Dena Cohen

Long-term treatment with eculizumab in paroxysmal nocturnal hemoglobinuria: sustained efficacy and improved survival

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired clonal hematopoietic disorder with increased mortality and morbidity resulting from intravascular hemolysis. Eculizumab, a monoclonal antibody against the complement protein 5, stops the intravascular hemolysis in PNH. We evaluated 79 consecutive patients treated with eculizumab in Leeds between May 2002 and July 2010. The survival of patients treated with eculizumab was not different from age- and sex-matched normal controls (P = .46) but was significantly better than 30 similar patients managed before eculizumab (P = .030). Three patients on eculizumab, all over 50 years old, died of causes unrelated to PNH. Twenty-one patients (27%) had a thrombosis before starting eculizumab (5.6 events per 100 patient-years) compared with 2 thromboses on eculizumab (0.8 events per 100 patient-years; P < .001). Twenty-one patients with no previous thrombosis discontinued warfarin on eculizumab with no thrombotic sequelae. Forty of 61 (66%) patients on eculizumab for more than 12 months achieved transfusion independence. The 12-month mean transfusion requirement reduced from 19.3 units before eculizumab to 5.0 units in the most recent 12 months on eculizumab (P < .001). Eculizumab dramatically alters the natural course of PNH, reducing symptoms and disease complications as well as improving survival to a similar level to that of the general population.

Genetic and epigenetic analysis of von Hippel-Lindau (VHL) gene alterations and relationship with clinical variables in sporadic renal cancer.

Genetic and epigenetic changes in the von Hippel-Lindau (VHL) tumor suppressor gene are common in sporadic conventional renal cell carcinoma (cRCC). Further insight into the clinical significance of these changes may lead to increased biological understanding and identification of subgroups of patients differing prognostically or who may benefit from specific targeted treatments. We have comprehensively examined the VHL status in tissue samples from 115 patients undergoing nephrectomy, including 96 with sporadic cRCC. In patients with cRCC, loss of heterozygosity was found in 78.4%, mutation in 71%, and promoter methylation in 20.4% of samples. Multiplex ligation-dependent probe amplification identified intragenic copy number changes in several samples including two which were otherwise thought to be VHL-noninvolved. Overall, evidence of biallelic inactivation was found in 74.2% of patients with cRCC. Many of the mutations were novel and approximately two-thirds were potentially truncating. Examination of these and other published findings confirmed mutation hotspots affecting codons 117 and 164, and revealed a common region of mutation in codons 60 to 78. Gender-specific differences in methylation and mutation were seen, although not quite achieving statistical significance (P = 0.068 and 0.11), and a possible association between methylation and polymorphism was identified. No significant differences were seen between VHL subgroups with regard to clinicopathologic features including stage, grade, tumor size, cancer-free and overall survival, with the exception of a significant association between loss of heterozygosity and grade, although a possible trend for survival differences based on mutation location was apparent.

Analysis of VHL gene alterations and their relationship to clinical parameters in sporadic conventional renal cell carcinoma

Purpose: This study aimed to carry out a comprehensive analysis of genetic and epigenetic changes of the von Hippel Lindau (VHL) gene in patients with conventional (clear cell) renal cell carcinoma and to determine their significance relative to clinicopathologic characteristics and outcome. Experimental Design: The VHL status in 86 conventional renal cell carcinomas was determined by mutation detection, loss of heterozygosity (LOH), and promoter methylation analysis, extending our original cohort to a total of 177 patients. Data were analyzed to investigate potential relationships between VHL changes, clinical parameters, and outcome. Results: LOH was found in 89.2%, mutation in 74.6%, and methylation in 31.3% of evaluable tumors; evidence of biallelic inactivation (LOH and mutation or methylation alone) was found in 86.0% whereas no involvement of VHL was found in only 3.4% of samples. Several associations were suggested, including those between LOH and grade, nodal status and necrosis, mutation and sex, and methylation and grade. Biallelic inactivation may be associated with better overall survival compared with patients with no VHL involvement, although small sample numbers in the latter group severely limit this analysis, which requires independent confirmation. Conclusions: This study reports one of the highest proportions of conventional renal cell carcinoma with VHL changes, and suggests possible relationships between VHL status and clinical variables. The data suggest that VHL defects may define conventional renal cell carcinomas but the clinical significance of specific VHL alterations will only be clarified by the determination of their biological effect at the protein level rather than through genetic or epigenetic analysis alone. (Clin Cancer Res 2009;15(24):7582–92)

SAMHD1 is mutated recurrently in chronic lymphocytic leukemia and is involved in response to DNA damage

SAMHD1 is a deoxynucleoside triphosphate triphosphohydrolase and a nuclease that restricts HIV-1 in noncycling cells. Germ-line mutations in SAMHD1 have been described in patients with Aicardi-Goutières syndrome (AGS), a congenital autoimmune disease. In a previous longitudinal whole genome sequencing study of chronic lymphocytic leukemia (CLL), we revealed a SAMHD1 mutation as a potential founding event. Here, we describe an AGS patient carrying a pathogenic germ-line SAMHD1 mutation who developed CLL at 24 years of age. Using clinical trial samples, we show that acquired SAMHD1 mutations are associated with high variant allele frequency and reduced SAMHD1 expression and occur in 11% of relapsed/refractory CLL patients. We provide evidence that SAMHD1 regulates cell proliferation and survival and engages in specific protein interactions in response to DNA damage. We propose that SAMHD1 may have a function in DNA repair and that the presence of SAMHD1 mutations in CLL promotes leukemia development.

Rituximab Plus Chlorambucil As First-Line Treatment for Chronic Lymphocytic Leukemia: Final Analysis of an Open-Label Phase II Study

PURPOSE Most patients with chronic lymphocytic leukemia (CLL) are elderly and/or have comorbidities that may make them ineligible for fludarabine-based treatment. For this population, chlorambucil monotherapy is an appropriate therapeutic option; however, response rates with chlorambucil are low, and more effective treatments are needed. This trial was designed to assess how the addition of rituximab to chlorambucil (R-chlorambucil) would affect safety and efficacy in patients with CLL. PATIENTS AND METHODS Patients with first-line CLL were treated with rituximab (375 mg/m(2) on day 1, cycle one, and 500 mg/m(2) thereafter) plus chlorambucil (10 mg/m(2)/d all cycles; day 1 through 7) for six 28-day cycles. For patients not achieving complete response (CR), six additional cycles of chlorambucil alone could be administered. The primary end point of the study was safety. RESULTS A total of 100 patients were treated with R-chlorambucil, with a median follow-up of 30 months. Median age of patients was 70 years (range, 43 to 86 years), with patients having a median of seven comorbidities. Hematologic toxicities accounted for most grade 3/4 adverse events reported, with neutropenia and lymphopenia both occurring in 41% of patients and leukopenia in 23%. Overall response rates were 84%, with CR achieved in 10% of patients. Median progression-free survival was 23.5 months; median overall survival was not reached. CONCLUSION These results compare favorably with previously published results for chlorambucil monotherapy, suggesting that the addition of rituximab to chlorambucil may improve efficacy with no unexpected adverse events. R-chlorambucil may improve outcome for patients who are ineligible for fludarabine-based treatments.

A randomized phase II trial of fludarabine, cyclophosphamide and mitoxantrone (FCM) with or without rituximab in previously treated chronic lymphocytic leukaemia.

Combination fludarabine (F), cyclophosphamide (C) and rituximab (R) is the standard front‐line therapy in chronic lymphocytic leukaemia (CLL), but appropriate treatment of relapsed/refractory CLL is less clear. Combined FC and mitoxantrone (M) has been reported to be effective in a single arm study, and rituximab when added to chemotherapy in CLL is synergistic. A randomized, two‐stage, Phase II trial of FCM and FCM‐R was conducted in relapsed CLL. The primary endpoint was response rate 2 months after therapy, assessed according to the 2008 International Workshop CLL criteria. In addition, minimal residual disease (MRD) in the marrow was studied 2 months after therapy, with MRD negativity defined as <0·01% CLL cells. Fifty‐two patients were entered, 26 in each arm. The overall response rates to FCM and FCM‐R were 58% and 65% respectively. Combined complete response (CR) and CR with incomplete marrow recovery [CR(i)] was 15% (95% confidence interval [CI]:4–35%) for FCM and 42% (95%CI:23–63%) for FCM‐R, with eight patients achieving MRD negativity (3 FCM; 5 FCM‐R). The toxicity of both regimens was acceptable. In conclusion, the addition of rituximab to FCM improves the response rates in relapsed CLL, resulting in more complete remissions and without additional safety concerns. Efficacy and safety should be fully tested in a randomized Phase III trial.

Proliferation index: a continuous model to predict prognosis in patients with tumours of the Ewing's sarcoma family.

The prognostic value of proliferation index (PI) and apoptotic index (AI), caspase-8, -9 and -10 expression have been investigated in primary Ewings sarcoma family of tumours (ESFT). Proliferating cells, detected by immunohistochemistry for Ki-67, were identified in 91% (91/100) of tumours with a median PI of 14 (range 0–87). Apoptotic cells, identified using the TUNEL assay, were detected in 96% (76/79) of ESFT; the median AI was 3 (range 0–33). Caspase-8 protein expression was negative (0) in 14% (11/79), low (1) in 33% (26/79), medium (2) in 38% (30/79) and high (3) in 15% (12/79) of tumours, caspase-9 expression was low (1) in 66% (39/59) and high (3) in 34% (20/59), and caspase-10 protein was low (1) in 37% (23/62) and negative (0) in 63% (39/62) of primary ESFT. There was no apparent relationship between caspase-8, -9 and -10 expression, PI and AI. PI was predictive of relapse-free survival (RFS; p = 0.011) and overall survival (OS; p = <0.001) in a continuous model, whereas AI did not predict outcome. Patients with tumours expressing low levels of caspase-9 protein had a trend towards a worse RFS than patients with tumours expressing higher levels of caspase-9 protein (p = 0.054, log rank test), although expression of caspases-8, -9 and/or -10 did not significantly predict RFS or OS. In a multivariate analysis model that included tumour site, tumour volume, the presence of metastatic disease at diagnosis, PI and AI, PI independently predicts OS (p = 0.003). Consistent with previous publications, patients with pelvic tumours had a significantly worse OS than patients with tumours at other sites (p = 0.028); patients with a pelvic tumour and a PI≥20 had a 6 fold-increased risk of death. These studies advocate the evaluation of PI in a risk model of outcome for patients with ESFT.

Adding a treatment arm to an ongoing clinical trial: a review of methodology and practice

Incorporating an emerging therapy as a new randomisation arm in a clinical trial that is open to recruitment would be desirable to researchers, regulators and patients to ensure that the trial remains current, new treatments are evaluated as quickly as possible, and the time and cost for determining optimal therapies is minimised. It may take many years to run a clinical trial from concept to reporting within a rapidly changing drug development environment; hence, in order for trials to be most useful to inform policy and practice, it is advantageous for them to be able to adapt to emerging therapeutic developments. This paper reports a comprehensive literature review on methodologies for, and practical examples of, amending an ongoing clinical trial by adding a new treatment arm. Relevant methodological literature describing statistical considerations required when making this specific type of amendment is identified, and the key statistical concepts when planning the addition of a new treatment arm are extracted, assessed and summarised. For completeness, this includes an assessment of statistical recommendations within general adaptive design guidance documents. Examples of confirmatory ongoing trials designed within the frequentist framework that have added an arm in practice are reported; and the details of the amendment are reviewed. An assessment is made as to how well the relevant statistical considerations were addressed in practice, and the related implications. The literature review confirmed that there is currently no clear methodological guidance on this topic, but that guidance would be advantageous to help this efficient design amendment to be used more frequently and appropriately in practice. Eight confirmatory trials were identified to have added a treatment arm, suggesting that trials can benefit from this amendment and that it can be practically feasible; however, the trials were not always able to address the key statistical considerations, often leading to uninterpretable or invalid outcomes. If the statistical concepts identified within this review are considered and addressed during the design of a trial amendment, it is possible to effectively assess a new treatment arm within an ongoing trial without compromising the original trial outcomes.

Modelling cost-effectiveness and value of information in clinical trials to inform stop go decisions: results from the arctic study

Methods The ARCTIC trial randomised patients with previously untreated Chronic Lymphocytic Leukaemia to receive fludarabine, cyclophosphamide, mitoxantrone and low dose rituximab (FCM-miniR) or fludarabine, cyclophosphamide and rituximab (FCR; standard care). An interim efficacy analysis was conducted after 103 patients had completed therapy. CEA and VOIA were conducted using a Markov decision model, based on subsequent data from 200 patients.

Experiences in the design and implementation of phase II trials in CLL

Since 2004, we have developed five phase II trials in Chronic Lymphocytic Leukaemia (CLL), utilising six different statistical methods. Two of the trials have closed to recruitment, two are currently open and a further one is in development. The rationale behind the different designs chosen for each trial will be explained. Difficulties and learning experiences with the implementation, wider understanding and interpretation of the trials will be discussed. CLL201 used Gehan’s two-stage approach to assess response, and randomised to a control arm which was not included for formal comparison, but to give validity of the study results. Challenges included the timing of the stage I analysis without halting recruitment, and the temptation to formally compare the two arms even though there was not power to do so. The inclusion of the control arm proved to be valuable since the response rates were not as expected. CLL207 is a single arm trial designed using Bryant and Day’s two-stage design, incorporating toxicity considerations as well as efficacy. The two-stage aspect worked well in this trial due to the short treatment duration and assessment time. However, implementation was difficult due to the definitions of unacceptable toxicity and unacceptability bounds, and the overlap with the role of the Data Monitoring Committee. ARCTIC and ADMIRE are two large, randomised phase IIb trials, both formally powered to compare responses against a common control arm. One of the trials assesses non-inferiority. Difficulties were experienced in convincing reviewers that these were not underpowered phase III trials. This design was necessary for the non-inferiority question, as it provides an acceptable certainty of finding the treatment inferior in terms of response before proceeding to a much larger trial to assess longer-term endpoints. COSMIC is a randomised selection design with two experimental arms. The A’Hern one-stage design is used to determine which of the treatments are eligible to be taken forward for further investigation. In the case where both are acceptable, Sargent & Goldberg’s selection criteria will be applied to determine whether to take forward the treatment with better response rate, or to use alternative selection criteria. The sample size was inflated to ensure acceptable power for selecting the best treatment.