Purpose: There are unmet needs associated with the current treatment strategies for relapsed/refractory diffuse large B-cell lymphoma (DLBCL) due to the poor treatment outcomes of these strategies. Roflumilast, a selective phosphodiesterase-4 inhibitor used for treating chronic obstructive pulmonary disease, is effective against B-cell malignancy via phosphoinositide 3-kinase (PI3K)–activity suppression. We analyzed the effects of roflumilast combined with ESHAP (etoposide, cisplatin, methylprednisolone, and cytarabine) chemotherapy in experimental and clinical settings. Materials and Methods: An in vitro study using lymphoma cell lines and a pilot study on relapsed/refractory DLBCL patients were conducted to investigate the effects and mechanism of the combination of roflumilast and chemotherapy. The complete response (CR), overall response rate (ORR), and 1-year progression-free survival (PFS) were analyzed. Results: We found that roflumilast is efficient when combined with other chemotherapy drugs, especially cytarabine. Synergistic effects between these two drugs influence the translation of mammalian target of rapamycin and myeloid cell leukemia 1, resulting in apoptosis and inhibition of B-cell lymphoma proliferation. In clinical setting, the roflumilast group showed better rates of CR (46.2% vs. 34.6%), ORR (76.9% vs. 53.8%), and 1-year PFS (50.0% vs. 25.9%) compared with the control group, though not statistically significant. The roflumilast group showed a higher incidence of asthenia and gastrointestinal adverse events. However, grade 3 or 4 adverse events were similar in both groups. Conclusion We found that roflumilast, when combined with ESHAP chemotherapy, for relapsed/refractory DLBCL was clinically active and well tolerated. This combined treatment was able to suppress PI3K activity, which is correlated with the degree of clinical response.

Purpose: Pegfilgrastim is widely used to prevent chemotherapy-induced neutropenia (CIN) and febrile neutropenia (FN) in patients with diffuse large B-cell lymphoma (DLBCL). We investigated the predictive factors affecting CIN and FN incidence in patients with DLBCL receiving rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy with pegfilgrastim and conducted experiments to find reason for the occurrence of CIN even when pegfilgrastim was used. Materials and Methods: We reviewed the CIN and FN events of 200 patients with DLBCL. Based on these data, we investigate the association with predictive factor and the levels of granulocyte-colony stimulating factor (G-CSF) receptor signaling pathway markers (pSTAT3, pAKT, pERK1/2, pBAD, and CXCR4) in bone marrow (BM) samples isolated from patients with DLBCL. Results: FN was significantly associated with stage III/IV (hazard ratio [HR], 12.74) and low serum albumin levels (HR, 3.87). Additionally, patients with FN had lower progression-free survival (PFS; 2-year PFS, 51.1 % vs. 74.0%) and overall survival (OS; 2-year OS, 58.2% vs. 85.0%) compared to those without FN. The occurrence of CIN was associated with overexpression of G-CSF receptor signaling pathway markers, and expression levels of these markers were upregulated in BM cells co-cultured with DLBCL cells. The rate of neutrophil apoptosis was also higher in neutrophils co-cultured with DLBCL cells and was further promoted by treatment with doxorubicin. Conclusion Our findings suggest that high DLBCL burden may alter the BM environment and G-CSF receptor signaling pathway, even in chemotherapy-naïve state, which may increase CIN frequency during R-CHOP chemotherapy.