Groundbreaking news in the fight against multiple myeloma! A new drug, gintemetostat, is showing promising early results in patients who have exhausted nearly all other treatment options. This is a significant development, especially for those with triple-class refractory disease – meaning their cancer has resisted the standard treatments.
Early findings from a Phase 1 trial (NCT05651932) are incredibly encouraging. Gintemetostat, an MMSET/NSD2 inhibitor (also known as KTX-1001), has demonstrated both safety and effectiveness in a group of heavily pretreated patients. These patients had relapsed or become resistant to previous therapies, including those with high-risk features like the t(4;14) genetic abnormality. The results were presented at the 2025 ASH Annual Meeting.
Let's dive into the specifics. Out of 40 patients who received gintemetostat, one achieved a very good partial response, another had a partial response, 2 showed a minimal response, and 12 experienced stable disease.
Lead author Dr. Saad Usmani, from Memorial Sloan Kettering Cancer Center, highlighted the significance: "Single-agent activity was demonstrated in heavily pretreated R/R multiple myeloma including t(4;14) positive patients across different dose-escalation cohorts."
But here's where it gets controversial... What about the side effects? The study revealed that 75% of patients experienced treatment-emergent adverse events (TEAEs) potentially linked to gintemetostat, and 45% had grade 3 or higher TEAEs related to the drug. Fortunately, only 3 patients needed a dose reduction due to these side effects. At the data cutoff date of June 13, 2025, 12 patients were still receiving treatment. Of the 28 patients who stopped treatment, the main reasons were progressive disease (82%), physician decision (7.1%), consent withdrawal (7.1%), and TEAEs (3.6%).
The most common severe side effects were related to blood counts: thrombocytopenia (low platelets) at grade 3 (10%) and grade 4 (20%), anemia (25%), neutropenia (25% and 5%), and febrile neutropenia (5%). Non-blood-related side effects included infections (12.5%) and fatigue (10%). There were 2 patient deaths, but neither was linked to gintemetostat.
And this is the part most people miss... Why is this drug so important? Dr. Usmani explained that the overexpression of MMSET (also known as NSD2) often stems from the t(4;14) genetic change, which is linked to poor outcomes in multiple myeloma. Gintemetostat aims to target and inhibit this protein.
The study included 40 patients with relapsed or refractory multiple myeloma, who had undergone at least 3 prior therapies, including a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and an anti-CD38 monoclonal antibody. The average age of the patients was 69 years, and the median time since diagnosis was 8 years. About a third (32.5%) had cancer outside the bone marrow, and 30% were considered high-risk based on IMWG criteria.
Regarding genetic abnormalities, 47.5% of patients had t(4;14). The patients had received a median of 6.5 prior lines of therapy, with 77.5% having had at least 5 lines. Prior treatments included IMiDs/PIs (100%), anti-CD38 antibodies (98%), BCMA CAR-T (42.5%), BCMA-targeted bispecific antibodies and antibody-drug conjugates (57.5%), GPRC5D-targeted BsAb (32.5%), and FcRH5-targeted BsAb (7.5%). Almost all patients (97.5%) had been exposed to at least 3 drug classes, and 80% had been exposed to 5.
Gintemetostat was administered orally in a 28-day cycle, across 9 different dose levels. Dr. Usmani noted that the drug's concentration in the blood increased with the dose, but there was moderate variability.
So, what's next? Dr. Usmani stated that the monotherapy showed a favorable safety and tolerability profile, and demonstrated disease control and efficacy. The next step is to evaluate combinations with other drugs like proteasome inhibitors, IMiDs, and next-generation CELMoDs.
What do you think? Are you encouraged by these early results? Do you have any questions about the potential of gintemetostat? Share your thoughts in the comments below!
