The rise of generics

With patents expiring on current 'blockbuster' glaucoma medications, such as Xalatan (latanoprost), and the rise of generic alternatives an inevitability, OTEurope spoke with Professor Gábor Holló on his opinions and concerns for the future of glaucoma medications and its impact on disease management.

Q. Do you use generic glaucoma medications?

I currently only use one generic medication, timolol, which is not available to me in its original formulation.

Personally, I do not recommend generic topical glaucoma medications, especially not if there is a possibility of the patient accessing the original product. For topical glaucoma medication pharmacokinetic assessment of the generics is not possible (the eye cannot be sampled for such studies), thus comparison with the original product can be made only via evidence based clinical headtohead comparison studies. However, such studies are lacking. Also, it is important to remember that the various generics differ between each other, thus there is a poor level of standardization in Europe ('minor differences' of the ingredients are allowed but not defined, just like the bottle shape, transparency and droplet size). As a result of these variances the total amount of drug exposure is not sufficiently regulated and, therefore, may differ considerably between the various generics of the same original drug. In brief, the efficacy and the side effects may vary unlike with the original branded version. There was an interesting paper published in Clinical Therapeutics by Dr Sriram Sonty et al.¹ and an interesting presentation by Dr Z. Mammo et al.² at ARVO in 2010 revealing some of the issues created through the use of generics.

Q. Do you think that there are any myths surrounding generic glaucoma medications that should be dispelled?

Only that there are issues surrounding the variability of efficacy, which is something that is generally not considered and definitely should be as the interest of our patient and their health should be our top priority.

Q. Is there a critical need for generics manufacturers to use colour-coded packaging or possibly a need for strict guidelines about this?

There is a reason that colour-coded packaging has been employed in the branded versions of drugs, which is that a lot of patients suffering with glaucoma may not be able to see the labelling on a bottle and should they have multiple drops to take each day then these medications could be mixed up and some could be over-used. Additionally, it will help to use colour coding to prevent any switching between generic products, so I believe that it is important.