Geron shares crater as Janssen bows out of imetelstat pact once worth up to $935M

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Janssen will provide Geron with imetelstat for up to two years during a transition period for clinical manufacturing, but will no longer support the drug's ongoing phase 2 trials. (Pexels)

In 2014, Janssen handed over $35 million, with a promise of up to $900 million more, to partner with Geron on its telomerase inhibitor imetelstat. Now, Janssen is pulling out of the deal after a “strategic portfolio evaluation” and “prioritization of assets.” The duo will now work to transition imetelstat back to Geron. 

Geron’s stock was down 68% in premarket trading, a reversal of its 40% spike when the companies inked the deal four years ago. 

The exclusive worldwide collaboration and licensing deal focused on developing imetelstat in oncology, including blood cancers. The pair agreed to split the R&D costs 50-50, with plans for phase 2 studies in imetelstat’s principal indications—myelofibrosis and myelodysplastic syndromes—and a phase 3 trial to follow if all went well. 

After a data review in April last year, Janssen put off deciding to continue with or abandon the partnership. While the inaction meant that the phase 2 trials of imetelstat would go on, it left the drug’s long-term future up in the air. 

The deal officially ends Friday, after which Janssen will return the rights to the imetelstat program to Geron, according to a statement. This transition is set to take about one year. While Janssen “is expected to supply” Geron with imetelstat for up to two years during a transition period for clinical manufacturing, it will have “no further obligations to fund any of the current ongoing imetelstat clinical trials.” 

The IMerge trial is testing imetelstat in transfusion-dependent patients with low or intermediate-1 risk myelodysplastic syndromes. The first part of the trial is a single-arm, open-label study, and the forthcoming second part will be a double-blind, placebo-controlled phase 3 study. The IMbark study was designed to evaluate two starting dose levels of the drug in patients with intermediate-2 or high risk myelofibrosis. Patients in both trials have disease that has relapsed after prior therapy or has not responded to treatments. 

“We are grateful for the collaboration with Janssen, who successfully managed two Phase 2 trials of imetelstat,” said Geron CEO and President John Scarlett, M.D., in the statement. “We believe the clinical results from IMbark provide valuable insights into the potential future development of imetelstat for an underserved relapsed and refractory myelofibrosis patient population. We also believe the combined data of 38 patients from the initial and expansion cohorts for the target patient population from the Phase 2 portion of IMerge support further development of imetelstat, and we are therefore prioritizing the initiation of the Phase 3 portion of IMerge.” 

Geron plans to kick off the phase 3 portion of IMerge after it takes financial responsibility for its ongoing trials back from Janssen. The company has hired a CRO to help develop imetelstat and plans to screen and enroll patients by mid-2019.