Assessment of the Efficacy of Therapies Following Venetoclax Discontinuation in CLL Reveals BTK Inhibition as an Effective Strategy.

PURPOSE: Venetoclax-based therapy is a standard-of-care option in first-line and relapsed/refractory chronic lymphocytic leukemia (CLL). Patient management following venetoclax discontinuation remains nonstandard and poorly understood. EXPERIMENTAL DESIGN: To address this, we conducted a large international study to identify a cohort of 326 patients who discontinued venetoclax and have been subsequently treated. Coprimary endpoints were overall response rate (ORR) and progression-free survival for the post-venetoclax treatments stratified by treatment type [Bruton's tyrosine kinase inhibitor (BTKi), PI3K inhibitor (PI3Ki), and cellular therapies]. RESULTS: We identified patients with CLL who discontinued venetoclax in the first-line (4%) and relapsed/refractory settings (96%). Patients received a median of three therapies prior to venetoclax; 40% were BTKi naïve (n = 130), and 81% were idelalisib naïve (n = 263). ORR to BTKi was 84% (n = 44) in BTKi-naïve patients versus 54% (n = 30) in BTKi-exposed patients. We demonstrate therapy selection following venetoclax requires prior novel agent exposure consideration and discontinuation reasons. CONCLUSIONS: For BTKi-naïve patients, selection of covalently binding BTKis results in high ORR and durable remissions. For BTKi-exposed patients, covalent BTK inhibition is not effective in the setting of BTKi resistance. PI3Kis following venetoclax do not appear to result in durable remissions. We conclude that BTKi in naïve or previously responsive patients and cellular therapies following venetoclax may be the most effective strategies.See related commentary by Rogers, p. 3501.

Prospective Study of 3'-Deoxy-3'-18F-Fluorothymidine PET for Early Interim Response Assessment in Advanced-Stage B-Cell Lymphoma.

UNLABELLED: Current clinical and imaging tools remain suboptimal for early assessment of prognosis and treatment response in aggressive lymphomas. PET with 3'-deoxy-3'-(18)F-fluorothymidine ((18)F-FLT) can be used to measure tumor cell proliferation and treatment response. In a prospective study in patients with advanced-stage B-cell lymphoma, we investigated the prognostic and predictive value of (18)F-FLT PET in comparison to standard imaging with (18)F-FDG PET and clinical outcome. METHODS: Sixty-five patients were treated with an induction/consolidation regimen consisting of 4 cycles of R-CHOP-14 (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone) followed by 3 cycles of ICE (ifosfamide, carboplatin, etoposide). (18)F-FLT PET was performed at baseline and at interim (iPET) after 1-2 cycles of therapy. (18)F-FDG PET was performed at baseline, after cycle 4, and at the end of therapy. The relationship between PET findings, progression-free survival (PFS) and overall survival (OS) was investigated. RESULTS: With a median follow-up of 51 mo, PFS and OS were 71% and 86%, respectively. (18)F-FLT iPET, analyzed visually (using a 5-point score) or semiquantitatively (using SUV and ΔSUV) predicted both PFS and OS (P < 0.01 for all parameters). Residual (18)F-FLT SUVmax on iPET was associated with an inferior PFS (hazard ratio, 1.26, P = 0.001) and OS (hazard ratio, 1.27, P = 0.002). When (18)F-FDG PET was used, findings in the end of treatment scan were better predictors of PFS and OS than findings on the interim scan. Baseline PET imaging parameters, including SUV, proliferative volume, or metabolic tumor volume, did not correlate with outcome. CONCLUSION: (18)F-FLT PET after 1-2 cycles of chemotherapy predicts PFS and OS, and a negative (18)F-FLT iPET result may potentially help design risk-adapted therapies in patients with aggressive lymphomas. In contrast, the positive predictive value of (18)F-FLT iPET remains too low to justify changes in patient management.

Surveillance imaging for lymphoma: pros and cons.

There is no international consensus on the optimal frequency or duration of computed tomography or positron emission tomography scanning for surveillance in patients who achieve complete remission after initial therapy for lymphoma. Although some clinical practice guidelines suggest periodic imaging is reasonable, others suggest little or no benefit to this practice. From a theoretical perspective, the frequency and duration of surveillance imaging is largely dependent upon the lymphoma subtype. Aggressive lymphomas with a fast growth rate will require surveillance more frequently and for a shorter duration compared to the indolent lymphomas. Historically, relapse has been detected in a majority of patients based upon clinically evident signs and symptoms. Currently, no study has demonstrated an overall survival difference for patients with relapse detected by imaging as opposed to clinical evaluation, although one study did demonstrate a lower second-line International Prognostic Index in patients with relapse detected by surveillance imaging. Enthusiasm for this finding has been tempered by recent studies highlighting the potential long-term risk of secondary malignancies because of ionizing radiation exposure from diagnostic imaging. These factors along with the significant costs associated with diagnostic imaging have contributed to an ongoing debate regarding the relative costs, risks, and benefits of radiographic surveillance. Herein we present perspectives for and against routine surveillance imaging in an effort to facilitate a better understanding of the issues relevant to what is ultimately a clinical decision made by an oncologist and his or her patient.

Association of quantitative assessment of the intrafollicular proliferation index with outcome in follicular lymphoma.

The role of the proliferation index (PI) as an outcome predictor in follicular lymphoma (FL) isn't clear. We have previously demonstrated that quantitative image analysis (QIA) is a robust tool for PI determination and the present study aimed to determine the significance of the PI for outcome in low-grade FL. One hundred and twenty-nine patients with grade 1-2 FL were retrospectively analysed. Slides were scanned digitally and follicle/tumour-involved areas were annotated. The intrafollicular PI was estimated by analysing a median of 10 follicles per case. Patients were divided into two groups: PI < 30%, PI ≥ 30% and clinical outcome was analysed. Among the 129 patients analysed, intrafollicular PI ranged from 0·6 to 63·2% with a median of 23·3%. Overall survival was not influenced by PI group. Among those patients initially observed, intrafollicular PI < 30% was associated with longer time to first therapy compared to patients with a PI ≥ 30%. In the group of patients that were treated at diagnosis, PI was not predictive of time to treatment failure (TTTF). Intrafollicular PI is an important predicator of TTFT for patients who are candidates for observation. Further confirmation in an independent cohort of patients is necessary to determine the clinical validity of the results.

NCCN Biosimilars White Paper: regulatory, scientific, and patient safety perspectives.

Biologics are essential to oncology care. As patents for older biologics begin to expire, the United States is developing an abbreviated regulatory process for the approval of similar biologics (biosimilars), which raises important considerations for the safe and appropriate incorporation of biosimilars into clinical practice for patients with cancer. The potential for biosimilars to reduce the cost of biologics, which are often high-cost components of oncology care, was the impetus behind the Biologics Price Competition and Innovation Act of 2009, a part of the 2010 Affordable Care Act. In March 2011, NCCN assembled a work group consisting of thought leaders from NCCN Member Institutions and other organizations, to provide guidance regarding the challenges health care providers and other key stakeholders face in incorporating biosimilars in health care practice. The work group identified challenges surrounding biosimilars, including health care provider knowledge, substitution practices, pharmacovigilance, naming and product tracking, coverage and reimbursement, use in off-label settings, and data requirements for approval.

Assessment of treatment-related myelodysplastic syndromes and acute myeloid leukemia in patients with non-Hodgkin lymphoma treated with tositumomab and iodine I131 tositumomab.

The incidence of treatment-related myelodysplastic syndromes and acute myeloid leukemia (tMDSs/tAML) after tositumomab and iodine I(131) tositumomab administration to previously treated and untreated patients with non-Hodgkin lymphoma (NHL) was evaluated. A total of 1071 patients were enrolled in 7 studies: 995 with relapsed/refractory low-grade NHL, +/- transformation (median, 3 prior regimens [range, 1-13 regimens]) and 76 patients with previously untreated low-grade follicular NHL. A single dose of iodine tositumomab and I(131) tositumomab was administered. For tMDS/tAML patients, baseline and posttherapy peripheral blood and marrow specimens were reviewed in a blinded fashion. Median follow-up was 6 years from diagnosis and 2 years from radioimmunotherapy (RIT) for previously treated patients, and 4.6 years from radioimmunotherapy for previously untreated patients. tMDS/tAML was reported in 35 (3.5%) of 995 patients (annualized incidence, 1.6%/y [95% confidence interval, 1.0%-2.0%/y]), and 52% of the tMDS/tAML diagnoses of tMDS/tAML were confirmed in a blinded review (annualized incidence of 1.1%/y [95% confidence interval, 0.7%-1.6%/y]). Of the 25 cases, 10 patients (40%) were diagnosed with tMDS/tAML prior to receiving radioimmunotherapy; 2 (8%) had no pathologic or clinical evidence to support such a diagnosis; and 13 (52%) were confirmed to have developed tMDS/tAML following RIT. This incidence is consistent with that expected on the basis of patients' prior chemotherapy for NHL. With a median follow-up approaching 5 years, no case of tMDS/tAML has been reported in any of the 76 patients receiving iodine I(131) tositumomab as their initial therapy (P = .011 compared with previously treated patients).

Patient-specific, 3-dimensional dosimetry in non-Hodgkin's lymphoma patients treated with 131I-anti-B1 antibody: assessment of tumor dose-response.

UNLABELLED: A comprehensive, SPECT-based, patient-specific 3-dimensional (3D) dosimetry analysis has been performed using 3D-ID, a previously developed software package. The role of the total-body tumor burden, individual lesion size, tumor absorbed dose, and the spatial distribution of the absorbed dose on response and on the time course of tumor shrinkage has been examined in patients with lymphoma treated by radioimmunotherapy. METHODS: Data from 15 patients participating in a phase II study of (131)I-labeled anti-B1 antibody (tositumomab) were used. Patients were administered a tracer dose of (131)I for imaging and pharmacokinetics. Dose estimates from the tracer studies were used to prescribe the therapeutic administration such that the whole-body absorbed dose did not exceed 75 cGy. All patients received a fixed mass amount of antibody for both the tracer and the therapeutic administrations. SPECT and planar imaging were performed 3-4 d after the therapeutic administration. CT or MRI scans were available on all patients. Total tumor burden was assessed by drawing contours around all lymphoma lesions identified on whole-body CT or MRI. Mean absorbed doses were estimated for selected, index lesions by conventional dosimetry and also by 3D SPECT-based dosimetry. Using a patient-specific dosimetry package, 3D-ID, dose-volume histograms were also generated to assess the spatial distribution of absorbed dose. This approach made it possible to obtain estimates of the minimum and maximum absorbed doses for individual tumors in addition to the mean. RESULTS: Mean absorbed dose estimates obtained by patient-specific SPECT-based dosimetry using 3D-ID were within 2%-5% of estimates obtained by conventional dosimetry. None of the absorbed dose parameters (mean, minimum, maximum, uniformity) were found to have a significant correlation with tumor response. The total-body tumor burden did not impact on overall response or toxicity. CONCLUSION: This analysis represents the first full reported implementation of a patient-specific 3D dosimetry package. The absence of a dose-response relationship for tumors is surprising and suggests that absorbed dose is not the sole determinant of tumor response in these patients. The absence of a correlation between the total-body tumor burden and overall response or toxicity suggests that tailoring the milligram amount of administered antibody to patient tumor burden is not likely to improve response or reduce toxicity.