Concomitant medication of cetirizine in advanced melanoma could enhance anti-PD-1 efficacy by promoting M1 macrophages polarization

BACKGROUND: The clinical observation showed a potential additive effect of anti-PD-1 agents and cetirizine in patients with advanced melanoma. METHODS: Clinical outcomes of concomitant cetirizine/anti-PD-1 treatment of patients with stage IIIb–IV melanoma were retrospectively collected, and a transcriptomic analysis was performed on blood samples obtained at baseline and after 3 months of treatment. RESULTS: Patients treated with cetirizine concomitantly with an anti-PD-1 agent had significantly longer progression-free survival (PFS; mean PFS: 28 vs 15 months, HR 0.46, 95% CI: 0.28–0.76; p = 0.0023) and OS (mean OS was 36 vs 23 months, HR 0.48, 95% CI: 0.29–0.78; p = 0.0032) in comparison with those not receiving cetirizine. The concomitant treatment was significantly associated with ORR and DCR (p < 0.05). The expression of FCGR1A/CD64, a specific marker of macrophages, was increased after the treatment in comparison with baseline in blood samples from patients receiving cetirizine, but not in those receiving only the anti-PD1, and positively correlated with the expression of genes linked to the interferon pathway such as CCL8 (rho = 0.32; p = 0.0111), IFIT1 (rho = 0.29; p = 0.0229), IFIT3 (rho = 0.57; p < 0.0001), IFI27 (rho = 0.42; p = 0.008), MX1 (rho = 0.26; p = 0.0383) and RSAD2 (rho = 0.43; p = 0.0005). CONCLUSIONS: This retrospective study suggests that M1 macrophage polarization may be induced by cetirizine through the interferon-gamma pathway. This effect may synergize with the immunotherapy of advanced melanoma with anti-PD-1 agents. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12967-022-03643-w.