Why eFFECTOR Therapeutics Shares Trading Higher Today

eFFECTOR Therapeutics Inc EFTR announced interim data updates from a Phase 2 expansion cohort evaluating zotatifin combined with fulvestrant and abemaciclib (ZFA triplet) in patients with ER+ metastatic breast cancer (mBC).
Five out of 19 (26%) RECIST-evaluable patients achieved a partial response (PR), including four confirmed and one unconfirmed.
The disease control rate (DCR) is 74%.
As of the data cut-off date, four patients remained on therapy, and progression-free survival (PFS) and clinical benefit rate (CBR) data are not yet mature.
The ZFA triplet was generally well tolerated.
New data were also reported for patients in resumed dose escalation cohorts utilizing the ZF doublet.
In the one fully enrolled cohort, patients receiving zotatifin dosed at 0.1 mg/kg every other week (Q2W) combined with fulvestrant, 1 of 3 (33%) patients achieved a PR on the first on-treatment scan.
Zotatifin has been generally well tolerated in dose escalation cohorts, with no dose-limiting toxicities or serious adverse events observed.
Data for the ZF doublet with zotatifin at 0.07 mg/kg dose on Days 1 and 8 of 21-day cycles, initially reported in January, were also updated.
The patient with a confirmed PR showed a duration of response (DOR) of approximately 13 months.
Price Action: EFTR shares are up 72.7% at $0.91 during the premarket session on the last check Friday.