PARP inhibitor therapy in patients with IDH1 mutated cholangiocarcinoma.

BACKGROUND: Isocitrate dehydrogenase 1 (IDH1) missense mutations occur at a frequency of 10%-15% in intrahepatic cholangiocarcinoma (iCCA). IDH1 mutations result in accumulation of (R)-2-hydroxyglutarate, an oncometabolite that leads to DNA hypermethylation and impairment of homologous recombination (HR). Impairment of HR results in a "BRCAness" phenotype which may confer sensitivity to poly(ADP ribose) polymerase (PARP) inhibition. METHODS: We conducted a retrospective cohort review to identify patients with advanced, IDH1 mutated iCCA treated with a PARP inhibitor (PARPi) at the University of Michigan between 2018 and 2023. Patients are described with respect to prior lines of therapy, response to platinum-based chemotherapy, and progression-free survival (PFS) and overall survival (OS) from the time of PARPi initiation. RESULTS: Between 2018 and 2023 we identified 40 patients with IDH1 mutated iCCA of which 6 patients were treated with a PARPi as monotherapy or in combination with an ATR inhibitor or anti-PD-1 immune checkpoint inhibitor. Majority of patients (n = 5) carried an IDH1 R132C mutation per tissue-based next generation sequencing. All patients had previously received at least one line of cisplatin-based systemic therapy for advanced disease prior to treatment with PARPi. PFS and OS from time of PARPi initiation ranged from 1.4 to 18.5 months and 2.8 to 42.4 months, respectively. Best response on PARPi therapy included 2 partial responses. CONCLUSION: This is the first case series to describe PARPi treatment in IDH1 mutated iCCA. Results underscore the limitation of PARPi monotherapy, potentially support combined PARPi therapies, and highlight a need for effective treatment options for patients with IDH1 mutated iCCA.

Enhancing precision: A predictive model for 177Lu-DOTATATE treatment response in neuroendocrine tumors using quantitative 68Ga-DOTATATE PET and clinicopathological biomarkers.

Purpose: This study aims to elucidate the role of quantitative SSTR-PET metrics and clinicopathological biomarkers in the progression-free survival (PFS) and overall survival (OS) of neuroendocrine tumors (NETs) treated with peptide receptor radionuclide therapy (PRRT). Methods: A retrospective analysis including 91 NET patients (M47/F44; age 66 years, range 34-90 years) who completed four cycles of standard 177Lu-DOTATATE was conducted. SSTR-avid tumors were segmented from pretherapy SSTR-PET images using a semiautomatic workflow with the tumors labeled based on the anatomical regions. Multiple image-based features including total and organ-specific tumor volume and SSTR density along with clinicopathological biomarkers including Ki-67, chromogranin A (CgA) and alkaline phosphatase (ALP) were analyzed with respect to the PRRT response. Results: The median OS was 39.4 months (95% CI: 33.1-NA months), while the median PFS was 23.9 months (95% CI: 19.3-32.4 months). Total SSTR-avid tumor volume (HR = 3.6; P = 0.07) and bone tumor volume (HR = 1.5; P = 0.003) were associated with shorter OS. Also, total tumor volume (HR = 4.3; P = 0.01), liver tumor volume (HR = 1.8; P = 0.05) and bone tumor volume (HR = 1.4; P = 0.01) were associated with shorter PFS. Furthermore, the presence of large lesion volume with low SSTR uptake was correlated with worse OS (HR = 1.4; P = 0.03) and PFS (HR = 1.5; P = 0.003). Among the biomarkers, elevated baseline CgA and ALP showed a negative association with both OS (CgA: HR = 4.9; P = 0.003, ALP: HR = 52.6; P = 0.004) and PFS (CgA: HR = 4.2; P = 0.002, ALP: HR = 9.4; P = 0.06). Similarly, number of prior systemic treatments was associated with shorter OS (HR = 1.4; P = 0.003) and PFS (HR = 1.2; P = 0.05). Additionally, tumors originating from the midgut primary site demonstrated longer PFS, compared to the pancreas (HR = 1.6; P = 0.16), and those categorized as unknown primary (HR = 3.0; P = 0.002). Conclusion: Image-based features such as SSTR-avid tumor volume, bone tumor involvement, and the presence of large tumors with low SSTR expression demonstrated significant predictive value for PFS, suggesting potential clinical utility in NETs management. Moreover, elevated CgA and ALP, along with an increased number of prior systemic treatments, emerged as significant factors associated with worse PRRT outcomes.

Devimistat in Combination with Gemcitabine and Cisplatin in Biliary Tract Cancer: Preclinical Evaluation and Phase Ib Multicenter Clinical Trial (BilT-04).

PURPOSE: Devimistat (CPI-613) is a novel inhibitor of tumoral mitochondrial metabolism. We investigated the effect of devimistat in vitro and in a phase Ib clinical trial in patients with advanced biliary tract cancer (BTC). PATIENTS AND METHODS: Cell viability assays of devimistat ± gemcitabine and cisplatin (GC) were performed and the effect of devimistat on mitochondrial respiration via oxygen consumption rate (OCR) was evaluated. A phase Ib/II trial was initiated in patients with untreated advanced BTC. In phase Ib, devimistat was infused over 2 hours in combination with GC on days 1 and 8 every 21 days with a primary objective to determine the recommended phase II dose (RP2D). Secondary objectives included safety, overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). RESULTS: In vitro, devimistat with GC had a synergistic effect on two cell lines. Devimistat significantly decreased OCR at higher doses and in arms with divided dosing. In the phase Ib trial, 20 patients received a median of nine cycles (range, 3-19). One DLT was observed, and the RP2D of devimistat was determined to be 2,000 mg/m2 in combination with GC. Most common grade 3 toxicities included neutropenia (n = 11, 55%), anemia (n = 4, 20%), and infection (n = 3, 15%). There were no grade 4 toxicities. After a median follow-up of 15.6 months, ORR was 45% and median PFS was 10 months (95% confidence interval, 7.1-14.9). Median OS is not yet estimable. CONCLUSIONS: Devimistat in combination with GC is well tolerated and has an acceptable safety profile in patients with untreated advanced BTC.

Integrating Medical Genetics Into Precision Oncology Practice in the Veterans Health Administration: The Time Is Now.

PURPOSE: Increased access and utilization of tumor profiling of cancers in our veteran population uncovered a modest number of potentially pathogenic germline variants (PPGVs) that require genetics referral for follow-up evaluation and germline sequencing. Challenges identified specific to the veteran population include paucity of genetics providers, either at a veteran's VA facility or nearby non-VA facilities. We sought to investigate the number of veterans who would benefit from having such resources at both local and national levels. METHODS: Annotated clinical reports of mutations identified by tumor-only profiling and medical records of veterans with solid tumors at the Veterans Administration Ann Arbor Healthcare System (VA AAHS) between 2015 and 2020 were reviewed. PPGVs were identified according to society recommendations (such as ESMO and American Board of Medical Genetics and Genomics), expert review, and/or previously published criteria. After the analysis of our local VA population, these same criteria were then applied to veterans in the National Precision Oncology Program (NPOP). RESULTS: Two hundred eight veterans underwent tumor profiling at the VA AAHS over the defined time period. This included 20 different primary tumor sites with over half (n = 130) being advanced cancer at diagnosis. Of these, 18 veterans (8.5%) had mutations suggestive of a PPGV. Applying these criteria to the larger NPOP database (n = 20,014), a similar percentage (6%) of PPGVs were identified. CONCLUSION: These results indicate a PPGV frequency (6%-9% of veterans) consistent with the prevalence of inherited cancer predisposition syndromes in the general population, underscoring the need for medical genetics as part of standard oncologic care for veterans. We explore current and future care delivery models to optimize incorporation of medical genetics and genetic counseling to best serve veterans needing such services.

Targeting Ribonucleotide Reductase Induces Synthetic Lethality in PP2A-Deficient Uterine Serous Carcinoma.

Uterine serous carcinoma (USC) is a highly aggressive endometrial cancer subtype with limited therapeutic options and a lack of targeted therapies. While mutations to PPP2R1A, which encodes the predominant protein phosphatase 2A (PP2A) scaffolding protein Aα, occur in 30% to 40% of USC cases, the clinical actionability of these mutations has not been studied. Using a high-throughput screening approach, we showed that mutations in Aα results in synthetic lethality following treatment with inhibitors of ribonucleotide reductase (RNR). In vivo, multiple models of Aα mutant uterine serous tumors were sensitive to clofarabine, an RNR inhibitor (RNRi). Aα-mutant cells displayed impaired checkpoint signaling upon RNRi treatment and subsequently accumulated more DNA damage than wild-type (WT) cells. Consistently, inhibition of PP2A activity using LB-100, a catalytic inhibitor, sensitized WT USC cells to RNRi. Analysis of The Cancer Genome Atlas data indicated that inactivation of PP2A, through loss of PP2A subunit expression, was prevalent in USC, with 88% of patients with USC harboring loss of at least one PP2A gene. In contrast, loss of PP2A subunit expression was rare in uterine endometrioid carcinomas. While RNRi are not routinely used for uterine cancers, a retrospective analysis of patients treated with gemcitabine as a second- or later-line therapy revealed a trend for improved outcomes in patients with USC treated with RNRi gemcitabine compared with patients with endometrioid histology. Overall, our data provide experimental evidence to support the use of ribonucleotide reductase inhibitors for the treatment of USC. SIGNIFICANCE: A drug repurposing screen identifies synthetic lethal interactions in PP2A-deficient uterine serous carcinoma, providing potential therapeutic avenues for treating this deadly endometrial cancer.

Comparison of Transumbilical Laparoscopically Assisted Appendectomy to Conventional Laparoscopic Appendectomy in Children.

PURPOSE: To compare surgical outcomes of children with appendicitis treated with the transumbilical laparoscopically assisted appendectomy (TULAA) versus the conventional 3-port laparoscopic appendectomy (TPLA). MATERIALS AND METHODS: Retrospective study of pediatric patients with appendicitis treated with TULAA or TPLA between January 2010 and December 2015. Operative time (OT), length of stay, cost, and surgical site infection rate were compared between the 2 groups. RESULTS: Six hundred twenty-five appendectomies were performed [263 TULAA, 362 TPLA: acute (457), gangrenous (39), and perforated (129)]. TULAA had a shorter OT (median, 40 vs. 67 min; P<0.001), a shorter length of stay (median, 20 vs. 23 h; P<0.001), and a lesser cost (median $6266 vs. $8927; P<0.001). Surgical site infection rate was slightly higher in the TULAA group (6% vs. 4%; P=0.19). CONCLUSIONS: TULAA had a shorter OT and was less costly than conventional TPLA. TULAA should be considered as the first surgical approach at treating appendicitis in children.

Transumbilical laparoscopically assisted extracorporeal appendectomy in children and young adults: A retrospective cohort study.

BACKGROUND: To compare surgical outcomes of pediatric patients aged 0-15 with acute appendicitis treated with single-port, transumbilical, extracorporeal laparoscopically assisted appendectomy (SP) with young adult patients aged 16-21. MATERIALS AND METHODS: Single center retrospective chart review in patients 21 years and younger with a pre-operative diagnosis of appendicitis who underwent SP between January 2010 and December 2015. Patients were divided into two groups based on age. Operative time (OT), length of stay (LOS), cost, rates of conversion to standard three-port laparoscopic appendectomy (TP), and rates of infection were compared between the groups. RESULTS: SP was performed in a total of 263 patients: 211 in pediatric patients aged 0-15 and 52 in patients aged 16-21. Age groups did not differ significantly on cost, LOS, operative time, rates of conversion to TP, or rates of infection. CONCLUSIONS: SP has comparable surgical outcomes in adolescent, adult, and pediatric patients.

Laparoscopic Extracorporeal Appendectomy in Overweight and Obese Children.

BACKGROUND AND OBJECTIVES: To compare surgical outcomes of overweight and obese patients with acute appendicitis who have undergone single-port extracorporeal laparoscopically assisted appendectomy (SP) with those who have had conventional 3-port laparoscopic appendectomy (TP). METHODS: This single-center retrospective chart review included patients 21 years of age and younger with a preoperative diagnosis of appendicitis who underwent laparoscopic appendectomy from January 2010 through December 2015. Cases of gangrenous and perforated appendicitis were excluded. Subgroup analyses of patients with acute appendicitis were performed. Operative time (OT), length of stay (LOS), and cost were compared between groups stratified by body mass index (BMI) and operative technique. RESULTS: A total of 625 appendectomies were performed-457 for acute appendicitis. Sixty-eight patients were overweight. The SP technique (n = 30) had shorter OT (median minutes, 41 vs 68; P < .001), lower cost (median , $5741 vs $8530; P < .001), and shorter LOS (median hours, 16 vs 19; P = .045) than the TP technique had (n = 38). Seventy patients were obese: 19 were treated with SP and 51 with TP. LOS did not differ significantly between the SP and TP groups, but subjects treated with SP had shorter OT (median minutes, 39 vs 63; P < .001) and lower cost (median, $6401 vs $8205; P = .043). CONCLUSIONS: The SP technique for acute appendicitis was found to have a significantly shorter OT and lower cost in all weight groups. There were minimal differences in LOS. SP should be considered in patients with acute appendicitis, regardless of their weight.