Even stem cell experts are worried that embryonic stem cells might cause tumours.
The announcement by the Geron
Corporation that it will begin the first human trial using stem cells
derived from human embryos has been greeted with applause from across the research community. Having invested $170m
developing its treatment for spinal cord injury, the biotechnology giant
becomes the world’s first recipient of a license to begin Phase 1 clinical trials
with human patients using embryonic stem cells (ESCs),
highly malleable cells derived from early stage embryos.
excited speculations made by some commentators
however, does Geron’s announcement really signify any major breakthrough?
The license, granted by the US Food and Drug Administration, follows
results indicating an improvement in the conditions of rats when treated
shortly after suffering spinal trauma. Yet Geron has carried out no testing of primates or in animals with a longer spinal cord than
rodents, instead proceeding directly to first-in-human trials using ESCs.
Concerned perhaps at
this irregular jump in the research process, even leading proponents for ESC
research have given a lukewarm reaction to Geron’s announcement. As Professor Ian Wilmut,
creator of the first cloned mammal, Dolly the Sheep, has admitted: “It is very
important to appreciate that the objective of trials at this stage is to
confirm first of all that no harm is done to patients, rather than to look for
These comments represent more
than just a management of expectations for two reasons. First, experiments
using embryonic stem cells have yielded little benefit in practical terms since they were first
identified in 1981, having led to no cures or insights despite significant
funding worldwide. Second, perhaps due to their early undifferentiated status,
ESCs tend to cause tumours. The main purpose of this trial is not to cure the
patient, but to see whether Geron’s scientists have been able to tame the
wildly proliferating ESCs. As Wilmut’s note
of caution suggests, Geron should be concerned with protecting both the human
subjects of this research – and their own commercial liability.
Given such concerns, to many patient groups – particularly those with
spinal injuries whom this announcement might be seen as holding out the
greatest promise – the overwhelming feeling may be: “So what?” ESCs hold no
imminent hope of success, and alternative treatments are already being used to
treat spinal patients.
For example, treatments have been carried out
using adult stem cells – that is, early
undifferentiated cells found in the human body – since as early as 2001, when Dr. Carlos Lima at the Egas Moniz hospital in Portugal used cells
harvested from patients’ nasal cavities to treat damaged and even severed
spinal cords. In comparison to Dr. Lima’s success, it has taken proponents of
ESCs a further nine years just to arrive at the starting gates.
the success of adult stem cell research does not begin and end
with treatments of spinal patients, having been used to treat no fewer than 73 conditions.
Of these, some of the most exciting results arising from adult stem cells include cures for
and sickle cell
disease, as well as being used to overcome tissue rejection issues in the
world’s first windpipe
transplant in a child.
The most interesting
aspect of this announcement was its timing. It comes just weeks before a vital
deadline. The US
Court of Appeal, currently considering whether federal money may be used to
fund experiments using ESCs, has set a cut-off date of November
4 for both sides to submit all relevant documents ahead of its ruling. In
the light of the Geron announcement, pro-ESC enthusiasts may be celebrating
both a PR coup and a potentially significant addition to their side’s
submission to the Court – as well as providing a pre-mid term election reminder
to American voters of an issue which has previously worked in the Democrats’
In terms of concrete
actual treatments however, ESC research is likely to take several years to
arrive at a therapy which has already been pioneered by adult stem cells –
therapies which themselves continue to be developed further by researchers, and
contain none of the ethical objections raised toward ESCs.
For this reason,
Geron’s big story is that there IS no story. There certainly is no imminent
reason for excitement among patients currently suffering from spinal injuries
(still less those with other debilitating conditions). While this announcement
has been noteworthy for headline-hunters, patient advocate groups may
eventually be left wondering what all the fuss was about.
Cusworth is a public affairs consultant in the UK, specialising in the science,
research and technology sector. He holds a Masters degree in Medical Law
and Ethics and has a particular interest in stem cell research.