A phase II trial of stereotactic body radiotherapy with concurrent anti-PD1 treatment in metastatic melanoma: evaluation of clinical and immunologic response

Immune Checkpoint Inhibitors in Advanced Cutaneous Squamous Cell Carcinoma: Real-World Experience from a Canadian Comprehensive Cancer Centre

Immune checkpoint inhibitors (ICI) cemiplimab and pembrolizumab have revolutionized the treatment of advanced cutaneous squamous cell carcinoma (cSCC). We aimed to evaluate the effectiveness and safety of ICI in a real-world cSCC population, including patients with conditions that would exclude clinical trial participation. In this single-center, retrospective cohort study, we included all non-trial patients with advanced cSCC treated with ICI between 2017 and 2022. We evaluated investigator-assessed best overall response (BOR) and immune-related adverse events (irAEs). We correlated survival outcomes with age, performance status, immune status and irAEs. Of the 36 patients identified, the best overall response (BOR) to ICI was a partial response (PR) in 41.7%, a complete response (CR) in 27.8%, and stable disease in (SD) 13.9%. The progression-free survival (PFS) rate for 1 year was 58.1%; the median PFS was 21.3 months (95% CI 6.4-NE). The 1-year overall survival (OS) was 76.7%, and the median OS was 38.6 months (95% CI 25.4-NE). Immune-compromised patients, ECOG performance 2-3, and age ≥ 75 years were not significantly associated with PFS or OS. IrAE grades 3-4 were seen in 13.9% of patients. In our Canadian experience with real-world patients, ICI was an effective and safe treatment for advanced cSCC patients. Patients achieved great benefits with ICI regardless of age, immune status or ECOG performance status. We acknowledge the small sample size and retrospective methodology as the main limitations of our study.

Immunotherapy for Cutaneous Squamous Cell Carcinoma: Results and Perspectives

Although initial surgical excision cures 95% of patients, a minority of cutaneous squamous cell carcinomas (cSCCs) are judged to be unresectable, either locally advanced or with unresectable regional lymph nodes or distant metastases. These patients are offered systemic treatments. Response rate to chemotherapy is relatively low and not durable, as well as the results obtained with epidermal growth factor inhibitors (EGFRi). Like other cutaneous tumors, cSCCs have high immunogenicity, driven by the high mutational burden, the ultraviolet signature, and the overexpressed tumor antigens. Two checkpoint inhibitors, cemiplimab and pembrolizumab, achieved high response rate and survival with fewer toxicities than other available systemic agents. These promising results prompted to investigate new combination strategies of systemic therapy and surgery or radiotherapy. Subgroup analysis showed promising role of immunotherapy to facilitate surgery in locally advanced cSCC and, in a small group of patients, long-term survivals without resection. However, some cSCCs treated with immunotherapy develop either early or late resistance, so new drugs and new combinations are in a clinical study to overcome the mechanism underpinning these resistances. The present review focuses on the progress with immunotherapy to date and on new therapeutic strategies for cSCC.

Impact of concomitant systemic treatments on toxicity and intracerebral response after stereotactic radiotherapy for brain metastases

Background

The aim of this study was to determine the safety and efficacy of fractionated stereotactic radiotherapy (SRT) in combination with systemic therapies (ST) for brain metastases (BM).

Methods

Ninety-nine patients (171 BM) received SRT and concurrent ST (group 1) and 95 patients (131 BM) received SRT alone without concurrent ST (group 2). SRT was planned on a linear accelerator, using volumetric modulated arc therapy. All ST were allowed including chemotherapy (CT), immunotherapy (IT), targeted therapy (TT) and hormonotherapy (HT). Treatment was considered to be concurrent if the timing between the drug administration and SRT did not exceed 1 month. Local control (LC), freedom for distant brain metastases (FFDBM), overall survival (OS) and radionecrosis (RN) were evaluated.

Results

After a median follow-up of 11.9 months (range 0.7–29.7), there was no significant difference between the two groups. However, patients who received concurrent IT (n = 30) had better 1-year LC, OS, FFDBM but a higher RN rate compared to patients who did not: 96% versus 78% (p = 0.02), 89% versus 77% (p = 0.02), 76% versus 53% (p = 0.004) and 80% versus 90% (p = 0.03), respectively. In multivariate analysis, concurrent IT (p = 0.022) and tumor volume < 2.07 cc (p = 0.039) were significantly correlated with improvement of LC. The addition of IT to SRT compared to SRT alone was associated with an increased risk of RN (p = 0.03).

Conclusion

SRT delivered concurrently with IT seems to be associated with improved LC, FFDBM and OS as well as with a higher rate of RN.

Evolving management of positive regional lymph nodes in melanoma: Past, present and future directions

Sentinel lymph node (SLN) biopsy has become the standard of care for lymph node staging in melanoma and the most important predictor of survival in clinically node-negative disease. Previous guidelines recommend completion lymph node dissection (CLND) in cases of positive SLN; however, the lymph nodes recovered during CLND are only positive in a minority of these cases. Recent evidence suggests that conservative management (i.e. observation) has similar outcomes compared to CLND. We sought to review the most current literature regarding the management of SLN in metastatic melanoma and to discuss potential future directions.

A case of small bowel adenocarcinoma wherein nivolumab conferred temporary benefit in disease control

Small bowel adenocarcinomas are rare. There is no definite consensus as to whether they should be treated in a manner similar to gastric or to colon cancer. We report the case of a young woman with a primary jejunal adenocarcinoma, bilateral ovary metastases, and peritoneal dissemination. First- and second-line chemotherapy for the gastric cancer failed. She was then treated with the immune checkpoint inhibitor nivolumab and had temporary improvement in her condition. To the best of our knowledge, this is the first case wherein nivolumab has been used to treat small bowel adenocarcinoma.

Immunotherapy in metastatic melanoma: a novel scenario of new toxicities and their management

Checkpoint inhibitors can cause an imbalance in immune tolerance that may clinically manifest as immune-related adverse events (irAEs). These events may involve many organs and tissues, including the skin, gastrointestinal (GI) tract, liver, endocrine system, kidneys, central nervous system (CNS), eyes and lungs. The incidence of irAEs appears to be lower with anti-programmed death antigen-1/programmed death antigen-ligand-1 agents than with the anti-cytotoxic T-lymphocyte-associated protein-4 antibody ipilimumab. Combined immunotherapy does not appear to be associated with novel safety signals compared with monotherapy, but more organs may be involved. Increased experience and the use of algorithms for the most common irAEs have resulted in severe toxicity and related deaths being reduced. However, continuous vigilance, especially regarding less common events, is needed to better characterize the wide spectrum of clinical manifestations.

The Benefit of Reactivating p53 under MAPK Inhibition on the Efficacy of Radiotherapy in Melanoma

Radiotherapy (RT) in patients with melanoma historically showed suboptimal results, because the disease is often radioresistant due to various mechanisms such as scavenging free radicals by thiols, pigmentary machinery, or enhanced DNA repair. However, radiotherapy has been utilized as adjuvant therapy after the complete excision of primary melanoma and lymph nodes to reduce the rate of nodal recurrences in high-risk patients. The resistance of melanoma cells to radiotherapy may also be in relation with the constitutive activation of the MAPK pathway and/or with the inactivation of p53 observed in about 90% of melanomas. In this study, we aimed to assess the potential benefit of adding RT to BRAF-mutated melanoma cells under a combined p53 reactivation and MAPK inhibition in vitro and in a preclinical animal model. We found that the combination of BRAF inhibition (vemurafenib, which completely shuts down the MAPK pathway), together with p53 reactivation (PRIMA-1Met) significantly enhanced the radiosensitivity of BRAF-mutant melanoma cells. This was accompanied by an increase in both p53 expression and activity. Of note, we found that radiation alone markedly promoted both ERK and AKT phosphorylation, thus contributing to radioresistance. The combination of vemurafenib and PRIMA-1Met caused the inactivation of both MAPK kinase and PI3K/AKT pathways. Furthermore, when combined with radiotherapy, it was able to significantly enhance melanoma cell radiosensitivity. Interestingly, in nude mice bearing melanoma xenografts, the latter triple combination had not only a synergistic effect on tumor growth inhibition, but also a potent control on tumor regrowth in all animals after finishing the triple combination therapy. RT alone had only a weak effect. In conclusion, we provide a basis for a strategy that may overcome the radioresistance of BRAF-mutated melanoma cells to radiotherapy. Whether this will translate into a rational to use radiotherapy in the curative setting in BRAF-mutated melanoma patients deserves consideration.

Potential Use of Gluconate in Cancer Therapy

We have recently discovered that cancer cells take up extracellular citrate through plasma membrane citrate transporter (pmCiC) and advantageously use citrate for their metabolism. Citrate uptake can be blocked with gluconate and this results in decreased tumor growth and altered metabolic characteristics of tumor tissue. Interestingly, gluconate, considered to be physiologically neutral, is incidentally used in medicine as a cation carrier, but not as a therapeutically active substance. In this review we discuss the results of our recent research with available literature and suggest that gluconate may be useful in the treatment of cancer.

Phase 2 Trial of Nivolumab Combined With Stereotactic Body Radiation Therapy in Patients With Metastatic or Locally Advanced Inoperable Melanoma

PURPOSE

Nivolumab improves survival in patients with metastatic melanoma. Unfortunately, most patients do not respond to this treatment. Preclinical data indicate that radiation therapy could work synergistically with nivolumab and improve response rates.

METHODS AND MATERIALS

We conducted a phase 2 trial in 20 patients with inoperable or metastatic melanoma with ≥2 measurable lesions (Response Evaluation Criteria in Solid Tumors v1.1). Stereotactic body radiation therapy (SBRT) of 3 × 8 Gy to the largest lesion was delivered before the second nivolumab cycle. The primary endpoint was overall response rate (ORR) in the nonirradiated lesions (Response Evaluation Criteria in Solid Tumors v1.1). Secondary endpoints included toxicity. An exploratory endpoint was mutant BRAF and NRAS circulating tumor DNA (ctDNA) on serial blood samples.

RESULTS

An ORR of 45% was noted with 3 complete and 6 partial responses. Three patients experienced stable disease and 7 had progressive disease as best response. All patients with a complete response in the nonirradiated lesions exhibited a local complete response in the irradiated lesion. Grade 1 to 2 treatment-related adverse events (AEs) occurred in 17 patients; 3 patients experienced grade 3 AEs (lymphopenia, gastroenteritis, and bullous pemphigoid). No grade 4 to 5 AEs occurred. ctDNA was detected in 8 patients, and changes corresponded to clinical response and suggested that a subset of patients with a low programmed death ligand-1 score only started responding after SBRT.

CONCLUSIONS

We conclude that the combination treatment was well tolerated and led to an ORR of 45% in patients with metastatic or inoperable melanoma, similar to historical response rates of nivolumab monotherapy. Although underpowered, our data therefore do not indicate a substantial abscopal response. Nonetheless, serial ctDNA analyses suggest that a subset of patients responded only after the addition of SBRT.

Radiotherapy for Melanoma: More than DNA Damage

Despite its reputation as a radioresistant tumour, there is evidence to support a role for radiotherapy in patients with melanoma and we summarise current clinical practice. Melanoma is a highly immunogenic tumour and in this era of immunotherapy, there is renewed interest in the potential of irradiation, not only as an adjuvant and palliative treatment, but also as an immune stimulant. It has long been known that radiation causes not only DNA strand breaks, apoptosis, and necrosis, but also immunogenic modulation and cell death through the induction of dendritic cells, cell adhesion molecules, death receptors, and tumour-associated antigens, effectively transforming the tumour into an individualised vaccine. This immune response can be enhanced by the application of clinical hyperthermia as evidenced by randomised trial data in patients with melanoma. The large fraction sizes used in cranial radiosurgery and stereotactic body radiotherapy are more immunogenic than conventional fractionation, which provides additional radiobiological justification for these techniques in this disease entity. Given the immune priming effect of radiotherapy, there is a strong but complex biological rationale and an increasing body of evidence for synergy in combination with immune checkpoint inhibitors, which are now first-line therapy in patients with recurrent or metastatic melanoma. There is great potential to increase local control and abscopal effects by combining radiotherapy with both immunotherapy and hyperthermia, and a combination of all three modalities is suggested as the next important trial in this refractory disease.

Effects of radiation on the metastatic process

Radiotherapy remains one of the corner stones in the treatment of various malignancies and often leads to an improvement in overall survival. Nonetheless, pre-clinical evidence indicates that radiation can entail pro-metastatic effects via multiple pathways. Via direct actions on cancer cells and indirect actions on the tumor microenvironment, radiation has the potential to enhance epithelial-to-mesenchymal transition, invasion, migration, angiogenesis and metastasis. However, the data remains ambiguous and clinical observations that unequivocally prove these findings are lacking. In this review we discuss the pre-clinical and clinical data on the local and systemic effect of irradiation on the metastatic process with an emphasis on the molecular pathways involved.

Pembrolizumab combined with stereotactic body radiotherapy in a patient with human immunodeficiency virus and advanced non-small cell lung cancer: a case report

Background

Pembrolizumab has significantly improved outcomes in patients with advanced non-small cell lung cancer. Combining programmed death-1 inhibitor with stereotactic body radiotherapy showed a slight toxicity and good benefits in recent clinical trials. However, patients infected with human immunodeficiency virus were excluded from most trials because it was assumed that their anti-tumor immunity was compromised compared with immunocompetent patients.

Case presentation

In June 2016, a 52-year-old Chinese man presented with human immunodeficiency virus and lung adenocarcinoma (T1bN3M1b). From November 2016 to December 2016, systemic chemotherapy and palliative radiotherapy for bone metastasis of femoral neck were carried out, but the tumor progressed. In January 2017, after immunochemistry detection of programmed death-1 and programmed death-ligand 1 expression (both > 50%), pembrolizumab was started. Three weeks after pembrolizumab, we combined stereotactic body radiotherapy for the primary lung tumor. He received no comfort and his CD4 lymphocyte count was stable. Human immunodeficiency virus-ribonucleic acid remained below the limits of detection. In March 2017, after three cycles of pembrolizumab and 5 weeks of stereotactic body radiotherapy therapy, he suddenly presented with palpitations. Emergency computed tomography scanning showed massive pericardial effusion and interstitial pneumonia. So we interrupted the pembrolizumab use and initiated treatment with prednisolone 1 mg/kg; however, the tumor progressed. Then, his CD4 lymphocyte count declined. Finally he died in June 2017 due to dyscrasia.

Conclusions

Pembrolizumab combined with SBRT therapy for patients with human immunodeficiency virus infection and non-small cell lung cancer may lead to serious immune-related adverse events and more clinical trials are needed.

Efficacy of combined hypo-fractionated radiotherapy and anti-PD-1 monotherapy in difficult-to-treat advanced melanoma patients

Information on the role of radiotherapy in anti-PD-1 monoclonal antibody-treated melanoma patients is limited. We report on a prospective cohort of advanced melanoma patients treated simultaneously with radiotherapy and anti-PD-1 therapy between 01/01/15 and 30/06/16. Tumor evaluations (RECIST 1.1) were performed every 3 months on radiated and non-radiated lesions. Twenty-five advanced melanoma patients (64% AJCC stage IV M1c, 64% on second-line treatment or more, 60% with elevated LDH serum levels) were included. Radiotherapy was performed early (median: 24 days) after the first anti-PD-1 dose in 15 patients with rapidly progressing symptomatic lesion(s) or later (median: 5.4 months) in 10 patients with progressive disease (PD) despite PD-1 blockade. Radiotherapy was limited to one organ in 24 patients and consisted mainly of hypo-fractioned radiotherapy (median dose 26 Gy in 3–5 fractions, 17 patients) or brain radiosurgery (5 patients). Median follow-up after first anti-PD-1 dose was 16.9 m (range 2.7-27.4), with 44% of patients alive at last follow-up. For radiated lesions, rates of complete (CR), partial (PR) responses, stable disease (SD) or PD were 24%, 12%, 24%, and 32%, respectively. For non-radiated lesions, rates of CR, PR, SD, and PD were 20%, 19%, 12%, and 40%, respectively. Responses achieved after radiotherapy for radiated and non-radiated areas were correlated (Pearson correlation r: 0.89, P<0.0001) suggesting an abscopal effect. Five patients with CR remained disease-free after discontinuation of anti-PD-1 for a median of 9.5 months. No unusual adverse event was recorded. Hypo-fractionated radiotherapy may enhance efficacy of anti-PD1 therapy in difficult-to-treat patients. Controlled studies are needed.

Cancer immunotherapy: A need for peripheral immunodynamic monitoring

Immunotherapy has become an important approach for treating different tumours which has shown significant efficacy in numerous clinical trials, especially those using new checkpoint inhibitors and adoptive cell therapy, which have rapidly become widespread after being approved. However, analysis of peripheral immune biomarkers before and after immunotherapy and their relationship to clinical responses and disease prognosis have rarely been performed in clinical trials. In this review, we examine dynamic changes in the immune system before and after therapy by analyzing recent clinical trials of immunotherapy in patients with cancer that focused on checkpoint inhibitors and adoptive cell therapy. Our aim was to identify circulating biomarkers which can specifically predict clinical response and prognosis, as well as toxicities of immunotherapy. Through this approach, we hope to advance our understanding of the mechanisms of immunotherapy with the goal of developing individualized treatment for cancer patients.

Pembrolizumab for the treatment of bladder cancer

INTRODUCTION

Until recently, patients with locally advanced or metastatic urothelial carcinoma after progression on cisplatin-containing chemotherapy had limited systemic treatment options with no significant survival benefit and poor tolerability. Advances in the field of immunotherapy with the introduction of checkpoint inhibitors have led to paradigm shifts in the treatment of various malignancies. Areas covered: The current review will summarize the clinical evidence of checkpoint inhibitors in bladder cancer, with a focus on pembrolizumab. Expert commentary: Category 1 evidence indicates that the checkpoint inhibitor pembrolizumab improves overall survival in patients with locally advanced or metastatic urothelial carcinoma who progressed after or during cisplatin-containing therapy as compared to current standard of care chemotherapy. Phase 1 and 2 evidence also indicates that checkpoint inhibitors are active in first line in patients who are ineligible for cisplatin-containing chemotherapy.

Clinical characteristics of patient selection and imaging predictors of outcome in solid tumors treated with checkpoint-inhibitors

The rapidly evolving knowledge on tumor immunology and the continuous implementation of immunotherapy in cancer have recently led to the FDA and EMA approval of several checkpoint inhibitors as immunotherapic agents in clinical practice. Anti-CTLA-4, anti-PD-1, and anti-PDL-1 antibodies are becoming standard of care in advanced melanoma, as well as in relapsed or metastatic lung and kidney cancer, demonstrating higher and longer response compared to standard chemotherapy. These encouraging results have fostered the evaluation of these antibodies either alone or in combination with other therapies in several dozen clinical trials for the treatment of multiple tumor types. However, not all patients respond to immune checkpoint inhibitors, hence, specific biomarkers are necessary to guide and monitor therapy. The utility of PD-L1 expression as a biomarker has varied in different clinical trials, but, to date, no consensus has been reached on whether PD-L1 expression is an ideal marker for response and patient selection; approximately 20-25% of patients will respond to immunotherapy with checkpoint inhibitors despite a negative PD-L1 staining. On the other hand, major issues concern the evaluation of objective response in patients treated with immunotherapy. Pure morphological criteria as commonly used in solid tumors (i.e. RECIST) are not sufficient because change in size is not an early and reliable marker of tumor response to biological therapies. Thus, the scientific community has required a continuous adaptation of immune-related response criteria (irRC) to overcome the problem. In this context, metabolic information and antibody-based imaging with positron emission tomography (PET) have been investigated, providing a powerful approach for an optimal stratification of patients at staging and during the evaluation of the response to therapy. In the present review we provide an overview on the clinical characteristics of patient selection when using imaging predictors of outcome in solid tumors treated with checkpoint-inhibitors.