A phase 2 study of glembatumumab vedotin, an antibody-drug conjugate targeting glycoprotein NMB, in patients with advanced melanoma.

BACKGROUND: Glembatumumab vedotin is an antibody-drug conjugate that produced preliminary clinical activity against advanced melanoma in a phase 1 dose-escalation trial. The objective of the current study was to investigate further the antitumor activity of glembatumumab vedotin at the recommended phase 2 dose in heavily pretreated patients with melanoma. METHODS: This single-arm, phase 2 study enrolled patients with stage IV melanoma who were refractory to checkpoint inhibition and to B-raf proto-oncogene, serine/threonine kinase (BRAF)/mitogen-activated protein kinase kinase (MEK) inhibition (in the presence of a BRAF valine mutation at codon 600). Patients received 1.9 mg/kg glembatumumab vedotin intravenously every 3 weeks until they developed disease progression or intolerance. The primary endpoint was objective response rate (ORR), which was determined according to Response Evaluation Criteria in Solid Tumors, version 1.1. Secondary endpoints included progression-free survival (PFS), duration of response, overall survival (OS), safety, and clinical efficacy versus tumor glycoprotein NMB (gpNMB) expression. Tumor expression of gpNMB was assessed using immunohistochemistry. RESULTS: In total, 62 patients received treatment. The ORR was 11% and the median response duration was 6.0 months (95% confidence interval [CI], 4.1 months to not reached). The median PFS was 4.4 months (95% CI, 2.6-5.5 months), and the median OS was 9.0 months (95% CI, 6.1-11.7 months). For patients who developed rash during the first cycle versus those who did not, the ORR was 21% versus 7%, respectively, and there was an overall improvement in PFS (hazard ratio, 0.43; P = .013) and OS (hazard ratio, 0.43; P = .017). The most frequent adverse events were alopecia, neuropathy, rash, fatigue, and neutropenia. With one exception, all evaluable tumors were positive for gpNMB, and 46 of 59 tumors (76%) had 100% gpNMB-positive epithelial cells. CONCLUSIONS: Glembatumumab vedotin had modest activity and an acceptable safety profile in patients with advanced melanoma who were refractory to checkpoint inhibitors and MEK/BRAF inhibition. Treatment-related rash may be associated with response.

Clinical Responses of Oncolytic Coxsackievirus A21 (V937) in Patients With Unresectable Melanoma.

PURPOSE: We evaluated the activity of intratumoral Coxsackievirus A21 (V937) in 57 patients with unresectable stage IIIC or IV melanoma. PATIENTS AND METHODS: In this multicenter, open-label, phase II study, patients received up to a total V937 dose of 3 × 108 TCID50 (50% tissue culture infectious dose) in a maximum 4.0-mL volume by intratumoral injection. Ten sets of V937 injections were administered between days 1 and 127 (NCT01227551). Patients who had stable disease or were responding could continue treatment in an extension study (NCT01636882). Response and progression status were based on contrast-enhanced computed tomography, magnetic resonance imaging, or caliper measurement and were categorized using immune-related Response Evaluation Criteria in Solid Tumors (irRECIST). Other evaluations included monitoring of adverse events and serum levels of V937 and anti-V937 antibody titers. The primary efficacy end point was 6-month progression-free survival (PFS) rate per irRECIST. RESULTS: The primary efficacy end point, 6-month PFS rate per irRECIST, was 38.6% (95% CI, 26.0 to 52.4). Durable response rate (partial or complete response for ≥ 6 months) was 21.1% per irRECIST. Best overall response rate (complete plus partial response) was 38.6% (unconfirmed) and 28.1% (confirmed) per irRECIST. Regression of melanoma was observed in noninjected lesions. Based on Kaplan-Meier estimation, 12-month PFS was 32.9% (95% CI, 19.5 to 46.9) per irRECIST and 12-month overall survival was 75.4% (95% CI, 62.1 to 84.7). No treatment-related grade ≥ 3 adverse events occurred. Viral RNA was detected in serum within 30 minutes of administration. Neutralizing antibody titers increased to > 1:16 in all patients after day 22, without effect on clinical or immunologic response. CONCLUSION: V937 was well tolerated and warrants further investigation for treatment of patients with unresectable melanoma. Studies of combination approaches with V937 and immune checkpoint inhibitors are ongoing.

Biological Effects of Anti-Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) Antibody Formation in Patients Treated With GM-CSF (Sargramostim) as Adjuvant Therapy of Melanoma.

OBJECTIVES: We investigated the development of binding and neutralizing antibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF) in patients receiving prolonged therapy with GM-CSF as adjuvant therapy of melanoma and the impact of these antibodies on biological effects. METHODS: Fifty-three patients with high-risk melanoma that had been surgically excised were treated with GM-CSF, 125 µg/m daily for 14 days every 28 days for 1 year after surgical resection of disease. Serum samples for antibodies to GM-CSF were measured before treatment and on study days 155 and 351. Blood draws for testing biological effects were keyed to GM-CSF administration: days 0 (before), 15 (after 14 d on GM-CSF), 29 (after 14 d off GM-CSF), 155, and 351 (after 14 d on GM-CSF in the sixth and 13th cycle of treatment). RESULTS: Of 53 patients enrolled, 43 were evaluable for the development of anti-GM-CSF antibodies. Of these, 93% developed binding antibodies and 42% developed both binding and neutralizing antibodies. The increase in the white blood cell count, percent eosinophils, or neopterin levels engendered by GM-CSF administration was abrogated or markedly decreased in patients with neutralizing antibodies but not in patients who developed only binding antibodies. CONCLUSIONS: Ninety-three percent of patients with melanoma treated with GM-CSF as adjuvant therapy develop antibodies to GM-CSF. In those with neutralizing antibodies, a diminution of the biological effects of GM-CSF was observed. The development of neutralizing antibodies might also abrogate the potential clinical benefit of this treatment and should be considered in the design of future clinical trials.

Low-dose outpatient chemobiotherapy with temozolomide, granulocyte-macrophage colony stimulating factor, interferon-alpha2b, and recombinant interleukin-2 for the treatment of metastatic melanoma.

PURPOSE: The objective of this study was to further investigate the efficacy and safety of low-dose outpatient chemobiotherapy in patients with unresectable metastatic melanoma. PATIENTS AND METHODS: Thirty-one patients with histologically confirmed unresectable measurable metastatic melanoma were enrolled onto an open-label, multicenter phase II study. The treatment regimen consisted of oral temozolomide followed by subcutaneous biotherapy with granulocyte macrophage colony-stimulating factor, interferon-alfa, and recombinant interleukin-2 (rIL-2). RESULTS: Twenty-eight patients (90%) had M1c disease, and 58% had three or more sites of metastasis. Four patients (13%), all with M1c disease, had a complete response, and four patients had a partial response. The median progression-free survival was 4.9 months and the median overall survival was 13.1 months. Two patients (6%) developed CNS metastasis as the first site of disease progression, and 7 (23%) of 30 experienced CNS progression after receiving chemobiotherapy. A total of 112 cycles of therapy were administered. Toxicity occurred in 78% of the cycles and was grade 1 or 2 in the majority of cases and easily managed. Grade 4 toxicity occurred in 3% of the cycles. CONCLUSION: This low-dose chemobiotherapy combination produces clinical responses in patients with metastatic melanoma, even in those with M1c disease, is well tolerated, and allows home dosing. It offers a reasonable alternative to high-dose regimens, such as high-dose biochemotherapy or rIL-2 requiring prolonged periods of hospitalization, or single agent outpatient regimens, such as dacarbazine, which is usually not effective in patients with M1c disease. Furthermore, it may protect against the development of brain metastases.

GM-CSF and ipilimumab therapy in metastatic melanoma: Clinical outcomes and immunologic responses.

We conducted a phase II clinical trial of anti-CTLA-4 antibody (ipilimumab) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in 22 patients with metastatic melanoma and determined clinical outcomes and immunologic responses. The treatment consisted of a 3-mo induction with ipilimumab at 10 mg/kg administered every 3 weeks for four doses in combination with GM-CSF at 125 µg/m2 for 14 d beginning on the day of the ipilimumab infusion and then GM-CSF for 3 mo on the same schedule without ipilimumab. This was followed by maintenance therapy with the combination every 3 mo for up to 2 y or until disease progression or unacceptable toxicity. Blood samples for determination of immune subsets were obtained before treatment, at week 3 (end of cycle 1) and at week 6 (end of cycle 2). Blood samples were also obtained from seven subjects who were cancer-free. The immune response disease control (irDC) rate at 24 weeks was 41% and the overall response rate (ORR) was 32%. The median progression free-survival (PFS) was 3.5 mo and the median overall survival (OS) was 21.1 mo. 41% of the patients experienced Grade 3 to 4 adverse events. We conclude that this combination is safe and the results suggest the combination may be more effective than ipilimumab monotherapy. Further, the results suggest that lower levels of CD4+ effector T cells but higher levels of CD8+ T cells expressing PD-1 at pre-treatment could be a potential biomarker for disease control in patients who receive immunotherapy with ipilimumab and GM-CSF. Further trials of this combination are warranted.

Phase II study of nab-paclitaxel and bevacizumab as first-line therapy for patients with unresectable stage III and IV melanoma.

OBJECTIVES: This study was an open-label multicenter phase II trial to investigate the efficacy and safety of nab-paclitaxel and bevacizumab as first-line therapy in patients with histologically confirmed unresectable metastatic melanoma. METHODS: The treatment regimen consisted of a 28-day cycle in which patients received nab-paclitaxel, 150 mg/m through intravenous (IV) infusion weekly for 3 weeks and bevacizumab, 10 mg/kg IV every 2 weeks without a rest period. The 28-day cycle was repeated until there was unacceptable toxicity or disease progression. If 1 drug had to be stopped because of toxicity, treatment was continued with the other drug until disease progression or unacceptable toxicity. The primary endpoint was the progression-free survival rate (PFS) at 4 months. RESULTS: Fifty patients were enrolled. The PFS rate at 4 months was 75%. The median PFS was 7.6 months and the median overall survival was 16.8 months with a median duration follow-up of 41.6 months. The overall survival rate was 64% at 1 year and 30% at 2 years. Ten patients (20%) remain alive. The objective response rate was 36%. Common adverse events associated with this regimen were peripheral neuropathy, fatigue, alopecia, and gastrointestinal disorders. CONCLUSIONS: In this phase II multicenter study, this doublet had significant activity in patients with metastatic melanoma, and was well tolerated. These results are promising and follow-up trials to further explore this regimen are warranted.

Talimogene Laherparepvec Improves Durable Response Rate in Patients With Advanced Melanoma.

PURPOSE: Talimogene laherparepvec (T-VEC) is a herpes simplex virus type 1-derived oncolytic immunotherapy designed to selectively replicate within tumors and produce granulocyte macrophage colony-stimulating factor (GM-CSF) to enhance systemic antitumor immune responses. T-VEC was compared with GM-CSF in patients with unresected stage IIIB to IV melanoma in a randomized open-label phase III trial. PATIENTS AND METHODS: Patients with injectable melanoma that was not surgically resectable were randomly assigned at a two-to-one ratio to intralesional T-VEC or subcutaneous GM-CSF. The primary end point was durable response rate (DRR; objective response lasting continuously ≥ 6 months) per independent assessment. Key secondary end points included overall survival (OS) and overall response rate. RESULTS: Among 436 patients randomly assigned, DRR was significantly higher with T-VEC (16.3%; 95% CI, 12.1% to 20.5%) than GM-CSF (2.1%; 95% CI, 0% to 4.5%]; odds ratio, 8.9; P < .001). Overall response rate was also higher in the T-VEC arm (26.4%; 95% CI, 21.4% to 31.5% v 5.7%; 95% CI, 1.9% to 9.5%). Median OS was 23.3 months (95% CI, 19.5 to 29.6 months) with T-VEC and 18.9 months (95% CI, 16.0 to 23.7 months) with GM-CSF (hazard ratio, 0.79; 95% CI, 0.62 to 1.00; P = .051). T-VEC efficacy was most pronounced in patients with stage IIIB, IIIC, or IVM1a disease and in patients with treatment-naive disease. The most common adverse events (AEs) with T-VEC were fatigue, chills, and pyrexia. The only grade 3 or 4 AE occurring in ≥ 2% of T-VEC-treated patients was cellulitis (2.1%). No fatal treatment-related AEs occurred. CONCLUSION: T-VEC is the first oncolytic immunotherapy to demonstrate therapeutic benefit against melanoma in a phase III clinical trial. T-VEC was well tolerated and resulted in a higher DRR (P < .001) and longer median OS (P = .051), particularly in untreated patients or those with stage IIIB, IIIC, or IVM1a disease. T-VEC represents a novel potential therapy for patients with metastatic melanoma.

Noninterferon-based adjuvant therapy for high-risk melanoma.

High-dose interferon is the only treatment approved by the FDA for adjuvant therapy of melanoma. However, its efficacy in this setting is questionable and its administration is associated with considerable toxicity. Many new agents are being tested clinically that hold the promise of greater efficacy and less toxicity but none of these have yet shown efficacy in controlled trials. These include biologics such as vaccines, cytokines, monoclonal antibodies, gene transfer, cellular therapies and angiogenesis inhibitors as well as chemotherapy combinations.

Adjuvant therapy of melanoma.

In 2001, the American Joint Committee on Cancer Melanoma Staging Committee proposed and created a new staging system for melanoma. This new system will become official in 2002, with the publication of the sixth edition of the AJCC Cancer Staging Manual. The new system identifies significant prognostic variables in patients with melanoma and validates them in an analysis of 17,600 patients, making it possible to precisely determine the patient's chance for survival In light of physicians' ability to determine with more precision which patients are at high risk for melanoma recurrence, they face the dilemma of which, if any, surgical adjuvant therapy to choose. Alpha-interferon is the only agent approved for adjuvant therapy of melanoma in the United States, but its questionable benefits and substantial side effects make it hard to justify recommending it to patients. Discussion of trials of high- and low-dose interferon is presented here. The author's group has conducted trials of granulocyte-macrophage colony-stimulating factor (GM-CSF [Leukine]) as surgical adjuvant treatment of patients at high-risk for melanoma recurrence. One of the most important activities of GM-CSF is its ability to activate macrophages and cause them to become cytotoxic for human melanoma cells, at doses low enough to avoid the toxicity associated with other cytokines. The author presents promising trial results, discusses GM-CSF in other malignancies, and includes discussion of tumor vaccines, biochemotherapy, and other agents being studied as adjuvant therapy of melanoma. It is hoped that these newer approaches will result in therapies that are more effective and less toxic than interferon.

Recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF, sargramostim) administered for 3 years as adjuvant therapy of stages II(T4), III, and IV melanoma.

A hypothesis generating study was conducted to evaluate the safety and efficacy of prolonged (3 y) administration of granulocyte-macrophage colony-stimulating factor (GM-CSF, sargramostim) as surgical adjuvant therapy in patients with melanoma at high risk of recurrence. Ninety-eight evaluable patients with stages II(T4), III, or IV melanoma were given prolonged treatment with GM-CSF after surgical resection of disease. The GM-CSF was administered subcutaneously in 28-day cycles, such that a dose of 125 microg/m2 was delivered daily for 14 days followed by 14 days rest. Treatment cycles continued for 3 years or until disease recurrence, which could not be surgically excised. Patients were evaluated for toxicity, disease-free survival, and melanoma-specific survival. Prolonged administration of GM-CSF was well tolerated; grade 1 or 2 side effects occurred in 82% of the patients. There were no grade 3 or 4 treatment-related side effects. Two patients developed acute myelogenous leukemia after completion of 3 years of GM-CSF administration. With a median follow-up of 5.3 years, the median melanoma-specific survival has not yet been reached. The 5-year melanoma-specific survival rate was 60%. The current study has expanded the preliminary evidence on GM-CSF as adjuvant therapy of patients with melanoma who are at high risk for recurrence.