Hemogenyx Pharmaceuticals plc (LSE: HEMO), the London-headquartered clinical-stage biopharmaceutical group, has announced that the first patient in the second adult dose cohort has been treated in its ongoing Phase I trial of HG-CT-1, a proprietary CAR-T therapy targeting relapsed or refractory acute myeloid leukaemia. The patient received twice the dose administered to the three patients in the first adult cohort, with dose escalation proceeding following a recommendation from the independent Data Safety Monitoring Board. The milestone also marks the first time HG-CT-1 product manufactured by contract development and manufacturing organisation Made Scientific has been administered in the trial, a significant operational step for the company.

Key Points

  • Hemogenyx Pharmaceuticals plc (LSE: HEMO) is a clinical-stage biopharmaceutical company listed on the London Stock Exchange
  • The first patient in the Phase I trial's second adult dose cohort has been treated with HG-CT-1 at twice the initial dose level
  • The independent DSMB cleared escalation after finding no dose-limiting toxicities in the first cohort; recruitment to both the second adult cohort and a paediatric arm is ongoing
  • Investors should watch for safety monitoring results from the second cohort and further recruitment updates as the trial progresses

DSMB Clears HG-CT-1 Dose Escalation After No Dose-Limiting Toxicities in First Cohort

The independent Data Safety Monitoring Board reviewed safety data from the three patients treated in the first adult dose cohort and found no dose-limiting toxicities, clearing the path to escalation. The announcement also notes that CAR-T cell expansion and persistence were observed in all three patients at the initial dose level, and reductions in leukaemic blast burden were recorded in peripheral blood and/or bone marrow. No immune effector cell-associated neurotoxicity syndrome was observed. The company cautions that these findings are preliminary, given the small number of patients treated to date, and further data from the second cohort will be required to draw firmer conclusions about efficacy and tolerability at the higher dose.

Made Scientific Completes First HG-CT-1 Manufacture Administered in the HEMO Trial

The treated patient's dose was manufactured entirely by Made Scientific, the contract development and manufacturing organisation to which Hemogenyx transferred production of HG-CT-1. That manufacturing transfer was completed and announced in March 2026. The announcement identifies the interval between the first and second cohorts as partly reflecting the time required to complete this transition. The second cohort's first administered dose therefore represents a combined clinical and operational milestone, confirming that Made Scientific's manufactured product has now been successfully used in a live patient setting within the ongoing Phase I dose-escalation study.

Five Patients Unable to Complete Treatment Due to Rapid R/R AML Disease Progression

The announcement reveals that five patients who consented to participate in the second cohort could not ultimately be treated, because rapid disease progression meant manufacture of their personalised HG-CT-1 CAR-T cells could not be completed before they were removed from the study. In two of those cases, the cells collected were of very poor quality, itself attributed to rapidly advancing disease. The company notes that rapid progression of this nature is characteristic of relapsed or refractory AML, and underlines the medical need for new treatments. This operational challenge highlights a risk specific to autologous CAR-T therapy development in aggressive haematological malignancies.

Phase I Trial Endpoints and Paediatric Arm Recruitment Now Under Way

The Phase I trial is a dose-escalation study designed primarily to assess the safety of HG-CT-1, with key secondary endpoints including anti-leukaemic activity, overall survival, progression-free survival, and duration of response. Hemogenyx is also recruiting patients to a paediatric arm of the trial, which opens at the initial adult dose level. The company operates research facilities in New York City through its US subsidiaries, Hemogenyx Pharmaceuticals LLC and Immugenyx LLC, alongside its London headquarters. Investors may be watching for further cohort updates and any additional safety or biological activity data as the trial continues to enrol patients across both adult and paediatric arms.