Multicenter retrospective analysis regarding the clinical manifestations and treatment results in patients with hairy cell leukemia: twenty-four year Turkish experience in cladribine therapy

A 3-decade multicenter European experience with cladribine as upfront treatment in 384 hairy cell leukemia patients

Cladribine is regarded as the first treatment of choice for symptomatic hairy cell leukemia.

This large international study reports a complete response in 72% of cases and a continuous complete response in 20% of patients.

Patients with relapsed/refractory hairy-cell leukemia

Background

Hairy cell leukemia (HCL) is a rare chronic B‐cell neoplasm with good long‐term prognosis. First and second‐line therapies include purine nucleoside analogues (PNAs) and rituximab, but until recently, limited alternative options were available for patients with two or more relapses.

Aim

The aim of this study is to describe our real‐life experience with HCL patients in third and fourth‐line therapies.

Methods and Results

Data from 49 HCL patients with two or more relapses, including 16 patients with three or more relapses, were collected from the French retrospective HCL cohort covering the period from 1980 until 2011. They were analyzed to assess hematological response, relapse free survival (RFS) and overall survival (OS) after third (L3) and fourth line (L4). The median age at diagnosis was 53 years. PNAs were the most frequently used treatments. As L3 therapy, 29 patients received PNAs (66%) and 15 (34%) other treatments (rituximab [11%] or interferon [7%] alone or in combination [16%]). The distribution of L4 treatments was similar. The overall hematological response rate (OHRR) after L3 was 97% (complete hematological response 86%) with a 40% five‐year cumulative incidence of relapse (CIR), a median RFS of 104 months, and a median OS of 235 months. After L4, the OHRR was 94% with a two‐year CIR of fourth relapse of 27%. Eleven secondary cancers (5‐year cumulative incidence of 12%) were diagnosed in 10 patients. Patients with ≥2 relapses experience frequent further relapses, with increasingly shorter time to next treatment as the number of treatment lines increases. Furthermore, treatment strategies are associated with substantial toxicities.

Conclusion

All these points lead to the need for novel treatments.

Management of Relapsed Hairy Cell Leukemia: A Systematic Review of Novel Agents and Targeted Therapies

BACKGROUND

Hairy cell leukemia (HCL) responds well to purine analogs with an overall median relapse free survival of 11-16 years. Most patients can be retreated with the same or a different purine analog however a subset of patients will become resistant or develop cumulative toxicities. Novel agents such as Vemurafenib (BRAF kinase inhibitor), Bendamustine/Rituximab (BR), Moxetumomab pasudotox (anti CD-22 recombinant immunotoxin) and Ibrutinib have emerging roles in patients with relapsed HCL.

METHODS

Five databases (PubMed, Embase, Cochrane Library, Web of Science and ClinicalTrials.gov) were searched using the following search terms: "hairy cell leukemia" or "leukemia, hairy cell" AND "relapse" or "recurrence". We included only prospective clinical trials with outcome data.

RESULTS

Vemurafenib monotherapy was evaluated in two separate arms of a phase 2 trial. In the US arm (n=24), the ORR was 100% (CR 42%; PR 58%). In the Italian arm (n=26), the ORR was 96% (CR 35%; PR 62%). In a phase 2 study (n=25), the combination of vemurafenib and rituximab showed CR of 100%. The combination of BR achieved an ORR of 100% whereas CR was 50% and 67% at a bendamustine dose of 70mg/m² (n=6) and 90 mg/m² (n=6) respectively. In a phase 3 trial, moxetumomab pasudotox (n=80) had an ORR of 75% (CR 41%). Single agent Ibrutinib (n=37) had an ORR of 54%. Therapies were generally well tolerated.

CONCLUSION

Novel agents have good efficacy in HCL in patients with multiple relapses.

Potential and promising anticancer drugs from adenosine and its analogs

In recent years, many studies have shown that adenosine has efficacy for treating cancer. More importantly, some adenosine analogs have been successfully marketed to fulfill anticancer purposes. In this review, we summarize the anticancer effects of adenosine and its analogs in clinical trials and preclinical studies, with focus on their anticancer mechanisms. In addition, we link the anticancer activities of adenosine analogs with their structures through structure-activity relationship (SAR) analysis, and highlight additional promising anticancer drug candidates. We hope that this review will be of help in understanding the importance of adenosine and its analogs with anticancer activities and directing future research and development of such compounds.

Analysis of a cohort of 279 patients with hairy-cell leukemia (HCL): 10 years of follow-up

In total, 279 patients with hairy-cell leukemia (HCL) were analyzed, with a median follow-up of 10 years. Data were collected up to June 2018. We analyzed responses to treatment, relapses, survival, and the occurrence of second malignancies during follow-up. The median age was 59 years. In total, 208 patients (75%) were treated with purine analogs (PNAs), either cladribine (159) or pentosatin (49), as the first-line therapy. After a median follow-up of 127 months, the median overall survival was 27 years, and the median relapse-free survival (RFS) was 11 years. The cumulative 10-year relapse incidence was 39%. In patients receiving second-line therapy, the median RFS was 7 years. For the second-line therapy, using the same or another PNA was equivalent. We identified 68 second malignancies in 59 patients: 49 solid cancers and 19 hematological malignancies. The 10-year cumulative incidences of cancers, solid tumors, and hematological malignancies were 15%, 11%, and 5.0%, respectively, and the standardized incidence ratios were 2.22, 1.81, and 6.67, respectively. In multivariate analysis, PNA was not a risk factor for second malignancies. HCL patients have a good long-term prognosis. PNAs are the first-line treatment. HCL patients require long-term follow-up because of their relatively increased risk of second malignancies.

Retrospective Analysis of Hairy Cell Leukemia Patients Treated with Different Modalities as First Line: Real-Life Experience Over 20 years

We aimed to analyze the characteristics and response rates of different treatment modalities in hairy cell leukemia patients over 20 diagnosed as hairy cell leukemia (HCL). Clinical data, response rates and survival outcome of the patients who were diagnosed with HCL were retrospectively analyzed. Fifty-two patients with a median age of 50 (28-87) years were enrolled in the study. 38 patients (73%) were male and male to female ratio was 2.7. First line therapy was cladrabine in 36 patients (69.2%). The overall response rate was 97%. CR and PR rates were 86.1% and 11.1%, respectively. Interferon was used in 10(19.2%) patients who were diagnosed before 2000s years. CR and PR rates were 70% and 30%, respectively. Although the CR rates were lower in IFN group, this difference could not be reached statistically significance (p = 0.24). The median follow up was 48 months (12-252). The median OS was not reached and median PFS was 150 months (95% CI, 116-214). The OS at 36 and 48 months were 95.9% and 92.3%, respectively and the PFS at 36 and 48 months were 90.2% and 83.4%, respectively. After the introduction of purine analogues, the fate of the HCL patients have been changed. Cladrabin achieved very high response rates in both young and older patients, in our study. Although relapse still constitutes a problem, another single dose of cladrabine results in good response rates.

Outcomes and second neoplasms in hairy cell leukemia: A retrospective cohort

Hairy cell leukemia (HCL) is a rare chronic B-cell lymphoproliferative disease which is treated on the basis of small studies, making the literature still scarce of reports, especially of those conducted in Latin America. Here we intend to describe clinical characteristics, rates of response, survival and second neoplasms in HCL patients treated in a reference center in Brazil. All patients diagnosed with HCL between July/1987 and Jun/2018 were included in this analysis. Fifty-four patients were included in this analysis. Median age at diagnosis was 55 years (range, 26-88), with 37% being above 60 years-old. Most patients were treated with cladribine in our cohort (n = 36; 68%), administered through intravenous continuous infusion. Remaining patients were firstly managed with splenectomy (n = 7; 13%), IFN (n = 6; 11%) and rituximab (n = 2; 4%). In a univariate analysis, platelet count and B2M level at diagnosis were statistically associated with CR achievement (p = 0.004 and p = 0.024, respectively). A median follow-up time of 9 years was calculated. Estimated 10-year overall survival was 91.1% (95% confidence interval, 77-97). In this cohort, 10 patients had any second neoplasm, diagnosed before or after HCL. Regarding the sites of cancer, 69% were of skin - 8/16 carcinoma-type and 3/16 melanoma-type. Our response and survival data are similar to those reported by literature, which reaffirms the role of purine analogs in current HCL management. With a very long follow-up we also have observed a high incidence of second neoplasm.

Long-term follow-up after purine analogue therapy in hairy cell leukaemia

Since 2006 when we last reviewed the literature concerning the use of purine analogues in hairy cell leukaemia (HCL), results from several new and updated series have been published. Here we examine these reports and consider their implications for patient management. The two purine analogues pentostatin and cladribine remain the first-line treatments of choice for all patients with HCL. Although they have not been compared in randomised trials, they appear to be equally effective. A complete response is important for the long-term outcome and we look at how best this can be achieved. Evidence is emerging which supports the use of either purine analogue plus an anti-CD20 monoclonal antibody after relapse, though questions remain concerning the scheduling of the monoclonal antibody. Patients refractory to the purine analogues may require alternative agents.