Nevertheless, thank you for your valuable comment and we can think of extending our novelty check also in respect to theoretical compounds in the future analysis since our collection is still growing. We believe that by focusing on exploring underrepresented chemical space of spiro-compounds and saturated, fused hetero rings we are offering a very competitive and unprecedented collection.

On 2016 Jan 14, Christopher Southan commented:

Interesting paper but it would have been more rigourous to define uniqueness against PubChem, especially since the recent patent-extracted chemistry expansion (see http://www.ncbi.nlm.nih.gov/pubmed/26194581)

On 2016 Jan 14, Christopher Southan commented:

Interesting paper but it would have been more rigourous to define uniqueness against PubChem, especially since the recent patent-extracted chemistry expansion (see http://www.ncbi.nlm.nih.gov/pubmed/26194581)

On 2016 Jan 25, Dimitrios Tzalis commented:

The European Public Compound Collection (PCC) is a very unique collection of compounds that are already synthesized and available for screening within ELF Screening Campaign. The goal of the paper was to compare PCC with other compounds that are available for biological screening or that were actually screened. That is why, with a full awareness, we have analyzed it against part of the PubChem collection called MLP of NIH, commercially available Maybridge and already tested compounds represented by ChEMBL. It might be interesting to collate the PCC and the 15 millions of patent-extracted compounds, in respect to broadly understood novelty, but we wanted to avoid the contamination of our comparison with theoretical compounds. In such a way the work is much more consistent. Nevertheless, thank you for your valuable comment and we can think of extending our novelty check also in respect to theoretical compounds in the future analysis since our collection is still growing. We believe that by focusing on exploring underrepresented chemical space of spiro-compounds and saturated, fused hetero rings we are offering a very competitive and unprecedented collection.