Optimal sequencing of ibrutinib, idelalisib, and venetoclax in chronic lymphocytic leukemia: results from a multicenter study of 683 patients

Background

Ibrutinib, idelalisib, and venetoclax are approved for treating CLL patients in the United States. However, there is no guidance as to their optimal sequence.

Patients and methods

We conducted a multicenter, retrospective analysis of CLL patients treated with kinase inhibitors (KIs) or venetoclax. We examined demographics, discontinuation reasons, overall response rates (ORR), survival, and post-KI salvage strategies. Primary endpoint was progression-free survival (PFS).

Results

A total of 683 patients were identified. Baseline characteristics were similar in the ibrutinib and idelalisib groups. ORR to ibrutinib and idelalisib as first KI was 69% and 81%, respectively. With a median follow-up of 17 months (range 1-60), median PFS and OS for the entire cohort were 35 months and not reached. Patients treated with ibrutinib (versus idelalisib) as first KI had a significantly better PFS in all settings; front-line [hazard ratios (HR) 2.8, CI 1.3-6.3, P = 0.01], relapsed-refractory (HR 2.8, CI 1.9-4.1, P < 0.001), del17p (HR 2.0, CI 1.2-3.4, P = 0.008), and complex karyotype (HR 2.5, CI 1.2-5.2, P = 0.02). At the time of initial KI failure, use of an alternate KI or venetoclax had a superior PFS when compared with chemoimmunotherapy. Furthermore, patients who discontinued ibrutinib due to progression or toxicity had marginally improved outcomes if they received venetoclax (ORR 79%) versus idelalisib (ORR 46%) (PFS HR .6, CI.3-1.0, P = 0.06).

Conclusions

In the largest real-world experience of novel agents in CLL, ibrutinib appears superior to idelalisib as first KI. Furthermore, in the setting of KI failure, alternate KI or venetoclax therapy appear superior to chemoimmunotherapy combinations. The use of venetoclax upon ibrutinib failure might be superior to idelalisib. These data support the need for trials testing sequencing strategies to optimize treatment algorithms.

A multicenter phase II study incorporating high-dose rituximab and liposomal doxorubicin into the CODOX-M/IVAC regimen for untreated Burkitt's lymphoma

BACKGROUND

Despite improvement with intensive multi-agent chemotherapy, 2-year progression-free survival (PFS) rates for adults with high-risk Burkitt's lymphoma (BL) remains <55%.

PATIENTS AND METHODS

We conducted a phase II trial for newly diagnosed classic BL utilizing liposomal doxorubicin (Adriamycin) in lieu of doxorubicin and incorporating intravenous rituximab (at 500 mg/m(2) twice/cycle) into the CODOX-M/IVAC regimen. Correlative analyses included paired serum and cerebrospinal fluid (CSF) rituximab levels and close examination of cardiac function.

RESULTS

Among 25 BL patients, the median age was 44 years (23-70) and 4 patients were HIV positive. There were 20 high-risk and 5 low-risk patients. At baseline, 40% of high-risk patients had bone marrow involvement, 35% had bulky disease and 15% had central nervous system involvement. The overall response rate was 100% (complete remission 92%). At 34-month median follow-up, the 2-year PFS and overall survival (OS) rates for all patients were 80% and 84%, respectively (low-risk: both 100%; high-risk: 76% and 81%, respectively). Furthermore, the 2-year PFS, OS, and disease-specific survival (DSS) rates for high-risk, HIV-negative patients were 84%, 89% and 100%, respectively. Adverse events (AEs) appeared to be consistent with prior CODOX-M/IVAC data, although there were several grade 3 cardiac events noted (all declined ejection fraction without clinical symptoms). The mean serum rituximab levels at 24 h after cycles 1 and 3 for patients without relapse were 258 and 306 μg/ml, respectively, versus 131 and 193 μg/ml, respectively, for patients with early progression (P = 0.002 and 0.002, respectively). The mean CSF rituximab levels for all patients were 0.11 and 0.24 μg/ml, respectively, at cycle 1 (24/72 h), which equated to serum:CSF ratios of 0.05% and 0.20%, respectively.

CONCLUSIONS

The integration of rituximab into CODOX-M/IVAC for adult BL was feasible and tolerable, while changes in cardiac function warrant continued examination. This regimen was associated with excellent survival rates for HIV-negative BL. Further investigation of the predictive value of serum rituximab is needed. Clinicaltrials.gov NCT00392990.

Vancomycin resistant enterococci (VRE) infections in hematopoietic stem cell transplant (HSCT) recipients

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Background: VRE blood stream infections (BSI) pose significant hazards to HSCT patients. Risk factors predisposing patients for a relatively nonpathogenic organism to become bacteremic include immune suppression, neutropenia, renal failure, antibiotic exposure, indwelling catheters, and VRE colonization. Some studies suggest that a VRE BSI is simply a marker of primary disease severity or an indicator of poor outcome, while other data demonstrate VRE BSI as an independent predictor of mortality. Methods: We performed a retrospective chart analysis of HSCT patient data using the electronic medical record and written charts using a standard data collection tool from February 1994 to October 2008. Vancomycin susceptibility was determined using the Dade Berhing panel. Results: We noted 625 infections in 385 HSCT patients; 26 patients developed 27 VRE infections over the course of 15 years. All isolates were Enterococcus faecium and not polymicrobial. Host characteristics included mean age of 49.5 yrs, all had central venous catheters, and 26 received linezolid treatment. Persistent infection was identified in 11 patients with central access removal in 4. VRE colonization was identified in stool (18 patients) and urine (5 patients) and 4 patients had a prior VSE BSI. 16 patients received vancomycin within 30 days of developing VRE BSI. 21 patients were neutropenic (mean duration15 days). 8 patients were not receiving immunosuppressants during time of bacteremia. Gastrointestinal endoscopy was identified in 6 patients prior to BSI. 16 patients died during the hospitalization. Conclusions: VRE accounted directly or indirectly for 13 of 16 deaths during incident hospitalization. In this population, blood, urine, stool surveillance is warranted to prevent morbidity/mortality related to developing a VRE BSI. Prolonged neutropenia was associated with development of a VRE BSI prophylactic granulocyte transfusion might be useful to prevent BSI. In contrast to prior studies, many patients were not receiving immunosuppressants and did not undergo GI instrumentation. VRE BSI prevention should include identifying patients with urinary or stool colonization, appropriate isolation and early central venous catheter removal if a VRE BSI is identified.

No significant financial relationships to disclose.

Adenosine depresses transmitter release but is not the basis for 'tetanic fade' at the neuromuscular junction of the rat

It has been suggested that during repetitive neural stimulation adenosine accumulates at the neuromuscular junction and the resulting negative feedback action of adenosine is the major basis for tetanic fade (decline in action of adenosine during repetitive stimulation) This hypothesis was examined at the rat neuromuscular junction by examining the effects of blocking adenosine A1-receptors. Intracellular recording techniques were used to monitor end-plate potentials and miniature end-plate potentials. The data suggest that while adenosine serves a role in depressing transmitter release, adenosine accumulation during brief periods of stimulation is minimal and adenosine is not the cause for tetanic fade.