Announcing the early-stage dose escalation results from its ongoing Phase I/II trial for BT8009, Bicycle Therapeutics ( NASDAQ: BCYC ) said Tuesday that the cancer candidate is linked to a complete response in a patient with bladder cancer.
BT8009 is a bicycle toxin conjugate (BTC) targeted at a protein called Nectin-4. As of September 20, 2022, data cut, the company had dosed 49 patients with a median of three prior lines of therapy in the trial.
The group included 24 urothelial cancer patients, out of whom eight received BT8009 5 mg/m2 weekly, one of the two recommended Phase II doses (RP2Ds).
In this eight-patient group, one patient had a complete response (13%), indicating no detectable evidence of cancer, while three had a partial response (38%), implying a decline in the tumor size.
The overall response rate (ORR) and the clinical benefit rate for this intent-to-treat (ITT) population stood at 50% and 75%, including stable disease in two additional patients, respectively.
Meanwhile, the results in the other RP2D cohort of 7.5 mg/m2 "were consistent with that of the 5 mg/m2 weekly cohort on an ITT basis," the company said, adding that the experimental therapy "was well tolerated at or below the two RP2Ds."
None of the patients discontinued the trial due to the treatment-related adverse events, many of which were GIT-related and fatigue.
Bicycle Therapeutics ( BCYC ) has currently focused its efforts on the 5 mg/m2 weekly dose while enrollments for expansion cohorts are underway. The company plans to commence a mid-stage study for BT8009 in combination with Merck's ( MRK ) FDA-approved cancer therapy Keytruda (pembrolizumab) this year.
Seeking Alpha contributor Avisol Capital Partners cites preclinical evidence to argue that BTCs have outperformed antibody drug conjugates in terms of potency, specificity and safety.
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Bicycle Therapeutics posts Phase 1 data for cancer candidate