Updated: Geron terminates late-stage clinical trial of blood cancer drug, stock price plummets

Update stock price information and add analyst comments in paragraphs 5 and 8.

Christy Santhosh

Reuters, Oct 28 - Geron (GERN.O) said on Wednesday it will pause a late-stage clinical trial of its blood cancer treatment drug, marking a setback for the company’s only commercial product and sending its shares plunging 20% in early trading.

The drug, branded Rytelo, was being evaluated as a treatment for myelofibrosis, a rare blood cancer that leads to the gradual buildup of scar tissue in the bone marrow.

Geron said the decision was based on recommendations from an independent data monitoring committee, which concluded that the IMpactMF trial was unlikely to achieve its primary endpoint of overall survival compared with the best available therapy.

Rytelo received U.S. approval in 2024 for the treatment of transfusion-dependent anemia in patients with lower-risk myelodysplastic syndromes (LR-MDS), a group of blood cancers.

TD Cowen analyst Tara Bancroft said that while the trial results were disappointing, no new safety concerns were observed despite higher dosing and more frequent administration compared to the LR-MDS trial, which supports confidence in the ongoing Rytelo commercial rollout.

Geron said it will conduct a comprehensive analysis of the data and publish the findings at a later date.

The trial enrolled 327 high-risk myelofibrosis patients whose disease relapsed or did not respond after treatment with JAK inhibitors, a drug used to control symptoms and reduce spleen enlargement.

“We do not believe this result will meaningfully change physician perceptions of Rytelo in LR-MDS, which is central to the drug’s approved indication and commercial strategy,” Wedbush analyst Robert Driscoll said.

Rytelo competes with Bristol-Myers Squibb’s Reblozyl. The drug reported second-quarter revenue of $57.5 million, with the company expecting full-year sales to range between $220 million and $240 million.

(To make its reporting accessible to readers whose native language is not English, Reuters automatically translates its articles into several other languages. Automatic translation may contain errors or lack the necessary context. Reuters does not guarantee the accuracy of translated texts and provides them for the convenience of readers. Reuters is not liable for any damage or loss caused by the use of automated translation features.)