Eftilagimod alpha (efti) - (TACTI-004/KEYNOTE-F91)

April 30, 2026: Immutep Limited (ASX: IMM; NASDAQ: IMMP) provided a quarterly update highlighting discontinuation of the Phase III TACTI-004 (KEYNOTE-F91) trial of eftilagimod alfa (efti) + KEYTRUDA + chemotherapy in first-line NSCLC after an IDMC recommendation following a planned interim futility analysis. The analysis (≈170 patients) reviewed baseline characteristics, safety and ORR; Immutep’s internal review also considered early interim PFS. The company said the efti arm underperformed the placebo control arm, prompting halted enrollment and an orderly wind-down.

Immutep is conducting a root cause analysis (clinical/operational/analytical/manufacturing), including sample collection across up to 150 sites; this may extend into Q3 CY2026. Dr. Reddy’s Laboratories continues to support the evaluation.

Other programs:

• INSIGHT-003 (Phase I, investigator-initiated, non-squamous 1L NSCLC): dosing completed; follow-up ongoing; reported strong ORR and DCR in 51 evaluable patients across PD-L1 levels.
• EFTISARC-NEO (Phase II, neoadjuvant resectable soft tissue sarcoma): met primary objective; statistically significant increases in CXCL9, CXCL10, IL-23 and IFN-γ; DFS follow-up ongoing; FDA orphan drug designation received (April 2026).
• AIPAC-003 (Phase II metastatic breast cancer): dosing complete (N=66; 30 mg vs 90 mg efti); OS follow-up ongoing; proposed neoadjuvant Phase II trial is on hold pending the TACTI-004 analysis.
• IMP761 (Phase I, LAG-3 agonist for autoimmune disease): SAD completed up to 14 mg/kg with no safety concerns; now in MAD phase with completion expected 3Q CY2026; presentation planned at EULAR 2026 (London, June 3–6, 2026) and additional data in 2H CY2026.

Financial: cash/cash equivalents and term deposits A$110.6m (as of March 31, 2026), with expected runway into H1 CY2028; US$10m payment due to Dr. Reddy’s by June 2026 triggered by TACTI-004 discontinuation.