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Last week the papers were full of claims that a therapy using embryonic stem cells was successfully treating patients with eye disease. Given the overwhelmingly bad news for embryonic stem cell research (ESCR) recently with the departure of Geron from the field and other setbacks, proponents of this type of unethical research were quick to herald a 'breakthrough'.

However, eminent stem cell expert Dr David Prentice has said that the company testing the ESCR therapy turned a "blind eye toward both good science and good ethics" and used preliminary data from a trial at early stages, with a low number of patients and lack of controls.

"The embryonic stem cell and cloning company, Advanced Cell Technology (ACT), has published a very preliminary online report regarding their first two patients injected with embryonic stem cell derivatives," Dr Prentice wrote.

"The two patients, one who has age-related macular degeneration, the most common cause of blindness, and the other with a rare form of blindness called Stargardt's disease, were injected with retinal cells made from human embryonic stem cells only 4 months before the report was submitted. This makes it far too early to know whether these embryonic stem cells will actually be safe or effective. In fact, it's surprising that any reputable scientific journal would publish such very preliminary data, given the early stage of the clinical trial (which is supposed to last at least two years), the short period of time after the patients were injected, and the low numbers of patients and lack of controls," he went on.

He quoted Dr Martin Friedlander, Professor of Ophthalmology at Scripps Health in La Jolla, California who noted that "To reach any conclusions on the safety or efficacy of two patients treated for four months without a control population for comparison is unreasonable. This is why anecdotal reports like this are not published. This falsely raises the hopes of millions of individuals suffering from these diseases."

Dr Prentice noted that while the study mentions that one patient who showed improvement in her eye that was injected with the cells, also showed improvement in her eye that was NOT injected with the cells, and that the authors admit that there is a general lack of hard data

"It is indeed surprising that this paper was published. The preliminary nature of the paper reinforces the image of ACT noted in a recent story in Nature," wrote the stem cell expert. (http://www.nature.com/news/stem-cell-research-never-say-die-1.9759)

"Since the late 1990s, ACT has gained a reputation as a renegade company, accused of overhyping results to raise attention and money. Critics say that the company has damaged the field more than once with its high-profile, controversial announcements, such as one describing the company's attempts to clone a human embryo in 2001..."

And he concluded "There are certainly better alternatives to embryonic stem cells. Similar stem cells–iPS cells–can be derived without any use of embryos. In fact, ACT scientist Bob Lanza has already said that they are planning to use iPS cells in the future, which potentially could remove the need for immunosuppressive drugs and provide an ethically-derived source of cells. However, since iPS cells are pluripotent, with a penchant to grow and make lots of cells, they face the same practical problem of tumor formation as embryonic stem cells.

"A practical, as well as ethical solution, would be the use of adult stem cells. Preliminary work has shown that retinal repair could be accomplished using adult stem cells from bone marrow, or possibly even adult stem cells from within the patient's own eye. Adult stem cells from the patient's own eye have already been used successfully to treat corneal blindness in people."

A report in the New York Times noted that: 'Advanced Cell Technology, which paid for the study, has been criticized in the past for overstating results, in part because it has been desperate to raise money to stay in business,' and that a specialist working on the ACT trial, Dr. Steven D. Schwartz, conceded that it was "extremely unusual" for researchers to publish a study after treating only two patients out of a planned 24.'