Ibrutinib Price Tag Keeps Rising, Despite Increased Competition

Roxanne Nelson, RN, BSN

April 11, 2023

Ibrutinib (Imbruvica) rapidly changed the treatment of chronic lymphocytic leukemia after it launched — as the first Bruton tyrosine kinase inhibitor — in 2013. Since then, it has become one of the best selling drugs in the United States. Although other drugs in this class are now available, including some with better clinical profiles, this competition has not brought down the price or rate of prescribing for ibrutinib.

In fact, the opposite has been seen: Both the price and prescribing of ibrutinib have increased markedly from 2014 to 2020, the authors of a new study say. The estimated net spending for a 30-day supply of ibrutinib increased by 46% during that period,   despite the entry of several less costly and comparable products into the marketplace.

"Further research is needed to understand why oncologists have not embraced clinically superior options for CLL being sold at prices similar to, if not lower than, ibrutinib," write the authors, led by Edward Scheffer Cliff, MBBS, MPH, from the Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital, Boston, Massachusetts.

The study was published online April 7 as a research letter in JAMA Network Open.

Ibrutinib is currently indicated for the treatment of mantle cell lymphoma (MCL), chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), Waldenström's macroglobulinemia (WM), marginal zone lymphoma (MZL), and chronic graft versus host disease. Among the top-selling drugs in the US, ibrutinib sales by 2020 accounted for more than $2.8 billion in annual net Medicare spending.

However, since ibrutinib's launch in 2013, there have been several new drugs approved for use in CLL, the authors note. They include acalabrutinib (Calquence), also a BTK inhibitor but associated with fewer adverse events, and venetoclax (Venclexta), the first-in-class, B-cell lymphoma-2 inhibitor that offers additional clinical advantages such as time-limited therapy and the potential for complete remission. In addition, phosphatidylinositol-3 kinase inhibitors (PI3K inhibitors) were also approved for CLL, but they are less effective and associated with higher toxicity and are usually reserved for patients who relapse multiple times.

Prescribing and Cost Increased

With the emergence of several new oral targeted drugs for CLL, the authors hypothesized that this might lower costs as a result of competition and affect overall spending on ibrutinib.

To test their theory, they analyzed trends in Medicare Part D use and spending on these drugs from 2014 to 2020 to determine annual spending on oral CLL drugs, the number of beneficiaries who received these drugs, and the average spending per 30-day fill.

A total of six oral medications were included in their analysis: three BTK inhibitors (ibrutinib, acalabrutinib, and zanubrutinib), two PI3K inhibitors (idelalisib and duvelisib), and one B-cell lymphoma-2 inhibitor (venetoclax).

During the study period, annual net Medicare spending for all six of these drugs and across all indications increased from $254 million to $3.7 billion.

At the start of the study period in 2014, 6180 Medicare beneficiaries were being treated with ibrutinib, and this number dramatically increased to 26,847 beneficiaries in 2020. Spending on ibrutinib constituted more than three quarters (77%) of the total Medicare costs for these six drugs in 2020.

The estimated net spending for a 30-day supply of ibrutinib rose by 46%, from $8206 in 2014 to $11,980 in 2020, despite the entry of the competitor drugs into the marketplace, some of which also had lower price tags: venetoclax in 2016 (2020 30-day fill price, $7787), acalabrutinib in 2017 ($11,428) and zanubrutinib in 2020 ($12,521).

In addition, a sensitivity analysis showed a similar trend outside of the Medicare system.

Unlike ibrutinib, net spending for other oral targeted drugs generally did not increase over time, and some drug prices even dropped slightly.

The authors note that one limitation of their study is that Medicare does not report spending by indication, so it was unknown what proportion of the cost was for CLL as opposed to the other B-cell lymphomas.

"Brand to brand competition may have been ineffective at lowering Medicare costs due to lags between approval and change in prescriber practices, constraints on payers' ability to effectively use formularies to negotiate prices, and financial incentives that can encourage intermediaries such as pharmacy benefit managers to accept high prices," they conclude.

This study was supported by a grant from Arnold Ventures. Several of the authors have reported relationships with industry as noted in the original article.

JAMA Network Open. Published online April 5, 2023. Research Letter

Roxanne Nelson is a registered nurse and an award-winning medical writer who has written for many major news outlets and is a regular contributor to Medscape.

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