October 15, 2020
The U.S. FDA has approved an expanded indication for Keytruda® (pembrolizumab), manufactured by Merck. The drug is now indicated for use as a monotherapy to treat adult patients diagnosed with relapsed or refractory (inoperable) classical Hodgkin lymphoma (cHL). It is the first anti-PD-1 therapy to be approved for this indication.
Classical Hodgkin lymphoma accounts for approximately 90% of all Hodgkin lymphoma diagnoses worldwide. Like other Hodgkin lymphomas, it is a cancer of the white blood cells that most often begins in the lymph nodes of the upper body. However, cHL is characterized by the presence of Reed-Sternberg cells – a type of abnormal B lymphocyte. Normal B lymphocytes are responsible for producing antibodies to fight infection. Reed-Sternberg cells have mutated to become both abnormally large and have lost the ability to create immunoglobulin antibodies.
Under a prior accelerated approval, Keytruda was indicated to treat adults diagnosed with refractory cHL or whose cHL had relapsed following treatment with at least three prior lines of therapy. Accelerated approvals require post-marketing verification and description of clinical benefit, without which the approval may be revoked. Merck has successfully met this post-marketing requirement for Keytruda in the treatment of cHL, and in the process has been granted the newly expanded indication.
In a clinical study, Keytruda reduced the risk of disease progression or death by 35% compared to treatment with brentuximab vedotin (BV), a current standard of care. It also delivered median progression-free survival of 13.2 months versus 8.3 months with BV, and a 20.7-month median duration of response versus 13.8 months with BV.
Recommended dosing under the expanded indication is 200mg administered via 30-minute intravenous infusion once every three weeks, or 400mg once every six weeks. Treatment with Keytruda should continue for up to a maximum of 24 months, or until disease progression or unacceptable toxicity occur.
Keytruda first received FDA approval in 2014 and has numerous indications for the treatment of cancer.