Cloud Computing: A Drug Discovery Game Changer?
Cloud computing has the potential to transform drug discovery in many
areas – heralding the dawn of no-compromise computer-aided drugdiscovery and making effective virtual screening a reality. Automation versus craftsmanship? High-throughput
teething problems, of course. How did you know the
screening was supposed to be the answer to declining
compound being tested was reliably what it claimed to be
pharmaceutical research productivity, but many feel it
on the tin? How could you handle that data deluge to
failed to deliver the benefits it initially promised. This is
tease out useful knowledge? But the market responded,
so often the case with a new technology. These great ideas
as markets do, and solutions appeared. HTS took its
come along, shake our world and then we wait for the
place as a $2 billion market in mainstream drug
promised revolution. Sometimes it comes through – often
discovery, but still can be said ultimately to have failed to
it does not. My question is: will cloud computing disrupt
deliver on its early promise. Let’s look at some of the
the drug discovery game, or just speed it up a little?
reported statistics that underpin that proposition:
My belief is that its effect will be transformational –
◆ The estimated costs associated with HTS in an
here’s why. Let’s start with a refresher, and make the link
average pharmaceutical drug discovery project are
between high-throughput screening, computer-aided
around $1 million. Pharmaceutical companies each
drug discovery and cloud computing along the way.
spend, on average, $50 million per year on HTS (1)
◆ A majority of HTS campaigns fail to find a lead
MODELLING & SCREENING
Back in the 1980s, the advent of computer-aided
drug discovery (CADD) promised to revolutionisepharmaceutical research. Teams of expert modellers were
brought together in dedicated groups in all of the world’smajor pharmaceutical, agrochemical and biotech
BRINGING IT ALL TOGETHER
companies. Software suppliers vied for leadership in the
– VIRTUAL SCREENING
space, and hardware suppliers made a killing from selling
The world of CADD was quick to recognise the value of
powerful graphics workstations and compute servers. In
the principle of HTS and soon a computer-driven
these heady days, rational drug design was proclaimed by
equivalent appeared – virtual screening. The principle
some as heralding a new dawn in the industry. There
was simple: obtain or build a 3D model of the target site
were success stories (the anti-flu drug Relenza, the cyclic
and dock into it as many candidate structures as you can
urea anti-AIDS treatments, and so on) to encourage
get hold of to estimate how well they might bind; select
things along. The craftsmen modellers remained in their
the most promising candidates and buy or make these for
teams, serving the organisation, but the vision of all
physical screening. The cost of modelling the whole
medicinal chemists relying on CADD technology never
process is negligible compared with physical HTS, so it
came to pass. Twenty-five years on, CADD still
must be a valuable pre-cursor and the return on
constitutes an enormously valuable component in drug
investment should be large – right? Wrong – if you
discovery research – but it has not torn up the rule book.
consider the effectiveness of the first wave of virtualscreening operations.
Then in the 1990s, along came high-throughputscreening (HTS). Automation had arrived and would
The virtual screening principle is sound, though, so we
completely revolutionise drug discovery, overturning
should examine its failings to date. There are three
rational design by either medicinal chemists or
modellers. It was a brilliant proposition: “Let’s make/buyand screen everything we can get our hands on and see
what sticks!” Robots were bought, compound
inventories amassed, and off we charged. There were
3. Simplistic, compromised modelling tools
There are three accessible sources of compound data for
want at any given time; and they are fully managed by the
virtual screening: supplier catalogues, (around 6 million
provider. The user needs nothing but a personal computer
entries), each company’s additional internal inventory (less
and internet access. Significant innovations in
than one million and lacking diversity) and publicly
virtualisation and distributed computing, as well as
available data sets (not necessarily subject to rigorous quality
improved access to high-speed internet and a weak
control). Considering the universe of possible candidates for
economy, have accelerated interest in cloud computing.
modelling, this is a very meagre set of data sources.
The flexibility of the cloud computing resource, allocatedon demand, is a compelling alternative to the huge
Virtual screening should not be a totally automated
internal resources that would be needed to cope with the
process, at least not with the software tools currently
peak requirement typical of computational chemistry.
available off the shelf. Not enough of the knowledge ofskilled practitioners has yet been encoded in the
The business model for CADD required the purchase of
commercially available software for the job. The range of
the most powerful compute servers and graphics systems
targets and challenges facing the modellers is wide, and
you could afford, along with licences for a wide range of
their skill and experience is of paramount importance in
expensive modelling software platforms, writing the cost
determining the outcome of the virtual screening study.
off over a given period – usually three years. This wasextremely capital intensive, so the investments were
Which brings us to the modelling tools themselves. The
constrained. This asset was utilised as needed by the
platforms in use today were developed over the last three
modellers, which meant it was sometimes churning jobs
decades and built on algorithms that optimised
through at maximum capacity – while the users queued
performance for the systems available at the time. Let’s be
patiently to get their work started – and at other times it
clear about what this means. Moore’s Law has accurately
sat idling, waiting for the next job. At any given
foreseen the doubling of computer processing power on a
moment, the modellers could have used 10-times its
less than two-year cycle for the last four decades. A system
power, or did not need it at all. This lumpy usage is
designed just 10 years ago (new, in CADD terms) would
have been built to deliver the most accurate results it couldwithin a ‘reasonable’ time, on hardware with three per cent
Cloud computing acts to lift the business constraint so
of the power of today’s equivalents. Scientists in industry
that there is, in effect, an immediate jump in the power
can be impatient souls, and rightly so; thus ‘reasonable’
available, over and above the evolutionary improvements
means up to a day for a large task, and a minute for a small
driven by Moore’s Law. So now all of those nasty software
activity along the way. Go beyond these limits, and
design compromises should come into question. Cloud
compromises have to be made in the algorithm or its
computing ought to herald the dawn of no-compromise
parameters to make the time taken acceptable. Modelling
computer-aided drug discovery and, specifically, it can
is a very complex, multivariate job – so this meant lots of
make effective virtual screening a reality. Virtual
deeply-seated compromises, embedded in the systems and
screening fits the cloud computing model perfectly
the way they are applied. March forward ten years and
because it is so inherently parallel: you pay no extra for
what would have taken a month could be achieved in a
using 1,000 CPUs for one hour, rather than waiting 100
day with the same software – so you don’t have to
hours for 10 CPUs to do the same job.
One only has to look at some examples to understand
the potentially dramatic effect of cloud computing in pharma.
CLOUD COMPUTING Cloud computing offers companies virtually unlimited
Take, for example, the treatment of the receptor site in
computing resource on tap – you effectively rent as much
virtual screening. The site is flexible and may well be
time and power as you need at any given occasion.
occupied with bound water molecules. Add in theflexibility of each candidate drug, and the complexity
Cloud computing is a general term for anything that
grows alarmingly. Few virtual screening approaches even
involves delivering services over the internet; the name
begin to attempt to account for such complexities. Yet
comes from the symbol often used to represent the
issues such as the flexible-ligand and flexible-receptor
internet in flowcharts and diagrams. Cloud services are
docking have to be considered according to Dr Garrett
sold on demand, typically by the hour; they are elastic –
Morris, co-author of AutoDock (3), the world’s most
a user can have as much or as little of a service as they
widely used docking package. AutoDock is used in
internet-distributed biomedical grid computing projects
Cloud computing is beginning to gain acceptance in
such as IBM’s World Community Grid project,
pharmaceutical and life sciences companies, with GSK,
FightAIDS@Home (4). He and Paul Finn, CSO at
Pfizer, Eli Lilly & Co, Johnson & Johnson and Genentech
InhibOx, are pioneering cloud-enabled approaches using
all quoted as using cloud computing resources.
an internal version of AutoDock and proprietarysoftware to bring new, necessary rigour to the art. They
IS CLOUD COMPUTING A GAME CHANGER?
have built a 100 million compound database of flexible
I think it is. And it’s not a question of automation versus
3D candidate models, with calculated shape,
craftsmanship – it’s a combination of the two.
stereochemistry (5), charge and physical properties toguide the virtual screening (6). It is massively computer-
The scientists behind developing CADD systems have
intensive, but it is appropriately rigorous and cloud
always been grasping for more computing power, to
make practical their developments. Ten years ago,Professor Graham Richards at Oxford University was
The visionaries have seen the potential for cloud
leading the screen-saver project (9), pulling spare CPU
computing to transform drug discovery in many areas –
power from over three million PCs across the world to
beyond the creation of effective virtual screening.
drive virtual screening of cancer drug candidates. Cloudcomputing makes that amazing vision a practical,
Dave Powers, Lilly’s Associate Information Consultant
commercial reality. At last, computing power is available
for Discovery IT, was recently quoted as describing a
and cost-effective enough to cause the design of
project the firm executed using Amazon’s Elastic
modelling systems to be fundamentally reassessed. It
Compute Cloud (EC2) service as follows (7): “We were
should herald the development of no-compromise
recently able to launch a 64-machine cluster computer
CADD and effective virtual screening – and that could
working on bioinformatics sequence information,
indeed change the drug discovery game.
complete the work and shut it down in 20 minutes. Itcost $6.40. To do that internally – to go from nothing to
References
getting a 64-machine cluster installed and qualified – is a
Industrialization of Drug Discovery, Handen JS (Ed), CRC Press, 2005 Chemogenomics in Drug Discovery, Methods and
There are already many examples of bioinformatics tools
Principles in Medicinal Chemistry, Vol 22
being deployed on EC2. These include HMMer for
Morris GM, Huey R, Lindstrom W et al, AutoDock4
protein sequence analysis and BLAST for general
and AutoDockTools4: Automated docking with
biological sequence analysis; in fact, pre-built Amazon
selective receptor flexibility, J Comput Chem
EC2 images are publicly available for these tools. Dec, 30 (16): pp2,785-2,791, 2009
Researchers at the Biotechnology and Bioengineering
4. FightAIDS@Home
Center at the Medical College of Wisconsin have created
http://www.worldcommunitygrid.org/
a scalable virtual proteomics data analysis cluster
research/faah/overview.do
(VIPDAC) that exploits cloud computing services, and
Armstrong MS, Morris GM, Finn PW et al, Molecular
they now distribute a pre-configured Amazon Machine
similarity including chirality, J Mol Graph Model 28:
Image (AMI) containing the OMSSA and X!Tandem
pp368-370, 2009
search algorithms and sequence databases (8). Ballester PJ, Finn PW and Richards WG, Ultrafast Shape Recognition: Evaluating a new ligand-based virtual screening technology, J Mol Graph Model Paul Davie is Chief Executive Officer at InhibOx Ltd, an Oxford 27: pp836-845, 2009
University Chemistry Department spin-out, pioneering theapplication of cloud computing to computer-aided drug
Mullin R, The New Computing Pioneers, Chemical
discovery. He has a long and successful track record in
& Engineering News 87 (21): pp10-14, 2009
commercial roles in computer-aided drug discovery. He held
Halligan BD, Geiger JF, Vellejos AK et al, Low
support and sales roles at Chemical Design before going on to
Cost, Scalable Proteomics Data Analysis Using
build and manage the European sales, marketing, support and
Amazon’s Cloud Computing Services and Open
consulting operations at Oxford Molecular. Paul went on Accelrys to establishtheir Consulting Division and serve as European General Manager, before
Source Search Algorithms, J Proteome Res 8 (6),
becoming Chief Operating Officer at InforSense. He then founded and was CEO
pp3,148-3,153, 2009
at Secerno, a successful database security company, before returning to research
Richards WG, Virtual screening using GRID
informatics with his consulting company, Davinger. Paul has an MBA and read
computing: the Screensaver Project, Nature
Chemistry at Oxford University. Email: paul.davie@inhibox.com
Reviews Drug Discovery 1:pp551-555, 2002
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