Prima to present new data on melanoma combination

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Prima BioMed (ASX:PRR), which recently announced plans to change its name to Immutep, has announced the presentation of new data from its TACTI-mel Phase I clinical trial investigating the use of eftilagimod alpha (LAG-3Ig or IMP321), the company’s lead product candidate, in combination with MSD's KEYTRUDA (pembrolizumab) in unresectable or metastatic melanoma patients.

According to the company, the data will be presented in a poster titled, 'Pushing the accelerator and releasing the brake: testing the soluble LAG-3 protein (IMP321), an antigen presenting cell activator, together with pembrolizumab in unresectable or metastatic melanoma', at the Society for Immunotherapy of Cancer (SITC) 2017 Annual Meeting in Maryland.

Eftilagimod alpha, which is a soluble LAG-3Ig fusion protein, is an APC activator boosting T cell responses. KEYTRUDA, a PD-L1 inhibitor, is currently listed on the PBS for the treatment of advanced melanoma.

“The data to be presented at the SITC meeting is very encouraging and demonstrates that anti-tumor activity was observed in patients following the administration of eftilagimod alpha in combination with pembrolizumab. Furthermore, 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 patients eligible to participate in the TACTI-mel Phase 1 clinical trial have either had a suboptimal response or disease progression with KEYTRUDA monotherapy as a first-line treatment. 12 patients from the first two cohorts of the trial were treated with 1 and 6mg doses of eftilagimod alpha respectively. The third cohort of patients, being treated with 30 mg doses, is ongoing.

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

The presentation at the SITC conference includes a number of results, including that the combination of eftilagimod alpha (1 and 6 mg) and KEYTRUDA in advanced metastatic melanoma patients is safe and well tolerated, and anti-tumor activity was observed in 7 out of 12 patients (58 per cent).

Prima CEO, Marc Voigt, added, “We believe the positive data, taken together with the excellent safety profile of eftilagimod alpha and data from our ongoing clinical trial in metastatic breast cancer, 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 tumors.”