When biosimilar growth hormones were approved in England in 2008, onlookers predicted that the lower cost of the new medicines would drive prescribers to choose them over branded biological drugs. A new study in BMJ Open, however, indicates that prescribing decisions are more commonly made on the basis of ease of use, not cost.
As of 2014, the biosimilar share of the growth hormone market was only 5% in England, while in countries like Poland they had a 99% market share due to reimbursement policies that required switching to the less expensive drugs. A group of researchers from Keele University in the United Kingdom set out to determine the trends in prescription of human growth hormone in primary and secondary care settings in England, as well as the causes of these trends. Their hypothesis, they wrote, was that “price would be the dominant influencing factor in the use of these medicines.”
Using data from the National Health Service from 2011 to 2015, the researchers analyzed prescribing trends of 12 preparations of growth hormone in primary and secondary care. Half of these came ready-to-use, while the other half required reconstitution before using. In primary care, they found that prices of the biosimilar growth hormones decreased by 15% over this time, while branded growth hormone prices remained steady, except for 1 product that saw its price decrease by 25%. They observed greater price reductions for more of the agents in secondary care.
Over the study period, growth hormone prescriptions declined by an average 0.45% per quarter in primary care, but increased by an average of 5.8% per quarter in secondary care. By the fourth quarter of 2015, 1 of the 2 biosimilar growth hormones accounted for 11% of the market.
In both primary and secondary care, statistical analyses did not find strong correlations between price per dose and usage for any of the products, although, for the biosimilar drugs, there were slight negative associations. Instead, the use of 5 out of 6 ready-to-use agents in primary care and all 6 in secondary care increased significantly over the study period, regardless of price. As both biosimilar products were ready-to-use, this pattern can account for some of the market growth of biosimilars. There were mostly decreases in the use of agents requiring more preparation in both care settings, although their prices had gone down.
According to the study authors, these factors suggest that “ease of use rather than price is the key driver for growth hormone product selection in primary and secondary care.” They noted that prescribing guidelines in England recommend that providers discuss the benefits and disadvantages of each product with their patients and respect the patients’ choice.
Previous studies of branded growth hormones have found that patients value ease of use and convenience. In addition to being quicker and easier to use, the ready-to-use drugs require smaller amounts of drug injected and have added buffers in the solution, which decreases the pain at the injection site.
This study confirms that patient opinions are affecting providers’ prescribing choices, as prescribers “take more account of patient preferences than central guidance on cost efficiency,” even if they adhere to the guidelines that attempt to control drug costs.
“This contrasts with other health economies, where mandated switching to growth hormone biosimilar meant that 99% of prescribing was the less expensive biosimilar,” the researchers concluded.