For Health Care Professionals

Red Cell Therapeutics™:
A New Era of Medicine for the Treatment of Cancer

Our innovations in creating human red blood cells and genetic engineering have made it possible to explore using these cells as a foundation for an entirely new class of cellular therapies, called Red Cell Therapeutics. Red Cell Therapeutics product candidates are manufactured from CD34+ hematopoietic progenitor cells from blood type O, Rh-negative, Kell-negative donors. The cells are expanded and transduced with a lentiviral vector to insert a gene or genes of interest, followed by further expansion and differentiation into enucleated red cells that express one or more therapeutic proteins inside or on the cell surface, resulting in cellular therapies for the potential treatment of cancer.

About RTX‑240

RTX‑240 is an engineered red blood cell that is being evaluated in a Phase 1/2 clinical trial for the treatment of patients with relapsed/refractory or locally advanced solid tumors. RTX‑240 is engineered to simultaneously present hundreds of thousands of copies of the costimulatory proteins 4-1BBL and IL‑15TP and is designed to stimulate innate and adaptive immunity by activating natural killer (NK) cells and T cells inside the patient’s body to generate an anti-tumor immune response.

To date, the use of agonists of 4-1BB for cancer immunotherapy has been limited because of hepatotoxicity.

However, in pre-clinical studies Red Cell Therapeutics such as RTX‑240 are restricted to the vasculature which may help limit toxicities unlike systemic administration of recombinant cytokines and agonist antibodies.

In preclinical studies, RTX-240 was shown to potently stimulate the immune system and generate anti-tumor activity, with no observed toxicity. The IND for RTX-240 has been cleared by the FDA and we are now enrolling patients into our ongoing Phase 1/2 clinical trial, which has two separate Phase 1 arms enrolling adult patients with advanced solid tumor cancers – an ongoing monotherapy dose escalation arm in adults with relapsed/refractory or locally advanced solid tumors and a combination therapy dose escalation arm with pembrolizumab in adults with relapsed/refractory or locally advanced solid tumors. We are primarily conducting the trial at small cancer centers, rather than large hospitals with ICUs and emergency rooms.

About the RTX‑240 Phase 1/2 Clinical Trial

This is a Phase 1/2 open label, multicenter, multidose, first-in-human dose-escalation and expansion study designed to determine the safety and tolerability, pharmacokinetics, maximum tolerated dose and a recommended Phase 2 dose and dosing regimen of RTX-240. The trial will also assess the pharmacodynamics of RTX-240 measured by changes in T and NK cell number and function relative to baseline and anti-tumor activity. The trial has two Phase 1 arms enrolling adult patients with advanced solid tumor cancers – one to evaluate RTX-240 as monotherapy and the other to evaluate RTX-240 in combination with pembrolizumab.

Inclusion/Exclusion Criteria

Adults who meet the following criteria may be able to participate in the trial.

  • Men and women aged 18 or older.
  • Participants must have a relapsed, refractory, or locally advanced, unresectable, histologically or cytologically confirmed solid tumor for which no standard therapy exists, or for which the patient is ineligible or has declined standard therapy.
  • Participants in the combination arm with pembrolizumab must have relapsed following or have been refractory to a prior programmed death receptor -1 (PD-1) or programmed cell death ligand 1 (PD-L1) blocking antibody (PD-1/PD-L1 Ab).
  • Participants must have completed prior therapy, including radiation, at least 28 days prior to study treatment.
  • For females of reproductive potential, agreement to use highly effective contraceptive throughout and for six months following last dose study treatment.

If you are interested in becoming a potential clinical trial site or would like more information about RTX‑240, please contact us at