Ryvu Therapeutics has unveiled new clinical data for its lead oncology candidate romaciclib (RVU120), reporting encouraging efficacy signals in relapsed/refractory acute myeloid leukemia (AML) and continued clinical benefit in myelofibrosis (MF).

 

The company also announced that the US FDA has reactivated the Investigational New Drug (IND) application for the Phase II RIVER-81 study, clearing the way for an expansion cohort in AML at the selected dose of 150 mg once daily.

 

The regulatory decision follows promising results from RIVER-81, where romaciclib combined with venetoclax demonstrated anti-leukemic activity in heavily pretreated AML patients whose disease had progressed after prior venetoclax-based therapy. 

 

At the recommended dose, the combination produced complete remission responses and durable clinical benefit, supporting further development of the program.

 

In parallel, updated data from the Phase II POTAMI-61 study showed romaciclib continues to generate clinical activity in myelofibrosis, both as a standalone treatment and in combination with ruxolitinib. 

 

Investigators reported spleen volume reductions alongside a favorable safety profile and manageable hematologic toxicity, key measures in a disease where treatment-related cytopenias remain a major challenge.

 

Reflecting ongoing patient benefit, eight participants from POTAMI-61 will continue receiving romaciclib through the ROVER-01 rollover study.

 

"We are pleased to share updated clinical data at EHA that reinforce the potential of romaciclib across hematologic malignancies. The poster presentations highlight consistent clinical activity and a manageable safety profile, both as a single agent and in rational combinations, including in difficult-to-treat patient populations. 

 

"Importantly, the FDA review of the program and the recent reactivation of the RIVER-81 IND in the US as well as the continued treatment of patients from POTAMI-61 in the ROVER-01 study, are meaningful signals reflecting both regulatory progress and continued patient benefit. 

 

"These milestones strengthen our confidence in romaciclib's differentiated mechanism of action and support its continued clinical advancement," said Hendrik Nogai, Chief Medical Officer of Ryvu Therapeutics.

 

Patients with AML who are ineligible for intensive chemotherapy are commonly treated with venetoclax and hypomethylating agents, yet roughly 70% eventually relapse or become refractory to treatment, with median survival dropping below three months.

 

Updated findings from the ongoing RIVER-81 trial suggest romaciclib may offer a new therapeutic option for this difficult-to-treat population. 

 

Among patients receiving romaciclib at 150 mg once daily alongside venetoclax at 400 mg daily, investigators observed two complete remissions and one complete remission with incomplete hematologic recovery, translating to a 43% CR/CRi rate.

 

The complete responders achieved a mean duration of response of 156 days as of the May 12, 2026 data cut-off. Based on safety, pharmacokinetic and efficacy findings, the regimen has been selected for further evaluation in an expansion cohort expected to enroll approximately 30 patients.

 

In myelofibrosis, romaciclib continued to demonstrate a favorable risk-benefit profile both as monotherapy and in combination with ruxolitinib.

 

Researchers reported prolonged treatment exposure, spleen volume reductions and encouraging tolerability, including among patients carrying high-molecular-risk mutations. Importantly, no significant treatment-related cytopenias were observed, a notable finding in a disease where blood count suppression frequently limits therapy.

 

The transfer of eight POTAMI-61 participants into the ROVER-01 rollover protocol further underscores the durability of benefit seen in a subset of treated patients.