pazopanib and Gastrointestinal-Stromal-Tumors

Patients with advanced gastrointestinal stromal tumours (GISTs) resistant to the tyrosine kinase inhibitors imatinib and sunitinib may be treated with regorafenib, which resulted in a median progression-free survival (PFS) of 4.8 months in the GRID trial. Also, pazopanib, another tyrosine kinase inhibitor, has been studied in a randomized, placebo-controlled trial (PAZOGIST) in the third line, which showed a PFS of 45.2% 4 months after study entry, but patients intolerant to sunitinib were also included. We designed another trial evaluating pazopanib, enrolling only patients with progression on both imatinib and sunitinib.. Since all eligible patients had progressive disease, we preferred a non-randomized, phase II multicentre trial so that all patients could receive a potentially active drug. Patients had a progressive metastatic or locally advanced GIST and were ≥18 years of age, with a performance status of 0-2, and sufficient organ functions. The primary endpoint was disease control rate (defined as complete remission + partial remission + stable disease) at 12 weeks on pazopanib. A Simon's two-stage analysis was used with an interim analysis 12 weeks after enrollment of the first 22 patients, and if passed, there was a full enrolment of 72 patients. GIST mutational analysis was done, and most patients had pazopanib plasma concentration measured after 12 weeks.. Seventy-two patients were enrolled. The disease control rate after 12 weeks was 44%, and the median PFS was 19.6 weeks (95% confidence interval 12.6-23.4 weeks). Pazopanib-related toxicity was moderate and manageable. No statistically significant differences were found related to mutations. Plasma concentrations of pazopanib had a formal but weak correlation with outcome.. Pazopanib given in the third line to patients with GIST progressing on both imatinib and sunitinib was beneficial for about half of the patients. The PAGIST trial confirms the results from the PAZOGIST trial, and the median PFS achieved seems comparable to the PFS achieved with regorafenib in the third-line setting.

Topics: Gastrointestinal Stromal Tumors; Humans; Indazoles; Indoles; Pyrimidines; Pyrroles; Sulfonamides

Gastrointestinal stromal tumours (GIST) are the most common mesenchymal neoplasms of the gastrointestinal tract. Imatinib followed by sunitinib and regorafenib is the standard sequence of treatment for advanced disease. Pazopanib is effective in soft tissue sarcomas but has never been assessed in advanced GIST in a randomised trial. We aimed to assess the efficacy and safety of pazopanib in patients with previously treated advanced GIST.. In this randomised, open-label phase 2 study, we enrolled adults (aged ≥18 years) with advanced GIST resistant to imatinib and sunitinib from 12 comprehensive cancer centres or university hospitals in France and randomly assigned them 1:1 using an interactive web-based centralised platform to 800 mg oral pazopanib once daily in 4-week cycles plus best supportive care or best supportive care alone. Randomisation was stratified by the number of previous treatment regimens (2 vs ≥3); no-one was masked to treatment group allocation. Upon disease progression, patients in the best supportive care group were allowed to switch to pazopanib as compassionate treatment. The primary endpoint was investigator-assessed progression-free survival, analysed by intention-to-treat. All randomised participants who received at least one dose of pazopanib were included in the safety analysis. This study is registered with ClinicalTrials.gov, number NCT01323400.. Between April 12, 2011, and Dec 9, 2013, 81 patients were enrolled and randomly assigned to pazopanib plus best supportive care (n=40) or best supportive care alone (n=41). The median follow-up was 26·4 months (IQR 22·0-37·8) in the pazopanib plus best supportive care group and 28·9 months (22·0-35·2) in the best supportive care group. 4-month investigator-assessed progression-free survival was 45·2% (95% CI 29·1-60·0) in the pazopanib plus best supportive care group versus 17·6% (7·8-30·8) in the best supportive care group (hazard ratio [HR] 0·59, 95% CI 0·37-0·96; p=0·029). Median progression-free survival was 3·4 months (95% CI 2·4-5·6) with pazopanib plus best supportive care and 2·3 months (2·1-3·3) with best supportive care alone (HR 0·59 [0·37-0·96], p=0·03). 36 (88%) of the patients originally assigned to the best supportive care group switched to pazopanib following investigator-assessed disease progression; these patients had a median progression-free survival from pazopanib initiation of 3·5 months (95% CI 2·2-5·2). 55 (72%) of the 76 pazopanib-treated patients had pazopanib-related grade 3 or worse adverse events, the most common of which was hypertension (15 [38%] in the pazopanib plus best supportive care group and 13 [36%] in the best supportive care group). 20 (26%) patients had pazopanib-related serious adverse events (14 [35%] in the pazopanib plus best supportive care group and six [17%] in the best supportive care group), including pulmonary embolism in eight (9%) patients (five [13%] in the pazopanib plus best supportive care group and three [7%] in the best supportive care group). Three pazopanib-related deaths occurred (two pulmonary embolisms [one in each group] and one hepatic cytolysis [in the best supportive care group]). Three adverse event-related but not pazopanib-related deaths occurred in the best supportive care group after switch to pazopanib; these deaths were from hyperammonaemic encephalopathy, pneumopathy, and respiratory failure.. Pazopanib plus best supportive care improves progression-free survival compared with best supportive care alone in patients with advanced GIST resistant to imatinib and sunitinib, with a toxicity profile similar to that reported for other sarcomas. This trial provides reference outcome data for future studies of targeted inhibitors in the third-line setting for these patients.. GlaxoSmithKline, French National Cancer Institute, EuroSARC (FP7-278742), Centre Léon Bérard.

Topics: Adult; Aged; Antineoplastic Combined Chemotherapy Protocols; Disease-Free Survival; Drug Resistance, Neoplasm; Drug-Related Side Effects and Adverse Reactions; Female; France; Gastrointestinal Stromal Tumors; Humans; Imatinib Mesylate; Indazoles; Indoles; Male; Middle Aged; Neoplasm Staging; Protein Kinase Inhibitors; Pyrimidines; Pyrroles; Sulfonamides; Sunitinib; Treatment Outcome

Advanced GISTs are incurable, but often treatable for years with tyrosine kinase inhibitors (TKIs). The majority of GISTs harbor an oncogenic activating mutation in KIT or PDGFRA. Inhibition of this activating mutation with TKIs most often leads to durable disease control for many patients. However, almost all patients develop resistance to these TKIs, typically due to the development of secondary mutations, heralding the need for new therapeutic options. We conducted a phase II study evaluating the efficacy and toxicity of pazopanib, a broad spectrum TKI inhibiting KIT, VEGFRs (-1, -2, and -3), and PDGFR (-α and-β) in patients with advanced GIST following failure of at least imatinib and sunitinib.. Patients received pazopanib 800 mg orally once daily. All patients were assessed for efficacy with CT scans every 8 weeks (two cycles). Patients continued pazopanib until progression or unacceptable toxicity. The primary end point was the 24-week nonprogression [complete response+partial response+stable disease (SD)] rate (NPR) per RECIST 1.1. Secondary end points included PFS, OS, and toxicity.. Between August 2011 and September 2012, a total of 25 patients were treated at two institutions. Median number of prior therapy was 3 (range 2-7). A total of 90 cycles of pazopanib were administered, with a median of two cycles (range 1 to 17+) per patient. Best response of SD at any time was observed in 12 (48%) patients. The NPR was 17% [95% confidence interval (CI) 4.5-37]. All but one patient discontinued protocol either due to PD (n = 19) or intolerance (n = 4). One patient with succinate dehydrogenase (SDH)-deficient GIST exhibited continuing disease control after 17 cycles. The median PFS for the entire cohort was 1.9 months (95% CI 1.6-5.2), and the median OS was 10.7 months (95% CI 3.9-NR).. Pazopanib was reasonably well tolerated with no unexpected toxicities. Pazopanib as a single agent has marginal activity in unselected heavily pretreated patients with advanced GIST.

Topics: Adult; Aged; Angiogenesis Inhibitors; Benzamides; Disease-Free Survival; Drug Resistance, Neoplasm; Female; Gastrointestinal Neoplasms; Gastrointestinal Stromal Tumors; Humans; Imatinib Mesylate; Indazoles; Indoles; Kaplan-Meier Estimate; Male; Middle Aged; Neoplasm Staging; Piperazines; Pyrimidines; Pyrroles; Sulfonamides; Sunitinib; Treatment Failure; Tumor Burden; Young Adult

With the approval of avapritinib for adults with unresectable or metastatic gastrointestinal stromal tumors (GISTs) harboring a platelet-derived growth factor receptor alpha (PDGFRA) exon 18 variant, including PDGFRA D842V variants, and National Comprehensive Cancer Network guideline recommendations as an option for patients with GIST after third-line treatment, it is important to estimate the potential financial implications of avapritinib on a payer's budget.. To estimate the budget impact associated with the introduction of avapritinib to a formulary for metastatic or unresectable GISTs in patients with a PDGFRA exon 18 variant or after 3 or more previous treatments from the perspective of a US health plan.. For this economic evaluation, a 3-year budget impact model was developed in March 2020, incorporating costs for drug acquisition, testing, monitoring, adverse events, and postprogression treatment. The model assumed that avapritinib introduction would be associated with increased PDGFRA testing rates from the current 49% to 69%. The health plan population was assumed to be mixed 69% commercial, 22% Medicare, and 9% Medicaid. Base case assumptions included a GIST incidence rate of 9.6 diagnoses per million people, a metastatic PDGFRA exon 18 mutation rate of 1.9%, and progression rate from first-line to fourth-line treatment of 17%.. The model compared scenarios with and without avapritinib in a formulary.. Annual, total, and per member per month (PMPM) budget impact.. In a hypothetical 1-million member plan, fewer than 0.1 new patients with a PDGFRA exon 18 variant per year and 1.2 patients receiving fourth-line therapy per year were eligible for treatment. With avapritinib available, the total increase in costs in year 3 for all eligible adult patients with a PDGFRA exon 18 variant was $46 875, or $0.004 PMPM. For patients undergoing fourth-line treatment, the total increase in costs in year 3 was $69 182, or $0.006 PMPM. The combined total budget impact in year 3 was $115 604, or $0.010 PMPM, including an offset of $3607 in postprogression costs avoided or delayed. The higher rates of molecular testing resulted in a minimal incremental testing cost of $453 in year 3.. These results suggest that adoption of avapritinib as a treatment option would have a minimal budget impact to a hypothetical US health plan. This would be primarily attributable to the small eligible patient population and cost offsets from reduced or delayed postprogression costs.

Topics: Antineoplastic Agents; Budgets; Cost-Benefit Analysis; Formularies as Topic; Gastrointestinal Neoplasms; Gastrointestinal Stromal Tumors; Humans; Imatinib Mesylate; Indazoles; Managed Care Programs; Medicaid; Medicare; Molecular Diagnostic Techniques; Phenylurea Compounds; Pyrazoles; Pyridines; Pyrimidines; Pyrroles; Receptor, Platelet-Derived Growth Factor alpha; Sulfonamides; Sunitinib; Treatment Failure; Triazines; United States

Topics: Aged; Ammonia; Anti-Bacterial Agents; Anticonvulsants; Antineoplastic Combined Chemotherapy Protocols; Female; Gastrointestinal Stromal Tumors; Humans; Hyperammonemia; Indazoles; Middle Aged; Neurotoxicity Syndromes; Phenylurea Compounds; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Pyridines; Pyrimidines; Sulfonamides; Sunitinib; Treatment Outcome; Withholding Treatment

The functional mutation of c-kit and platelet-derived growth factor receptor α (PDGFRA) which encode proto-oncogene receptor tyrosine kinase are the crucial pathogeneses of gastrointestinal stromal tumors(GISTs). 80%-85% c-kit gene mutation including exon 11,exon 9,exon 13,exon 17 and 5%-10% PDGFRA gene mutation such as exon 18, exon 12 are examined in GISTs. Neither of c-kit or PDGFRA gene mutation are called wide type GISTs. The pathogeneses of wild type GISTs are not clear. The deficiency of succinate dehydrogenase B(SDHB)-related insulin-like growth factor 1(IGF-1R) activation, BRAF gene mutation and neurofibromatosis type 1 may be related to progression of wild type GISTs. More than half of metastatic GISTs patients receiving imatinib treatment can develop to c-kit secondary mutations, which are responsible for secondary resistance. However, the reasons of imatinib resistance in GISTs without c-kit secondary mutation need to be explored. At present, many clinical trials are ongoing to evaluate new drugs in GISTs treatment, including nilotinib, masitinib, pazopanib, dovitinib, ponatinib, dasatinib, crenolanib, linsitinib and immunotherapy, which may bring resistance GISTs treatment to new hope. Next generation sequencing (NGS) and liquid biopsy will be very important in GISTs research and clinical practice.

Topics: Benzimidazoles; Exons; Gastrointestinal Stromal Tumors; High-Throughput Nucleotide Sequencing; Humans; Imatinib Mesylate; Indazoles; Mutation; Piperidines; Protein Kinase Inhibitors; Proto-Oncogene Mas; Proto-Oncogene Proteins c-kit; Pyrimidines; Quinolones; Succinate Dehydrogenase; Sulfonamides

Targeted therapy is the first line treatment for patients with recurrent/metastatic gastrointestinal stromal tumors(GIST). Sunitinib is effective for patients who have failed imatinib, specially with c-kit exon 9 gene mutation. Tyrosine kinase inhibitors combined with partial hepatectomy may increase the overall survival of GIST patients with liver metastasis. Selective patients with recurrent or metastatic GIST can benefit from surgical resection. Regorafenib and pazopanib can provide a significant improvement in progression-free survival in patients after failure of standard treatment.

Topics: Benzamides; Disease-Free Survival; Gastrointestinal Neoplasms; Gastrointestinal Stromal Tumors; Hepatectomy; Humans; Imatinib Mesylate; Indazoles; Indoles; Liver Neoplasms; Phenylurea Compounds; Piperazines; Pyridines; Pyrimidines; Pyrroles; Recurrence; Sulfonamides; Sunitinib