Company: KROS
Filing Date: 2025-02-26
Form Type: 10-K
Source: 0001664710-25-000018
Chunk: 119

Company: Keros Therapeutics, Inc.
Filing Date: 2025-02-26
Form: 10-K
Item: Item 1
Chunk 119
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 as of the August 30, 2024 data cutoff date. Evaluations of markers of hematopoiesis and anemia over 12 weeks, along with measurements of spleen volume and symptom scores (by the Myelofibrosis-Symptom Assessment form-Total Symptom Score, or MF-SAF-TSS) over 24 weeks, were presented for dose levels 1 through 4 in Part 1 and the RP2D, ranging from 0.75 mg/kg to 5.0 mg/kg, which we refer to as the efficacy evaluable patients. Enrollment of Part 1 of the trial, the dose escalation portion, is complete. Part 2, the dose expansion portion, is enrolling with an RP2D of 3.75 mg/kg with the option to up-titrate to 5.0 mg/kg.

Elritercept was generally well tolerated by the safety population as of the data cut-off date. There were six cases of fatal TEAEs in the trial that were each deemed unrelated to treatment. The most commonly reported TEAEs (in ≥15% of patients) were thrombocytopenia and diarrhea. The majority of treatment-related TEAEs were mild to moderate, with 12 patients experiencing Grade 3 or higher treatment-related TEAEs of thrombocytopenia. 93.3% (n=14/15) of patients with a TEAE of thrombocytopenia had baseline platelets below 150 x 109/L.

Additional data from the efficacy evaluable patients as of the data cut-off date include:

•Increases in hemoglobin were observed in 82.8% (n=24/29) of evaluable non-transfusion dependent patients in both arms over a 12-week period within the first 24 weeks, suggesting that elritercept has the potential to address anemia due to MF and ruxolitinib-associated anemia.

•63.4% (n=26/41) of patients that received at least three red blood cell units per 12 weeks at baseline in both arms and all dose levels tested showed reductions in transfusion burden over 12 weeks within the first 24 weeks. 24.4% (n=10/41) of the patients who showed reductions in transfusion burdens achieved TI.

◦Additionally, within the subgroup of these patients in the combination arm who received a starting dose of 3.0 mg/kg of elritercept or higher,