A recent analysis by IMS of 68 brands found that for the most heavily advertised products, DTC advertising typically generated around 4 to 9 percent of their new prescription volume, whereas samples accounted for 7.8 percent, details for 21.1 percent, and the base (or, what could be expected with no promotion) for the remaining 67.7 percent.

DTC's contribution, while small in relative terms, is nonetheless significant in absolute terms; with a $2 billion brand, for instance, a 3 percent contribution to new prescriptions equates to $60 million in sales.

It is also clear that each channel has a unique role in the promotion process and in maintaining the balance between garnering new patient starts and supporting therapy continuation. TV advertising tends to drive a sharp increase in new therapy starts for the first week or two after exposure, whereas print media have a longer, more gradual impact in maintaining a brand's patient base.

The median return on investment (ROI) for those brands employing DTC advertising in the IMS normative database is $2.20 for each $1 invested, and the majority of these brands realized a positive ROI on by the second year of a sustained campaign (see figure 2). Several factors affect a given product's ROI:

• Degree to which the market is controlled by managed care
• Size of the brand and the market
• The refill rates in the therapeutic class
• Price of the brand.

In all fairness, DTC advertising's ROI should be measured only on that portion of the market that is promotionally sensitive.

In some markets, as much as 30 percent is "locked up" by managed care formularies. On the other hand, reaching the patients in the open-access plans favored by labor unions (an estimated 50 million consumers) is worthwhile.

BIGGEST BANG

In general, the best ROIs are seen for products that can command premium prices in sizeable markets (such as statins and asthma medications) where patients tend to stay on therapy for a long time.

Products such as allergy medications, for which there is a lot of market variation and patients are not persistent in their therapy, tend to achieve ROIs in the midrange.

Products achieving ROIs on the low end of the spectrum tend to fall into classes like dermatology and weight loss, in which prices and persistency are both low.

Note that a high ROI ratio does not necessarily spell DTC advertising success. DTC advertising often drives performance across brands in more consumer-driven and/or specialty markets.

For better or worse, unbranded DTC advertising spreads a halo over the entire market that is typically twice as strong as that which is cast by the sponsor's own brand. And the largest brands in a class reap the biggest benefit. In one case, in the depression market, an unbranded ad contributed 1.5 percent of new prescriptions to the entire market and .6 percent to the sponsor.

IMPACT ON PATIENTS

While it is undoubtedly valuable to know if a DTC campaign succeeded in increasing a product's prescription volume or market share, it is now possible to evaluate the success of a DTC campaign by its impact on patient behavior.

By tapping into anonymized, patient-level data (APLD), brand managers can determine:

• The ROI of the campaign over the patient's lifetime, which is vitally important in chronic therapy areas
• Whether the ads are expanding the market, as measured by NBRxs, not NRxs
• When patients are most vulnerable to switching brands
• How the promotion impacts consumer loyalty and patient persistence
• Whether the promotion is reaching the most appropriate types of patients and working according to the strategy.