Published papers

44歳、女性。左鼠径リンパ節の生検にてanaplastic lymphoma kinase(ALK)陽性未分化大細胞型リンパ腫(anaplastic large cell lymphoma、 ALCL)と診断された。節性病変に加え膀胱壁への浸潤を認め、臨床病期IVAと判断した。CHOP療法により完全奏効となったが、最後の化学療法から1年後、節性病変を伴わず、複数の皮膚病変で再発した。化学療法により第2完全奏効となり、自家末梢血幹細胞移植を施行した。移植2ヵ月後に再度、皮膚病変として再発し電子線治療を行ったが、他の部位にも複数の皮膚病変が出現した。しかし、これらの皮膚病変は自然消退し、現在自家末梢血幹細胞移植3.4年経過し、完全奏効を維持している。ALK陽性ALCLの皮膚限局再発例は節性病変再発例とは異なる経過をたどる可能性がある。症例の蓄積により皮膚限局再発例の特徴を明らかにする必要がある。(著者抄録)

Ravulizumabは,発作性夜間ヘモグロビン尿症(PNH)の治療薬として承認された長時間作用型補体阻害薬である。補体阻害薬未治療のPNH患者に対するALXN1210-PNH-301試験と,eculizumab投与歴のある患者に対するALXN1210-PNH-302試験において,eculizumabからravulizumabへの切り替えを経験した23例を対象に治療の選好性を評価した。PNH特異的患者選好調査票による評価では,23例中19例(82.6%)がravulizumabを選好し,eculizumabを選択した患者はなく,4例(17.4%)は「どちらでもよい」と回答した(p<0.005)。8週間毎投与のravulizumabは,2週間毎投与のeculizumabに比べて投与回数が少ないことから,予定が立てやすい,治療が受けやすい,全般的な生活の質が高い,などの理由で選好された。患者視点に基づいた両薬剤の評価は,PNH患者における治療方針の決定に役立つと考えられた。(著者抄録)

Plerixafor, a CXCR4 inhibitor, has the potential to mobilize leukemic cells, which may contribute to their chemosensitization. This phase 1 study evaluated the safety of myeloablative conditioning combined with plerixafor for allogeneic hematopoietic stem cell transplantation (HSCT). Patients with high-risk leukemia undergoing allogeneic HSCT after total body irradiation (TBI, 12 Gy)-based myeloablative conditioning were eligible; 9 patients were enrolled. The study was performed using a 3 + 3 design with an escalating total dose of plerixafor. Plerixafor was given subcutaneously 8 h before TBI and chemotherapeutic agents. Plerixafor was successfully escalated to the maximum dose (0.72 mg/kg) without dose-limiting toxicities. Underlying diseases were acute myelogenous and lymphoblastic leukemia, chronic myeloid leukemia, and myelodysplastic syndrome. As adverse events, plerixafor administration was associated with transient Grades 2–3 diarrhea (n = 7) and abdominal pain (n = 4). In 6 patients, leukemic cell mobilization into the peripheral blood by plerixafor was confirmed by a morphological or molecular method. All patients achieved neutrophil engraftment and 5 were alive in remission at a follow-up after 30–40 months. Plerixafor-combined myeloablative conditioning for allogeneic HSCT was well tolerated. Leukemic-cell mobilization into peripheral blood was observed in half of the patients. Further study is required to evaluate the efficacy and safety of this concept.

Toxoplasmosis caused by Toxoplasma gondii (T. gondii) is a serious infectious complication after allogeneic hematopoietic stem cell transplantation (HSCT). The incidence of toxoplasmosis varies widely because of the variabilities of seroprevalence among patient populations. The incidence and the optimal management of toxoplasmosis after allogeneic HSCT in a patient population with a low seroprevalence have not been fully evaluated. We conducted a single-center retrospective study evaluating toxoplasmosis in Japanese patients who underwent allogeneic HSCT. Of the 728 evaluable patients, only 5 developed toxoplasmosis with a median onset of day 60 post-transplant (range, day 55-393). The cumulative incidence was 0.7% (95% CI: 0.3%-1.5%) at day 500 post-transplant. Four of the five patients succumbed due to toxoplasmosis. The more recently treated 220 patients (not the earlier 508 patients) were screened for the T. gondii serostatus, and prophylactic treatment with trimethoprim/sulfamethoxazole was applied. All five patients with toxoplasmosis were in the unscreened group, and there was no case of toxoplasmosis after the introduction of the screening and prophylactic treatment. Our results suggest that toxoplasmosis after allogeneic HST is rare but can develop as a life-threatening complication even in the populations with low seroprevalence, and that prophylactic treatment for seropositive patients could effectively prevent toxoplasmosis.

Background: Letermovir has been approved as a novel cytomegalovirus (CMV) prophylactic agent after allogeneic hematopoietic stem cell transplantation (HSCT). However, there are still insufficient data to properly evaluate the real-world role of letermovir, and the risk factors for CMV reactivation under letermovir prophylaxis have not been clarified. Methods: We performed a single-institution retrospective analysis of patients under prophylaxis with or without letermovir who underwent allogeneic HSCT between March 2012 and December 2019. In August 2018, letermovir was added to the clinical practice at our institution for the prophylaxis of CMV reactivation in allogeneic HSCT recipients. Patients who underwent HSCT without prophylactic letermovir from March 2012 until September 2018 served as a historical control. Results: The cumulative incidence of clinically significant CMV infection (CS-CMVi) was significantly lower in the letermovir group than in the historical control group not receiving letermovir (30.2% vs. 71.6%, p <.05, at 100 days). In addition, the cumulative incidence of non-relapse mortality (NRM) at day 500 was significantly lower in the letermovir group (4.7% vs. 19.8%, p <.05). We then performed a risk factor analysis for developing CS-CMVi in the letermovir group. The only significant factor identified by this multivariable analysis was transplantation from a CMV seronegative donor to a seropositive recipient (Hazard ratio = 2.76, 95% confidence interval 1.14–6.68, p <.05). Conclusion: Our study showed that letermovir prophylaxis significantly reduced the incidence of CS-CMVi and NRM in a real-world setting and that the CMV serostatus of the donor remained as a risk factor for CS-CMVi even under letermovir prophylaxis.

Background: Dasatinib, nilotinib, and bosutinib, second-generation tyrosine kinase inhibitors (TKIs), and ponatinib, a third-generation TKI, are approved pharmaceuticals used in the treatment of chronic myeloid leukemia (CML). Although liquid chromatography-tandem mass spectrometry assays for simultaneous quantification of the four TKIs in human serum have been reported in the literature, a high-performance liquid chromatography (HPLC) assay that simultaneously quantifies these compounds has not yet been developed. This study aims to establish and validate an efficient HPLC analytical method using a photodiode array (PDA) detector for the simultaneous quantification of the four TKIs. Methods: Calibration standards were prepared by serial dilution of serum samples containing the four TKIs, followed by solid-phase extraction. The four TKIs were eluted in order within 10 min using a binary HPLC gradient system. Results: The calibration ranges were 2–500 ng/ml for dasatinib, 100–5000 ng/ml for nilotinib, and 10–500 ng/ml for bosutinib and ponatinib. Intra-day and inter-day precision and accuracy values were found to be in accordance with the U.S. Food and Drug Administration guidelines. The recovery rates were 92.9%–96.0%, 80.7%–86.1%, 91.6%–99.0%, and 86.4%–92.6% for dasatinib, nilotinib, bosutinib, and ponatinib, respectively. Conclusion: To the best of our knowledge, this is the first report of an HPLC-PDA analytical method that allows efficient simultaneous quantification of the four TKIs in the serum of patients with CML. We believe that the method developed herein can improve the efficiency of therapeutic drug monitoring in patients with CML in clinical practice.

Transient abnormal myelopoiesis (TAM) generally affects newborns with Down syndrome and is associated with constitutional trisomy 21 and a somatic GATA1 mutation. Here we describe a case of TAM which evolved after umbilical cord blood transplantation (UCBT), whose origin was identified as a GATA1 mutation-harboring clone in umbilical cord blood (UCB) by detailed genetic analyses. A 58-year-old male who received UCBT for peripheral T-cell lymphoma presented progressive anemia and thrombocytopenia, and leukocytosis with blast cells in the peripheral blood (PB). Bone marrow (BM) aspiration showed granulocytic and megakaryocytic dysplasia with excess blasts whose karyotype was trisomy 21. Short tandem repeat analysis showed complete donor chimerism. He was initially diagnosed as donor-derived myelodysplastic syndrome (MDS) and treated with azacitidine, followed by secondary transplantation using unrelated BM, providing durable complete remission. Retrospective targeted-capture sequencing analysis of PB/BM samples collected at multiple timepoints identified trisomy 21 and a GATA1 mutation, suggestive of a diagnosis of donor cell-derived TAM (DC-TAM). Importantly, a minor clone with the same GATA1 mutation was detected in UCB by droplet digital PCR. DC-TAM is a rare UCBT-related complication which resembles MDS, but the identification of GATA1 mutation may be useful for its diagnosis. Our genetic analyses revealed that a pre-existing clone in UCB may contribute to the development of donor cell-derived hematologic neoplasms, highlighting the potential relevance of genetic screening of donor UCB.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an important therapeutic option for patients with hematologic malignancies. However, the development of graft-versus-host disease (GVHD) after allo-HSCT remains a challenge. Although systemic steroid therapy is the established first-line therapy for acute GVHD (aGVHD) and chronic GVHD (cGVHD), many patients are unresponsive or resistant to corticosteroid therapy, and the response is insufficient. This study aimed to evaluate the clinical characteristics of patients who developed aGVHD and cGVHD after allo-HSCT. This noninterventional, retrospective study used large national registry data from the Transplant Registry Unified Management Program. The study included 29,690 patients with a hematologic disease who underwent their first allo-HSCT between January 2010 and December 2019. The primary study endpoints were the cumulative incidence of aGVHD and cGVHD. The secondary endpoints were overall survival (OS) and nonrelapse mortality (NRM) of patients with aGVHD and cGVHD and OS and NRM of patients who received second-line therapy for aGVHD. Of 29,690 patients who underwent allo-HSCT, the graft source was related bone marrow (RBM) in 2807, related peripheral blood (RPB) in 6167, unrelated bone marrow in 10,556, unrelated peripheral blood (UPB) in 774, and unrelated cord blood in 9339. The cumulative incidence of grade II-IV aGVHD at 100 days was high after the related and unrelated mismatched transplantation. The response rates for first- and second-line therapy for aGVHD were low in the RBM/RPB-mismatched (59.6%/61.6%) and UPB-mismatched subgroups (45.5%), respectively. The 3-year NRM in patients with aGVHD was high in the RPB and UPB mismatched subgroups (37.9% and 31.2%, respectively). Developing a novel treatment for steroid-refractory aGVHD is necessary to improve transplantation outcomes, particularly for patients undergoing HLA-mismatched allo-HSCT.

Background: Chimeric antigen receptor (CAR) T-cell therapy has transformed treatment for patients with relapsed or refractory large B-cell lymphoma (LBCL). However, real-world data in Japan remain limited. Methods: We retrospectively analyzed 489 LBCL patients treated with tisagenlecleucel (tisa-cel) using a nationwide registry. Results: The median patient age was 62 years, with 89% having undergone ≥3 prior therapies. At infusion, 22% were in a complete response. The estimated 1-year progression-free survival (PFS) and overall survival (OS) rates were 43.2% (95%CI, 37.8–49.3%) and 65.9% (95% CI, 61.0–71.1%), respectively. Multivariable analysis revealed that better Karnofsky performance status, a history of stem cell transplantation, absence of extranodal lesion, higher absolute lymphocyte count, and lower lactate dehydrogenase level prior to lymphodepleting therapy were significantly associated with better PFS and OS. Older age (≥65 years) at infusion was associated with better PFS, while shorter duration from apheresis to infusion (<60 days) was associated with better OS. Cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome occurred in 71% and 5% of patients, respectively. Conclusions: This study provides the largest real-world dataset on tisa-cel treatment for LBCL. Our results showed real-world outcomes and early safety consistent with prior trials.