46TiP - AIPAC (Active Immunotherapy PAClitaxel): A phase IIb trial in hormone receptor-positive metastatic breast carcinoma patients receiving IMP321 (LAG-...

Date 05 November 2016
Event ESMO Symposium on Immuno-Oncology 2016
Session Lunch and general poster viewing
Presenter Christian Mueller
Citation Annals of Oncology (2016) 27 (suppl_8): viii4-viii17. 10.1093/annonc/mdw527
Authors C. Mueller1, F. Triebel2
  • 1Clinical Development, Prima Biomed GmbH, 04103 - Leipzig/DE
  • 2Medical Sciences, Immutep S.A.S., 91893 - Orsay/FR



This ongoing Phase IIb clinical trial aims to investigate the safety and efficacy of the active immunotherapy IMP321 in combination (adjunctive) with paclitaxel chemotherapy in patients with hormone receptor-positive metastatic breast cancer. IMP321 consists of the extracellular portion of the human lymphocyte activation gene 3 (LAG-3) protein fused to the Fc fraction of a human IgG1. This soluble LAG-3Ig fusion protein, like the membrane form of LAG-3 naturally expressed on human T cells, binds to major histocompatibility complex (MHC) class II molecules on the surface of antigen presenting cells (APC) and leads to their activation with enhanced presentation of tumour antigens to T cells. As a result, strong and sustained anti-tumour cytotoxic T cell responses are obtained.

Trial design

This is a multicentre, placebo-controlled, double-blind, 1:1 randomised Phase IIb clinical trial (N = 211) that consists of two stages. In the open-label, safety run-in stage the recommended Phase 2 dose (RPTD) of IMP321 in combination with paclitaxel will be confirmed. In the placebo-controlled, double-blind randomisation stage, paclitaxel + IMP321 at the RPTD will be compared to paclitaxel + placebo. In both study stages, treatment consists of a chemo-immunotherapy phase followed by a maintenance phase. The chemo-immunotherapy phase consists of 6 cycles of 4 weeks. During each cycle the patient will receive weekly paclitaxel (80 mg/m2) at Days 1, 8 and 15 with adjunctive treatment of study agent, either IMP321 or placebo, on Days 2 and 16 of each 4-week cycle. After completion of the 6-cycle chemo-immunotherapy phase, responding or stable patients will receive study agent (IMP321 or placebo) every 4 weeks during the maintenance phase for an additional period of 52 weeks. Patients will be evaluated for progression-free survival (PFS) and overall survival (OS). Tumour response will be radiologically assessed according to response evaluation criteria in solid tumours (RECIST) version 1.1 until progressive disease, death, unacceptable toxicity, or until the end of the study, whichever occurs first.

Clinical trial identification

The AIPAC trial protocol has been released on 28 August 2015. The trial identifiers are IMP321-P011 (sponsor code), 2015-002541-63 (EudraCT) and NCT02614833 (ClinicalTrials.gov).

Legal entity responsible for the study

Immutep S.A.S


Immutep S.A.S


C. Mueller: Employed at Prima Biomed which investigates MP321 as a commercial sponsor. F. Triebel: CMO and CSO of Immutep S.A.S.