From Triple- to Penta-Exposed Multiple Myeloma: A Real-World Study in a Medicare Population.

INTRODUCTION: Treatment of multiple myeloma (MM) has been transformed by novel therapies, including CD38 monoclonal antibodies (mAbs), immunomodulatory drugs (IMiDs), and proteasome inhibitors (PIs), resulting in increasing numbers of patients who are triple-class exposed (TCE; exposed to ≥ 1 drug in each class). Many patients are penta-exposed (PE; ≥ 2 IMiDs, ≥ 2 PIs, and a CD38 mAb), some are triple-class refractory (TCR), and some are PE and TCR (PE-TCR). Data on real-world outcomes in elderly patients with MM across this spectrum of exposure are limited. METHODS: Data from the Medicare Chronic Conditions Warehouse Database from November 2006-December 2020 were used to examine cohorts of TCE, TCR, PE, and PE-TCR patients. Outcomes were assessed from the start of the index line of therapy (LOT), defined as the first LOT after becoming TCE or PE. RESULTS: A total of 2830 TCE, 1371 TCR, 1121 PE, and 774 PE-TCR patients were identified. Pomalidomide was the most frequently used medication for the index LOT in all cohorts (32.6% [PE-TCR] to 43.3% [TCR]). The most frequently used regimens for the index LOT were pomalidomide plus daratumumab for TCE (17.2%) and PE (7.0%), pomalidomide plus carfilzomib for TCR (10.3%), and pomalidomide plus elotuzumab for PE-TCR (7.4%). Median time to discontinuation (TTD) ranged from 4.2 (PE-TCR) to 6.9 (TCE) months, and overall survival (OS) ranged from 13.0 (TCR) to 15.9 (PE) months. Healthcare resource utilization (HRU) was lowest for TCE and highest for PE-TCR patients. Mean monthly healthcare costs (HCC) ranged from $23,091 (TCE) to $24,412 (PE-TCR). MM medications represented 66.2% (PE-TCR) to 72.8% (TCE) of costs. CONCLUSIONS: In this study across a spectrum of Medicare TCE patients, there was heterogeneity in treatment regimens, suggesting no standard of care. TTD and OS were short, and HRU and HCC were high. These results underscore the potential for new therapies in this population.

Linvoseltamab for Treatment of Relapsed/Refractory Multiple Myeloma.

PURPOSE: We present a phase I/II first-in-human trial evaluating the safety and efficacy of 50 mg and 200 mg doses of linvoseltamab, a B-cell maturation antigen × CD3 bispecific antibody in relapsed/refractory multiple myeloma (RRMM). METHODS: Phase II eligible patients had RRMM that either progressed on/after ≥three lines of therapy including a proteasome inhibitor (PI), an immunomodulatory drug (IMiD), and an anti-CD38 antibody or was triple-class (PI/IMiD/anti-CD38) refractory. Phase II treatment was once a week through week 14 and then once every 2 weeks. Phase II 200 mg patients who achieved a ≥very good partial response by week 24 received linvoseltamab once every 4 weeks. The primary end point in phase II was overall response rate (ORR). RESULTS: Among the 117 patients treated with 200 mg, the median age was 70 years, 39% had high-risk cytogenetics, and 28% had penta-refractory disease. At a median follow-up of 14.3 months, the ORR was 71%, with 50% achieving ≥complete response (CR). In 104 patients treated with 50 mg at a median follow-up of 7.4 months, the ORR was 48%, with 21% achieving ≥CR. The median duration of response (DOR) for 200 mg patients (n = 83) was 29.4 months (95% CI, 19.2 to not evaluable). Among 200 mg patients, the most common adverse events included cytokine release syndrome (35.0% Gr1, 10.3% Gr2, 0.9% Gr3), neutropenia (0.9% Gr2, 18.8% Gr3, 23.1% Gr4), and anemia (3.4% Gr1, 4.3% Gr2, 30.8% Gr3). Immune effector cell-associated neurotoxicity syndrome occurred in 7.7% of patients (2.6% each Gr1, Gr2, Gr3). Infections were reported in 74.4% of patients (33.3% Gr3, 2.6% Gr4); infection frequency and severity declined over time. CONCLUSION: Linvoseltamab 200 mg induced deep and durable responses, with a median DOR of 29.4 months, in patients with RRMM with an acceptable safety profile.

Phase I Study of Fianlimab, a Human Lymphocyte Activation Gene-3 (LAG-3) Monoclonal Antibody, in Combination With Cemiplimab in Advanced Melanoma.

PURPOSE: Coblockade of lymphocyte activation gene-3 (LAG-3) and PD-1 receptors could provide significant clinical benefit for patients with advanced melanoma. Fianlimab and cemiplimab are high-affinity, human, hinge-stabilized IgG4 monoclonal antibodies, targeting LAG-3 and PD-1, respectively. We report results from a first-in-human phase-I study of fianlimab and cemiplimab safety and efficacy in various malignancies including advanced melanoma. METHODS: Patients with advanced melanoma were eligible for enrollment into four cohorts: three for patients without and one for patients with previous anti-PD-1 therapy in the advanced disease setting. Patients were treated with fianlimab 1,600 mg and cemiplimab 350 mg intravenously once every 3 weeks for up to 51 weeks, with an optional additional 51 weeks if clinically indicated. The primary end point was objective response rate (ORR) per RECIST 1.1 criteria. RESULTS: ORRs were 63% for patients with anti-PD-1-naïve melanoma (cohort-6; n = 40; median follow-up 20.8 months), 63% for patients with systemic treatment-naïve melanoma (cohort-15; n = 40; 11.5 months), and 56% for patients with previous neo/adjuvant treatment melanoma (cohort-16; n = 18, 9.7 months). At a median follow-up of 12.6 months for the combined cohorts (6 + 15 + 16), the ORR was 61.2% and the median progression-free survival (mPFS) 13.3 months (95% CI, 7.5 to not estimated [NE]). In patients (n = 13) with previous anti-PD-1 adjuvant therapy, ORR was 61.5% and mPFS 12 months (95% CI, 1.4 to NE). ORR in patients with previous anti-PD-1 therapy for advanced disease (n = 15) was 13.3% and mPFS 1.5 months (95% CI, 1.3 to 7.7). Treatment-emergent and treatment-related adverse events ≥grade 3 (G3) were observed in 44% and 22% of patients, respectively. Except for increased incidence of adrenal insufficiency (12%-G1-4, 4%-G3-4), no new safety signals were recorded. CONCLUSION: The current results show a promising benefit-risk profile of fianlimab/cemiplimab combination for patients with advanced melanoma, including those with previous anti-PD-1 therapy in the adjuvant, but not advanced, setting.

Evaluation of cardiovascular ischemic event rates in dasatinib-treated patients using standardized incidence ratios.

With high survival rates for chronic myeloid leukemia (CML) patients treated with BCR-ABL1 tyrosine kinase inhibitors (TKIs), emerging consequences, such as arterial ischemic events, require consideration when evaluating treatment options. Cardiovascular ischemic event incidence in clinical trials was evaluated in 2712 dasatinib-treated patients with Philadelphia chromosome-positive (Ph+) leukemias from 11 first- and second-line trials (pooled), newly diagnosed CML patients treated with dasatinib or imatinib (DASISION), and prostate cancer patients treated with dasatinib or placebo plus docetaxel/prednisone (READY). Overall, 2-4% of dasatinib-treated patients had cardiovascular ischemic events. Most dasatinib-treated patients with an event had a history of and/or risk factor for atherosclerosis (pooled 77 with history/risk and event/96 with events; DASISION 8/10; READY 15/18). Most cardiovascular ischemic events occurred within 1 year of initiating dasatinib (pooled 69/96; DASISION 7/10; READY 16/18). Comparison of observed and expected event rates through standardized incidence ratios indicates that dasatinib does not increase risk for cardiovascular ischemic events compared with external reference populations.

Phase II trial of sunitinib in patients with metastatic non-clear cell renal cell carcinoma.

Sunitinib is associated with a robust objective response rate in patients with metastatic clear cell renal cell carcinoma (RCC). The primary objective of this phase II clinical trial was to assess the overall response rate for sunitinib in patients with papillary metastatic RCC as well as other non-clear cell histologies. A Simon 2-stage design was used to determine the number of papillary metastatic RCC patients for enrollment, and allowed for descriptive response data for other non-clear cell histologies. Twenty-three patients were enrolled, including 8 with papillary renal cell carcinoma (RCC) and the remainder with other non-clear cell histologies (unclassified in 5 patients). All patients received 50 mg of oral sunitinib in cycles of 4 weeks followed by 2 weeks of rest (4/2). The trial was stopped early because of slow accrual; no responses were observed in the 8 patients with papillary RCC. In the 22 evaluable patients, best response to sunitinib included a partial response in 1 patient with unclassified RCC, stable disease in 15, and progression in 6. The median progression-free survival was 5.5 months (95% CI, 2.5-7.1) in all 23 patients, and 5.6 months for the 8 papillary patients (95% CI, 1.4-7.1). The robust objective responses sunitinib had produced in clear cell RCC could not be demonstrated in this study comprised of patients with non-clear cell histologies.

Nephrotoxicities associated with the use of tyrosine kinase inhibitors: a single-center experience and review of the literature.

BACKGROUND: Sunitinib is an oral multitargeted tyrosine kinase receptor inhibitor (MTKI) used for the treatment of renal cell carcinoma. These small-molecule agents inhibit signaling through receptor tyrosine kinases such as vascular endothelial growth factor receptor, platelet-derived growth factor receptor and cytokine stem cell factor receptor, among others. Although the development of these novel molecular-targeted agents represents a substantial advance in the treatment of metastatic cancer, the spectrum of their adverse effects may be broader than initially predicted. METHOD: We performed a retrospective chart review of patients who had received sunitinib and developed renal insufficiency. RESULTS: We describe 4 patients with renal cell carcinoma and 1 patient with transitional cell carcinoma treated with sunitinib who experienced various degrees of nephrotoxicity including hypertension, proteinuria, thrombotic microangiopathy, and acute and chronic kidney injury which resolved upon cessation of MTKI. CONCLUSIONS: Nephrologists and oncologists should be aware of the potential for toxic renal effects, and we recommend guidelines for early recognition and treatment of these conditions in patients receiving MTKI.

Leupaxin is similar to paxillin in focal adhesion targeting and tyrosine phosphorylation but has distinct roles in cell adhesion and spreading.

Focal adhesion (FA) formation is induced by extracellular matrix-stimulated integrin clustering and activation of receptors for diffusible factors. Leupaxin (LPXN) is a member of the paxillin family of FA proteins expressed in many cancer cell lines. We found activation of gastrin-releasing peptide receptor (GRPr) by bombesin (BN) stimulated LPXN translocation from cytoplasm to FAs. Using mutagenesis, we identified LIM3 as the primary FA targeting domain for LPXN and showed BN-induced LPXN tyrosine phosphorylation on residues 22, 62 and 72. A LIM3 point mutant of LPXN failed to target to FAs and had no BN-stimulated tyrosine phosphorylation. Conversely, a non-phosphorylatable mutant (Y22/62/72F) translocated to FAs after BN addition. Stimulation of FA formation using vinblastine also induced LPXN translocation and tyrosine phosphorylation. Therefore, dynamic LPXN tyrosine phosphorylation requires translocation to FAs. LPXN and paxillin had opposite roles in adhesion to collagen I (CNI) in MDA-MB-231 breast cancer cells. LPXN siRNA stimulated whereas paxillin siRNA inhibited cell adhesion. Knockdown of both LPXN and paxillin behaved similarly to paxillin knockdown alone, suggesting LPXN's function in adhesion might depend on paxillin. Additionally, LPXN regulated cell spreading on CNI but not on fibronectin whereas paxillin knockdown suppressed spreading on both substrates. These results demonstrate that although LPXN and paxillin's FA targeting and tyrosine phosphorylation are similar, each protein has distinct functions.

Systemic therapy for metastatic renal cell carcinoma.

Renal cell cancer (RCC) is the most common form of cancer of the kidney and accounts for approximately 44,000 cases per year in the United States. Historically, only immunotherapy showed activity in metastatic RCC. The improved survival and quality of life for patients with metastatic RCC over the last several years are direct results of advances made in understanding the development of RCC. Three targeted therapies-sunitinib, sorafenib, and temsirolimus-have been approved for use in the United States recently. Current research is aimed at developing new drugs and combining available drugs to improve upon the responses and survival seen with approved single agents.

Enhanced sensitivity to the HER1/epidermal growth factor receptor tyrosine kinase inhibitor erlotinib hydrochloride in chemotherapy-resistant tumor cell lines.

PURPOSE: Erlotinib (Tarceva, OSI-774) is a potent and specific inhibitor of the HER1/epidermal growth factor receptor (EGFR) tyrosine kinase. In phase II clinical studies, oral erlotinib monotherapy has shown antitumor activity in patients with advanced non-small cell lung cancer, head and neck cancer, and ovarian cancer after the failure of standard chemotherapy. We hypothesized that some tumors treated with multiple cytotoxic therapies may become more dependent on the HER1/EGFR signaling pathways for survival. EXPERIMENTAL DESIGN: The growth-inhibitory effect of erlotinib was tested on 10 pairs of chemosensitive, parental, and chemoresistant tumor cell lines. RESULTS: Enhanced sensitivity to erlotinib was observed in the doxorubicin-resistant human breast cancer cell line MCF-7, paclitaxel-resistant human ovarian carcinoma cell line A2780, and cisplatin-resistant human cervical carcinoma cell line ME180. The IC(50) values of erlotinib in the resistant cell lines were 2- to 20-fold lower than those in the corresponding parental cell lines. This enhanced sensitivity to erlotinib correlated with higher HER1/EGFR and phospho-HER1/EGFR expression when compared with the corresponding parental cell lines. Acquired resistance to cytotoxic agents was not associated with cross-resistance to erlotinib. AE-ME180/CDDP-resistant xenografts showed greater sensitivity to erlotinib than parental ME180 xenografts did. CONCLUSIONS: Our findings suggest that acquired resistance to cytotoxic therapy in some tumors is associated with enhanced sensitivity to HER1/EGFR inhibitors, which correlates with increased HER1/EGFR expression. These data may explain some of the observed clinical activity of HER1/EGFR inhibitors in patients previously treated with multiple therapies. HER1/EGFR tyrosine kinase inhibitors may be more effective as second- or third-line treatment for certain patients with tumors that were previously treated with multiple chemotherapy regimens.

Alterations in receptor expression or agonist concentration change the pathways gastrin-releasing peptide receptor uses to regulate extracellular signal-regulated kinase.

G protein-coupled receptors activate extracellular signal-regulated kinases (ERKs) via different pathways in different cell types. In this study, we demonstrate that gastrin-releasing peptide receptor (GRPr) regulates ERK through multiple pathways in a single cell type depending upon receptor expression and agonist concentration. We examined stably transfected BALB/c 3T3 fibroblasts expressing GRPr constructs at different levels and treated the cells with several concentrations of bombesin (BN, a GRPr agonist) to activate a variable number of GRPr per cell. GRPr induced two waves of ERK activation and one wave of ERK inhibition. One wave of activation required an intact GRPr carboxyl-terminal domain (CTD). It peaked 6 min after addition of high BN concentration ([BN]) in cells with high GRPr expression. Another wave of activation was CTD-independent. It peaked 2 to 4 min after BN addition in cells when [BN] and/or GRPr expression were lower. The early wave of ERK activation was more sensitive than the later one to pretreatment with Bisindolylmaleimide I (GF 109203X) (a protein kinase C inhibitor) or hypertonic sucrose. Because these two waves of activation differ in time course, dose-response curve, requirement for GRPr CTD, and sensitivity to inhibitors, they result from different signaling pathways. A third pathway in these cells inhibited ERK phosphorylation 2 min after addition of high [BN] in cells with high GRPr expression. Furthermore, a GRPr-expressing human duodenal cancer cell line showed differential sensitivity to GF 109203X throughout BN-induced ERK activation, indicating that GRPr may activate ERK via multiple pathways in cells expressing endogenous GRPr.

Agonist- and protein kinase C-induced phosphorylation have similar functional consequences for gastrin-releasing peptide receptor signaling via Gq.

Acute desensitization of many guanine nucleotide-binding protein-coupled receptors (GPCRs) requires receptor phosphorylation and subsequent binding of an arrestin. GPCRs are substrates for phosphorylation by several classes of kinases. Gastrin-releasing peptide receptor (GRPr) is phosphorylated by a kinase other than protein kinase C (PKC) after exposure to agonist and is also a substrate for PKC-dependent phosphorylation after treatment with 12-O-tetradecanoylphorbol 13-acetate (TPA). Using GRPr mutants, we examined receptor domains required for agonist- and TPA-induced phosphorylation of GRPr and consequences of these phosphorylation events on GRPr signaling via Gq. Agonist- and TPA-stimulated GRPr phosphorylation in cells require an intact carboxyl terminal domain (CTD). GRPr is phosphorylated in vitro by GPCR kinase 2 (GRK2) and multiple PKC isoforms. An intact DRY motif is required for agonist-stimulated phosphorylation in cells, and agonist-dependent GRK2 phosphorylation in vitro. Although GRPr CTD mutants do not show enhanced in vitro coupling to Gq relative to intact GRPr, CTD mutants have more potent Gq-dependent signaling in cells. Acute desensitization involves CTD-independent processes because desensitization can precede ligand binding in intact GRPr and CTD mutants. TPA-mediated impairment of GRPr-Gq signaling in cells also requires an intact CTD. Similar to GRK2 phosphorylation, PKC phosphorylation reduces GRPr-Gq coupling by approximately 80% in vitro. Arrestin translocation to plasma membrane requires agonist, an intact DRY motif, and GRPr phosphorylation. Therefore, agonist- and PKC-induced GRPr phosphorylation sites are in nearby regions of the receptor, and phosphorylation at both sites has similar functional consequences for Gq signaling.

Phase I study of weekly gemcitabine as a radiation sensitizer for unresectable pancreatic cancer.

PURPOSE: To determine the maximal tolerated dose and dose-limiting toxicities (DLTs) of weekly gemcitabine with concurrent radiotherapy (RT) in patients with unresectable adenocarcinoma of the pancreas. METHODS AND MATERIALS: Patients who had locally advanced or recurrent unresectable pancreatic cancer were eligible. Gemcitabine was administered as a 30-min infusion once weekly for a total of five cycles during the course of RT. The starting dose of gemcitabine was 350 mg/m(2)/wk. Doses were escalated by increments of 25% in successive cohorts of 3-6 patients. RT was delivered at 180 cGy/d to a total dose of 5400-5580 cGy to the gross tumor volume. RESULTS: Nineteen patients were entered in this study through three dose levels (350-550 mg/m(2)/wk). The maximal tolerated dose was determined to be 440 mg/m(2)/wk. The DLTs were neutropenia, thrombocytopenia, and failure to receive all five cycles of gemcitabine. Other non-DLTs included 16 Grade III toxicities, which consisted of thrombosis, infection, nausea, vomiting, hypotension, constipation, diarrhea, and fatigue. One patient at each gemcitabine dose level experienced Grade IV vomiting, and the patient at the 550 mg/m(2) dose developed Grade IV anorexia. CONCLUSION: The maximal tolerated dose of gemcitabine when administered as a 30-min infusion once weekly during RT for unresectable pancreatic cancer was found to be 440 mg/m(2)/wk. The DLTs were neutropenia, thrombocytopenia, and failure to receive all five cycles of chemotherapy. Concurrent gemcitabine and RT is reasonably well tolerated and deserves additional evaluation against the current standard of care.