Rubius makes hard pivot after reviewing clinical data, dumping lead assets and laying off 75% of staffers

Rubius Therapeutics has torn up its strategy. After reviewing human data on its lead candidates, the cell therapy biotech concluded investment in its two clinical prospects “is no longer justified,” leading it to stop studies and lay off 75% of its workforce. 

Massachusetts-based Rubius went public in 2018, pulling off an IPO that grossed $277 million to fund development of therapies based on biologically engineered red blood cells. The plan was to develop selective, potent and ready-to-use cellular therapies for rare diseases, cancer and autoimmune diseases. Yet the plan has unraveled slowly over the years, culminating in Rubius’ decision to tear it up and start again using a new platform.

Rubius’ workforce is paying a heavy penalty for the change in strategy. To enable investment in the new platform, the biotech is set to lay off 75% of its employees, with clinical development, manufacturing and general and administrative staff bearing the brunt. Rubius had 213 employees as of July, down from 269 at the end of January, meaning around 160 people will lose their jobs.

The focus on clinical development cuts reflects Rubius’ decision to stop studies of its two lead assets, RTX-240 and RTX-224, in solid tumors. Rubius has given RTX-240, a cell therapy that co-expresses 4-1BBL and IL-15TP, to 36 patients as a monotherapy and 14 patients in combination with Keytruda. 

RTX-224, which expresses 4-1BBL and IL-12 on its surface, is earlier in development but has also failed to make the case for continued investment. None of the seven advanced solid tumor patients treated across two dose cohorts have responded to the therapy. One patient with melanoma is not yet evaluable for response. The results follow the decision to exit rare diseases in response to “uninterpretable data.”

The hard pivot away from the platform and the candidates it generated will extend Rubius’ cash runway through to the end of 2023. During that period, in which Rubius plans to try to sell a manufacturing site, the biotech will seek to drum up enthusiasm for its new cell conjugation platform. 

“Cell conjugation creates a covalent link between the cell surface and the molecule of interest,” Rubius CEO Pablo Cagnoni, M.D., told investors on a call this morning. “This cell conjugation approach is anticipated to deliver a higher effective dose. We expect that conjugated red cell therapeutics will enable a longer circulation time with a resulting enhancement in the pharmacodynamic effects, and that we might be able to administer a higher cell dose, potentially leading to greater potency.”

Rubius plans to share preclinical data, including results in nonhuman primates, and a timeline to the first application for human trials by the end of the year. While full details of the revised pipeline are under wraps, Cagnoni revealed it features a broad immune agonist with similarities to RTX-240 and RTX-224, an antigen-specific immune agonist and a Type 1 diabetes program.

Shares in Rubius fell 25% to $0.80 in premarket trading on Sept. 13.