SAMHD1 expression contributes to doxorubicin resistance and predicts survival outcomes in diffuse large B-cell lymphoma patients

Diffuse large B-cell lymphoma (DLBCL) is a commonly diagnosed, aggressive non-Hodgkin's lymphoma. While R-CHOP chemoimmunotherapy is potentially curative, about 40% of DLBCL patients will fail, highlighting the need to identify biomarkers to optimize management. SAMHD1 has a dNTPase-independent role in promoting resection to facilitate DNA double-strand break (DSB) repair by homologous recombination. We evaluated the relationship of SAMHD1 levels with sensitivity to DSB-sensitizing agents in DLBCL cells and the association of SAMHD1 expression with clinical outcomes in 79 DLBCL patients treated with definitive therapy and an independent cohort dataset of 234 DLBCL patients. Low SAMHD1 expression, Vpx-mediated, or siRNA-mediated degradation/depletion in DLBCL cells was associated with greater sensitivity to doxorubicin and PARP inhibitors. On Kaplan-Meier log-rank survival analysis, low SAMHD1 expression was associated with improved overall survival (OS), which on subset analysis remained significant only in patients with advanced stage (III-IV) and moderate to high risk (2-5 International Prognostic Index (IPI)). The association of low SAMHD1 expression with improved OS remained significant on multivariate analysis independent of other adverse factors, including IPI, and was validated in an independent cohort. Our findings suggest that SAMHD1 expression mediates doxorubicin resistance and may be an important prognostic biomarker in advanced, higher-risk DLBCL patients.

Phase 2 Trial of Anti-PD1 and 8 Gy in 1 Fraction for Relapse/Refractory Myeloma

PURPOSE/OBJECTIVE(S)

Relapsed, refractory multiple myeloma is associated with poor outcome. Role of radiotherapy is mainly for palliation. Anti-PD1 inhibitors have failed to show efficacy in relapsed refractory myeloma patients. A phase 2 trial (NCT03267888) was conducted to see if radiotherapy (8 Gy in 1 fraction) and anti-PD1 (Pembrolizumab) could provide early signals of safety and response.

MATERIALS/METHODS

A prospective single-center phase 2 trial involving patients >18 years of age with ECOG 0-1 was conducted after obtaining IRB approval. Patients had to have ISS stage I-III multiple myeloma that was either relapsed or refractory, an osseous and/or extraosseous lesion that could be radiated, and who were candidates for pembrolizumab. Patients had to have either measurable disease per the International Myeloma Working Group Criteria (IMWG) and/or had to have progressive disease on imaging. Radiotherapy was given on day 0, cycle 1 followed by pembrolizumab (200 mg/kg iv on day 2 or 3, then every 3 weeks +/- 7 days) on day 2-3 for at least 2 years or until progression. Primary endpoint was toxicity. Secondary endpoints were IMWG response, abscopal response, overall survival, and immunological changes in patient's blood. Patients were assessed at 3 months, 6 months, and 12 months IMWG criteria as well as serial PET/CT based imaging. Patients with stable disease or better were continued on the trial. Patients that progressive were removed. Standard statistical analysis was performed, and included Kaplan-Meier to estimate OS and PFS.

RESULTS

From June, 2018 until October, 2021, 32 patients were screened and 25 were enrolled. Of the enrolled patients, 76% were Caucasian, 64% had ECOG 1, and the mean age was 60 years. Prior to enrollment, the mean number of prior lines of therapy that the patients had failed was 5.20 (range: 2 - 11), suggesting a cohort with poor expected outcome. These cohort also had limited alternative options. Toxicity, as its primary endpoint, was acceptable. There were no grade 2 or higher radiation related toxicity within the irradiated volume. Only one case of grade 3 or higher pembrolizumab-related toxicity was noted amongst the 25 patients. Abscopal response was noted in 5 of 25 patients (20% patients). Several patients showed robust reductions in the paraproteins and other myeloma labs, suggesting response to radiotherapy and anti-PD1 combination. These patients were also associated to have a robust CD 8 T cell activation and an abscopal response. The secondary outcomes were better than expected for this cohort.

CONCLUSION

Combination therapy of single-fraction, low-dose radiation therapy with pembrolizumab in patients with relapsed or refractory multiple myeloma is worth assessing in future trials.

Risk Factors and Clinical Features of Fistula after Concurrent Chemoradiation and Brachytherapy for Locally Advanced Cervical Cancer

PURPOSE/OBJECTIVE(S)

The standard treatment for locally advanced cervical cancer (LACC) is concurrent chemoradiation and brachytherapy (CRT-B). Fistula formation is a serious complication of treatment; however, risk factors and clinical outcomes are not well described. We sought to identify the incidence, risk factors and prognosis of radiation-induced fistula in women who underwent CRT-B for LACC.

MATERIALS/METHODS

A single institution retrospective review of patients treated with CRT-B for LACC from July 2013 to August 2022 across 3 centers was performed. Inclusion criteria were Stage IB-IVB cervical cancer treated with definitive intent. Patients with upfront or adjuvant surgery were excluded. Cox-proportional hazards model was performed to assess factors associated with fistula. Local control and fistula-free survival were estimated using the Kaplan-Meyer method. Clinical significance was defined as p < 0.05.

RESULTS

A total of 105 patients met the inclusion criteria and were included in this analysis. Patients consisted of FIGO Stage I (n = 20, 19%), Stage II (n = 22, 21%), Stage III (n = 46, 43.8%) or Stage IV disease (n = 17, 16.2%). 12 (11.4%) patients developed fistula following CRT-B; 1/12 patients (8.3%) had fistula present at time of diagnosis. Median time to fistula development was 12 months. Fistula was characterized as vesicovaginal/urethrovaginal in 58.3% (n = 7) and rectovaginal/intestinovaginal in 83.3% (n = 10), including 8 patients (66.7%) who had more than one type of fistula. 4/12 (33.3%) of patients with fistula had concurrent local recurrence. Patients were treated with conservative management (41.7%), hyperbaric oxygen (16.7%) and/or surgery (83.3%). Complications included infection (50.0%), urinary/bowel diversion (83.3%), hospitalization (50.0%) and death (8.3%). Fistula was resolved in 7/12 patients (58.3%) at time of last follow up. Higher BMI (p = 0.04) and use of hybrid applicators (p = 0.02) were associated with decreased likelihood of fistula development. Disease extension into bladder was associated with increased likelihood of fistula development (p = 0.03). Compared to former and never smoking, current smoking was associated with a higher risk of developing fistula (p = 0.04, OR 4.42, CI:1.07-18.34). Compared to intracavitary and hybrid applicators, the use of a Syed applicator was associated with increased likelihood of fistula development (p = 0.02, OR 8.00, CI: 1.37-46.55). Two-year local control was 82.5% (CI: 64.5-91.9) for Stage I-II, 80.7% (CI: 62.8-90.6) for Stage III, and 62.2% (CI: 30.1-82.9) for Stage IV. Two-year fistula free survival was 89.9% (CI: 80.6 - 94.9).

CONCLUSION

Women who undergo definitive chemoradiation for treatment of LACC have a 11.4% risk of fistula formation overall. The risk is higher amongst patients with current smoking, disease extension into bladder and Syed applicators. Overall two-year local control was 78.7% and fistula free survival was 89.9%.

Disparities in Time to Prostate Cancer Treatment Initiation before and after the Affordable Care Act

PURPOSE/OBJECTIVE(S)

Delayed access to care may contribute to disparities in prostate cancer (PCa). The Affordable Care Act (ACA) aimed at increasing access and reducing healthcare disparities, but its impact on timely treatment initiation for men with PCa is unknown.

MATERIALS/METHODS

Men with intermediate- and high-risk PCa diagnosed 2010-2016 and treated with curative surgery or radiotherapy were identified in the National Cancer Database. Multivariable logistic regression modeled the effect of race and insurance type on treatment delay >180 days after diagnosis to start of surgery, radiotherapy, or hormonal therapy. Cochran-Armitage test measured annual trends in delays, and join point regression assessed if 2014, the year the ACA became fully operationalized, was significant for inflection in crude rates of major delays.

RESULTS

Of 422,506 eligible men, 18,720 (4.4%) experienced >180-day delay in treatment initiation. Compared to White patients, Black (OR 1.79, 95% CI 1.72-1.87, p<.001) and Hispanic (OR 1.37, 95% CI 1.28-1.48, p<.001) patients had higher odds of delay. These disparities persisted when analyzing only patients treated after 2014 or for patients who had Medicare or Private insurance. Compared to uninsured patients, those with Medicaid had no difference in odds of delay (OR 0.94, 95% CI 0.84-1.06, p = .31), while those with private insurance (OR 0.57, 95% CI 0.52-0.63, p<.001) or Medicare (OR 0.64, 95% CI 0.58-0.70, p<.001) had lower odds of delay. These disparities persisted when analyzing only patients treated after 2014. Mean time to treatment significantly increased from 2010 to 2016 across all racial/ethnic groups (trend p<.001); 2014 was associated with a significant inflection for increase in rates of major delays.

CONCLUSION

The impact of race and insurance status were independently associated with longer delays to PCa treatment in the US. These disparities were unaffected by implementation of the ACA. In fact, implementation of ACA was associated with increased delays in treatment initiation for all men, regardless of race. As the epidemiology of newly diagnosed prostate cancer in the United States continues to shift due to tempered screening and the COVID pandemic, further work will be needed to increase equity in prostate cancer care.

Combined Analysis of a Phase III Randomized Trial and Phase II Prospective Trial with Blind Control Matching of Patients Receiving Whole-Lung, Low-Dose Radiation for COVID-19: Full Results and Immunologic Correlates of the RESCUE 1-19 Trial

PURPOSE/OBJECTIVE(S)

Whole-lung, low-dose radiation (LD-RT) for COVID-19 requires randomization and biologic correlates to determine causality and mechanism.

MATERIALS/METHODS

A phase III trial randomized COVID-19 patients to physician's choice of drug therapy with or without LD-RT. Primary endpoint was intubation-free survival (IFS). The trial was designed with 80% power (two-sided log rank, alpha 0.05) to detect a hazard ratio of 0.3 after 12 intubation events. Estimating a 25% event rate, the planned sample size was 84 patients plus 25 to account for declining intubation rates and screen failures. Due to hospitalization declines and other barriers, the trial closed prematurely. Available randomized data were analyzed by intention-to-treat and combined with phase II results and immunologic correlates, using one-sided significance and an alpha of 0.1 to inform future trial design.

RESULTS

From Jun 2020-Jun 2022, 14 patients were randomized on a phase III trial. From Apr 2020-Dec 2020, 42 patients were enrolled on a phase II trial and blindly matched to 40 controls from contemporaneous trials. 96 total patients and 193 blood samples were available for analysis. Mean hospital duration with LD-RT was 12.9 vs 15.4 days in controls (p = 0.12). Oxygen flow rate >15 L/min (26% vs 38%, p = .27), high-flow oxygen >30 L/min (24% vs 38%, p = 0.18), non-invasive positive-pressure >60 L/min (9% vs 27%, p = 0.03), and mechanical ventilation (9% vs 24%, p = 0.05) reduced with LD-RT. Mean supplemented oxygen volume was 171,759 vs 547,626 liters in controls, with daily means of 10 vs 23 L/min (p = 0.03). Radiographs worsened in 43% vs 71% of controls (p = 0.03). Arterial blood gas mean P/F ratios improved 22% after LD-RT vs declined 8% in controls (p = 0.12). Mean days febrile were 1.8 vs 2.9 in controls (p = 0.10). Rate of myocardial injury was 47% vs 40% in controls (p = 0.77). Flow cytometry revealed 4-fold and 30-fold larger expansions, respectively, in CD8- and CD4-positive CD3+PD1+Ki67-high proliferating cytotoxic T-cells (300% vs 75% expansion, p = 0.07) and helper T-cells (200% expansion vs 6% contraction, p = 0.03) at day 7. In the randomized cohort, mean oxygen volume fell 75% with LD-RT to 78,336 vs 316,786 liters in controls (p = 0.13), mean flow rates were 5.1 vs 18.4 L/min (p = 0.13), radiographs worsened in 50% vs 100% (p = .17), P/F ratios improved 31% vs declined 68% in controls (p = 0.03), hospital duration was 8.9 vs 11.5 days (p = 0.22), and zero LD-RT patients vs one control intubated.

CONCLUSION

Combined analysis of a phase II/III randomized trial suggests that LD-RT prevents ventilation, reduces supplemental oxygen need, improves clinical course, and enhances immune response. LD-RT may have both immediate direct effects and delayed enhanced immunity in COVID-19. Larger multi-institutional trials are justified.

Accounting for the High Enrollment of African Americans on Winship Cancer Institute's Myeloma Clinical Trials

Background

Thirty-four percent of Multiple Myeloma (MM) clinical trial participants at Winship Cancer Institute (Winship) are African American (AA); however, AAs make up only 4.5 percent of myeloma clinical trial participants in the United States. Given our high enrollment, we aimed to measure AAs' trust in providers and identify if clinical trial enrollment barriers exist.

Methodology

A member of the ethics research team surveyed AA patients who had consented to a MM clinical trial at Winship. Three validated surveys were used: Trust in Medical Research (TMR); Human Connection (THC) which measures how much patients feel they are heard and valued by their physicians; and the Duke Intrinsic Religiosity Scale (DUREL) which measures strength of religious engagement and belief. The survey also included questions about the impact of side effects, distance to the trial center and trial related costs on the decision to participate in clinical trial.

Results

Ninety-two percent (61/67) of patients approached consented. The mean TMR score and the mean THC score were significantly higher (P-value < 0.001) than the results obtained in key national surveys (TMR 14.9 compared to 11.65; THC 57.7 compared to 54.6). These two surveys were significantly correlated, meaning trust and human connection increase or decrease in tandem. The 3 religiosity subscale results showed high religiosity (3.84, 4.36, and 4.35 with 5 being the highest score). The mean scores of the importance of the investigational agent's side effects, trial costs, and distance to trial center on the decision to enroll in a clinical trial were also high (8.5, 7.8, and 6.5, respectively, with 10 being the most important).

Conclusion

In our study population, high trust and human connection overcame other trial participation barriers: strong religious beliefs and concerns about side effects, costs, and travel distance. We present a roadmap to guide investigators to increase human connection, and hopefully trust.

The role of radiotherapy for patients over age 60 with diffuse large B-cell lymphoma in the rituximab era

The role of consolidative radiotherapy (RT) in patients ≥60 years old with DLBCL in the rituximab era is controversial. We examined the impact on disease control and overall survival by the addition of consolidative RT after completion of chemotherapy, while adjusting for known adverse risk factors. Retrospective chart review from 2004 to 2012 of 83 consecutive patients ≥60 years old with DLBCL treated in the rituximab era, 68 of which had a complete response to chemotherapy, was performed. Amongst patients with a complete response, consolidative RT use was associated with 100% 5-year local control, improved progression-free survival (p = 0.047), and a trend for overall survival (p = .098) on multivariate analysis. Amongst all patients, the use of consolidative RT was associated with improved overall survival (p = 0.03). The use of consolidative RT should be considered for patients ≥60 years old independent of stage and response to chemotherapy.