aibioAptevo says ten frontline AML patients on mipletamig reached stem cell transplant
Tickers APVO
Ten patients with newly diagnosed AML advanced to transplant after treatment with mipletamig, venetoclax and azacitidine, according to Aptevo's October 26, 2026 release.
Key facts
- Company
- Aptevo Therapeutics Inc. (NASDAQ: APVO)
- News type
- Company Updates
- Primary source
- Aptevo Therapeutics Inc. 8-K (2026-10-26)
Aptevo Therapeutics Inc. said on October 26, 2026 that ten patients with newly diagnosed acute myeloid leukemia (AML) have advanced to allogeneic stem cell transplant after treatment with mipletamig in combination with venetoclax and azacitidine. In its exhibit to the 8-K, the company said ten of 47 evaluable frontline patients treated with that combination, or 21%, proceeded to transplantation. Aptevo describes transplant as a potentially curative treatment option.
The results
Nine of the ten patients came from the ongoing Phase 1b RAINIER trial. The tenth came from a previously completed dose expansion trial. The release says the patients were initially deemed unfit for intensive induction chemotherapy, a population in which advanced age, underlying health conditions and other factors can limit treatment options.
Stem cell transplant uses donor cells to replace a patient's blood-forming stem cells and can offer eligible patients the possibility of long-term remission or cure. The release explains that remission reflects a reduction in leukemia, while transplant is an optimal outcome for selected patients. It also says that reaching transplant requires an adequate response to initial treatment, medical eligibility, and a suitable donor and treatment plan.
Dirk Huebner, M.D., Chief Medical Officer of Aptevo, said: "Now, we are seeing ten patients advance to stem cell transplant, a treatment that can offer AML patients the possibility of long-term remission or cure."
The release also sets these results against historical experience with venetoclax and azacitidine alone. In the Phase 3 VIALE-A trial, three of 286 patients (0.7%) receiving that regimen later underwent stem cell transplantation. Aptevo acknowledges that cross-trial comparisons are limited by differences in patient populations, study design and follow-up. It says the observations add to a growing body of evidence for mipletamig's potential to improve treatment outcomes. The release does not say how the transplanted patients are doing, how long they survived, or how many patients dropped out before transplant. Reaching transplant is a step, not a survival result. The comparison pits a Phase 1b group against a different, historical trial, and the release reports no p-value or control arm.
The trial and next steps
RAINIER is a two-part Phase 1b/2 trial of mipletamig with venetoclax and azacitidine in frontline AML. The company's 10-K says part one of the program was initiated in August 2024. The release says the current stage is evaluating mipletamig dosing to guide the next stage of clinical testing.
Aptevo expects to complete this dosing work by year-end 2026 and to discuss next steps with regulators in the first half of 2027. The release's headline also anticipates FDA interaction and the start of a Phase 2 trial in the first half of 2027. Those dates are the company's plan, and Phase 2 is a long way from approval.
The company and its financial position
Mipletamig is a CD123xCD3 T cell engager, according to the 10-K. The release says it is designed to redirect a patient's immune system to destroy leukemic cells and leukemic stem cells that express CD123. It uses a CRIS-7-derived CD3 binding pathway that the company says is designed to reduce the likelihood and severity of cytokine release syndrome. Mipletamig has orphan drug designation for AML under the Orphan Drug Act.
Aptevo calls itself a clinical-stage biotechnology company focused on cancer immunotherapy. It has two clinical candidates and six preclinical candidates, all built on its ADAPTIR and ADAPTIR-FLEX platforms.
The XBRL data show research and development expense of $14.5 million for 2025, compared with $14.4 million for 2024. The net loss was $26.0 million in 2025 and $24.1 million in 2024. Operations used $25.6 million of cash in 2025 and $23.8 million in 2024.
Year-end 2025 cash and cash equivalents were $21.6 million, according to a 10-Q filed August 14, 2026. Year-end 2024 cash and cash equivalents were $8.7 million. The XBRL data also show $9.8 million of cash and cash equivalents at June 30, 2026, well below the $25.6 million used in operations in 2025. The company has no product revenue to offset that burn, so the Phase 2 plan depends on raising more money, which could dilute current holders.