The European Commission granted a marketing authorisation valid throughout the European Union for Holoclar on 17 February 2015. Holoclar is a stem-cell treatment used in the eye to replace damaged cells on surface (epithelium) of the cornea, the transparent layer in front of the eye covering the iris. It is used in adult patients with moderate to severe limbal stem-cell deficiency caused by burns, including chemical burns, to the eyes. Patients with this condition do not have enough limbal stem cells which normally act as a regeneration system, replenishing the outer corneal cells when they get damaged and when they age.
Holoclar is a type of advanced therapy product called a ‘tissue engineered product’. It consists of cells taken from the patient’s limbus (at the edge of the cornea) and then grown in a laboratory so that they can be used to repair the damaged corneal surface. Because the number of patients with limbal stem-cell deficiency due to burns to the eyes is low, the disease is considered ‘rare’, and Holoclar was designated an ‘orphan medicine’. Holoclar must only be used by an appropriately trained and qualified eye surgeon in a hospital, and must only be given to the patient whose limbal cells were used to manufacture the medicine. In the first stage of treatment, a small part of healthy limbal tissue (1-2 mm2 in size) is taken from the patient in hospital and sent to the manufacturer on the same day. Next, the cells in the tissue are grown in a laboratory and frozen until the date of surgery is confirmed. Thawed cells are used to make Holoclar by growing them on a membrane made of a protein called fibrin. Holoclar, comprising the cells and the membrane, is then sent back to the hospital, where it is immediately surgically implanted in the patient’s eye. Antibiotics to prevent eye infection should be given to patients after limbal tissue has been taken from them. Following the surgery, the patient should receive antibiotics and an appropriate anti-inflammatory medicine. The active substance in Holoclar is the patient’s own limbal cells, which include cells from the surface of the cornea and limbal stem cells grown in a laboratory. Before Holoclar is used, the damaged corneal surface tissue of the affected eye is removed. Once implanted in the eye, the corneal cells of Holoclar help to replace the corneal surface, while the limbal stem cells serve as a reservoir of new cells that continuously replenish the cornea. Holoclar was shown to be effective in restoring a stable corneal surface in patients with moderate or severe limbal stem-cell deficiency caused by burns in a retrospective study using patients’ past medical records. One year after Holoclar implantation, 75 out of 104 patients studied (72%) were judged to have had successful implants based on the presence of stable corneal surface with no surface defects and little or no ingrown blood vessels (a common feature of limbal stem-cell deficiency). There were also reductions in patients’ symptoms, such as pain and inflammation, and improvements in vision. The most common side effect with Holoclar (seen in more than 1 patient in 10) is blepharitis (inflammation of the eye lid). Since Holoclar has been granted a conditional approval, the company that markets Holoclar will provide further data on Holoclar. The company is to provide data on the benefits and risks of Holoclar from a prospective clinical study.
