On May 27, 2026 Gemini Therapeutics, Inc., a privately held biotechnology company focused on advancing aldoxorubicin for patients with cancer, reported two aldoxorubicin abstracts at the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting. The analyses examine complementary elements of aldoxorubicin’s development rationale: tumor-targeted anthracycline delivery and cardiac safety at cumulative doxorubicin-equivalent exposures that are difficult to achieve with conventional doxorubicin.
Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:
Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing
Schedule Your 30 min Free Demo!
Aldoxorubicin is an investigational albumin-binding prodrug of doxorubicin designed to bind endogenous albumin after intravenous administration, limit freely circulating doxorubicin, and release native doxorubicin in acidic tumor-associated and intracellular compartments. This exposure profile is intended to exploit albumin transport into tumors while reducing systemic exposure patterns associated with conventional doxorubicin, including exposure to cardiotoxic metabolites such as doxorubicinol.
"Doxorubicin remains one of oncology’s most important cytotoxic therapies, but its use is constrained by tumor-delivery limitations and cumulative cardiotoxicity," said Diego Rey, PhD, Chief Executive Officer of Gemini Therapeutics. "These ASCO (Free ASCO Whitepaper) analyses support a focused re-evaluation of aldoxorubicin from two complementary directions: higher tumor exposure than conventional doxorubicin and better preservation of cardiac function despite substantially higher cumulative doxorubicin-equivalent exposure. The lower systemic doxorubicinol burden provides an important mechanistic bridge between aldoxorubicin’s albumin-bound design and the cardiac-safety findings observed in randomized soft tissue sarcoma studies. Together, these findings support the rationale that a better exposure-toxicity tradeoff could make meaningful anthracycline exposure feasible for more patients and in more tumor settings where conventional doxorubicin has been limited by delivery or cumulative cardiotoxicity."
The first ASCO (Free ASCO Whitepaper) analysis, a poster presentation titled "Cardiac safety of aldoxorubicin compared to doxorubicin: Integrated results from two randomized studies in advanced soft tissue sarcoma," evaluated cardiac safety across two randomized soft tissue sarcoma studies. The pooled analysis included 383 patients in the aldoxorubicin-versus-doxorubicin cardiac safety population: 296 treated with aldoxorubicin and 87 treated with doxorubicin comparator.
In the analysis, patients treated with aldoxorubicin received approximately 3.5-fold higher cumulative doxorubicin-equivalent exposure than patients treated with doxorubicin. Despite this higher exposure, aldoxorubicin was associated with smaller mean declines in left ventricular ejection fraction, fewer patients reaching selected on-treatment LVEF thresholds, and fewer prespecified heart-failure-related treatment-emergent adverse events.
Mechanistically, the cardiac-safety findings are supported by pharmacokinetic data showing that aldoxorubicin plasma exposure is dominated by albumin-bound doxorubicin, with substantially lower free doxorubicin and doxorubicinol concentrations. In Phase 1 aldoxorubicin data, the doxorubicinol-to-free-doxorubicin exposure ratio was approximately 5% to 6%, compared with approximately 40% to 60% reported for conventional doxorubicin, consistent with lower systemic exposure to this cardiotoxic metabolite.
Lowest on-treatment mean LVEF change from baseline was -3.17 percentage points with aldoxorubicin versus -5.77 percentage points with doxorubicin. On-treatment LVEF below 50% occurred in 3.8% of aldoxorubicin-treated patients versus 9.0% of doxorubicin-treated patients; on-treatment LVEF below 45% occurred in 1.1% versus 3.8%, respectively. Prespecified heart-failure-related treatment-emergent adverse events occurred in 3.0% of aldoxorubicin-treated patients versus 6.9% of doxorubicin-treated patients.
The second ASCO (Free ASCO Whitepaper) analysis, titled "Tumor Delivery and Exposure of Aldoxorubicin Compared with Doxorubicin: Integrated Clinical and Preclinical Analysis," evaluated human tumor-biopsy pharmacokinetic data and preclinical biodistribution data comparing aldoxorubicin with doxorubicin. In human Kaposi’s sarcoma tumor biopsies, aldoxorubicin was detected in all sampled lesions and increased with dose. When normalized for dose and adjusted for potency, aldoxorubicin delivered up to approximately 10-fold higher intratumoral doxorubicin-equivalent exposure than conventional doxorubicin.
Aldoxorubicin has previously been evaluated across a broad clinical development and early access program involving more than 750 aldoxorubicin-exposed patients. Gemini acquired the aldoxorubicin program from LadRx Corporation in 2025 and is advancing it under a focused, evidence-guided development strategy informed by the substantial clinical, pharmacokinetic, and safety data generated to date.
ASCO 2026 Abstract Details
Poster Presentation
Abstract #: 11565
Poster Board #: 355
Date and Time: June 1, 2026, 1:30 PM-4:30 PM CDT
Title: Cardiac safety of aldoxorubicin compared to doxorubicin: Integrated results from two randomized studies in advanced soft tissue sarcoma
First Author: Philip Sager, MD
Presenter: Diego Rey, PhD
Citation: J Clin Oncol 44, 2026 (suppl 16; abstr 11565)
DOI: 10.1200/JCO.2026.44.16_suppl.11565
Publication Only Abstract
Abstract #: e15134
Title: Tumor delivery and exposure of aldoxorubicin compared with doxorubicin: Integrated clinical and preclinical analysis
First Author: Joyce James, PhD
Citation: J Clin Oncol 44, 2026 (suppl 16; abstr e15134)
DOI: 10.1200/JCO.2026.44.16_suppl.e15134
About Aldoxorubicin
Aldoxorubicin, also known historically as INNO-206 or DOXO-EMCH, is an investigational albumin-binding prodrug of doxorubicin. Aldoxorubicin is designed to bind endogenous serum albumin after intravenous administration and release native doxorubicin under acidic conditions found in tumor-associated and intracellular compartments. The intended therapeutic rationale is to alter the exposure pattern of doxorubicin by increasing tumor-directed anthracycline delivery while reducing systemic exposure patterns associated with conventional doxorubicin.
Aldoxorubicin is investigational and has not been approved by the U.S. Food and Drug Administration. Safety and effectiveness have not been established.
(Press release, Gemini Therapeutics, MAY 27, 2026, View Source [SID1234666128])