The PBAC has raised concerns that people with Crohn’s disease are staying on biologic medicines longer than expected, contributing to a blow-out in PBS costs.
But an expert has told the limbic that the high rate of biologic continuation was a positive sign that patients were responding well to treatment and getting on with their lives.
PBS spending on infliximab, adalimumab and vedolizumab to treat Crohn’s disease rose from $1.3 million to $158 million in a decade, according to a new report by the PBAC’s drug utilisation sub-committee (DUSC).
Since 2007, the three bDMARDs have been progressively listed on the PBS to treat refractory disease in adults and children as well as fistulising Crohn’s disease.
There has been steady growth in the uptake for these medications in all indications between 2007 and 2016, for example a fivefold increase for adult patients with severe Crohn’s disease from 1500 to 7500 in eight years.
This trend was observed by the PBAC in 2015, which duly ordered the DUSC to investigate and report back in two years.
At the time the PBAC noted a “higher than expected” proportion of patients was continuing the medication with their use to treat the disease yet to stabilise, and that “the cost-effectiveness of infliximab and adalimumab may be affected if patients are continuing treatment without achieving remission”.
The DUSC report – released last month – found 60% of patients with severe refractory Crohn’s disease who started bDMARD therapy in 2011 remained on treatment after five years.
The figure is much higher than the continuation rates in the clinical trials, the DUSC said in the report – speculating this may partly be due to some patients switching to a second or third bDMARD agent.
It also found the continuation rates in fistulising Crohn’s disease patients “seem high” and patients may not be ceasing treatment after fistula closure, but noted that the PBS restrictions don’t include rules or advice about when patients should stop or restart treatment.
Use of bDMARDs in this area is likely continue to grow, with a trend to treat patients earlier and use them in combination with immunotherapy, the report concluded.
“It is unknown if the use of these medicines with higher than expected continuation rates is cost effective,” the report said.
“DUSC considered that the co-administration with immunotherapies may be contributing to the longer than anticipated continuation rates of bDMARDs. DUSC also considered that other practices, such as patients receiving treatment earlier, may be involved in driving the continuation rates.
An Australian study found 89% of Crohn’s disease patients commencing infliximab or adalimumab under the PBS luminal indications achieved and maintained remission for a median time of 63 and 61 weeks respectively.
One of the study’s co-authors, Professor Jane Andrews, Head IBD Service at the Royal Adelaide Hospital’s Department of Gastroenterology and Hepatology, said the high rates of continuation beyond five years was positive and meant patients are “staying well and getting on with life”.
It made little sense to compare these real-life results to that of clinical trials which are known to be non-representative of real world medicine, she added, giving the example of the initial infliximab trials in which subjects did not need to have inflammation to enrol.
“In Australian expert centres, where a large percentage of biologic patients are treated, active inflammation is always documented before using a biologic regardless of symptoms – and as biologics work really well for inflammation, people respond really well and stay on therapy,” she said.
Overall, the DUSC reports findings of continued uptake is a good news story for patients, she said.
“These drugs are changing lives and getting these people back into the mainstream – this fact is not taken into account in the current narrow financial assessments undertaken by DUSC.
“A “whole person” cost effectiveness model should be used to better inform value in care.”