Advaxis and Merck have started patient enrolment in the Phase I/II clinical trial (KEYNOTE-046) to evaluate an investigational combination of two new immunotherapy candidates ADXS-PSA (ADXS31-142) and pembrolizumab (Keytruda) in patients with previously treated, metastatic castration-resistant prostate cancer (mCRPC).

KEYNOTE-046 is the first-in-human study of Advaxis’s Lm-LLO immunotherapy, ADXS-PSA for prostate cancer. The second trial started to evaluate the use of Keytruda in patients with advanced prostate cancer.

Both ADXS-PSA and Keytruda are members of a class of cancer treatments known as immuno-oncology therapies.

Results from preclinical trials show that Advaxis Lm-LLO immunotherapies in combination with a PD-1 antibody may lead to an improved anti-tumour immune response.

"Both ADXS-PSA and Keytruda are members of a class of cancer treatments known as immuno-oncology therapies."

Principal investigator for KEYNOTE-046 Naomi Hass said: "A synergistic anti-tumour immune response has been observed in preclinical studies evaluating the combination of a PD-1 antibody with an Lm-LLO immunotherapy, and we look forward to the possibility of seeing these results in patients.

"This immunotherapy combination could be a promising alternative treatment option to current standards of care."

Approximately 51 mCRPC patients will be included in the multi-centre, dose determining, open-label Phase I/II KEYNOTE-046 trial, which will evaluate the safety and efficacy of this combination therapy.

The first part of the trial will be a dose escalating study designed to establish the maximum tolerated dose of ADXS-PSA as a monotherapy, while the second part will include a dose escalating trial of ADXS-PSA in combination with Keytruda, followed by an expansion cohort phase.

The trial’s primary objective is to evaluate safety and tolerability of the two immunotherapies, with the secondary objective to evaluate anti-tumour activity and progression-free survival (PFS).

According to the company, results from the Phase I/II KEYNOTE-046 trial will determine a future clinical development programme for the combination.