Life-threatening toxicities upon Pembrolizumab intake: could pharmacokinetics be the bad guy?

PURPOSE: We report the case of an adult patient diagnosed with Hodgkin's lymphoma who was scheduled for Pembrolizumab after failure of standard therapy. After three well-tolerated courses of Pembrolizumab, a PET scan showed a favorable outcome and a fourth course of Pembrolizumab was started. Unexpectedly, extremely severe toxicities (i.e., autoimmune peripheral hypothyroidism, rhabdomyolysis and severe acute renal failure) occurred after this last course, requiring transfer to the intensive care unit. METHODS: Therapeutic drug monitoring was performed to measure residual Pembrolizumab levels at intervals from the last dose (i.e., 120 and then 170 days), as well as pharmacogenetics investigations on the FCγR gene. RESULTS: Pembrolizumab plasma concentrations that were still pharmacologically active months after the last administration, suggesting impaired elimination of Pembrolizumab in this patient. Further pharmacokinetic modeling based on the population approach showed that both half-life (47.8 days) and clearance (0.12 L/day) values were significantly different from the standard values usually reported in patients. Further in silico simulations showed that pharmacologically active concentrations of Pembrolizumab were maintained for up to 136 days after the last dose. The search for possible polymorphisms affecting the genes coding for FCγR (i.e., rs1801274 on FCGR2A and rs396991 on FCGR3A gene) was negative. Further TDM showed that Pembrolizumab could be detected up to 263 days after the last administration. CONCLUSION: This case report suggests that persistent overexposure in plasma could lead to life-threatening toxicities with Pembrolizumab.

A phase II study of lenalidomide and rituximab (R2) combination in patients with high-risk refractory/relapsed diffuse large B-cell lymphoma.

Relapsed/Refractory Diffuse Large B Cell Lymphoma have a dismal prognosis in need of innovative treatments. This prospective phase 2 study enrolled 32 patients between 2013 and 2017 with Relapsed/Refractory Diffuse Large B Cell Lymphoma treated with Rituximab and Lenalidomide (R2). Median age was 69 years (40-86), 90.1% had received at least 2 prior lines of treatment, 81% were defined as having High Risk disease according to our criteria and ECOG performance status was > 2 in 51.6%. Patients received a median number of 2 cycles of R2 (1-12). With a median follow up of 22.6 months, the objective response rate was 12.5%. Median progression free survival was 2.6 months (95% CI, [1.7-2.9]) and median overall survival was 9.3 months (95% CI, [5.1-Not estimable]). This study therefore did not achieve its primary endpoint and the R2 regimen cannot be recommended in Relapsed/Refractory Diffuse Large B Cell Lymphoma patients with High Risk features.

Peripheral T-cell lymphomas: analysis of histology, staging and response to treatment of 208 cases at a single institution.

Peripheral T-cell lymphomas are characterized by a poor clinical outcome. We retrospectively analyzed 208 adults treated in our institution between 2000 and 2011. Median age at diagnosis was 55 years. Fifty-one percent had B symptoms and 51% serum elevated lactate dehydrogenase (LDH) levels. Eastern Cooperative Oncology Group (ECOG) performance status (PS) was 0-1 in 63% and 2-4 in 37%. According to Ann Arbor classification, 16% were at stage I-II and 84% at stage III-IV. Histological subtypes were: 39% peripheral T-cell non-Hodgkin lymphoma (NHL) unspecified (PTCL-U), 19.5% anaplastic large cell lymphoma (ALCL), with 9.5% ALK+ and 10% ALK-, and 25% angioimmunoblastic lymphoma (AILT). Primary extranodal lymphoma represented 17%, and 8% were diagnosed with hemophagocytosis. Induction chemotherapy was CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) in 87% of patients. The median number of chemotherapy cycles was 2 (1-7). A complete response was obtained in 57% of the patients. Among them, 32% had an autologous stem cell transplant (ASCT) and 10% allogeneic SCT, while 38% were primary refractory. Five-year overall survival (OS) was 28.5% (22.3-36.3), and 5-year event-free survival (EFS) was 18.4% (13.4-25.3). A multivariate analysis showed that ALCL-ALK+ (p = 0.004), AILT (p < 0.01), extranodal involvement (p = 0.001), PS > 1 (p = 0.04), LDH < normal (p = 0.003) and hemophagocytosis (p = 0.001) were independent adverse factors for OS. We conclude that conventional chemotherapy with intensive treatment is not sufficient to improve the response rate. Optimal management is required.