The US drug giant has exercised an option to develop and commercialise an unnamed investigational compound in addition to the steroid drug triamcinolone acetonide (TA), under a deal signed by the two companies in June.
Both compounds are aimed at treating serious retinal diseases.
In line with the existing agreement, Merck & Co will lead and fund development and marketing of the drug candidate combined with the I-vation system.
Its partner, which specialises in surface modification and drug delivery technologies for the healthcare industry, will receive a licensing fee and payment for its development activities.
SurModics, which will be responsible for the manufacture and supply of clinical and commercial products under the expanded agreement, will also be eligible for development milestones as the candidate compound moves towards US and EU approvals.
On top of that, SurModics will get royalties on any future product sales.
In addition to reimbursement for development activities and the product royalties already mentioned, SurModics received an upfront licensing fee of $20m and stands to gain up to $288m in fees and development milestones contingent on successful product development and regulatory clearance in the US and Europe.
The ophthalmology market includes front-of-eye conditions such as glaucoma, where drugs can be delivered using eye drops and other conventional ophthalmic formulations; and retinal diseases affecting the vitreous or back of the eye, such as age-related macular degeneration (AMD) and diabetic macular edema (DME), which are the leading causes of vision loss in the western world.
While new drugs have emerged for the treatment of these latter diseases, the current standard of care is administration by direct injection into the vitreous.
Since the drugs used have a relatively short intraocular half life, the injections must be repeated every 4-6 weeks.
This kind of regime is not only hard for patients to endure but carries a growing risk of tissue damage and infection, SurModics points out.
Topical drops rarely make it to the back of the eye and a blood-ocular barrier prevents systemically administered drugs from penetrating ocular tissue.
Hence the need for optimal drug delivery technologies that not only skirt the difficulties of injecting into the eye but can offer a viable alternative to topical eye drops for anterior diseases such as glaucoma, where compliance may be a significant barrier to treatment success (e.g. in the elderly).
The I-vation system is an intravitreal implant comprising a rigid non-ferrous metallic scaffold coated with SurMedics' Bravo durable polymer matrix, which controls the release of the active drug for periods ranging from six months to two years.
The Bravo polymer is already on the market as a critical component of Cordis' Cypher (sirolimus) drug-eluting coronary stent.
SurModics has a number of polymer families available for use in site-specific delivery of drugs to the eye, which increases the flexibility of the I-vation system to encompass a range of therapeutic molecules from small hydrophobic drugs to larger macromolecules and proteins, the company notes.
The helix design allows for minimally invasive implantation of the delivery system using a pars plana needlestick less than 0.5 mm in diameter while maximising the surface area available for drug delivery.
It also ensures secure anchoring of the implant against the sclera (the 'white' of the eye), keeping the implant out of the visual field and facilitating retrieval.
I-vation TA is currently in a Phase I US clinical trial - STRIDE (Sustained Triamcinolone Release for Inhibition of Diabetic Macular Edema) - evaluating the safety and tolerability of the drug/implant combination in patients with DME.
At its recent annual shareholders' meeting, SurModics said patient acceptance/tolerability to date had been excellent and I-vation TA had shown a good safety profile, with no uncontrollable intraocular pressure and no reportable serious adverse reactions.
The retinal thickness data confirmed a sustained steroid effect, it added.