Phase 1b trial finds tafasitamab combinations manageable in Japanese B-cell NHL patientsEarly study tests tafasitamab alone and in combinations for Japanese lymphoma patients

Cancer science Published April 3, 2026 Study authors: Izutsu Koji, Fukuhara Noriko, Yuda Junichiro, Suehiro Youko, Kusumoto Shigeru, Casadebaig Marie-Laur… PubMed ↗ NCT04661007 ↗ DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

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Key Takeaway

Interpret early phase 1b safety data for tafasitamab in Japanese NHL patients with caution due to small sample size.

This phase 1b clinical trial evaluated the safety and tolerability of tafasitamab as monotherapy or in combination with lenalidomide, parsaclisib, or lenalidomide plus R-CHOP in 24 Japanese patients aged ≥18 years with relapsed/refractory B-cell non-Hodgkin lymphoma (NHL), relapsed/refractory diffuse large B-cell lymphoma (DLBCL), or untreated DLBCL. The comparator and follow-up duration were not reported.

All 24 patients experienced treatment-emergent adverse events (TEAEs). The most common hematological TEAEs were neutropenia, leukopenia, thrombocytopenia, and anemia. The most common non-hematological TEAEs were increased alanine aminotransferase, increased aspartate aminotransferase, diarrhea, nausea, constipation, and infusion-related reactions. No serious TEAEs considered related to tafasitamab and no fatal TEAEs were observed. Two dose-limiting toxicities occurred: a grade 4 liver disorder related to lenalidomide and grade 3 febrile neutropenia related to lenalidomide and R-CHOP. Preliminary efficacy results were reported, but no specific effect sizes or absolute numbers were provided.

The key limitation is the small sample size (n=24). The study's practice relevance is that the results suggest tafasitamab alone or in combination may have a manageable safety profile in this population. However, the authors note these findings should be interpreted with caution due to the small sample size, and further studies are warranted for confirmation.

Researchers conducted a small, early-stage study to check the safety of a drug called tafasitamab in Japanese patients with B-cell non-Hodgkin lymphoma (NHL). The study included 24 patients with different types of this blood cancer. They tested tafasitamab by itself and combined with other cancer drugs like lenalidomide and parsaclisib.

All 24 patients experienced side effects from the treatments. Common side effects included low blood cell counts, changes in liver tests, diarrhea, and nausea. Two patients had severe side effects that were linked to other drugs in the combinations, not to tafasitamab alone. Importantly, there were no serious or fatal side effects that the researchers considered to be caused by tafasitamab itself.

The main reason to be careful with these results is the very small number of patients. With only 24 people, it's hard to know how common or rare side effects might be in a larger group. This study was designed to look at safety first, not to see if the treatments were effective against the cancer.

Readers should understand this as a first step in testing these drug combinations. It provides initial information that the safety profile appears manageable in this group, but much larger and longer studies are needed to confirm these findings and to learn if the treatments are effective.

What this means for you:

Early safety data for a lymphoma drug combination looks manageable, but it's from a very small study.

Study Details

Study typePhase1

Sample sizen = 24

EvidenceLevel 4

PublishedApr 2026

PMID41563911

TrialNCT04661007

View Original Abstract ↓

We conducted a phase 1b study evaluating safety and tolerability of tafasitamab, a CD19-targeting immunotherapy, in Japanese patients with B-cell non-Hodgkin lymphoma (NHL). Eligible patients were ≥ 18 years old with relapsed/refractory (R/R) B-cell NHL (Group 1), R/R diffuse large B-cell lymphoma (DLBCL; Groups 3 and 4), or untreated DLBCL (Group 5). Patients received tafasitamab starting at 12 mg/kg qw (Group 1, n = 6), tafasitamab + lenalidomide starting at 25 mg qd for ≤ 12 cycles (Group 3, n = 6), tafasitamab + parsaclisib starting at 20 mg qd (Days 1-56) then 2.5 mg qd (Group 4, n = 6), or tafasitamab + lenalidomide combined with R-CHOP for ≤ 6 cycles (Group 5, n = 6). Primary objective was safety and tolerability of tafasitamab alone and in combination; exploratory objectives included efficacy. At data cutoff (August 31, 2023), 24 patients were treated. All patients experienced treatment-emergent adverse events (TEAEs). Two patients experienced a dose-limiting toxicity; liver disorder (grade 4) considered related to lenalidomide (Group 3, n = 1), and febrile neutropenia (grade 3) considered related to lenalidomide and R-CHOP (Group 5, n = 1). Most common TEAEs across groups were hematological and included neutropenia, leukopenia, thrombocytopenia, and anemia; most common non-hematological TEAEs included increased alanine aminotransferase, increased aspartate aminotransferase, diarrhea, nausea, constipation, and infusion-related reactions. No serious tafasitamab treatment-related or fatal TEAEs were observed. Results suggest tafasitamab alone or in combination demonstrates a manageable safety profile in Japanese patients with B-cell NHL. Preliminary efficacy results from the study are reported. However, results should be interpreted with caution due to the small sample size, with further studies warranted to confirm these findings. Trial Registration: NCT04661007; jRCT2031200357.

Phase 1b trial finds tafasitamab combinations manageable in Japanese B-cell NHL patientsEarly study tests tafasitamab alone and in combinations for Japanese lymphoma patients

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Phase 1b trial finds tafasitamab combinations manageable in Japanese B-cell NHL patientsEarly study tests tafasitamab alone and in combinations for Japanese lymphoma patients

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Study Details

Biomarkers and clinical factors show statistical associations with sepsis-induced coagulopathy in 37,459 patients

Your Blood May Signal a Deadly Clotting Crisis Before It Strikes

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