Successful alemtuzumab retreatment in progressive B-cell chronic lymphocytic leukemia: a multicenter survey in 30 patients

Guidelines for Diagnosis and Treatment of Chronic Lymphocytic Leukemia. Krohem B-Cll 2017

Recent developments in the diagnosis and treatment of chronic lymphocytic leukemia (B-CLL) have led to change of approach in clinical practice. New treatments have been approved based on the results of randomized multicenter trials for first line and for salvage therapy, and the results of numerous ongoing clinical trials are permanently providing new answers and further refining of therapeutic strategies. This is paralleled by substantial increase in understanding the disease genetics due to major advances in the next generation sequencing (NGS) technology. We define current position of the Croatian Cooperative Group for Hematologic Disease on diagnosis and treatment of CLL in the transition from chemo-immunotherapy paradigm into a new one that is based on new diagnostic stratification and unprecedented therapeutic results of B-cell receptor inhibitors (BRI) and Bcl-2 antagonists. This is a rapidly evolving field as a great number of ongoing clinical trials con-stantly accumulate and provide new knowledge. We believe that novel therapy research including genomic diagnosis is likely to offer new options that will eventually lead to time limited therapies without chemotherapy and more effective clinical care for B-CLL based on individualized precision medicine.

Relationship between progression-free survival and overall survival in chronic lymphocytic leukemia: a literature-based analysis

BACKGROUND

The endpoints of progression-free survival (pfs) and time-to-progression (ttp) are frequently used to evaluate the clinical benefit of anticancer drugs. However, the surrogacy of those endpoints for overall survival (os) is not validated in all cancer settings. In the present study, we used a trial-based approach to assess the relationship between median pfs or ttp and median os in chronic lymphocytic leukemia (cll).

METHODS

The pico (population, interventions, comparators, outcomes) method was used to conduct a systematic review of the literature. The population consisted of patients with cll; the interventions and comparators were standard therapies for cll; and the outcomes were median pfs, ttp, and os. Two independent reviewers screened titles, abstracts, and full papers for eligibility and then extracted data from selected studies. Correlation coefficients were calculated to assess the relationship between median pfs or ttp and median os. Subgroup correlation analyses were also conducted according to the characteristics of the selected studies (such as line of treatment and type of treatment under investigation).

RESULTS

Of the 1263 potentially relevant articles identified during the literature search, twenty-three were included. On average, median pfs or ttp was 16.0 months (standard deviation: 12.4 months) and median os was 43.5 months (standard deviation: 31.2 months). Results of the correlation analysis indicated that median pfs or ttp is highly correlated with median os (Spearman correlation coefficient: 0.813; p ≤ 0.001). A significant correlation between median pfs or ttp and median os was observed in second- and subsequent-line therapies, but not in the first-line setting.

CONCLUSIONS

Our study demonstrates a strong correlation between median pfs or ttp and median os in previously treated cll, which reinforce the hypothesis that pfs and ttp could be adequate surrogate endpoints for os in this cancer setting.

Alemtuzumab in chronic lymphocytic leukemia: final results of a large observational multicenter study in mostly pretreated patients

This retrospective study evaluated the benefit of alemtuzumab monotherapy in unselected patients with advanced B-cell chronic lymphocytic leukemia (CLL) and prolymphocytic leukemia (B-PLL) to definitely describe the impact of this antibody in clinical routine use. Data were collected from 208 consecutive, mainly pretreated, patients with CLL (n = 202), and B-PLL (n = 6) who had received alemtuzumab. Response, progression-free survival (PFS), and overall survival (OS) in various settings were assessed, and toxicities were documented. In these routine patients, a comparably low cumulative dose of alemtuzumab (median, 403 mg) was applied. In CLL, overall response rate was 32 %, and various pre-therapeutic parameters were predictive for inferior response, among them, the prior administration of ≥3 therapy lines (P < 0.001), refractoriness to fludarabine (P = 0.002), and bulky lymphadenopathy (P = 0.003). PFS and OS after start of alemtuzumab were 6.2 and 21.0 months, respectively. Bulky lymphadenopathy was the prominent risk factor for both inferior PFS (P < 0.001) and OS (P = 0.002). In B-PLL, four patients experienced a fatal outcome, whereas two patients had some benefit with alemtuzumab. The main adverse effects were CMV reactivation (20 %) and a broad spectrum of infections, which together were the main reasons for treatment interruption and/or premature termination. In conclusion, alemtuzumab administered even at low dose levels was effective but overall considerably toxic in routine CLL patients. We emphasize that alemtuzumab remains an important therapeutic option in subsets of CLL patients.

Drug rechallenge and treatment beyond progression--implications for drug resistance

The established dogma in oncology for managing recurrent or refractory disease dictates that therapy is changed at disease progression, because the cancer is assumed to have become drug-resistant. Drug resistance, whether pre-existing or acquired, is largely thought to be a stable and heritable process; thus, reuse of therapeutic agents that have failed is generally contraindicated. Over the past few decades, clinical evidence has suggested a role for unstable, non-heritable mechanisms of acquired drug resistance pertaining to chemotherapy and targeted agents. There are many examples of circumstances where patients respond to reintroduction of the same therapy (drug rechallenge) after a drug holiday following disease relapse or progression during therapy. Additional, albeit limited, evidence suggests that, in certain circumstances, continuing a therapy beyond disease progression can also have antitumour activity. In this Review, we describe the anticancer agents used in these treatment strategies and discuss the potential mechanisms explaining the apparent tumour re-sensitization with reintroduced or continued therapy. The extensive number of malignancies and drugs that challenge the custom of permanently switching to different drugs at each line of therapy warrants a more in-depth examination of the definitions of disease progression and drug resistance and the resulting implications for patient care.

Alemtuzumab use in relapsed and refractory chronic lymphocytic leukemia: a history and discussion of future rational use

In this review, we outline the clinical experience with single-agent alemtuzumab as a treatment for relapsed and refractory chronic lymphocytic leukemia (CLL) in both prospective and retrospective trials and describe the multiagent use of the drug with the goal of updating clinicians on recent developments and possible future rational combinations. Alemtuzumab, an antibody targeting the lymphocyte-specific surface marker CD52, is an approved agent for the treatment of CLL. Despite its demonstrated efficacy, likely secondary to concerns regarding infectious complications, it is most commonly used in the relapsed and refractory setting. Given alemtuzumab's unique mechanism of action it has been demonstrated to have activity in disease that is refractory to both alkylating agents and purine analogs. Furthermore, it has activity in TP53-mutated disease, which has the worst prognosis of any subset of CLL. Alemtuzumab has greater efficacy on circulating disease relative to nodal disease. Rational combinations are attempting to use these attributes to increase response rates in patients with relapsed and refractory disease.