May 16, 2008

how soon can we expect embryonic stem cell clinical trials? Two leading scientists discuss.

During a debate on the Human Fertilisation and Embryology Bill in parliament, questions have been raised about how soon we can expect clinical trials for treatments involving embryonic stem cells. Two experts in the field gave their responses.

Dr Stephen Minger, Director of Stem Cell Biology Laboratory, King’s College London, said:

“In the US, Geron Corp is in negotiations with the FDA for treating acute spinal cord injury with spinal cord cells derived from human ES cells – they are likely to get approval for later this year. This will be a fairly big multi-centre trial. They are also progressing their cardiac and diabetes work very quickly and are hoping for approval for one or both of these by next year.

Advanced Cell Technology (also from the US) is also discussing with the FDA a hES cell based therapy for macular degeneration. Time line for taking this into the clinic is thought to be 2008-09. Professor Peter Coffey at UCL is also making significant progress in generating retinal pigmented epithelium from human ES cells for macular degeneration and expects to be in clinical trials here in the UK in 18 months to three years.

There are several groups who have now shown considerable efficacy in rodent and primate models of Parkinson’s using hES cell-derived dopaminergic neurons. It is anticipated that clinical trials for Parkinson’s are likely within 5 years. I also heard a presentation at a meeting here in London that Novacell (US) has successfully reversed (in a sustained way) the symptoms of type I diabetes in rodents – they anticipate clinical trials beginning within the next 3-5 years.

It is also worth pointing out that the reason cord blood and haematopoietic stem cell-based therapies are so far advanced compared to hES cells is that we have been in the clinic with these cells since the 1950s. Although the first human ES cells were created in 1998, hES cells have only been available since 2003 when President Bush put $1M into four centres in the US and Singapore to generate cells from pre-existing cell lines for distribution. The first human ES cells lines were derived in the UK in 2003 by my research group and my colleagues in Newcastle and so most labs in the world have only been working with human ES cells for five years or less. Given that it takes on average 10-15 years and $1 Billion to take a drug to the market, it is astounding that progress with hES cells has been so rapid.”

Prof Pete Coffey, Professor of Cellular Therapy and Visual Sciences, University College London, said:

“We are researching the development of embryonic stem cell therapies for age-related macular degeneration. This eye disease typically affects 25% of people over 60 in the UK – that’s over 500,000 cases. The dry form, which represents 90% of the cases, has absolutely no effective treatment. At present the support cells at the back of the eye effectively deteriorate and die and the patients go blind. It’s particularly traumatic because people lose the ability to read, to recognise their loved ones and to navigate the world around them. As well as this human cost there is a huge socio–economic cost to society.

In our research we have successfully turned embryonic stem cells into those support cells at the back of the eye (called retinal pigmented epithelial cells). We have done a proof-of-principle in animal models (in pigs who have similar sized eyes to humans). We’ve also done a proof-of-concept in patients – using patients own cells to re-populate the diseased cells and found we can stop the progression of the disease and stop people going blind – but only in 25% of cases. The reason we didn’t get better results is that the operation is complex and involves several operations and is not feasible as a standard operation.

So what we’ve now developed is human embryonic stem cells which we can turn into the rights kind of cells (rpe cells). We then put them on a patch and a surgeon can deliver them without any re-training. This is a 45 minute procedure which is more efficient, has less complications and covers more of the diseased area.

We are now going through final safety checks in a long term study. Our worst time-line is clinical trials in 3 years – our best time line is 18 months. Either way the suggestion that embryonic stem cell treatments are many, many years away is wrong. We are still looking at adult stem cells and constantly making the comparison between the two. For us in this research ES cells are better and hold out real hope for tens of thousands of people whose last years are destroyed by losing their sight. To stop this work will, without doubt, condemn thousands of people to life without sight as there are no other alternative therapies on the horizon.”