Gemcitabine, Dexamethasone and Cisplatin (GDP regimen) As First Salvage Treatment of Patients with Refractory or Relapsed Diffuse large B Cell Non Hodgkin Lymphoma (DLBCL)

Many chemotherapy regimens have been used for patients with refractory or relapsed DLBCL. No regimen has demonstrated superiority to another in this setting. Specific markers could predict the response to certain agents. Aim: to evaluate the response of GDP regimen in relapsed and refractory DLBCL patients and to assess ribonucleotide reductase subunit M1 (RRM1) as a possible predictor marker to Gemcitabine response. Patients and method: Patients with Relapsed or refractory DLBCL after one previous anthracycline-containing chemotherapy regimen were treated with the GDP regimen. RRM1 was assessed by immunohistochemistry in 55 cases and its expression was correlated to treatment outcome. Patients who could not proceed to stem cell transplantation (SCT) were followed for chemotherapy response and their results are presented. Results: The study included 70 patients with a median age of 40 years (range 18–73). At start of GDP, 19 patients (27.1%) were refractory and 51 (72.9%) were relapsed. After 4 cycles of treatment, 42 patients achieved CR, with a CR rate of 60% (95% CI: 53–68%). The median DFS was 6 months (95% CI: 5 to7 months), this DFS didn't include patients who underwent auto SCT. After a median follow-up of 20 months (range 6 to 30 months), the median OS of the patients who achieved CR was not reached, while those who didn't achieve CR had a median OS of 27.4 months (p= 0.01). Correlation between response and the pretreatment prognostic factors including IPI score or any of its elements, previous line of chemotherapy, time to relapse and status at time of salvage were studied with only significant difference in response to GDP between patients with refractory and those with relapsed disease (CR= 21.1% versus 60% respectively, p < 0.001). There was significant correlation between RRMI study results and response to GDP, 30/31 cases with low RRM1 expression achieved CR (96.8%), while only 7/24 cases with high expression achieved CR (29.2%), (p=0.001). No significant relation could be found between RRM1 expression and DFS. Conclusion: GDP regimen is active for patients with refractory or relapsed DLBCL however, the duration of response is short and high-dose therapy with SCT support is the reference postremission treatment. RRM1expression can predict response to Gemcitabine-based chemotherapy.

No relevant conflicts of interest to declare.