NSCLC has a diverse genomic background with mutations in key proto-oncogenic drivers including Kirsten rat sarcoma (KRAS) and epidermal growth factor receptor (EGFR). Roughly 40% of adenocarcinoma harbor Kras activating mutations regardless of smoking history. Most KRAS mutations are located at G12, which include G12C (roughly 40%), G12V (roughly 20%), and G12D (roughly 15%). KRAS mutated NSCLC have higher tumor mutational burden and some have increased PD-1 expression, which has resulted in better responses to immunotherapy than other oncogenes. While initial treatment for metastatic NSCLC still relies on chemo-immunotherapy, directly targeting KRAS has proven to be efficacious in treating patients with KRAS mutated metastatic NSCLC. To date, two G12C inhibitors have been FDA-approved, namely sotorasib and adagrasib. In this review, we summarize the different drug combinations used to target KRAS G12c, upcoming G12D inhibitors and novel therapies targeting KRAS.

Abstract There are only a few options for patients with relapsed/refractory B-cell acute lymphoblastic leukemia (B-ALL), thus, this is a major area of unmet medical need. In this study, we reveal that the inclusion of a poison exon in RBM39, which could be induced by both CDK9 or CDK9 independent cyclin-dependent kinases, mitogen-activated protein kinases, glycogen synthase kinases, CDC-like kinases (CMGC) kinase inhibition, is recognized by the nonsense-mediated messenger RNA decay pathway for degradation. Targeting this poison exon in RBM39 with CMGC inhibitors led to protein downregulation and the inhibition of ALL growth, particularly in relapsed/refractory B-ALL. Mechanistically, disruption of cotranscriptional splicing by the inhibition of CMGC kinases, including DYRK1A, or inhibition of CDK9, which phosphorylate the C-terminal domain of RNA polymerase II (Pol II), led to alteration in the SF3B1 and Pol II association. Disruption of SF3B1 and the transcriptional elongation complex altered Pol II pausing, which promoted the inclusion of a poison exon in RBM39. Moreover, RBM39 ablation suppressed the growth of human B-ALL, and targeting RBM39 with sulfonamides, which degrade RBM39 protein, showed strong antitumor activity in preclinical models. Our data reveal that relapsed/refractory B-ALL is susceptible to pharmacologic and genetic inhibition of RBM39 and provide 2 potential strategies to target this axis.

Protection from viral infections depends on immunoglobulin isotype switching, which endows antibodies with effector functions. Here, we find that the protein kinase DYRK1A is essential for B cell-mediated protection from viral infection and effective vaccination through regulation of class switch recombination (CSR). Dyrk1a-deficient B cells are impaired in CSR activity in vivo and in vitro. Phosphoproteomic screens and kinase-activity assays identify MSH6, a DNA mismatch repair protein, as a direct substrate for DYRK1A, and deletion of a single phosphorylation site impaired CSR. After CSR and germinal center (GC) seeding, DYRK1A is required for attenuation of B cell proliferation. These findings demonstrate DYRK1A-mediated biological mechanisms of B cell immune responses that may be used for therapeutic manipulation in antibody-mediated autoimmunity.

DYRK1A, located in the Down syndrome critical region of chromosome 21, is a serine and threonine kinase that controls multiple cellular processes including apoptosis, cell cycle, transcription and signal transduction. We previously demonstrated that DYRK1A is required for maturation of B cells and is a therapeutic target in B-cell ALL, including both DS and non-DS subtypes. Key substrates within the B-cell lineage include D-type cyclins, FOXO1, and STAT3. Given that several studies have reported that DYRK1A phosphorylates various splicing factors and participates in splicing of Tau in neuronal cells, we investigated the contribution of DYRK1A to splicing in malignant B cells. We first treated B-ALL cell lines with two DYRK1A inhibitors, EHT 1610 and GNF 2133 and performed RNA-sequencing to detect changes in alternative splicing (AS). GO analysis of AS events showed RNA binding proteins among top differentially spliced genes. Of note, mis-splicing of RBM39 was one of the top differentially AS events associated with DYRK1A inhibition; this event involves inclusion of a “poison” exon that contains a premature termination codon and leads to a transcript predicted to be degraded by nonsense-mediated mRNA decay (NMD). We confirmed NMD by knocking down an essential NMD factor, UPF1, which stabilized the NMD isoform. The NMD isoform was also detected in B-ALL patient samples treated with DYRK1A inhibitors and in NALM6 cells in which DYRK1A was inducibly degraded. RBM39 has been reported to be a therapeutic target in AML, where cells with splicing factor mutations are more sensitive to loss of RBM39 than cells lacking splicing factor mutations. To determine whether RBM39 is a therapeutic target in B-ALL, we silenced RMB39 with shRNAs in vitro and in vivo. Genetic knockdown of RBM39 impeded B-ALL cell growth both in vitro and in xenograft models. Furthermore, inducible silencing of RBM39 hampered B-ALL progression in vivo evidenced by a significant increase in survival of mice engrafted with human B-ALL cells. We also found that indisulam and its analogs, which lead to DCAF15-mediated degradation of RBM39, suppressed the growth of B-ALL cells in vitro and in vivo. Importantly, the anti-tumor effect of RBM39 disruption extended beyond DS-ALL to Ph-like B-ALL, which continues to be an area of unmet medical need. We next analyzed the contributions of splicing factors that are known DYRK1A substrates to AS of RBM39. Knockdown of SRSF1 and SRSF2 led to increased inclusion of the poison exon even in the absence of DYRK1A inhibition, indicating that they normally function to exclude the exon. By contrast, knockdown of SF3B1 led to a reduction of the NMD isoform in the presence of EHT1610. Surprisingly, phosphorylation of SF3B1 by DYRK1A was not essential for the change in RBM39 splicing, as cells engineered to harbor two SF3B1 T434A phospho-deficient mutant alleles, did not show aberrant splicing. These results indicate that SF3B1, SRSF1, and SRSF2 are not the key substrates that mediate the effect of DYRK1A on alternative splicing. Next, given that DYRK1A is known to phosphorylate the C-terminal domain (CTD) of RNA polymerase II (Pol II) on Ser2 and Ser5, we investigated the contribution of Pol II phosphorylation to RBM39 splicing. IP-MS revealed an interaction between RNA Pol II and SF3B1, consistent with previous reports of co-transcriptional splicing. We found that inhibition of DYRK1A disrupted the colocalization of SF3B1 and RNA Pol II as well as with RBM39 RNA. However, DYRK1A inhibition had a transient effect on Ser2 and Ser5 phosphorylation, suggesting that cells have alternative pathways for Ser2/5 phosphorylation. Combining DYRK1A inhibition with inhibition or loss of CDK9, which also phosphorylates the CTD of RNA Pol II, led to a persistent decrease in RNA Pol II phosphorylation, marked increased NMD isoform and a profound reduction in RBM39 protein. Finally, we found that combining the CDK9 inhibitor dinaciclib with EHT 1610 synergistically inhibited growth of B-ALL patient cells in vitro and in vivo shown by significantly improved survival. Ectopic expression of RBM39 partially rescued the growth inhibition upon dinaciclib and EHT 1610 treatment suggesting downregulation of RBM39 is the key event in drug targeting. Together, our results reveal that DYRK1A controls RNA splicing by regulating the SF3B1-RNA Pol II interaction and that RBM39 is a therapeutic target in B-ALL.

Patients with recurrent or metastatic NPC are left with limited treatment options. The close association between EBV and NPC make therapeutic vaccination targeting EBV-antigens an emerging new treatment modality. Therapeutic vaccination provides a stimulus to allow the patient to mount their own targeted immune response against the cancer. The two approaches that have led the field into the clinic are dendritic-cell based vaccines and virus-based vaccines. Clinical trials have shown the vaccines to be well-tolerated, and able to elicit a targeted immune response to tumor specific epitopes. Clinical efficacy data, however, is more limited given the early stage of the trials. Other approaches to developing a therapeutic vaccine for NPC include using cancer stem cell lysates, EBV-antigen peptides, and EBV-antigen plasmid DNA. Readout of ongoing trials and progression of preclinical vaccines into Phase I will shed additional light on the efficacy of vaccines and the feasibility of these different approaches to developing a therapeutic vaccine. Future studies may explore combination therapies with multiple vaccines, adoptive T-cell therapy, or checkpoint inhibitors.

Dual-specificity tyrosine phosphorylation-regulated kinase 1 A (DYRK1A) is a serine/threonine kinase that belongs to the DYRK family of proteins, a subgroup of the evolutionarily conserved CMGC protein kinase superfamily. Due to its localization on chromosome 21, the biological significance of DYRK1A was initially characterized in the pathogenesis of Down syndrome (DS) and related neurodegenerative diseases. However, increasing evidence has demonstrated a prominent role in cancer through its ability to regulate biologic processes including cell cycle progression, DNA damage repair, transcription, ubiquitination, tyrosine kinase activity, and cancer stem cell maintenance. DYRK1A has been identified as both an oncogene and tumor suppressor in different models, underscoring the importance of cellular context in its function. Here, we review mechanistic contributions of DYRK1A to cancer biology and its role as a potential therapeutic target.

DYRK1A is a serine/threonine kinase encoded on human chromosome 21 (HSA21) that has been implicated in several pathologies of Down syndrome (DS), including cognitive deficits and Alzheimer's disease. Although children with DS are predisposed to developing leukemia, especially B cell acute lymphoblastic leukemia (B-ALL), the HSA21 genes that contribute to malignancies remain largely undefined. Here, we report that DYRK1A is overexpressed and required for B-ALL. Genetic and pharmacologic inhibition of DYRK1A decreased leukemic cell expansion and suppressed B-ALL development in vitro and in vivo. Furthermore, we found that FOXO1 and STAT3, transcription factors that are indispensable for B cell development, are critical substrates of DYRK1A. Loss of DYRK1A-mediated FOXO1 and STAT3 signaling disrupted DNA damage and ROS regulation, respectively, leading to preferential cell death in leukemic B cells. Thus, we reveal a DYRK1A/FOXO1/STAT3 axis that facilitates the development and maintenance of B-ALL.

e18041 Background: SCS assist in managing symptoms and outcomes for patients in palliative care settings. But impact of services in curative intent settings is not well defined. Here we evaluate this for head and neck cancer patients. Methods: Following IRB approval, we retrospectively reviewed charts of patients with HNC treated from 2014-2017 at the University of Illinois Hospital. Of 260 patient charts reviewed, 67 patients fit the study criteria, which included completing treatment with curative intent at University of Illinois Hospitals, not living at a skilled nursing facility, and follow-up of at least 3 months. Demographic data and treatment course data were collected. SCS included opioid use, tracheostomy use, G-tube use, prophylaxis for mucositis, speech and swallow f/u, nutritionist visits, social worker visits, and anti-emetic prophylaxis. Outcomes included number of hydration visits, number of ER visits, and number of days in the hospital. We tested the significance of correlations between continuous variables using Pearson correlation and the significance of difference in a continuous variable between two groups using the Wilcoxon ranked sum test. We used Cox proportional hazards model for analyses of overall survival (OS). Analyses were univariable. Results: 20 patients had oropharyngeal cancer. 47 had non-oropharyngeal disease. 57 patients received cisplatin and 10 patients received cetuximab, concurrently with radiation therapy. Median weight loss was 6.0kg during treatment. Highest potency opioid at end of treatment was not associated with outcomes. Among the full cohort, having a G-tube was associated with increased number of ER visits (median 1.5 vs. 0.0, p < 0.01), hospitalizations (median 2.0 vs. 0.0, p < 0.01), and number of days in the hospital (median 7.0 vs. 0.0, p < 0.01). Increased hydration appointments, meanwhile, did not predict outcomes. In subgroup analysis of patients who received G-tubes, ER visits before or after G-tube placement did not predict OS (HR 0.64, p = 0.56 for ER visits before G-tube placement, HR 1.06, p = 0.75 for ER visits after G-tube placement). Number of hydration visits after starting treatment for cetuximab vs cisplatin was significant (median 8 for cisplatin and 2 for cetuximab, p = 0.02). Conclusions: G-tube placement, even after placement, was associated with medical care needs during treatment, suggesting an unmet need for this patient population. Further studies are needed to determine how to best provide support for this vulnerable patient population.

The U.S. Department of Veterans Affairs and U.S. Department of Defense (VA/DoD) published updated guidelines for the treatment of headache disorders based on a systematic review.

Objectives: Given that immune checkpoint inhibitors (ICIs) are now preferred agents in first-line treatment of recurrent/metastatic (R/M) squamous cell carcinoma of the head and neck (SCCHN), we retrospectively studied outcomes on post-ICI therapies. Materials and methods: We collected data from the medical records of 60 patients with R/M SCCHN who received ICIs followed by at least one further line of cytotoxic or biologic therapy at our institution from 2014 to 2019. We also compared outcomes with those of historical trials in the ICI-naive, second-line or greater setting. Results: Patients who received platinum-based regimens as their post-ICI therapies experienced improved overall response (ORR) (50% versus 10%, p < 0.01) and improved overall survival (OS) (15.1 months versus 7.3 months, HR 0.46, p = 0.04) compared to the rest of the cohort. Patients receiving platinum re-challenge were more likely to respond than all other patients in the cohort (OR 8.37, p = 0.01). The ORR for patients on 5-fluorouracil (5-FU)-containing regimens (63%) was also higher than other patients in the cohort (p = 0.03). Immunotherapy-based regimens compared favorably to historical data of first exposure to ICIs (disease control rate 54% versus 36%). Singlet regimens were associated with shorter OS than other regimens (HR = 2.38, p = 0.01). Conclusions: Platinum- and 5-FU-based doublet or triplet regimens may be superior options in the post-ICI setting. Immunotherapy re-challenge following ICI therapy may also be a reasonable option.

Background Circulating tumors cells (CTCs) are considered an early step towards metastasis and have been linked to poor prognosis in several types of cancer. CTCs in squamous cell carcinoma of the head and neck (SCCHN) have an unclear role. Methods In this prospective study, patients with locally advanced or metastatic SCCHN had CTC counts assessed before starting systemic treatment using the CellSearch System. Select cases also had sequential CTC evaluation. Presence of CTCs was correlated with patient characteristics and outcomes. Results Forty-eight patients enrolled, and 36 had evaluable clinical data and baseline CTC counts. Twenty-five patients had locally advanced disease (LAD) and 11 had metastatic disease. >= 1 CTCs were detected in six patients with LAD (24%) and four with metastatic disease (36%). On univariate analysis, smoking was associated with CTCs. Conclusion CTCs are not associated with prognosis in patients with LAD and metastatic disease; however, they are present in this patient population, and >= 1 CTCs is associated with a history of smoking. Level of evidence 1b; individual prospective cohort study.

6513 Background: Treatment options for aggressive TC are limited. Pre-clinical data suggests efficacy of CTLA-4 plus PD-1 blockade in aggressive RAIR TC. Methods: This investigator initiated phase II study tested N (3mg/kg every 2 weeks) plus I (1mg/kg every 6 weeks) until disease progression or completion of 24 mo of treatment in RAIR differentiated TC including poorly differentiated TC (PDTC) with exploratory cohorts in anaplastic (ATC) and medullary TC (MTC). Radiographic response rate by RECIST v1.1 (CR+PR) was primary endpoint. At least 6 pts with disease response among n=32 DTC provided 84% power to distinguish between a 10% and a 25% RR (one-sided 9% binomial test). Results: Accrual is complete with n=32 patients with DTC, 10 with ATC and 7 with MTC enrolled between October 2017 and May 2019. Thirty-two DTC included: n=17 papillary, n=7 Hurthle, n=4 follicular TC, n=4 PDTC. Among n=49, median (range) age was 65 (30-88), 51% (25/49) were female. To date, in DTC, 3/32 achieved a PR (n=2 Hurthle and n=1 PDTC), 9.4% RR (.95CI:2%-25%). One near complete response has been observed. Among pts w ATC, 3/ 10 profound PR by RECIST occurred (30% RR, .95CI: 7%-65%). Among them, two remain without clear evidence of disease at 26 and 13 mo after treatment start. No PR's were observed in MTC. Most frequent grade 3-4 TRAEs were as expected and included increased lipase (n=8), increased serum amylase (n=4). There was an unexpected number of treatment related adrenal insufficiency (AI) (n=4) which was associated with long PFS (range 10.1—16.4+mo). Conclusions: N+I appears to have considerable activity in ATC. In unselected RAIR DTC, activity was low but responses were seen in PDTC and Hurthle cell TC. Exceptional responses with prolonged remissions were observed. Clinical trial information: NCT03246958 .

Microcystic adnexal carcinoma (MAC) is a rare, indolent, low-grade, malignant cutaneous neoplasm believed to arise from the sweat glands most commonly seen in the head and neck area.1,2 Since MAC was first described as a distinct histologic entity in 1982,3 less than 700 cases have been reported worldwide. MAC typically affects middle aged to elderly whites. MAC lesions usually present as a solitary, slow-growing 1- to 3-cm white yellowish papule or plaque located primarily over the face.1,4-6 Patients are generally asymptomatic and may present years after initial development of the skin lesion.

Aims: The activity that the immune checkpoint inhibitor (ICI) cemiplimab has recently demonstrated has led to a paradigm shift in the management of patients with advanced cutaneous squamous cell carcinoma (cSCC). To identify predictive biomarkers of response to ICIs in advanced cSCC, we studied 33 patients who received ICI therapy at the Dana-Farber/Harvard Cancer Center (DF/HCC) and analysed sequencing data for a subset of these patients. Methods: We collected clinical data using electronic health records and genomic data using the institutional OncoPanel platform of the DF/HCC. We compared tumour genomics with data from previously sequenced cSCC cohorts. Results: We observed high tumour mutational burden regardless of smoking status and response to ICI and longer median overall survival among those patients who achieved an ICI response. We compared the genetic data from our cohort with data from other cohorts that included fewer patients with distant metastatic disease. Although our cohort had a similar genetic landscape to those of comparator cohorts, mutations in PIK3C2B were more common in our study. In our cohort, copy number alterations (CNAs) in the 3q chromosomal arm appeared to predict response to ICI therapy. Conclusion: CNAs in the 21-27 bands of chromosome arm 3q, a region that includes PIK3CA, ETV5 and BCL6, may represent predictors of response to ICI and may be candidates for drug targeting in combination or sequence with ICI agents. (C) 2019 Elsevier Ltd. All rights reserved.

e18230 Background: Medical insurance coverage is known to correlate with improved long-term (LT) outcomes in head and neck cancers (HNC) patients. However, associations with dental insurance coverage (DI) are not established. Methods: In 2012, we sent surveys to determine DI and LT symptom (Sx) burden (EORTC QLQ-30, National Health and Nutrition Examination Survey Oral Health, and Vanderbilt Head and Neck Sx Survey) to patients who had completed definitive chemoradiotherapy (sequential or concurrent) for locally advanced (LA) HNC at the Dana-Farber Cancer Institute from 2002-2011 (2013 ASCO annual meeting, abstract 9530). In 2019, we retrospectively collected demographic and clinical information from patient charts and publicly available records and correlated these data with 2012 survey data. We used Fisher’s exact tests for association of categorical variables and Student’s t-tests for continuous variables. We used univariate and multivariate Cox proportional hazard modeling for hazard ratios (HRs). Results: Of the 103 survey responders, 84% were male. Most had oropharyngeal (90, 88%) or unknown primary (9, 9%) and 52 (50%) tested positive for human papilloma virus-associated disease (40% not tested). 71 (69%) had DI, while 100 (98%) had medical health insurance. Subjects with DI were diagnosed (Dxed) at a younger age (53 vs. 59, p < 0.01). Stage at Dx did not vary by DI status (p = 0.27). At median follow-up of 10.4 years from Dx (range 2.0 -16.6), recurrence was not associated with DI status (6 (8%) for DI vs. 4 (13%) for no DI, p = 0.27, HR 0.55, 95% CI 0.15-1.93, p = 0.35). We identified 9 subjects (9%) who had died of any cause. Subjects with DI experienced lower mortality from all causes than those without (3% vs. 19%, p = 0.01) and longer median overall survival (OS) (range 4.3 - 16.6 years, HR 0.19, 95% CI 0.05-0.76, p = 0.02) on univariate analysis. The longer OS was not significant when controlling for age and stage at Dx (p = 0.12). DI was also associated with less frequent need for liquid supplements to maintain weight (p = 0.01). Conclusions: In our cohort, DI was associated with Dx at a younger age and longer OS, although future work should consider possible confounding factors such as differences in socioeconomic status. Our data highlight the need for further research to investigate the importance of DI in improving LT outcomes in HNC patients.

Background: Anaplastic thyroid cancer (ATC) is a very aggressive disease and accounts for over 50% of thyroid-cancer related deaths. mTOR inhibition has shown anti-tumor activity in ATC. We report our experience treating patients with ATC with everolimus off-protocol. Methods: Patients with confirmed ATC and treated with everolimus at DFCI were identified and reviewed retrospectively. NexGen sequencing was performed, and radiologic responses were correlated with mutational profile. Results: Five patients were treated from 2013 to 2016. Three patients had a response, which included one patient who achieved a partial response for 27.9 months, and two patients who had stable disease for 3.7 and 5.9 months, respectively. Genomic analysis was available in two patients and revealed that the partial responder had mutations involving the PI3K/mTOR pathway. Conclusion: Everolimus has anti-tumor activity in ATC, and responses may correlate with mutations involving the PI3K/mTOR pathway. Further studies are warranted.