Inoperable bulky melanoma responds to neoadjuvant therapy with vemurafenib

Efficacy of Neoadjuvant Targeted Therapy for Borderline Resectable III B-D or IV Stage BRAF V600 Mutation-Positive Melanoma

Simple Summary

Neoadjuvant therapy for locally advanced disease or potentially resectable metastatic melanoma is expected to improve operability and clinical outcomes over upfront surgery. 46 patients were treated with BRAFi/MEKi or BRAFi before surgery with 78% R0 resection. In patients with a major pathological response with no, or less than 10%, viable cells in the tumor, median DFS and PFS were significantly longer than in patients with a minor pathological response.

Abstract

Neoadjuvant therapy for locally advanced disease or potentially resectable metastatic melanoma is expected to improve operability and clinical outcomes over upfront surgery and adjuvant treatment as it is for sarcoma, breast, rectal, esophageal, or gastric cancers. Patients with locoregional recurrence after initial surgery and those with advanced regional lymphatic metastases are at a high risk of relapse and melanoma-related death. There is an unmet clinical need to improve the outcomes for such patients. Patients with resectable bulky stage III or resectable stage IV histologically confirmed melanoma were enrolled and received standard-dose BRAFi/MEKi for at least 12 weeks before feasible resection of the pre-therapy target and then received at least for the next 40 weeks further BRAFi/MEKi. Of these patients, 37 were treated with dabrafenib and trametinib, three were treated with vemurafenib and cobimetinib, five with vemurafenib, and one with dabrafenib alone. All patients underwent surgery with 78% microscopically margin-negative resection (R0) resection. Ten patients achieved a complete pathological response. In patients with a major pathological response with no, or less than 10%, viable cells in the tumor, median disease free survival and progression free survival were significantly longer than in patients with a minor pathological response. No patient discontinued neoadjuvant BRAFi/MEKi due to toxicity. BRAFi/MEKi pre-treatment did not result in any new specific complications of surgery. Fourteen patients experienced disease recurrence or progression during post-operative treatment. We confirmed that BRAFi/MEKi combination is an effective and safe regimen in the perioperative treatment of melanoma. Pathological response to neoadjuvant treatment may be considered as a surrogate biomarker of disease recurrence.

Neoadjuvant BRAF-targeted therapy in regionally advanced and oligometastatic melanoma

Current management of locoregional and oligometastatic melanoma is typically with surgery; however, some patients are unable to undergo resection due to location/size of their tumors and/or the anticipated morbidity of the surgery. While there are currently no established guidelines for neoadjuvant therapy in melanoma, neoadjuvant BRAF-targeted therapy may make resection more feasible. A retrospective analysis was conducted of 23 patients with BRAFV600-mutant, stage III/IV melanoma treated with BRAF-targeted therapy prior to surgery, with no adjuvant treatment. Surgical specimens, preoperative imaging, and clinical outcomes were evaluated. Results: Ten of 23 patients (44%) attained a pathologic complete response (pCR), with no correlation between RECIST response based on preoperative imaging and pathologic response. After a median of 43-month follow-up, only 1 patient (10%) with a pCR recurred, while 8 of 13 (62%) patients without a pCR recurred. Patients with a pCR had significantly improved relapse-free (RFS) and overall survival (OS) compared to patients with residual tumor. Neoadjuvant BRAF-targeted therapy is associated with a high pCR rate in patients with stage III-IV melanoma, which may correlate with improved RFS and OS.

The emergence of neoadjuvant therapy in advanced melanoma

The discovery of immunotherapy and targeted therapy has introduced new and effective treatment options for advanced melanoma, providing therapeutic options where none existed before. The natural extension of these novel therapies is to identify their role in the neoadjuvant setting. Neoadjuvant therapy for advanced melanoma is still in its infancy, with a wealth of clinical trials underway. Early results are promising, allowing for management of a disease that previously had few options. We review the current literature and interim results from several ongoing investigations to understand the current state of neoadjuvant treatment options and what is to come. These studies pave the way for further advancements in melanoma therapy.

Preoperative BRAF inhibition in patients with irresectable locally advanced stage III melanoma

Aim

Neoadjuvant treatment of locally advanced disease with BRAF inhibitors is expected to increase the likelihood of a R0 resection. We present six patients with stage III unresectable melanoma, neoadjuvantly treated with BRAF inhibitors.

Methods

Patients with unresectable, BRAF-mutated, stage III melanoma, were treated with BRAF inhibitors between 2012 and 2015. Unresectability was determined based on clinical and/or radiological findings. At maximal response, resection was performed. The specimen was reviewed to determine the degree of response.

Results

In five of six patients a radical resection was achieved. Postoperative complications were unremarkable. In five of six resected specimens, vital tumor tissue was found.

Conclusion

Neoadjuvant BRAF inhibitor treatment of locally advanced melanoma is feasible and has the potential to facilitate an R0 resection.

Adjuvant treatment for stage III melanoma in the era of targeted medicine and immunotherapy

The accelerated development in the treatment of metastatic melanoma, both in molecular targeted therapy and immunotherapy, is already starting to impact on adjuvant therapy in stage III melanoma. Following the approval of ipilimumab for adjuvant therapy in melanoma, clinical trials assessing other checkpoint modulators and MAPK pathway inhibitors as adjuvant treatments for melanoma are currently ongoing. As results from these trials mature in the next few years, a change in the landscape of adjuvant treatment for melanoma is expected, resulting in new challenges in treatment decisions such as optimizing patients selection through predictive and prognostic biomarkers, and management of treatment related adverse events, in particular immune related toxicities.

Intralesional administration of L19-IL2/L19-TNF in stage III or stage IVM1a melanoma patients: results of a phase II study

The intratumoral injection of cytokines, in particular IL2, has shown promise for cutaneous melanoma patients with unresectable disease or continuous recurrence despite surgery. We recently reported that the intralesional injection of L19-IL2, an immunocytokine combining IL2 and the human monoclonal antibody fragment L19, resulted in efficient regional control of disease progression, increased time to distant metastasis and evidence of effect on circulating immune cell populations. We have also shown in preclinical models of cancer a remarkable synergistic effect of the combination of L19-IL2 with L19-TNF, a second clinical-stage immunocytokine, based on the same L19 antibody fused to TNF. Here, we describe the results of a phase II clinical trial based on the intralesional administration of L19-IL2 and L19-TNF in patients with stage IIIC and IVM1a metastatic melanoma, who were not candidate to surgery. In 20 efficacy-evaluable patients, 32 melanoma lesions exhibited complete responses upon intralesional administration of the two products, with mild side effects mainly limited to injection site reactions. Importantly, we observed complete responses in 7/13 (53.8 %) non-injected lesions (4 cutaneous, 3 lymph nodes), indicating a systemic activity of the intralesional immunostimulatory treatment. The intralesional administration of L19-IL2 and L19-TNF represents a simple and effective method for the local control of inoperable melanoma lesions, with a potential to eradicate them or make them suitable for a facile surgical removal of the residual mass.

New options for the adjuvant treatment of cutaneous melanoma?

High-dose interferon is the current standard of care for the adjuvant treatment of high-risk cutaneous melanoma. Despite numerous clinical trials using interferon in a variety of doses and schedules, none have demonstrated a meaningful clinical improvement relative to standard high-dose interferon. Recently however, a phase III trial using biochemotherapy demonstrated a superior relapse-free survival benefit over standard interferon. In addition, several agents approved for use in metastatic melanoma are being investigated in the adjuvant setting.

Neoadjuvant therapy for locally advanced melanoma: new strategies with targeted therapies

Neoadjuvant chemotherapy has been successfully tested in several bulky solid tumors, but it has not been utilized in advanced cutaneous melanoma, primarily because effective medical treatments for this disease have been lacking. However, with the development of new immunotherapies (monoclonal antibodies specific for cytotoxic T lymphocyte-associated antigen 4 [anti-CTLA-4] and programmed death protein-1 [anti-PD1]) and small molecules interfering with intracellular pathways (anti-BRAF and mitogen-activated protein kinase kinase [anti- MEK]) the use of this approach is becoming a viable treatment strategy for locally advanced melanoma. The neoadjuvant setting provides a double opportunity for a better knowledge of these drugs: a short-term evaluation of their intrinsic activity, and a deeper analysis of their action and resistance-induction mechanisms. BRAF inhibitors seem to be ideal candidates for the neoadjuvant setting, because of their prompt, repeatedly confirmed response in V600E BRAF-mutant metastatic melanoma. In this report we summarize studies focused on the neoadjuvant use of traditional medical treatments in advanced melanoma and anecdotal cases of this approach with the use of biologic therapies. Moreover, we discuss our experience with neoadjuvant targeted therapy as a priming for radical surgery in a patient with BRAF V600E mutation-positive advanced melanoma.

A new role of vemurafenib as a neoadjuvant treatment of axillary and brain melanoma metastases

Vemurafenib is approved by the FDA for the management of unresectable or metastatic melanoma. However, its role as a neoadjuvant therapy has not been determined. We present the first documented case in which vemurafenib induced complete tumor necrosis of both lymph node and brain metastases within one month or less, an outcome that indicated that the patient was a good candidate for excisional surgery.

Neoadjuvant treatment of melanoma: case reports and review

Neoadjuvant therapy is an under-utilized regimen for the treatment of metastatic melanoma. The use of this approach has been increasing in other tumor types. Neoadjuvant therapy may reduce occult circulating tumor cell burden in the face of bulky disease and afford a real time evaluation of treatment effectiveness. Neoadjuvant approach can also provide preoperative histologic and molecular analysis of treated tissue that may guide the postoperative treatment planning in patients with resectable metastatic melanoma lesions. The putative benefits of better margin control and clearance of occult systemic disease would theoretically improve surgical outcome. With the advent of effective agents against metastatic melanoma, this common approach to the treatment of rectal cancer, metastatic colon cancer, and breast cancer should also be evaluated as a viable treatment strategy for advanced stage melanoma.