Cost will limit uptake of off-label Gilead/Bristol-Myers Squibb Hep C combo, despite best-in-class data
Published: April 30, 2013
ViewPoints: Cost will limit uptake of off-label Gilead/Bristol-Myers Squibb Hep C combo, despite best-in-class data
Ref: ViewPoints Desk
April 30th, 2013
Once again, a combination of Gilead Sciences' sofosbuvir and Bristol-Myers Squibb's daclatasvir appears to offer the most efficacious way of treating patients with hepatitis C without the need for either interferon or ribavirin. However, Gilead has chosen not to pursue development of this combination – prompting speculation that off-label usage could prove a feasible alternative for physicians. Such an outcome is possible, say experts, although cost is likely to be a deciding – and ultimately limiting – factor.
Insight, Analysis & Opinion
Data unveiled last week showed that among a cohort of 41 patients treated with the sofosbuvir/daclatasvir combination, 40 patients were virus free (100 percent SVR) after 12 weeks of therapy. It is not the first time this combination has impressed; a year ago similarly robust data was released, providing a backdrop against which Gilead's decision to not pursue a combination therapy with Bristol-Myers Squibb was met with some consternation. See Spotlight On: Bristol-Myers Squibb and Gilead Sciences deliver stellar HCV results, decide to go separate ways?
Gilead claims that its decision to focus on internal developments, rather than partnering with Bristol-Myers Squibb has accelerated the development of its own efforts to bring a single tablet, interferon-sparing treatment to market. Gilead remains the leading player in this development race, albeit if its own impressive-looking combinations have yet to fully match the efficacy seen with sofosbuvir/daclastasvir, which are regarded as the best in class nucleotide NS5B inhibitor and NS5A inhibitor products, respectively.
With different assets in the HCV development space offering various mechanisms of action, mechanism diversity and potency, one suggestion is that once individual components become available, physicians will prescribe them together in an off-label capacity. In this respect, the HIV market – where combinations of best-in-class molecules are used despite different companies owning them – could prove to be a valid benchmark. Key opinion leaders (KOLs) suggest that such activity is likely to occur in the early period following the approval of new treatments, with off-label use also likely to be driven by independently-run clinical trials looking at cross-company regimens. See KOL Insight: Hepatitis C: the race for the first interferon-free regimen
Potential off-label use will have a direct impact on how companies price their own fixed-dose combinations, note KOLs, while the broader cost of treating an expanding HCV population will in turn limit the use of off-label prescribing, they add – particularly as Gilead, for example, has shown robust data for its own combination. One KOL told FirstWord that "there are just too many patients out there and the system could go bankrupt if screening and diagnosis rate of hepatitis C go up and everybody is just put on just a combination of the best drug classes. You may have people prescribing daclatasvir, simeprevir plus sofosbuvir, three drugs off label in a combination just because they feel that is really the best they can provide to their patients, but which from a healthcare perspective would be a disaster."
Related - Hepatitis C - Will physicians go off label, and prescribe Sofosbuvir and Daclatasvir?
HCV Combo Impresses, but Use Unlikely
In a small phase II cohort of very difficult-to-treat patients, the combination of sofosbuvir and daclatasvir led to viral cures in 40 of 41 patients 12 weeks after the end of therapy, according to Mark Sulkowski, MD, of Johns Hopkins University.
The 41st patient did not appear to be tested at week 12 and so was counted as a treatment failure, but was tested 24 weeks after the end of therapy and found to have unquantifiable levels of HCV RNA, Sulkowski reported at the meeting of the European Association for the Study of the Liver.
He added that of the 21 patients who have completed 24 weeks of follow-up after treatment, all have undetectable virus – the so-called 24-week sustained virologic response (SVR24).
In addition, the combination was well-tolerated with few adverse events, and no patient has yet relapsed, he said.
In other words, the all-oral, once-daily combination "looks exceedingly useful," commented Geoffrey Dusheiko, MD, of Royal Free Hospital in London, who was not involved with the study but who moderated the session at which it was presented.
But the combination is running afoul of diverging corporate interests, he noted. Daclatasvir, an NS5A replication complex inhibitor, is owned by Bristol-Myers Squibb, while sofosbuvir, a nucleotide analogue NS5B polymerase inhibitor, is being developed by Gilead Sciences.
The companies have stopped collaborating on the drugs, with each firm preferring to develop its own version of the other's medication.
The result, Dusheiko said, is that "we don't have a large body of phase III data and that may restrict physicians from prescribing this particular combination."
"Unless there's a change in the thinking," he said, it's unlikely the companies will get back together, adding that for clinicians, "It's a conundrum."
Sulkowski reported on 41 patients with the hard-to-treat genotype 1 of the virus who had failed treatment with the current standard of care: a protease inhibitor -- either telaprevir (Incivek) or boceprevir (Victrelis) -- combined with pegylated interferon and ribavirin.
Such patients have no treatment options, Sulkowski said. He and colleagues randomly assigned the 41 volunteers to take sofosbuvir and daclatasvir alone or with ribavirin for 24 weeks. The primary endpoint of the analysis was unquantifiable HCV RNA 12 weeks after the end of therapy – the so-called SVR12.
All patients but one had unfavorable variants of the IL28B gene, which predicts response to interferon treatment, and 33 of 41 had HCV genotype 1a, which is regarded as more difficult to treat than 1b.
Nevertheless, Sulkowski reported, high response rates were seen early in treatment and by the end of therapy all 41 patients had unquantifiable virus, a state that persisted (with the one technical exception) through 12 weeks post-treatment.
There were no serious adverse events in patients taking the combination alone, no discontinuations owing to adverse events, and no grade 3 or 4 adverse events.
In the other arm, the combination plus ribavirin was nearly as well-tolerated with one serious adverse event – a single patient with hypokalemia.
Adverse events reported by at least 10% of patients included fatigue, headache, hair loss, muscle aches, constipation, and diarrhea, Sulkowski said, but all were mild or moderate.
The study had support from Gilead and Bristol-Myers Squibb. Sulkowski reported financial links with the company, as well as with Novartis, BMS, Gilead, Janssen, Vertex, BIPI, Abbott, Merck, Roche/Genentech, BIPI, and Pfizer.
Dusheiko reported financial links with Gilead, GSK, BMS, and Boehringer Ingelheim.
Primary source: European Association for the Study of the Liver
Sulkowski MS, et al "Sustained virologic response with daclatasvir plus sofosbuvir ± ribavirin (RBV) in chronic HCV genotype (GT) 1-infected patients who previously failed telaprevir (TVR) or boceprevir (BOC)" EASL 2013; Abstract 1417.