Rapid adaptation to CDK2 inhibition exposes intrinsic cell-cycle plasticity.

CDK2 is a core cell-cycle kinase that phosphorylates many substrates to drive progression through the cell cycle. CDK2 is hyperactivated in multiple cancers and is therefore an attractive therapeutic target. Here, we use several CDK2 inhibitors in clinical development to interrogate CDK2 substrate phosphorylation, cell-cycle progression, and drug adaptation in preclinical models. Whereas CDK1 is known to compensate for loss of CDK2 in Cdk2-/- mice, this is not true of acute inhibition of CDK2. Upon CDK2 inhibition, cells exhibit a rapid loss of substrate phosphorylation that rebounds within several hours. CDK4/6 activity backstops inhibition of CDK2 and sustains the proliferative program by maintaining Rb1 hyperphosphorylation, active E2F transcription, and cyclin A2 expression, enabling re-activation of CDK2 in the presence of drug. Our results augment our understanding of CDK plasticity and indicate that co-inhibition of CDK2 and CDK4/6 may be required to suppress adaptation to CDK2 inhibitors currently under clinical assessment.

Senescence Evasion in Chemotherapy: A Sweet Spot for p21.

Time-lapse imaging reveals a nuanced role for p21 in cancer cells challenged with chemotherapeutic drugs: cells with either high or low p21 are biased toward senescence, whereas intermediate p21 allows cells to re-enter the cell cycle after drug treatment.

Clinical outcomes of adjuvant nivolumab in resected stage III melanoma: comparison of CheckMate 238 trial and real-world data.

OBJECTIVES: Nivolumab is approved as adjuvant therapy for resected stage III/IV melanoma based on the phase 3 CheckMate 238 trial. This analysis compared outcomes from CheckMate 238 with those from the real-world Flatiron Health electronic health record-derived de-identified database in patients with resected stage III melanoma (per AJCC-8) treated with adjuvant nivolumab. MATERIALS: Outcomes included baseline characteristics, overall survival (OS) in the CheckMate 238 cohort (randomization until death or last known alive), and real-world overall survival (rwOS) in the Flatiron Health cohort (nivolumab initiation until death or data cutoff). rwOS was compared with OS using unadjusted and adjusted Cox proportional hazards models. Inverse probability of treatment weighting (IPTW) was combined with the adjusted model to reduce baseline discrepancies. RESULTS: The CheckMate 238 and real-world cohorts included 369 and 452 patients, respectively (median age, 56.0 and 63.0 years; median follow-up, 61.4 vs. 25.5 months). rwOS was not different from OS in the unadjusted (hazard ratio [HR] 1.27; 95% CI 0.92-1.74), adjusted (HR 1.01; 95% CI 0.67-1.54), and adjusted IPTW (HR 1.07; 95% CI 0.70-1.63) analyses. In the adjusted analysis, 2-year OS and rwOS rates were 84%. Median OS and rwOS were not reached. After IPTW, OS and rwOS were not different (HR 1.07; 95% CI 0.70-1.64). CONCLUSIONS: In this comparative analysis, OS in the CheckMate 238 trial was similar to rwOS in the Flatiron Health database after adjustments in patients with resected stage III melanoma (per AJCC-8) treated with adjuvant nivolumab, validating the trial results.

Neoadjuvant PD-1 Inhibitors: A Tale of Two Cases.

Treatment responses for locally advanced cutaneous squamous cell carcinoma (cSCC) and Merkel cell carcinoma (MCC) are often short lived and are marred with recurrences. The introduction of adjuvant PD-1 inhibitors has demonstrated significant improvement in both, response rates, and duration of response. For patients with high-risk resectable disease, adjuvant treatments have not demonstrated an ability to reduce recurrence risk. However, there is an opportunity in the neoadjuvant setting to alter recurrence risk. Here we dem-onstrate two cases of neoadjuvant treatment of cSCC and MCC with impressive results.  J Drugs Dermatol. 2024;23(2):     doi:10.36849/JDD.7043e.

Phase 1 study to determine the safety and dosing of autologous PBMCs modified to present HPV16 antigens (SQZ-PBMC-HPV) in HLA-A*02+ patients with HPV16+ solid tumors.

We conducted a dose escalation Phase 1 study of autologous PBMCs loaded by microfluidic squeezing (Cell Squeeze® technology) with HPV16 E6 and E7 antigens (SQZ-PBMC-HPV), in HLA-A*02+ patients with advanced/metastatic HPV16+ cancers. Preclinical studies in murine models had shown such cells resulted in stimulation and proliferation of antigen specific CD8+ cells, and demonstrated antitumor activity. Administration of SQZ-PBMC-HPV was every 3 weeks. Enrollment followed a modified 3+3 design with primary objectives to define safety, tolerability, and the recommended Phase 2 dose. Secondary and exploratory objectives were antitumor activity, manufacturing feasibility, and pharmacodynamic evaluation of immune responses. Eighteen patients were enrolled at doses ranging from 0.5 × 106 to 5.0 × 106 live cells/kg. Manufacture proved feasible and required < 24 h within the overall vein-to-vein time of 1 - 2 weeks; at the highest dose, a median of 4 doses were administered. No DLTs were observed. Most related TEAEs were Grade 1 - 2, and one Grade 2 cytokine release syndrome SAE was reported. Tumor biopsies in three patients showed 2 to 8-fold increases in CD8+ tissue infiltrating lymphocytes, including a case that exhibited increased MHC-I+ and PD-L1+ cell densities and reduced numbers of HPV+ cells. Clinical benefit was documented for the latter case. SQZ-PBMC-HPV was well tolerated; 5.0 × 106 live cells/kg with double priming was chosen as the recommended Phase 2 dose. Multiple participants exhibited pharmacodynamic changes consistent with immune responses supporting the proposed mechanism of action for SQZ-PBMC-HPV, including patients previously refractory to checkpoint inhibitors.

Uveal melanoma: laboratory advances and new frontiers in patient care.

PURPOSE OF REVIEW: To review recent advancements in the genetic understanding, diagnosis, prognosis, and treatment of uveal melanoma (UM). RECENT FINDINGS: UM is a molecularly distinct melanocytic malignancy driven by mutations in GNAQ or GNA11, with mitogen-activated protein kinase pathway upregulation. Earlier diagnosis and treatment are important factors for improving life prognosis. These goals can be aided by more objective multimodal imaging risk factors for the prediction of malignant nevus transformation and novel treatment strategies such as customized radiation fields and nanoparticle therapy to reduce vision-threatening treatment side effects. The risk for metastatic disease can be reliably predicted through gene expression profiling or the Cancer Genome Atlas project classification, and combined use of clinical tumor features with molecular data allows for highly individualized patient prognosis. Patients with high-risk UM should be considered for clinical trials of adjuvant therapy to prevent metastatic disease. For patients with clinically evident metastasis, combination immunotherapy regimens, T cell-based therapies, and focal adhesion kinase inhibitors offer hope for improved clinical response rates. SUMMARY: Improved understanding of UM molecular pathogenesis and clinical trials of targeted therapy for prevention and treatment of metastatic disease may improve patient survival for this challenging disease.

Comparative effectiveness of second-line ipilimumab vs. nivolumab in combination with ipilimumab in patients with advanced melanoma who received frontline anti-PD-1 antibodies.

INTRODUCTION: Anti-PD-1 antibodies are commonly used as frontline therapy for patients with metastatic melanoma. Although these medications can cause long term responses, a significant number of patients will not respond or will lose response. Optimal second-line therapy after losing response to anti-PD-1 antibodies is not well established. Therefore, we retrospectively compared the overall survival of patients who lost response to anti-PD1 antibodies between patients treated with single agent ipilimumab or ipilimumab and nivolumab. METHODS: A de-identified U.S. nationwide electronic health record-derived database was reviewed for patients with advanced melanoma treated with single agent anti-PD1 antibodies in the frontline setting and who subsequently received second-line ipilimumab or combination ipilimumab and nivolumab. Overall survival from initiation of second-line therapy was compared using Kaplan Meier curves and log-rank analysis. Other known prognostic markers for melanoma were analyzed for correlation with survival in a similar fashion. Disease characteristics between the two groups were compared using chi-square analysis. RESULTS: A total of 842 patients with advanced melanoma who received frontline anti-PD-1 antibodies were included for analysis. Of these, 57 received either ipilimumab (n = 22) or ipilimumab in combination with nivolumab (n = 35) in the second-line setting. Median survival from second-line therapy initiation for those treated with ipilimumab alone was 6 months and was 5.6 months for those treated with combination ipilimumab and anti-PD-1 antibodies, p = 0.81. CONCLUSIONS: In this small, retrospective analysis, for patients who lost response to frontline anti-PD-1 therapy, patients treated with ipilimumab had similar survival to those who received ipilimumab in combination with anti-PD-1 antibodies.

Control of the Restriction Point by Rb and p21.

The Restriction Point was originally defined as the moment that cells commit to the cell cycle and was later suggested to coincide with hyperphosphorylation of the retinoblastoma protein (Rb). Current cell cycle models posit that cells exit mitosis into a pre-Restriction Point state, where they have low cyclin-dependent kinase (CDK) activity and hypophosphorylated Rb; passage through the Restriction Point then occurs in late G1. Recent single-cell studies have challenged the current paradigm, raising questions about the location of the Restriction Point and the notion that cells exit mitosis into a pre-Restriction Point state. Here, we use a variety of single-cell techniques to show that both noncancer and cancer cells bifurcate into two subpopulations after anaphase, marked by increasing vs. low CDK2 activity and hyper- vs. hypophosphorylation of Rb. Notably, subpopulations with hyper- and hypophosphorylated Rb are present within minutes after anaphase, delineating one subpopulation that never "uncrosses" the Restriction Point and continues cycling and another subpopulation that exits mitosis into an uncommitted pre-Restriction Point state. We further show that the CDK inhibitor p21 begins rising in G2 in mother cells whose daughters exit mitosis into the pre-Restriction Point, CDK2low state. Furthermore, degradation of p21 coincides with escape from the CDK2low state and passage through the Restriction Point. Together, these data support a model in which only a subset of cells returns to a pre-Restriction Point state after mitosis and where the Restriction Point is sensitive to not only mitogens, but also inherited DNA replication stress via p21.

Correlation of novel ALKATI with ALK immunohistochemistry and clinical outcomes in metastatic melanoma.

AIMS: Recently, a novel isoform of anaplastic lymphoma kinase, with alternative transcription initiation (ALKATI ), has been described in melanoma and is susceptible to targeted ALK-inhibitor therapy. Clinical outcomes of patients with ALKATI mutated melanoma as well as correlation with immunohistochemical (IHC) methods have not yet been described. METHODS AND RESULTS: Clinicopathological characteristics were abstracted for 324 patients with metastatic melanoma (MM). IHC, fluorescence in-situ hybridisation and RNA-based digital molecular analysis assays were performed on archival tissue from 173 stage III and 192 stage IV tumours. ALKATI was identified in 12.7 and 4.8% stage III and IV tumours, respectively. Discrete presentations of the ALKATI are seen: isolated ALKATI (n = 20) and mixed ALKATI (combined ALKATI and ALKWT ; n = 7). Isolated ALKWT expression (n = 4) was seen with no ALK fusions. Stage III patients showed improved survival with ALKATI expression compared to those with ALKWT or no expression [5-year survival 80, 95% confidence interval (CI) = 57-100% versus 43%, 95% CI = 34-55%, P = 0.013]. Clinicopathological characteristics were not statistically significant. Strong diffuse cytoplasmic staining of ALK IHC (n = 12) has a sensitivity of 52.2%, specificity 100%, PPV of 100% and NPV of 92.5% of detecting isolated ALKATI . CONCLUSION: Presence of ALKATI is a good prognostic indicator in MM. ALK IHC and digital molecular analysis can be incorporated into MM evaluation to identify patients with ALKATI for targeted therapy.

A map of protein dynamics during cell-cycle progression and cell-cycle exit.

The cell-cycle field has identified the core regulators that drive the cell cycle, but we do not have a clear map of the dynamics of these regulators during cell-cycle progression versus cell-cycle exit. Here we use single-cell time-lapse microscopy of Cyclin-Dependent Kinase 2 (CDK2) activity followed by endpoint immunofluorescence and computational cell synchronization to determine the temporal dynamics of key cell-cycle proteins in asynchronously cycling human cells. We identify several unexpected patterns for core cell-cycle proteins in actively proliferating (CDK2-increasing) versus spontaneously quiescent (CDK2-low) cells, including Cyclin D1, the levels of which we find to be higher in spontaneously quiescent versus proliferating cells. We also identify proteins with concentrations that steadily increase or decrease the longer cells are in quiescence, suggesting the existence of a continuum of quiescence depths. Our single-cell measurements thus provide a rich resource for the field by characterizing protein dynamics during proliferation versus quiescence.

Characterization of uveal melanoma clinical trial design: a systematic review to establish an elusive standard of care.

BACKGROUND: There is currently no FDA or EMA-approved standard of care for metastatic uveal melanoma. MATERIAL AND METHODS: A systematic review of all interventional uveal melanoma trials on the ClinicalTrials.gov database and EU Clinical Trials Register was conducted from January 15, 2019 through November 30, 2019. Categorical data analysis and descriptive statistics were generated. RESULTS: A total of 119 trials met inclusion criteria for this systematic review, of which 39 were active. Of all trials, 47% were NIH-funded while 59% of active trials were industry funded. Of all trials, 86% were concerned with treatment of metastasis, 7% with adjuvant therapy, and 8% with treatment of primary tumor. In trials treating metastasis, 62% reported response rates as their primary outcome measure. Non-randomized patient allocation to treatment arms was reported in 73% of trials, and 8% of trials were in phase 3. Pharmaceutical drugs were utilized by 69% of trials. Of the 6 negative randomized trials, all reported no significant effect from intervention compared to a control arm and were usually initiated on preclinical or early phase data. CONCLUSION: Given decreased NIH funding for uveal melanoma trials, clinicians should consider industry funding partnerships. Standardization of primary outcome measures between trials will also allow for statistical meta-analyses of results in this rare patient population. Finally, clinicians should use single arm studies to establish significant treatment response rates before proceeding with randomized trials.

Comparative-effectiveness of pembrolizumab vs. nivolumab for patients with metastatic melanoma.

Background: Pembrolizumab (P) and nivolumab (N) are commonly used therapies for advanced melanoma. However, their effectiveness has never been directly compared, leaving little guidance for clinicians to select the best therapy. Therefore, we sought to retrospectively compare the overall survival of patients with metastatic melanoma treated with front line P or N in the real-world setting.Material and methods: This study included patients with advanced melanoma, diagnosed between 1 January 2011 and 31 July 2018, treated with frontline P or N who were included in a nationwide, longitudinal de-identified electronic health record (EHR)-derived database. Overall survival (OS) was estimated for each treatment group using Kaplan-Meier curves with a log-rank test. Comparison of OS was estimated using an inverse probability weighting model to reduce bias between the groups. The model was adjusted using age, sex, ECOG, LDH (elevated or not), BRAF (mutated or not), Kit (mutated or not), NRAS (mutated or not), PD-L1 expression (0% or greater), Body Mass Index, and primary site.Results: 888 patients with advanced disease who received treatment with frontline P (n = 486) or N (n = 402) were identified. Median OS for all patients treated with P was 22.6 months (m) and was 23.9 m for those treated with N (p = 0.91). In the inverse probability weight analysis there was no difference in survival between patients treated with P or N 1.06 (95% CI 0.84-1.33).Concluding Statement: In our retrospective, real-world analysis of patients with advanced melanoma, no statistical difference in OS was noted between patients treated with frontline P compared to N. This supports the current practice of choosing either P or N based on patient and provider preference.

First-line pembrolizumab therapy in a cisplatin-ineligible patient with plasmacytoid urothelial carcinoma: A case report.

BACKGROUND: Plasmacytoid urothelial carcinoma (PUC) is a rare but aggressive variant of transitional cell carcinoma. In patients with unresectable disease, cisplatin-based combination chemotherapy is the most commonly used treatment. However, many patients are cisplatin-ineligible due to poor performance status or other comorbidities. We report a case of a cisplatin-ineligible patient with metastatic PUC who was treated with pembrolizumab. CASE REPORT: A 71-year-old man with 30 pack-year smoking history and schizoaffective disorder was found to have multiple right-sided lung nodules after presenting with atypical chest pain. Staging CT showed bilateral adrenal masses and a large soft tissue mass in the right iliac fossa. Tissue pathology and immunohistochemical staining was consistent with PUC. As the patient was cisplatin-ineligible due to poor performance status and multiple medical comorbidities, the decision was made to treat with pembrolizumab. Repeat CT chest and abdomen showed partial response at three months and stable disease at six months. DISCUSSION: The KEYNOTE-052 study found that first-line pembrolizumab in cisplatin-ineligible patients with urothelial cancer resulted in complete or partial response in 24% of patients with few adverse effects. However, it is unclear if patients with plasmacytoid variant were included. To our knowledge, this is the first case report of a patient with metastatic PUC not only treated with pembrolizumab but shown to have clinical response. CONCLUSION: Given our patient's clinical response, pembrolizumab is a promising first-line agent for treating cisplatin-ineligible patients with metastatic PUC. Further evaluation is warranted to confirm the benefit of treating this patient population with pembrolizumab.

Combination of Colloidal Silicon Dioxide with Spray-Dried Solid Dispersion to Facilitate Discharge from an Agitated Dryer.

A feasibility evaluation of the addition of fumed silica (SiO2) into an agitated dryer to aid spray-dried solid dispersion intermediate (SDSDi) flow during secondary drying and discharge is described. The quantity of SiO2 to enhance the flow character of SDSDi was assessed by measuring particle size distribution, bulk density, and flow-through-an-orifice. Results indicate that the addition of the SiO2 did not alter the drying kinetics and did not impact the bulk particle size distribution of the SDSDi. While bulk density of SDSDi increased with the addition of SiO2, the flow, and thus the recovery of the SDSDi-SiO2 batch from the secondary dryer, was significantly higher than that for the intermediate alone. Imaging indicated uniform distribution of SiO2 in the bulk powder and coating on intermediate particles. Premixing and co-sieving of the SiO2 with a portion of pre-dry SDSDi promotes the uniform distribution of SiO2 within the bulk powder bed.

Adjuvant therapy for resected high-risk melanoma.

Melanoma is an aggressive cancer that arises from melanocytes that can both locally invade surrounding tissues as well as metastasize systemically. If detected early, melanoma can be curable with surgical resection. However, despite complete removal, high-risk resected melanomas have a significant rate of both local and distant recurrence. Curative treatment options are typically limited for patients who develop distant recurrence after resections of their primary melanoma. Therefore, adjuvant therapy is typically given after complete resection of high-risk melanomas to try and reduce the risk of recurrent disease. Adjuvant therapy for high-risk resected melanoma has changed considerably over the past couple of years due to the availability of new melanoma therapies that are active in the metastatic setting. Here, we review the new treatment options and ongoing clinical research for adjuvant therapy.

c-Met expression and MET amplification in malignant pleural mesothelioma.

c-Met is a receptor tyrosine kinase shown to be overexpressed in malignant pleural mesothelioma (MPM). Whereas MET mutations have been identified in 3%-16% of MPMs, MET amplification has recently been reported in a single epithelioid MPM. We studied c-Met expression and MET amplification in a large MPM cohort and correlated results with morphologic and clinical features. We report the first case of MET amplification in sarcomatoid MPM. MPMs from surgical pathology files (1989-2014) were reviewed. c-Met immunohistochemistry was performed. Staining intensity and distribution were multiplied (H-score). Staining localization (cytoplasmic and/or membranous) was noted. Fluorescence in situ hybridization was performed using probes for MET and centromere 7. One hundred forty-nine patients (median age, 68.0years; interquartile range, 61-75) had epithelioid (n=97), biphasic (n=18), or sarcomatoid (n=34) MPM. Median follow-up was 10.1months (range, 0.1-222.5). One hundred thirty patients died of disease; 2 were alive with disease. c-Met was expressed in 147 MPMs. c-Met staining intensity, distribution, and H-score differed among the histologic subtypes (P=.015; P=.0001, and P=.0005, respectively), but none were predictive of survival. Epithelioid subtype had greater c-Met expression. MET amplification was identified in 1 sarcomatoid MPM and MET duplication in 1 epithelioid MPM; both had poor outcomes. Chromosome 7 aneusomy was observed in 54 of 144 (37.5%) MPMs and associated with decreased overall survival in sarcomatoid MPMs (hazard ratio=2.81; 95% confidence interval, 1.21-6.51; P=.01). In conclusion, c-Met is expressed in MPM, with significant differences in expression among histologic subtypes. MET amplification is a rare event in MPM, making it an unlikely common pathogenesis for c-Met expression.

Botensilimab plus balstilimab in relapsed/refractory microsatellite stable metastatic colorectal cancer: a phase 1 trial.

Microsatellite stable metastatic colorectal cancer (MSS mCRC; mismatch repair proficient) has previously responded poorly to immune checkpoint blockade. Botensilimab (BOT) is an Fc-enhanced multifunctional anti-cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibody designed to expand therapy to cold/poorly immunogenic solid tumors, such as MSS mCRC. BOT with or without balstilimab (BAL; anti-PD-1 antibody) is being evaluated in an ongoing expanded phase 1 study. The primary endpoint is safety and tolerability, which was evaluated separately in the dose-escalation portion of the study and in patients with MSS mCRC (using combined dose-escalation/dose-expansion data). Secondary endpoints include investigator-assessed RECIST version 1.1-confirmed objective response rate (ORR), disease control rate (DCR), duration of response (DOR) and progression-free survival (PFS). Here we present outcomes in 148 heavily pre-treated patients with MSS mCRC (six from the dose-escalation cohort; 142 from the dose-expansion cohort) treated with BOT and BAL, 101 of whom were considered response evaluable with at least 6 months of follow-up. Treatment-related adverse events (TRAEs) occurred in 89% of patients with MSS mCRC (131/148), most commonly fatigue (35%, 52/148), diarrhea (32%, 47/148) and pyrexia (24%, 36/148), with no grade 5 TRAEs reported and a 12% discontinuation rate due to a TRAE (18/148; data fully mature). In the response-evaluable population (n = 101), ORR was 17% (17/101; 95% confidence interval (CI), 10-26%), and DCR was 61% (62/101; 95% CI, 51-71%). Median DOR was not reached (NR; 95% CI, 5.7 months-NR), and median PFS was 3.5 months (95% CI, 2.7-4.1 months), at a median follow-up of 10.3 months (range, 0.5-42.6 months; data continuing to mature). The combination of BOT plus BAL demonstrated a manageable safety profile with no new immune-mediated safety signals and encouraging clinical activity with durable responses. ClinicalTrials.gov identifier: NCT03860272 .

Regulation of pancreatic cancer growth by superoxide.

K-ras mutations have been identified in up to 95% of pancreatic cancers, implying their critical role in the molecular pathogenesis. Expression of K-ras oncogene in an immortalized human pancreatic ductal epithelial cell line, originally derived from normal pancreas (H6c7), induced the formation of carcinoma in mice. We hypothesized that K-ras oncogene correlates with increased non-mitochondrial-generated superoxide (O 2.-), which could be involved in regulating cell growth contributing to tumor progression. In the H6c7 cell line and its derivatives, H6c7er-Kras+ (H6c7 cells expressing K-ras oncogene), and H6c7eR-KrasT (tumorigenic H6c7 cells expressing K-ras oncogene), there was an increase in hydroethidine fluorescence in cell lines that express K-ras. Western blots and activity assays for the antioxidant enzymes that detoxify O 2.- were similar in these cell lines suggesting that the increase in hydroethidine fluorescence was not due to decreased antioxidant capacity. To determine a possible non-mitochondrial source of the increased levels of O 2.-, Western analysis demonstrated the absence of NADPH oxidase-2 (NOX2) in H6c7 cells but present in the H6c7 cell lines expressing K-ras and other pancreatic cancer cell lines. Inhibition of NOX2 decreased hydroethidine fluorescence and clonogenic survival. Furthermore, in the cell lines with the K-ras oncogene, overexpression of superoxide dismutases that detoxify non-mitochondrial sources of O 2.-, and treatment with the small molecule O 2.- scavenger Tempol, also decreased hydroethidine fluorescence, inhibited clonogenic survival and inhibited growth of tumor xenografts. Thus, O 2.- produced by NOX2 in pancreatic cancer cells with K-ras, may regulate pancreatic cancer cell growth.

On the Risk of Nitrosamine Contamination During Drug Product Blister Packaging.

Most N-Nitrosamine compounds are found to be genotoxic in several animal species. Some are classified as probable or possible human carcinogens and very low acceptable daily intake has been established such as 96 ng/day for N-nitrosodimethylamine (NDMA) and 26.5 ng/N-nitrosodiethylamine (NDEA). The pharmaceutical industry has considered all processing areas for potential formation or contamination of N-nitrosamine. One risk is the potential contamination of nitrosamine during drug product blister packaging using lidding foils containing nitrocellulose, and different approaches have been used by pharmaceutical companies to evaluate and mitigate this risk. Herein we share a perspective from IQ Consortium N-nitrosamine Working Group on some of the approaches and corresponding results. From these assessments, it was concluded that the risk of nitrosamine contamination during blister packaging is negligible. The approaches shared in this perspective can be incorporated into risk assessment for nitrosamine contamination during drug product packaging at other pharmaceutical companies.

Use of Talimogene Laherparepvec to Treat Cutaneous Squamous Cell Carcinoma in a Renal Transplant Patient.

A 66-year-old female with a history of two renal transplants due to recurrent thrombotic thrombocytopenic purpura presented to clinic with multiple lesions identified to be non-metastatic cutaneous squamous cell carcinoma (CSCC). The patient previously underwent multiple Mohs procedures and radiation therapy treatment but continued to develop CSCC lesions with increasing frequency. After discussing multiple treatment options, it was elected to pursue treatment with Talimogene laherparepvec (T-VEC) given the systemic immune responses it can cause, with low theoretical risk of graft rejection. After starting intratumoral T-VEC injections, treated lesions began to decrease in size, and a reduction in the rate of new CSCC lesions was observed. Treatment was held due to unrelated renal complications during which time new CSCCs developed. Patient was restarted on T-VEC therapy with no recurrent renal issues. Upon reinitiating treatment, injected and non-injected lesions showed reduction in size, and the development of new lesions again ceased. One injected lesion was resected via Mohs micrographic surgery due to its size and discomfort. On sectioning, this demonstrated an exuberant lymphocytic perivascular infiltrate which was consistent with treatment response to T-VEC, with little active tumor. With high rates of non-melanoma skin cancer in renal transplant patients, their transplant status significantly limits treatment options, specifically with regards to anti-PD-1 therapy. This case suggests T-VEC can generate local and systemic immune responses in the setting of immunosuppression and that T-VEC may be a beneficial therapeutic option for transplant patients with CSCC.