Baricitinib Continuation Rate High in Real-World Practice

Sara Freeman

May 04, 2021

Around three-quarters of patients remained on treatment with baricitinib (Olumiant) for rheumatoid arthritis after their first 6-month assessment in an independent analysis of British Society for Rheumatology Biologics Register (BSRBR) data.

The rate of continuation was even higher, at almost 85%, in patients who had not previously been treated with a biologic or targeted synthetic disease-modifying antirheumatic drug (b/ts DMARD) before being given baricitinib. The 6-month continuation rate was also higher, at 80%, in patients who received baricitinib without additional DMARDs or steroid therapy.

Overall, the Disease Activity Score in 28 joints using erythrocyte sedimentation rate (DAS28-ESR) score was reduced from a baseline of 5.7 to 3.4, with similar reductions seen among the subgroups of patients who had received baricitinib as monotherapy, after prior b/tsDMARDs, or no prior b/tsDMARDs.

"We've looked at an RA study population using data from the BSR biologics registry, to try and have a look at how patients with baricitinib are being treated and how they're doing in this real-world setting, within the U.K.," explained consultant rheumatologist Christopher J. Edwards, MD, of University Hospital Southampton (England) at the British Society for Rheumatology annual conference.

"Overall, effectiveness and tolerability seem to be pretty good indeed," he said. "Sample size, of course, was small and it will be nice to see a little bit more data collected over time that allow us to be more confident in any conclusions."

' Getting to Grips ' With Baricitinib

Baricitinib is a drug that clinicians in the United Kingdom are "just getting to grips with," observed Jon Packham, BM, DM, a consultant rheumatologist at Haywood Hospital in Stoke-on-Trent (England) who was not involved in the analysis.

"We look forward to when we've got a few more patients through that 6-month hurdle and we were getting even more data coming through," Packham said.

Baricitinib was given marketing authorization in Europe for the treatment of moderate to severe RA in 2017 and so is a relatively new addition into the BSRBR-RA, which has been running for the past 20 years. It includes data on patients with RA who are newly starting a bDMARD or tsDMARD, and patients are followed up every 6 months for the first 3 years of their treatment and then annually thereafter.

Edwards presented data on some of the baseline characteristics and status of patients at the first 6-month follow-up of the BSRBR-RA. He was clear that this analysis was done independently of the BSRBR-RA study team and performed under an agreement between Eli Lilly and the BSR to allow access to the data.

Between Jan. 1, 2018, and March 31, 2019, there were 409 patients who were just starting baricitinib treatment and who were entered into the BSRBR-RA. The mean age of patients was 61 years, and the majority (76%) was female. On average, patients starting baricitinib had been diagnosed with RA for 11 years, and 62% had previously been treated with a biologic.

As per the European label, most patients were being treated with baricitinib in combination with a conventional synthetic DMARD (61%), with 40% of patients receiving it in combination with methotrexate. Around 38% of patients received baricitinib as monotherapy, and just under 30% were receiving concomitant glucocorticoids.

The majority (84%) were prescribed a 4-mg daily dose of baricitinib, with the remainder on a daily dose of 2 mg.

There were 163 patients with data available at the first 6-month follow up, and of those, 103 had prior experience of being treated with a b/ts DMARD, 59 did not, and 65 had been given baricitinib as monotherapy.

Reasons for Discontinuation

Overall, around a quarter of patients discontinued treatment with baricitinib, and "the reasons for this were lack of efficacy in approximately a quarter and adverse events in about two-thirds of the patients," Edwards said.

Breaking down the types of adverse events was not part of this analysis, and that information is likely to come from the BSRBR-RA study team directly.

"We have some experience in our practice in Southampton," Edwards observed. This experience was outlined in a separate abstract at the meeting and presented by May Nwe Lwin, a clinical research fellow within Edwards' group.

Lwin presented data on 83 patients who had received baricitinib at University Hospital Southampton between October 2017 and July 2020, 55 (65.2%) of whom remain on treatment to date, with mean follow-up of 17 months. Of the 28 patients who stopped baricitinib, 21 stopped within 12 months.

"Patients who continued on baricitinib appeared more likely to be older and female," Lwin said.

The mean age of patients who continued on treatment after 12 months was 61.5 years but was 49 years for those who stopped earlier. The percentage of women continuing treatment at 12 months versus those stopping earlier were a respective 82% and 67%. Both findings were significant (P < .001) but "could mean nothing, or could be very interesting data to explore more," Lwin suggested.

"However, there was no significant difference in discontinuation rates for those using mono or combination therapy, and also no effect of disease duration or seropositivity," Lwin said.

"Most people stopped baricitinib in the first 3 months of their treatment," Lwin reported, noting that the most common reason was a lack of efficacy in 64% of patients, with 28.5% of patients discontinuing because of side effects.

"When you look at the adverse events, the reasons for discontinuation are quite variable," Lwin said. These included infections (one urinary tract infection, two chest infections, and a urinary tract infection), and one case each of discitis, deranged liver function, lymphoma, and personality change.

Update on the Long-Term Safety Profile

Also at the BSR annual conference, an update on the long-term safety profile of baricitinib seen in clinical trials was presented, using data from the 'All-BARI-RA' dataset. This includes data from nine clinical trials and one long-term extension study.

"We recently published a long-term safety analysis of this molecule involving 3,700-plus patients with exposure up to 7 years," said Kevin L. Winthrop, MD, MPH, professor of infectious diseases and epidemiology at Oregon Health Sciences University in Portland.

Winthrop provided an update on this, adding in another 13,148 patient-years of follow-up and giving data on the safety experience with baricitinib with up to 8.4 years of exposure for some patients.

"In short, not much has changed," Winthrop said, noting that event rates have remained stable.

The overall major adverse cardiovascular event (MACE) and overall deep vein thrombosis/pulmonary embolism event rate were both 0.5 per 100 patient-years. Referring to the latter, Winthrop called them "rock solid stable" and "it's been that way really all the way through the development program."

Overall, event rates per 100 patient-years for serious infections, herpes zoster, and tuberculosis were a respective 2.7, 3.0, and 0.2. Serious infection rates over time have remained similar, but "clearly age is a risk factor for infection," Winthrop said. "I would just say it's similar to what we see with all biologics and small molecules in this setting."

Malignancy and death rates were also higher in older patients, but after age adjustment, these had been stable across the different analysis points.

"Malignancy overall, excluding NMSC [nonmelanoma skin cancer], the event rate is 0.9 per 100 patient-years, very similar to what we've seen in the prior data cuts," he said. "The same is true for lymphoma," he added, with an overall event rate of 0.1 per 100 patient-years.

This updated analysis, Winthrop concluded, "suggests a safety profile really very similar to what was published recently."Edwards has received research and educational grants and advisory panel and speaker fees from Eli Lilly and from multiple other pharmaceutical companies. The analysis of BSRBR-RA data he presented was sponsored by Eli Lilly and performed independently of the BSRBR-RA study team. Packham reported no conflicts of interest; he chaired the oral abstracts sessions in which Edwards presented his findings.

Lwin did not report having any disclosures.

Winthrop has acted as a consultant to Eli Lilly and several other pharmaceutical companies and had received research or grant support from Bristol-Myers Squibb and Pfizer. The work he presented was sponsored by Eli Lilly.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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