Prima BioMed announces positive data, pre-IND meeting for anticancer candidate

Biotechnology company Prima BioMed (ASX:PRR) has presented new data from a phase I clinical trial investigating eftilagimod alpha (LAG-3Ig or IMP321), its anticancer candidate, in combination with pembrolizumab (KEYTRUDA) in unresectable or metastatic melanoma patients.

Eftilagimod alpha is based on the LAG-3 immune control mechanism, which plays a vital role in the regulation of the T cell immune responses. A soluble LAG-3Ig fusion protein, the product is an APC activator boosting T cell responses.

Patients eligible to participate in the trial were those that have had either a suboptimal response or had disease progression following KEYTRUDA monotherapy as a first line of treatment. 12 patients from the first two cohorts were treated with 1 and 6 mg doses of eftilagimod alpha respectively. The third cohort of patients, being treated with 30 mg doses, is still ongoing.

Presented at the Society for Immunotherapy of Cancer (SITC) 2017 Annual Meeting, held from 10–12 November in Maryland, USA, the new data demonstrates that the combination of eftilagimod alpha and pembrolizumab in advanced metastatic melanoma patients is safe and well tolerated. Furthermore, tumour reduction was observed in seven out of 12 patients.

“It is important to note that, prior to coming into this study, these patients were treated with pembrolizumab monotherapy and did not achieve a meaningful therapeutic benefit from this treatment,” said Dr Frédéric Triebel, Prima’s chief scientific officer and medical officer.

“The data also supports the hypothesis that there is a therapeutic synergy when administering an APC activator, which enhances antitumour T cell production, in combination with a checkpoint inhibitor, which releases the brake on the T cells.”

According to Prima CEO Marc Voigt, the positive data and safety profile “further validate the therapeutic utility of modulating the LAG-3 immune control mechanism”.

“We are very pleased with the clinical progress of eftilagimod alpha and look forward to presenting additional data from the TACTI-mel clinical trial and exploring the potential therapeutic benefit of combining it with other checkpoint inhibitors in other solid tumours,” Voigt said. The data further supports investigation of IMP321 in combination with PD-1/PD-L1 checkpoint inhibitors in different tumour types, according to the company.

Shortly after the meeting, the company announced that it has held a Pre-Investigational New Drug Application meeting with the US FDA to discuss the regulatory pathway for the development of eftilagimod alpha in the United States. The meeting saw the FDA address Prima’s questions related to preclinical, non-clinical and clinical data and design of clinical trials of eftilagimod alpha in a chemo-immunotherapy setting and in an immuno-oncology combination trial.

Prima intends to file an Investigational New Drug Application in the first half of 2018. After having successfully started clinical development of eftilagimod alpha in Australia and Europe, an IND would provide the company with the opportunity to commence clinical studies and regulatory interactions in the US.

“The US is the largest pharmaceutical market in the world, so the pre-IND meeting regarding eftilagimod alpha was an important milestone,” said Voigt. “Our meeting with the FDA was very productive and their guidance will be most valuable in assessing the appropriate US clinical and regulatory strategies for eftilagimod alpha.”

Prima BioMed (ASX:PRR) shares were trading 4.17% higher at $0.025 as of around 12 noon on Thursday.