Protara Therapeutics has commenced subject dosing in the Phase Ib ADVANCED-1EXP expansion trial of TARA-002 to treat high-grade non-muscle invasive bladder cancer (NMIBC) patients with carcinoma in situ (CIS).

The open-label expansion Phase Ib trial has been designed for assessing intravesical TARA-002 at the 40KE dose in 12 CIS patients, including Bacillus Calmette-Guérin (BCG)-naïve, BCG-unresponsive, and BCG-inadequately treated patients.

In the trial, all the participants will receive six intravesical TARA-002 instillations once a week.

Its primary objective is to assess the signs of anti-tumour activity along with tolerability and safety of TARA-002.

The complete response (CR) rate at three months is the trial’s planned primary endpoint.

Last month, the company announced positive preliminary data from the Phase Ia dose-escalation component of the ongoing ADVANCED-1 clinical trial to treat high-grade NMIBC patients.

Protara Therapeutics chief medical officer Jathin Bandari said: “Following positive preliminary results from the ADVANCED-1 trial, we are pleased to have dosed the first patients in our ADVANCED-1EXP trial.

“We believe TARA-002 has the potential to play a meaningful role in the NMIBC treatment landscape, as there continues to be limited treatment options for this highly recurrent disease.

“We look forward to gaining additional clinical experience with TARA-002 in NMIBC patients with CIS.”

Based on the data, the company intends to commence an open-label Phase Ib/II ADVANCED-2 trial of intravesical TARA-002 in up to 102 CIS patients in the second half of this year.

Approximately 27 subjects with CIS (± Ta/T1), BCG-naïve or BCG-exposed who have previously not received intravesical BCG for at least 24 months before CIS diagnosis, are expected to be enroled in the Phase Ib trial.

The Phase II trial is anticipated to enrol 75 patients with BCG-unresponsive CIS (± Ta/T1).