Estimation of Percentage of Patients With Fibroblast Growth Factor Receptor Alterations Eligible for Off-label Use of Erdafitinib

FGFR-Altered Urothelial Carcinoma: Resistance Mechanisms and Therapeutic Strategies

Fibroblast growth factor receptor (FGFR) 2/3 alterations have been implicated in tumorigenesis in several malignancies, including urothelial carcinoma. Several FGFR inhibitors have been studied or are in development, and erdafitinib is the sole inhibitor to achieve regulatory approval. Given the rapidly evolving treatment landscape for advanced urothelial carcinoma, including regulatory approvals and withdrawals, determining the most appropriate treatment strategies and sequencing for FGFR-altered urothelial carcinoma is becoming increasing critical. However, the clinical efficacy of FGFR inhibitors is limited by acquired resistance similar to that seen with other tyrosine kinase inhibitors. Additional challenges to the clinical use of FGFR inhibitors include treatment-related adverse events and the financial costs associated with treatment. In this review, we describe known mechanisms of FGFR inhibitor resistance, including gatekeeper mutations, domain mutations, and the development of new mutations. In addition, we discuss management strategies, including ongoing clinical trials evaluating FGFR inhibitors, antibody-drug conjugates, and combination therapies with immune checkpoint inhibitors that may provide additional treatment options for localized and metastatic urothelial carcinoma.

Phase 3 THOR Japanese subgroup analysis: erdafitinib in advanced or metastatic urothelial cancer and fibroblast growth factor receptor alterations

BACKGROUND

In the THOR trial (NCT03390504) Cohort 1, erdafitinib demonstrated significantly prolonged overall survival (OS) (median 12.1 versus 7.8 months) and reduced risk of death by 36% (hazard ratio 0.64, P = 0.005) compared with chemotherapy in metastatic urothelial carcinoma (mUC) patients with FGFR alterations who progressed after ≥ 1 prior treatments, including anti-PD-(L)1. There have been no reports of the Japanese subgroup results yet.

METHODS

THOR Cohort 1 randomized patients to erdafitinib once daily or docetaxel/vinflunine once every 3 weeks. Primary endpoint was OS. Secondary endpoints included progression-free survival (PFS) and objective response rate (ORR). No specific statistical power was set for this Japanese subgroup analysis.

RESULTS

Of 266 patients randomized, 27 (14 erdafitinib; 13 chemotherapy) were Japanese. Baseline characteristics were generally similar between treatments and to the overall population, except for more males, lower body weight, and more upper tract primary tumors among Japanese patients. Compared with chemotherapy, erdafitinib showed improved OS (median 25.4 versus 12.4 months), PFS (median 8.4 versus 2.9 months) and ORR (57.1% versus 15.4%). Any grade treatment-related adverse events (AEs) occurred in all patients from both arms but Grade 3/4 AEs and AEs leading to discontinuation were lower in the erdafitinib arm. No new safety signals were observed in the Japanese subgroup.

CONCLUSION

In the Japanese subgroup, erdafitinib showed improved survival and response compared to chemotherapy, with no new safety concerns. These results support erdafitinib as a treatment option for Japanese mUC patients with FGFR alterations, and early FGFR testing after diagnosis of mUC should be considered.

Genetic Signature of Human Pancreatic Cancer and Personalized Targeting

Pancreatic cancer is a highly lethal disease with a 5-year survival rate of around 11-12%. Surgery, being the treatment of choice, is only possible in 20% of symptomatic patients. The main reason is that when it becomes symptomatic, IT IS the tumor is usually locally advanced and/or has metastasized to distant organs; thus, early diagnosis is infrequent. The lack of specific early symptoms is an important cause of late diagnosis. Unfortunately, diagnostic tumor markers become positive at a late stage, and there is a lack of early-stage markers. Surgical and non-surgical cases are treated with neoadjuvant and/or adjuvant chemotherapy, and the results are usually poor. However, personalized targeted therapy directed against tumor drivers may improve this situation. Until recently, many pancreatic tumor driver genes/proteins were considered untargetable. Chemical and physical characteristics of mutated KRAS are a formidable challenge to overcome. This situation is slowly changing. For the first time, there are candidate drugs that can target the main driver gene of pancreatic cancer: KRAS. Indeed, KRAS inhibition has been clinically achieved in lung cancer and, at the pre-clinical level, in pancreatic cancer as well. This will probably change the very poor outlook for this disease. This paper reviews the genetic characteristics of sporadic and hereditary predisposition to pancreatic cancer and the possibilities of a personalized treatment according to the genetic signature.

A comprehensive overview of selective and novel fibroblast growth factor receptor inhibitors as a potential anticancer modality

The arrival of comprehensive genome sequencing has accelerated the understanding of genetically aberrant advanced cancers and target identification for possible cancer treatment. Fibroblast growth factor receptor (FGFR) gene alterations are frequent findings in various rare and advanced cancers refractive to mainstay chemo-therapy or surgical interventions. Several FGFR inhibitors have been developed for addressing these genetically altered FGFR-harboring malignancies, and some have performed well in clinical trials. In contrast, others are still being investigated in different phases of clinical trials. FDA has approved four anticancer agents such as erdafitinib, pemigatinib, infigratinib, and futibatinib, for clinical use in oncogenic FGFR-driven malignancies. These include cholangiocarcinoma, urothelial carcinoma, and myeloid/lymphoid malignancies. Pemigatinib is the only FGFR inhibitor globally approved (USA, EU, and Japan) and available as a targeted therapy for two types of cancer, including FGFR2 fusion or other rearrangements harboring cholangiocarcinoma and relapsed/refractory myeloid/lymphoid neoplasms with FGFR1 rearrangements. Myeloid/lymphoid neoplasm is the latest area of application added to the therapeutic armamentarium of FGFR inhibitors. Furthermore, futibatinib is the first-in-class covalent or irreversible pan-FGFR inhibitor that has received FDA approval for locally advanced or metastatic intrahepatic cholangiocarcinoma harboring FGFR2 gene aberrations. This review highlights the current clinical progress concerning the safety and efficacy of all the approved FGFR-TKIs (tyrosine kinase inhibitors) and their ongoing investigations in clinical trials for other oncogenic FGFR-driven malignancies.

Discovery of KIN-3248, An Irreversible, Next Generation FGFR Inhibitor for the Treatment of Advanced Tumors Harboring FGFR2 and/or FGFR3 Gene Alterations

Fibroblast growth factor receptor (FGFR) alterations are present as oncogenic drivers and bypass mechanisms in many forms of cancer. These alterations can include fusions, amplifications, rearrangements, and mutations. Acquired drug resistance to current FGFR inhibitors often results in disease progression and unfavorable outcomes for patients. Genomic profiling of tumors refractory to current FGFR inhibitors in the clinic has revealed several acquired driver alterations that could be the target of next generation therapeutics. Herein, we describe how structure-based drug design (SBDD) was used to enable the discovery of the potent and kinome selective pan-FGFR inhibitor KIN-3248, which is active against many acquired resistance mutations. KIN-3248 is currently in phase I clinical development for the treatment of advanced tumors harboring FGFR2 and/or FGFR3 gene alterations.

Untying the Gordian knot of composite hemangioendothelioma: Discovery of novel fusions

Composite hemangioendothelioma is a rare, locally aggressive, and rarely metastasizing vascular neoplasm which affects both children and adults. Recently, a number of gene fusions including YAP1::MAML2, PTBP1::MAML2, and EPC1::PHC2 have been detected in a small subset of cases with or without neuroendocrine expression. Herein, we present four additional cases with novel in-frame fusions. The cohort comprises two females and two males with a wide age range at diagnosis (24-80 years). Two tumors were deep involving the right brachial plexus and mediastinum, while the remaining were superficial (right plantar foot and abdominal wall). The size ranged from 1.5 to 4.8 cm in greatest dimension. Morphologically, all tumors had an admixture of at least two architectural patterns including retiform hemangioendothelioma, hemangioma, epithelioid hemangioendothelioma, or angiosarcoma. The tumors were positive for endothelial markers CD31 (3/3), ERG (4/4), and D2-40 (1/4, focal), while SMA was expressed in 2/3 highlighting the surrounding pericytes. Synaptophysin showed immunoreactivity in 2/3 cases. One patient had a local recurrence after 40 months, while two patients had no evidence of disease 4 months post-resection. Targeted RNA sequencing detected novel in-frame fusions in each of the cases: HSPG2::FGFR1, YAP1::FOXR1, ACTB::MAML2, and ARID1B::MAML2. The two cases with neuroendocrine expression occurred as superficial lesions and harbored YAP1::FOXR1 and ARID1B::MAML2 fusions. Our study expands on the molecular spectrum of this enigmatic tumor, further enhancing our current understanding of the disease.

Precision Medicine in Bladder Cancer: Present Challenges and Future Directions

Bladder cancer (BC) is characterized by significant histopathologic and molecular heterogeneity. The discovery of molecular pathways and knowledge of cellular mechanisms have grown exponentially and may allow for better disease classification, prognostication, and development of novel and more efficacious noninvasive detection and surveillance strategies, as well as selection of therapeutic targets, which can be used in BC, particularly in a neoadjuvant or adjuvant setting. This article outlines recent advances in the molecular pathology of BC with a better understanding and deeper focus on the development and deployment of promising biomarkers and therapeutic avenues that may soon make a transition into the domain of precision medicine and clinical management for patients with BC.

Clinical Evidence and Selecting Patients for Treatment with Erdafitinib in Advanced Urothelial Carcinoma

Erdafitinib received accelerated approval on April 12, 2019, for patients with metastatic or locally advanced urothelial carcinoma with susceptible fibroblast growth factor receptor (FGFR) 3 or FGFR2 genetic alterations and who have progressed during or following at least one platinum-based chemotherapy. It thus became the first-ever targeted therapy to receive accelerated FDA approval for metastatic bladder cancer. In the BLC2001 trial, erdafitinib demonstrated an overall response rate of 40% in patients with urothelial carcinoma. Common adverse events include hyperphosphatemia and retinopathy and require regular monitoring. While the increase in serum phosphate levels has been determined to be a pharmacodynamic marker of response, further interrogation of other clinical, genomic, and transcriptomic biomarkers is warranted. Results of the ongoing Phase III trial, THOR, which is comparing erdafitinib to the standard of care (chemotherapy or immunotherapy), are expected to confer full approval. Establishing guidelines for optimal erdafitinib sequencing with immunotherapy and other approved targeted therapies (enfortumab vedotin and sacituzumab govitecan) remains an unmet need.

FGFR Pathway Inhibition in Gastric Cancer: The Golden Era of an Old Target?

Gastric cancer (GC) is the third leading cause of cancer-associated death worldwide. The majority of patients are diagnosed at an advanced/metastatic stage of disease due to a lack of specific symptoms and lack of screening programs, especially in Western countries. Thus, despite the improvement in GC therapeutic opportunities, the survival is disappointing, and the definition of the optimal treatment is still an unmet need. Novel diagnostic techniques were developed in clinical trials in order to characterize the genetic profile of GCs and new potential molecular pathways, such as the Fibroblast Growth Factor Receptor (FGFR) pathway, were identified in order to improve patient's survival by using target therapies. The aim of this review is to summarize the role and the impact of FGFR signaling in GC and to provide an overview regarding the potential effectiveness of anti-FGFR agents in GC treatment in the context of precision medicine.

TROPHY-U-01: A Phase II Open-Label Study of Sacituzumab Govitecan in Patients With Metastatic Urothelial Carcinoma Progressing After Platinum-Based Chemotherapy and Checkpoint Inhibitors

PURPOSE

Patients with metastatic urothelial carcinoma (mUC) who progress on platinum-based combination chemotherapy (PLT) and checkpoint inhibitors (CPIs) have limited options that offer objective response rates (ORRs) of approximately 10% with a median overall survival (OS) of 7-8 months. Sacituzumab govitecan (SG) is a TROP-2-directed antibody-drug conjugate with an SN-38 payload that has shown preliminary activity in mUC.

METHODS

TROPHY-U-01 (ClinicalTrials.gov identifier: NCT03547973) is a multicohort, open-label, phase II, registrational study. Cohort 1 includes patients with locally advanced or unresectable or mUC who had progressed after prior PLT and CPI. Patients received SG 10 mg/kg on days 1 and 8 of 21-day cycles. The primary outcome was centrally reviewed ORR; secondary outcomes were progression-free survival, OS, duration of response, and safety.

RESULTS

Cohort 1 included 113 patients (78% men; median age, 66 years; 66.4% visceral metastases; median of three [range, 1-8] prior therapies). At a median follow-up of 9.1 months, the ORR was 27% (31 of 113; 95% CI, 19.5 to 36.6); 77% had decrease in measurable disease. Median duration of response was 7.2 months (95% CI, 4.7 to 8.6 months), with median progression-free survival and OS of 5.4 months (95% CI, 3.5 to 7.2 months) and 10.9 months (95% CI, 9.0 to 13.8 months), respectively. Key grade ≥ 3 treatment-related adverse events included neutropenia (35%), leukopenia (18%), anemia (14%), diarrhea (10%), and febrile neutropenia (10%), with 6% discontinuing treatment because of treatment-related adverse events.

CONCLUSION

SG is an active drug with a manageable safety profile with most common toxicities of neutropenia and diarrhea. SG has notable efficacy compared with historical controls in pretreated mUC that has progressed on both prior PLT regimens and CPI. The results from this study supported accelerated approval of SG in this population.

Fibroblast Growth Factor Receptor (FGFR) Signaling in GIST and Soft Tissue Sarcomas

Sarcomas are a heterogeneous group of rare malignancies originating from mesenchymal tissues with limited therapeutic options. Recently, alterations in components of the fibroblast growth factor receptor (FGFR) signaling pathway have been identified in a range of different sarcoma subtypes, most notably gastrointestinal stromal tumors, rhabdomyosarcomas, and liposarcomas. These alterations include genetic events such as translocations, mutations, and amplifications as well as transcriptional overexpression. Targeting FGFR has therefore been proposed as a novel potential therapeutic approach, also in light of the clinical activity shown by multi-target tyrosine kinase inhibitors in specific subtypes of sarcomas. Despite promising preclinical evidence, thus far, clinical trials have enrolled very few sarcoma patients and the efficacy of selective FGFR inhibitors appears relatively low. Here, we review the known alterations of the FGFR pathway in sarcoma patients as well as the preclinical and clinical evidence for the use of FGFR inhibitors in these diseases. Finally, we discuss the possible reasons behind the current clinical data and highlight the need for biomarker stratification to select patients more likely to benefit from FGFR targeted therapies.

Case Report: Molecular Features and Treatment Options for Small Bowel Adenocarcinoma

Small bowel adenocarcinoma (SBA) is a rare malignancy characterized by poor prognosis. Recent efforts have sought to elucidate the genetic landscape and the molecular drivers behind this disease. Herein, we report the main molecular alterations in two metastatic (stage IV) SBA patients. Interestingly, one of them had gene alterations that affected signaling pathways previously described for SBA. However, a second patient displayed previously unreported alterations in this particular tumor type. Based on these findings we discuss potential treatment options for patients affected by this rare, aggressive disease.

Potentially life‑threatening severe cutaneous adverse reactions associated with tyrosine kinase inhibitors (Review)

Tyrosine kinase inhibitors (TKIs) have emerged as a new frontier of cancer therapy. These agents include inhibitors of epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), BRAF, mitogen‑activated protein kinase kinase (also referred to as MEK), bcr‑abl, c‑KIT, platelet‑derived growth factor (PDGFR), fibroblast growth factor receptor (FGFR), anaplastic lymphoma kinase (ALK) and vascular endothelial growth factor (VEGF). Along with the evolving applications of TKIs, there has been an increased recognition of the breadth of potential cutaneous toxicities to these agents. In this review, we provide an overview of potentially life‑threatening severe cutaneous adverse reactions (SCARs) that may occur during therapy with TKIs. These toxicities include Stevens‑Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), drug reaction with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP).

Analysis of estimated clinical benefit of newly approved drugs for US patients with acute myeloid leukemia

The increased number of available United States Food and Drug Administration (FDA)-approved drugs indicated for acute myeloid leukemia (AML) have generated considerable interest and may have the potential to influence practice. We performed a retrospective cross-sectional study performed from September to November 2019 to determine 1) demographic and subgroup characteristics of patients with newly diagnosed cases of acute myeloid leukemia, 2) FDA data on drugs indicated for AML approved from 1969 through November 2019, 3) measures of response from drug labels, and 4) published reports documenting the response for drugs approved before the 1979 Labeling Act. We used publicly available data from the Food and Drug Administration (FDA), the American Cancer Society, the Leukemia and Lymphoma Society, and the U.S. Census Bureau. According to our estimation methods, cytarabine infused continuously for 7 days, with three short boluses of anthracycline over Days 1-3, the standard of care known as "7 + 3", continues to have the largest population benefit. The maximum cost per course of treatment for an average regimen is enasidenib for salvage therapy, estimated to be around $120,131. The minimum cost was $1,662.50 for standard 7 + 3 chemotherapy. The mean and median cost for all AML treatments was $43,784.26 and $35,083.70, respectively. While it is true that the number of available therapies approved by the FDA has increased dramatically, it is not yet clear how large of a clinical benefit we can expect to see from these new lines of therapies.