WPP’s Grey Healthcare Group acquired a minority interest in OptimizeRx, which markets electronic trial vouchers and copay coupon cards that can be accessed through an EHR, for $4.7 million in stock, according to financial filings.

The deal builds on a partnership formed by the two companies in January 2014. At the time, the companies said they planned to jointly market new and existing products and services to pharmaceutical companies.

Ghg’s decision to make a financial investment in the company highlights the growing interest among pharma marketers to engage physicians through EHR platforms. As part of the partnership, Grey and OptimizeRx have trained sales representatives about EHR sales opportunities through ePrescribe Training, according to OptimizeRx’s most recent financial filings. Grey has also rebranded the company’s promotional marketing, including brochures, presentations and digital media.

OptimizeRx announced in August that it has expanded its work with Allscripts’ EHR platform. It has also partnered with TrialCard and PracticeFusion.

One of the most significant changes underway in healthcare right now is the growing and more sophisticated utilization of EHRs. Physicians on average spend 2.8 hours per day using an EHR, according to Decision Resources Group. As a result, pharmaceutical companies are increasingly viewing the platforms as a new way for their sales forces and marketers to engage with physicians and promote financial assistance, clinical decision-making and other types of support.

“Now pharma companies are recognizing, ‘If I’m going to engage with physicians, I need to figure out their new workflow,’” said Lynn O’Connor Vos, Ghg’s CEO. “It’s a very important channel.”

Ghg and OptimizeRx said they plan to build a tool that will provide services at the point-of-care. O’Connor Vos said they also plan to expand the EHR network into specialty drugs, including oncology.

OptimizeRx added that it will use the proceeds from the purchase for working capital and other business-related expenses. It also named O’Connor Vos a member of its board of directors.

The company reported $1.7 million in revenue in the first quarter of 2015, up from $1.4 million in the year-ago period, and a net loss of $157,000.