Efficacy of anti-PD-1 and ipilimumab alone or in combination in acral melanoma

BACKGROUND

Acral melanoma is a rare melanoma subtype with poor prognosis. Importantly, these patients were not identified as a specific subgroup in the landmark melanoma trials involving ipilimumab and the anti-programmed cell death protein-1 (PD-1) agents nivolumab and pembrolizumab. There is therefore an absence of prospective clinical trial evidence regarding the efficacy of checkpoint inhibitors (CPIs) in this population. Acral melanoma has lower tumor mutation burden (TMB) than other cutaneous sites, and primary site is associated with differences in TMB. However the impact of this on the effectiveness of immune CPIs is unknown. We examined the efficacy of CPIs in acral melanoma, including by primary site.

METHODS

Patients with unresectable stage III/IV acral melanoma treated with CPI (anti-PD-1 and/or ipilimumab) were studied. Multivariable logistic and Cox regression analyses were conducted. Primary outcome was objective response rate (ORR); secondary outcomes were progression-free survival (PFS) and overall survival (OS).

RESULTS

In total, 325 patients were included: 234 (72%) plantar, 69 (21%) subungual and 22 (7%) palmar primary sites. First CPI included: 184 (57%) anti-PD-1, 59 (18%) anti-PD-1/ipilimumab combination and 82 (25%) ipilimumab. ORR was significantly higher with initial anti-PD-1/ipilimumab compared with anti-PD-1 (43% vs 26%, HR 2.14, p=0.0004) and significantly lower with ipilimumab (15% vs 26%, HR 0.49, p=0.0016). Landmark PFS at 1 year was highest for anti-PD-1/ipilimumab at 34% (95% CI 24% to 49%), compared with 26% (95% CI 20% to 33%) with anti-PD-1 and 10% (95% CI 5% to 19%) with ipilimumab. Despite a trend for increased PFS, anti-PD-1/ipilimumab combination did not significantly improve PFS (HR 0.85, p=0.35) or OS over anti-PD-1 (HR 1.30, p=0.16), potentially due to subsequent therapies and high rates of acquired resistance. No outcome differences were found between primary sites.

CONCLUSION

While the ORR to anti-PD-1/ipilimumab was significantly higher than anti-PD-1 and PFS numerically higher, in this retrospective cohort this benefit did not translate to improved OS. Future trials should specifically include patients with acral melanoma, to help determine the optimal management of this important melanoma subtype.

Talimogene laherparepvec resulting in near-complete response in a patient with treatment-refractory Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous tumour of neuroendocrine cell origin, which can grow rapidly and metastasise early. Localised disease is treated with surgery and radiotherapy. Disease that reaches a more advanced stage can be treated with a variety of different treatment modalities including surgery, radiotherapy, chemotherapy, radionuclide therapy, immunotherapy, and intralesional therapy. We report a case of a patient who had exhausted all local and systemic treatment options and who subsequently had an exceptional response to intralesional injection of Talimogene laherparepvec (TVEC).

Targeting Mutated KRAS Genes to Treat Solid Tumours

Kirsten rat sarcoma (KRAS) is one of the most frequently mutated oncogenes in solid tumours. It encodes an important signalling pathway that drives cellular proliferation and growth. It is frequently mutated in aggressive advanced solid tumours, particularly colorectal, lung and pancreatic cancer. Since the first mutated KRAS was discovered in the 1980s, decades of research to develop targeted inhibitors of mutant KRAS have fallen short of the task, until recently. Multiple agents are now in clinical trials, including specific mutant KRAS inhibitors, pan-KRAS inhibitors, therapeutic vaccines and other targeted inhibitors. Mutant-specific KRAS G12C inhibitors are the most advanced, with two inhibitors, adagrasib and sotorasib, achieving approval in 2021 for the second-line treatment of patients with KRAS G12C mutant lung cancer. In this review, we summarise the importance of mutant KRAS in solid tumours, prior attempts at inhibiting mutant KRAS, and the current promising targeted agents being investigated in clinical trials, along with future challenges.

383 Durable responses with intratumoral electroporation of plasmid interleukin 12 plus pembrolizumab in patients with advanced melanoma progressing on an anti-PD-1 antibody: updated data from keynote 695

Background

Electroporated plasmid interleukin-12 (pIL-12-EP; tavokinogene telseplasmid; TAVO) induces sustained intratumoral expression of IL-12, a cytokine that is integral for response to anti-PD-1 antibodies. Here, we present updated safety and response duration data from KEYNOTE 695, a Phase 2, multicenter, open-label trial of pIL-12-EP in combination with pembrolizumab in patients with stage III/IV melanoma immediately following confirmed progression on an anti-PD-1 antibody.

Methods

Patients with confirmed disease progression after ≥12 weeks‘ treatment with an anti-PD-1 antibody alone or in combination were eligible. Patients received intratumoral pIL-12-EP on days 1, 5 and 8 every 6 weeks and pembrolizumab 200 mg every 3 weeks. Responses were assessed by the investigator at 12-week intervals using RECIST v1.1; overall survival (OS) and duration of response (DoR) assessments were conducted using the Kaplan-Meier method.

Results

Of the first 56 patients treated, 50% had visceral disease (M1b-d), 80% had received 1–2 and 20% ≥3 prior lines of therapy, 27% had prior ipilimumab and 21% prior BRAF/MEK inhibitors. 61% of patients were primary refractory to anti-PD-1. 54 patients were efficacy evaluable, defined as patients who had at least one post-treatment scan. The investigator-assessed objective response rate (ORR) per RECIST was 27.8% (4 CR, 11 PR); ORR per iRECIST was 29.6%. In patients with M1b-d staging, ORR was 33.3% (n=9/27), and in those receiving prior ipilimumab, ORR was 33.3% (n=5/15). Seven patients had 100% reduction in target lesions, and regression was observed in non-injected lesions. The median DoR had not been reached. With a median follow up of 19.3 months, the median OS (95% CI) was 24.5 (14.4, NR) months (figure 1). The study is now fully enrolled. In 105 patients with safety data, there were no Grade 4/5 treatment-related adverse events (TRAEs) reported. Grade 3 TRAEs occurred in 5.7% and comprised cellulitis in two patients and arthralgia, pneumonitis, enteritis, keratoacanthoma, lichen planus and musculoskeletal chest pain in one patient each. The Grade 1/2 TRAEs in ≥10% patients were fatigue (27.6%), procedural pain (20.0%), diarrhea (17.1%), nausea (10.5%) and pruritus (10.5%). ORR by blinded independent central review has commenced and a global phase 3 trial is planned.

Abstract 383 Figure 1

Overall survival in patients treated with pIL-12-EP in combination with pembrolizumab. Dark grey bars: time on study treatment, light grey bars: end of treatment to death or censoring

Conclusions

Patients with anti-PD-1 therapy refractory advanced melanoma can achieve deep, durable responses in both injected and non-injected lesions with pIL-12-EP plus pembrolizumab. Intratumoral pIL-12-EP in combination with pembrolizumab was generally well tolerated, with minimal Grade 3 and no Grade 4/5 TRAEs.

Trial Registration

NCT03132675

Ethics Approval

The study was approved by a central IRB and/or local institutional IRB/Ethics Committee as required for each participating institution.

Consent

Written informed consent was obtained from the patients participating in the trial; the current abstract does not include information requiring additional consent

Contemporary management of locoregionally advanced melanoma in Australia and New Zealand and the role of adjuvant systemic therapy

Australia and New Zealand have the highest incidence and mortality rates for melanoma in the world. Local surgery is still the standard treatment of primary cutaneous melanoma, and it is therefore important that surgeons understand the optimal care pathways for patients with melanoma. Accurate staging is critical to ensure a reliable assessment of prognosis and to guide treatment selection. Sentinel node biopsy (SNB) plays an important role in staging and the provision of reliable prognostic estimates for patients with cutaneous melanoma. Patients with stage III melanoma have a substantial risk of disease recurrence following surgery, leading to poor long-term outcomes. Systemic immunotherapies and targeted therapies, known to be effective for stage IV melanoma, have now also been shown to be effective as adjuvant post-surgical treatments for resected stage III melanoma. These patients should be made aware of this and preferably managed in an integrated multidisciplinary model of care, involving the surgeon, medical oncologists and radiation oncologists. This review considers the impact of a recent update to the American Joint Committee on Cancer (AJCC) staging system, the role of SNB for patients with high-risk primary melanoma and recent advances in adjuvant systemic therapies for high-risk patients.

Recent advancements in melanoma management

The treatment options for patients with melanoma have expanded significantly over the past decade. In particular, the use of targeted therapy and immunotherapy has dramatically transformed the outlook for patients with advanced disease. These treatments are now being utilised as adjuvant therapy for patients with earlier stage melanoma after surgical resection. We review the latest updates for melanoma staging, surgical resection, radiotherapy and systemic therapies.

Duration of immunotherapy - should we continue ad infinitum?

The optimal duration of immunotherapy treatment for cancer patients is unknown. As the survival data from early immunotherapy trials mature we are beginning to appreciate how durable responses can be post-discontinuation. The purpose of this brief communication is to comment on treatment duration of immunotherapy in patients with melanoma and non-small cell lung cancer and to provide practice guidance in support of discontinuation.

Immunotherapy in Older Patients with Advanced Melanoma: A Review of the Current Evidence

Despite the increasing incidence of metastatic melanoma in the older population, there is relatively limited specific data surrounding the use of immunotherapy for the treatment of advanced melanoma for patients above the age of 65 years. To date, there has not been a prospective trial done to evaluate the safety and efficacy of using immunotherapy to treat older patients with advanced melanoma. Older patients are often under-represented in clinical trials. In addition, older patients in clinical trials may have lower Eastern Cooperative Oncology Group (ECOG) performance score and fewer co-morbidities, and thus trial data may not truly reflect the experience of treating older patients. The purpose of this descriptive review is to examine the efficacy and safety data of the three currently approved immune checkpoint inhibitors for advanced melanoma treatment in older patients. Our review of available data established that the efficacy and tolerability of immunotherapy in older patients are comparable to results seen in younger patients. However, a dedicated, prospective, randomised trial to assess the safety, tolerability, and quality-of-life parameters of immunotherapy in the older population would provide further insight on the value of these treatments.

A retrospective analysis of eosinophilia as a predictive marker of response and toxicity to cancer immunotherapy

Aim:

To investigate eosinophilia as a potential on-treatment biomarker for patients receiving cancer immunotherapy.

Materials & methods:

We evaluated the association between eosinophilia and treatment response and toxicity in a retrospective cohort of patients receiving cancer immunotherapy.

Results:

The study involved 146 patients. Eosinophilia developed in 22%. Patients who developed eosinophilia were more likely to achieve disease control (p = 0.009), with every 0.1 × 10⁹/l rise in eosinophil count, while receiving treatment was associated with a 28% relative increased chance achieving disease control. Although there was a trend toward improved survival, there was no significant association between eosinophilia and improved overall survival (p = 0.136). Patients with eosinophilia were more likely to develop toxicity (p = 0.042).

Conclusion:

Eosinophilia is a potentially useful biomarker warranting further prospective clinical investigation.

Immunotherapy has revolutionized the way we treat many cancers. However, we do not have good predictors for which patients are going to respond to treatment or experience side effects. ‘Eosinophilia’ is when a particular type of white blood cell is present at high levels in the blood. This can occur in patients on immunotherapy. This paper reports a possible link between eosinophilia and the likelihood of responding well to immunotherapy but also the possibility of developing side effects.

P4335The incidence of acute rheumatic fever in indigenous adults in the Northern Territory, South Australia and Western Australia

Background

Worldwide, knowledge of the contemporary incidence of acute rheumatic fever (ARF) in Indigenous adult populations is limited, with little understanding of patterns of ARF recurrence according to age and geographical location. This has created uncertainty in the development of rheumatic heart disease (RHD) guidelines surrounding the appropriate duration of antibiotic prophylaxis for these patients.

Purpose

This study aimed to describe the incidence rates of ARF in Indigenous Australian adults, analyse patterns of recurrence according to sex, age and geographical location, and assess adherence to secondary prophylaxis.

Methods

ARF episodes in Indigenous adults, aged 18 years and older, recorded within three Australian jurisdictions (Northern Territory, South Australia and Western Australia) ARF registers, diagnosed between 2007 to 2017, were included. Poisson and negative binomial regression were used to estimate incidence rate ratios (IRR) and 95% confidence intervals (CI) for first and recurrent episodes according to age, sex and remoteness. Adherence rates to secondary prophylaxis was described in the 12 months preceding recurrent ARF episodes in the Northern Territory.

Results

481 episodes were analysed. The incidence of ARF episodes in these jurisdictions from 2007 to 2017 was relatively constant. The overwhelming burden of disease occurred in remote areas (105 episodes per 100,000 people). An increased rate occurred in females (IRR 2.34, 95% CI 1.81–3.03). The 18–24 year olds had the highest incidence rates (115 episodes per 100,000 people). High rates of recurrence were also observed in those aged 25–34 years (96 episodes per 100,000 people). Adherence to secondary prophylaxis in those having a recurrent episode was only achieved in 10% of cases.

Conclusions

The incidence of ARF remains very high amongst adult Indigenous Australians. Adherence to secondary prophylaxis continues to play a role in recurrent episodes. RHD guidelines should take into account remoteness as a significant risk factor when deciding the duration of secondary prophylaxis.

Incidence, features and management of radionecrosis in melanoma patients treated with cerebral radiotherapy and anti-PD-1 antibodies

BACKGROUND

Brain radiotherapy is used in the management of melanoma brain metastases (MBM) and can result in radionecrosis. Anti-PD-1 is active in the brain and may increase the risk of radionecrosis when combined with radiotherapy. We studied the incidence, associated factors and management of radionecrosis in longer-term survivors with MBM treated with this combination.

METHODS

Patients with MBM treated with radiotherapy and anti-PD-1 who survived >1 year were identified to determine radionecrosis incidence (Cohort A, n = 135). Cohort A plus additional radionecrosis cases were examined for factors associated with radionecrosis and management (Cohort B, n = 148).

RESULTS

From Cohort A, 17% developed radionecrosis, with a cumulative incidence at 2 years of 18%. Using Cohort B, multivariable analysis confirmed an association between radionecrosis and elevated lactate dehydrogenase (p = 0.0496) and prior treatment with ipilimumab (p = 0.0319). Radionecrosis was diagnosed based on MRI (100%), symptoms (69%) and pathology (56%). Treatment included corticosteroids, bevacizumab and neurosurgery.

CONCLUSIONS

Radionecrosis is a significant toxicity in longer-term melanoma survivors with MBM treated with anti-PD-1 and radiotherapy. Identification of those at risk of radionecrosis who may avoid radiotherapy is required.

Incidence, features and management of radionecrosis (RN) in melanoma patients (pts) treated with cerebral radiotherapy (RT) and anti-PD-1 antibodies (PD1)

9513

Background: Melanoma brain metastases confer poor prognosis, with various treatments used including RT and PD1. While RT and PD1 may have a synergistic effect to improve efficacy, RN may complicate RT, and whether PD1 potentiates this is unknown. We examined the incidence and features of RN and other neurotoxicities in melanoma pts treated with PD1 and whole brain radiotherapy (WBRT) or stereotactic radiosurgery (SRS). Methods: Pts treated with PD1 who received WBRT/SRS during or within 1 year (y) of PD1 who survived > 1y were examined for short and long term neurotoxicity. 2 cohorts were included: (A) consecutive pts fulfilling eligibility criteria from 8 melanoma centers, (B) additional cases of RN from 3 centers. Pt demographics, disease features, treatment details, neurotoxicity, and outcome data were collected. Results: Cohort A included 118 pts, with median follow-up of 24.3 months (mo). Median age was 56yo, 51% had mutant BRAF, 41% elevated LDH and 65% were ECOG 1-2 at PD1 start. 58% had prior ipilimumab and 43% prior MAPK inhibitors. 85% were treated with pembrolizumab, 10% nivolumab and 5% combination ipilimumab/nivolumab. Most pts (82, 69%) had SRS, 22 (19%) had WBRT alone and 14 pts (12%) had both. Median PFS was 24mo and OS was 45.8mo. 21 pts (18%) developed RN, (14/82) 17% after SRS, (2/22) 9% after WBRT and (5/14) 36% after both. With 13 further cases from cohort B (total 34), all had radiological signs on MRI, 78% had neurological symptoms and 56% had pathological confirmation of RN. Median time to symptom onset and to first radiological sign was 9.8mo and 10.8mo, respectively. 52% were treated with steroids and 30% had bevacizumab, with clinical improvement in 64% and 100%, respectively. Updated analysis including clinical variables associated with RN development will be presented, including RT dose and schedule. Conclusions: RN is a significant toxicity in melanoma pts with brain metastases treated with RT and PD1, particularly in long term survivors. Further research to identify those at risk of RN, those who do not require RT, and studies exploring RT and PD1 schedules are required.

Optimizing combination dabrafenib and trametinib therapy in BRAF mutation-positive advanced melanoma patients: Guidelines from Australian melanoma medical oncologists

BRAF mutations occur commonly in metastatic melanomas and inhibition of mutant BRAF and the downstream kinase MEK results in rapid tumor regression and prolonged survival in patients. Combined therapy with BRAF and MEK inhibition improves response rate, progression free survival and overall survival compared with single agent BRAF inhibition, and reduces the skin toxicity that is seen with BRAF inhibitor monotherapy. However, this combination is associated with an increase in other toxicities, particularly drug-related pyrexia, which affects approximately 50% of patients treated with dabrafenib and trametinib (CombiDT). We provide guidance on managing adverse events likely to arise during treatment with combination BRAF and MEK inhibition with CombiDT: pyrexia, skin conditions, fatigue; and discuss management of CombiDT during surgery and radiotherapy. By improving tolerability and in particular preventing unnecessary treatment cessations or reduction in drug exposure, best outcomes can be achieved for patients undergoing CombiDT therapy.