With over 7000 medicines in development, new treatments will continue to change patients’ lives; slowing disease progression, avoiding illness and reducing overall costs for healthcare systems. But developing a new medicines is a long, complex and risky process with no guarantees of success. Over the coming weeks we look at number of new medicines and role pharmaceutical incentives or IP has played in their development.

Paediatric glaucoma, a rare condition that is often misdiagnosed, is responsible for 5% of the blindness in children worldwide, and accounts for up to 18% of the children in institutions for the blind around the world.[1]

In open-angle glaucoma, the eye’s drainage canals become clogged over time, causing an increase in internal eye pressure and subsequent damage to the optic nerve.[2] The outer areas of vision (peripheral vision) are affected first. Without treatment, central vision of the eye may eventually be lost.[3]

In ocular hypertension, the pressure inside the eye is higher than normal. Ocular hypertension is not the same as glaucoma. In people with ocular hypertension, the optic nerve appears normal and no signs of glaucoma are found during tests of peripheral vision; i.e., they have a normal visual field. However, people with ocular hypertension are considered “glaucoma suspects,” meaning they should be monitored closely by an ophthalmologist to make sure that they do not develop glaucoma. Both open-angle glaucoma and ocular hypertension are linked with an increase in the pressure within the eye, eventually affecting eye sight.[4] 

Xalatan (latanoprost) eye drops are used to treat both these conditions. Latanoprost belongs to a group of medicines known as prostaglandin analogues and works by increasing the outflow of fluid from inside the eye into the bloodstream,[5] thereby reducing intraocular pressure (IOP). 

Before the approval of latanoprost for paediatric use, few IOP-lowering treatments had been approved for use in children. It was the first prostaglandin analogue to complete safety and efficacy trials in the paediatric population and to be authorised for use in patients aged 18 years or younger in Europe.

The Paediatric Medicines Regulation as a stimulus for R&D

Several teams at Pfizer worked collaboratively with the European Medicines Agency (EMA) to complete the agreed paediatric investigation plan (PIP). This involved the completion of two studies with children from birth to less than 18 years of age by December 2009 (Phase III clinical trial programme, known as the Panda study). The completion of these studies led to the approval, in January 2012, of latanoprost to treat increased eye pressure and glaucoma in babies and children of all ages. 

The product received a paediatric extension under Article 8 of the Paediatric Medicines Regulation (PMR). This extended the Supplementary Protection Certificate (SPC) for latanoprost by 6 months in the 15 EU member states where there was an SPC. Since expiry of the SPCs, multiple generics manufacturers have marketed latanoprost in Europe.[6]

As latanoprost was first authorised prior to the PMR, there was no mandatory requirement to conduct a PIP. Nevertheless, it was the possible SPC extension resulting from the completion of a PIP that acted as a key incentive and influential factor for Pfizer to develop this product for children and pursue a paediatric indication.

[1] The British Infantile and Childhood Glaucoma (BIG) Eye Study, 2007: http://iovs.arvojournals.org/article.aspx?articleid=2125358

[2] http://www.glaucoma.org/glaucoma/symptoms-of-primary-open-angle-glaucoma.php

[3] http://www.nhs.uk/Conditions/Glaucoma/Pages/Symptoms.aspx#open

[4] PIL: http://www.mhra.gov.uk/home/groups/spcpil/documents/spcpil/con1469768838652.pdf

[5] PIL: http://www.mhra.gov.uk/home/groups/spcpil/documents/spcpil/con1469768838652.pdf

[6] https://www.rcophth.ac.uk/wp-content/uploads/2014/12/2013_PROF_226_Generic_Latanoprost_Prescribing.pdf