GSK Korea has launched Blenrep (belantamab), a BCMA-targeted antibody-drug conjugate for relapsed or refractory multiple myeloma, in Korea as a non-reimbursed treatment, raising expectations that the therapy could reshape treatment strategies for patients who relapse after initial therapy.
Professor Kim Jin-seok at Severance Hospital presents the clinical value of GSK’s Blenrep during a press conference at the Plaza Hotel in Seoul on Wednesday. (Credit: GSK Korea)
Blenrep received approval from the Ministry of Food and Drug Safety in December for two combination regimens in adult patients with multiple myeloma. It can be used with bortezomib and dexamethasone in patients who have received at least one prior therapy, and with pomalidomide and dexamethasone in patients who have received at least one prior therapy including lenalidomide.
At a press conference held in Seoul on Wednesday, Professor Kim Jin-seok of the Division of Hematology at Severance Hospital said the entry of Blenrep was meaningful because many patients with multiple myeloma eventually relapse despite advances in first-line therapy.
Multiple myeloma is a blood cancer caused by abnormal plasma cells, which produce antibodies. The disease often causes systemic symptoms and organ damage, and is characterized by repeated cycles of remission and relapse. As patients undergo more lines of treatment, the duration of remission tends to shorten, treatment response weakens and toxicity increases, worsening quality of life.
Kim said the number of multiple myeloma patients in Korea has more than tripled over the past 20 years, making it one of the fastest-growing blood cancers in the country. He noted that 28 percent of patients relapse within 24 months after first-line treatment, while 10 percent relapse within 12 months.
“Multiple myeloma repeatedly goes through remission and relapse, and over time, the remission period gradually shortens before patients eventually reach a refractory stage,” Kim said. “This has a significant impact on patients’ emotional and physical quality of life.”
Although current first-line treatment often includes proteasome inhibitors, immunomodulatory agents and anti-CD38 antibodies in triplet or quadruplet regimens, relapse remains common. “The need for new mechanisms has become more urgent as more patients become refractory to lenalidomide, particularly from the first relapse,” Kim said. “In patients who are refractory to lenalidomide, the progression-free survival of existing second-line regimens often does not even reach one year.”
Even the daratumumab, bortezomib and dexamethasone regimen shows similar limitations in this setting and good drugs lose their power when they are used too late, which is why new mechanisms should be used as early as possible, he added.
Blenrep targets B-cell maturation antigen, or BCMA, a key target in multiple myeloma. As an antibody-drug conjugate, it links a monoclonal antibody to a cytotoxic payload, allowing the drug to deliver cancer-killing activity more selectively to BCMA-expressing myeloma cells.
The Korean approval was based mainly on the global phase 3 DREAMM-7 and DREAMM-8 trials, which evaluated Blenrep-based combinations in previously treated multiple myeloma patients.
In DREAMM-7, 494 adult patients with multiple myeloma who had received at least one prior therapy were assigned to receive Blenrep, bortezomib and dexamethasone, known as BVd, or daratumumab, bortezomib and dexamethasone, known as DVd. The study included patients previously treated with lenalidomide, those refractory to lenalidomide and patients with high-risk cytogenetic features.
At a median follow-up of 28.2 months, the median progression-free survival was 36.6 months in the BVd group, compared with 13.4 months in the DVd group. The result translated into a 59 percent reduction in the risk of disease progression or death, with a hazard ratio of 0.41.
At a median follow-up of 39.4 months, BVd also reduced the risk of death by 42 percent compared with DVd, showing a significant overall survival benefit. Although median overall survival had not been reached in either group, post-hoc modeling estimated median overall survival at 84 months for BVd and 51 months for DVd.
Kim explained that the overall survival benefit was particularly important because patients in the control arm could still receive other new therapies later.
“The fact that an overall survival difference emerged despite the availability of various subsequent treatment options sends a strong message that Blenrep-based treatment should not be missed in second-line therapy,” he said.
In DREAMM-8, 302 patients with relapsed or refractory multiple myeloma who had received at least one prior treatment including lenalidomide were treated with Blenrep, pomalidomide and dexamethasone, known as BPd, or pomalidomide, bortezomib and dexamethasone, known as PVd. All patients had prior lenalidomide exposure, and 78 percent were refractory to lenalidomide.
At a median follow-up of 21.8 months, the median progression-free survival had not been reached in the BPd group, while it was 12.7 months in the PVd group. The result represented a 48 percent reduction in the risk of disease progression or death. The estimated 12-month progression-free survival rate was 71 percent for BPd and 51 percent for PVd.
Kim explained that the DREAMM-8 results were notable because the study included a patient group with a poor prognosis.
“The DREAMM-8 population had a lenalidomide-refractory rate of nearly 80 percent, meaning these were more difficult-to-treat patients,” he said. “Data showing progression-free survival two to three times longer than existing regimens are rarely seen in this field.”
Across both trials, the improvement in progression-free survival was consistent regardless of prior lines of therapy. Benefits were also observed in difficult-to-treat subgroups, including patients with high-risk cytogenetics, prior bortezomib exposure, lenalidomide-refractory disease and prior or refractory anti-CD38 antibody treatment. Blenrep-based regimens also showed improvements in key endpoints such as duration of response and minimal residual disease negativity.
Safety was another focus of the press conference, particularly because Blenrep has been associated with ocular adverse events, including blurred vision, dry eyes, foreign body sensation and corneal findings.
Kim said these events are generally manageable through regular ophthalmologic monitoring, dose delays and dose reductions. He added that treatment efficacy was maintained after dose adjustment, while discontinuation due to ocular adverse events was around 9 to 10 percent in the major trials.
“In actual practice, most cases can be managed through dose adjustment and changes to dosing intervals,” Kim said. “In Korea, cancer treatment is commonly provided at institutions where hematology and ophthalmology departments are both available, so building a collaborative care system should not be difficult.”
He also emphasized that Blenrep can be administered through short outpatient infusion, making it less burdensome for patients.
Compared with BCMA-targeted bispecific T-cell engagers or CAR-T cell therapy, Kim explained Blenrep is expected to have a lower risk of some complex toxicities, which could make adverse event management simpler in real-world practice.
Still, Kim believes reimbursement will be critical for patient access.
“The drug has been launched as a non-reimbursed treatment, but Korean patients will ultimately need reimbursement to actually access it,” he said. “As chairman of the Korean Multiple Myeloma Working Party, I will work with the academic community to help accelerate reimbursement as much as possible.”
Lee Han-soo
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