Cancer may be the fastest-growing specialty therapy area in the world, but sales reps are facing increasingly higher barriers when it comes to getting access to US oncologists.

So claims a report from sales and marketing consulting firm ZS Associates, which is compiled using a tool that incorporates call reports from more than 200 different US pharmaceutical sales teams. The study examines how often 350,000 prescribers met with reps and defines 'accessible' as doctors who met with more than 70% of reps who call on them and 'access restricted' as physicians who talk to 31%-70% of sales people who call. The third category, 'severely access restricted', equates to no more than 30% of reps getting through the door.

About 61% of oncologists placed moderate-to-severe restrictions on visits from reps, making cancer the most restrictive of the 20 most common medical specialties measured in the report. By comparison, about 47% of cardiologists and 38% of primary care physicians restrict rep access to the same degree.

Only 39% of oncologists were classed as accessible, compared to 65% of all prescribers, and 11% of the former placed severe access restrictions on reps, compared to just 9%. About half of oncologists put moderate access restrictions on reps compared to 26% of all physicians.

Ganesh Vedarajan, head of the oncology and specialty therapeutics practice at ZS, noted that while oncologists "still see some value in rep visits, increased patient load and more time spent on reimbursement issues limit the time they have available". He also pointed to regulatory constraints and the fact that doctors are increasingly "able to access scientific data in real time through other channels".

The study goes on to note that because many oncologists limit the number of times they see any single rep each year, pharma companies are tempted to secure more doctor visits by sending several different reps to promote the same drug. "These conditions are ripe for a new pharma sales rep 'arms race'," said Mr Vedarajan, noting that drugmakers which hire more reps "must be careful not to overwhelm prescribers with sales calls".

Mr Vedarajan concludes by saying "the sales model also must evolve to take a different sales approach to institutions", as some of them "do not allow sales reps at all". He claims that as the pharma industry consolidates "and more physician practices are acquired by institutions, this problem will become worse".