Deciphering radiological stable disease to immune checkpoint inhibitors

BACKGROUND

'Stable disease (SD)' as per RECIST is a common but ambiguous outcome in patients receiving immune checkpoint inhibitors (ICIs). This study aimed to characterize SD and identify the subset of patients with SD who are benefiting from treatment. Understanding SD would facilitate drug development and improve precision in correlative research.

PATIENTS AND METHODS

A systematic review was carried out to characterize SD in ICI trials. SD and objective response were compared to proliferation index using The Cancer Genome Atlas gene expression data. To identify a subgroup of SD with outcomes mirroring responders, we examined a discovery cohort of non-small-cell lung cancer (NSCLC). Serial cutpoints of two variables, % best overall response and progression-free survival (PFS), were tested to define a subgroup of patients with SD with similar survival as responders. Results were then tested in external validation cohorts.

RESULTS

Among trials of ICIs (59 studies, 14 280 patients), SD ranged from 16% to 42% in different tumor types and was associated with disease-specific proliferation index (ρ = -0.75, P = 0.03), a proxy of tumor kinetics, rather than relative response to ICIs. In a discovery cohort of NSCLC [1220 patients, 313 (26%) with SD to ICIs], PFS ranged widely in SD (0.2-49 months, median 4.9 months). The subset with PFS >6 months and no tumor growth mirrored partial response (PR) minor (overall survival hazard ratio 1.0) and was proposed as the definition of SD responder. This definition was confirmed in two validation cohorts from trials of NSCLC treated with durvalumab and found to apply in tumor types treated with immunotherapy in which depth and duration of benefit were correlated.

CONCLUSIONS

RECIST-defined SD to immunotherapy is common, heterogeneous, and may largely reflect tumor growth rate rather than ICI response. In patients with NSCLC and SD to ICIs, PFS >6 months and no tumor growth may be considered 'SD responders'. This definition may improve the efficiency of and insight derivable from clinical and translational research.

Combinatorial Approaches to the Treatment of Advanced Melanoma

The treatment landscape for patients with advanced melanoma has dramatically improved over the past decade, leading to unprecedented survival. Despite the robust activity of single-agent immune-checkpoint blockade with anti-CTLA-4 or anti-PD-1 agents, and the efficacy of targeted therapies capable of interrupting aberrant signaling resulting from BRAF mutations, the benefit from these therapies is not universal. Advanced understanding of immune and molecular processes underlying melanoma tumorigenesis has demonstrated the promise of combined, multidrug regimens. We discuss the currently available evidence that supports using combinatorial approaches in advanced melanoma treatment and provide insights into promising new combination strategies under investigation.

Clinical Development of PD-1 in Advanced Melanoma

The development of new treatment options has dramatically improved the landscape for patients with advanced melanoma. Part of these advances emerged through the identification of the importance of factors that regulate the immune system, including proteins that negatively modulate T cell-mediated responses termed "immune checkpoints." Indeed, blockade of the cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) immune checkpoint served as a proof of principle that the manipulation of these molecules could induce robust anticancer effects, yet limited to a small percentage of patients. Targeting a distinct checkpoint, the PD-1 yielded improved outcomes and reduced toxicity compared with CTLA-4 blockade and, in separate studies, chemotherapy. More recently, combined CTLA-4/PD-1 blockade was shown to result in higher response rates, while accompanied by increased toxicity. In this article, we review the clinical development of anti-PD-1 monotherapy and combinations that may expand the benefit of immunotherapy for patients with advanced melanoma.

A case report of disappearing pigmented skin lesions associated with pembrolizumab treatment for metastatic melanoma

Pembrolizumab is an immune checkpoint inhibitor that targets the programmed cell death (PD)-1 receptor. Common cutaneous adverse side-effects of PD-1 inhibitors include maculopapular rash, pruritus, vitiligo and lichenoid skin and mucosal reactions. Here we describe a man in his sixties with metastatic melanoma treated with pembrolizumab who subsequently developed fading or disappearance of pigmented skin lesions, lightening of the skin, and poliosis of the eyebrows, eyelashes and scalp and body hair. Compared with baseline high-resolution three-dimensional total-body photography, we observed fading or disappearance of solar lentigines, seborrhoeic keratoses and melanocytic naevi, suggesting that PD-1 inhibitors may affect the evolution of these benign skin lesions. With dermatoscopic follow-up, altered lesions showed either blue-grey peppering/granularity or fading in colour without other identifiable features. No halo lesions or lesions with surrounding inflammation were identified. One changed pigmented lesion that showed blue-grey peppering/granularity on dermoscopy was biopsied and interpreted as a macular seborrhoeic keratosis with melanophages. Further studies are required to elucidate the effects of PD-1 inhibition on benign skin lesions.

Efficacy and safety of nivolumab (NIVO) plus ipilimumab (IPI) in patients with melanoma (MEL) metastatic to the brain: Results of the phase II study CheckMate 204

9507

Background: Brain metastases (BMts) are a major cause of morbidity/death in MEL. We report the first efficacy data in MEL patients (pts) with BMts who received NIVO+IPI in study CheckMate 204. Methods: In this multicenter US trial (NCT02320058), MEL pts with ≥1 measurable BMt 0.5-3.0 cm and no neurologic symptoms or steroid Rx received NIVO 1 mg/kg + IPI 3 mg/kg Q3W x 4, then NIVO 3 mg/kg Q2W until progression or toxicity. Pts with severe adverse events (AEs) during NIVO+IPI could receive NIVO when toxicity resolved; stereotactic radiotherapy (SRT) was allowed for brain oligo-progression if an assessable BMt remained. The primary endpoint was intracranial (IC) clinical benefit rate (complete response [CR] + partial response [PR] + stable disease [SD] > 6 months). The planned 90-pt accrual is complete; we report efficacy and updated safety for 75 pts with disease assessment before the Nov 2016 database lock. Results: Median age was 59 yrs (range 22–79). Median number of induction doses was 3; 26 pts (35%) received 4 NIVO+IPI doses and 38 pts (51%) began NIVO maintenance. Response data are reported at a median follow-up of 6.3 months (Table). The IC objective response rate (ORR) was 56% (95% CI: 44–68); 19% of pts had a complete response. IC and extracranial responses were largely concordant. Rx-related grade 3/4 AEs occurred in 48% of pts, 8% neurologic, including headache and syncope. Only 3 pts (4%) stopped Rx for Rx-related neurologic AEs. One pt died of immune-related myocarditis. Conclusions: In CheckMate 204, prospectively designed to investigate NIVO+IPI in MEL pts with BMts, NIVO+IPI had high IC antitumor activity with objective responses in 56% of pts, CR in 19%, and no unexpected neurologic safety signals. The favorable safety and high anti-melanoma activity of NIVO+IPI may represent a new Rx paradigm for pts with asymptomatic MEL BMts and could change practice to avoid or delay whole brain RT or SRT. Clinical trial information: NCT02320058. [Table: see text]

Analysis of mutational burden and adaptive immune response in desmoplastic melanomas treated with PD-1/L1 inhibitors

9558

Background: Desmoplastic melanoma (DM) is a rare subtype of melanoma characterized by a dense fibrous stroma, resistance to chemotherapy and no actionable driver mutation for targeted therapy. We investigated the efficacy of PD-1/L1 inhibitors and correlation with genetic landscape and tumor immune microenvironment in DM. Methods: Retrospective analysis of 1054 pts with melanoma treated with anti-PD-1/L1, resulting in 57 pts with unresectable or metastatic DM. Available baseline biopsies were analysed by digital quantitative immunohistochemistry (IHC) for CD8 and PD-L1 and by whole exome sequencing (WES), compared to available tissue from non-DM pts treated with anti-PD1/L1 at UCLA. Results: At a median follow up of 20 mo, 40 pts (70%, 95% CI 57-82) had an objective response by RECIST 1.1 criteria, including 18 (45%) CRs with no relapse observed to date. Responses were similar in DM subsets (23 pure, 29 mixed and 5 indeterminate). Kaplan-Meier estimated 1-year and 2-year overall survival were 85% (95% CI 78-98) and 74% (95% CI 64-89). WES revealed a median of 1282 (interquartile range 517-1692) non-synonymous somatic mutations per tumor in DM tumors (n = 17), significantly higher (p = 0.02) than the median of 462 (interquartile range 230-1150) in non-DM (n = 23). Mutations in NF-1 were the most common (13/17) followed by loss-of-function TP53 and ARID2, and > 82% of single nucleotide mutations were UV damage signatures. IHC analysis from 19 DM and 13 non-DM revealed a strikingly higher percentage of PD-L1 positive cells in the tumor parenchyma in DM (p = 0.04), highly associated with CD8 density and PD-L1 expression in the tumor invasive margins, indicating an active adaptive immune response. No genetic mechanisms known to cause constitutive PD-L1 expression were detected in these samples. Conclusions: Patients with advanced DM derive significant clinical benefit from PD-1/L1 inhibitors, likely related to the high mutational burden and a highly active adaptive immune response as the main mechanism of immune escape prior to therapy. Our results challenge the general conception that dense fibrous stroma around the malignant cells interferes with immune cell infiltration and efficacy of immunotherapy.

Phase 1 study to evaluate safety and efficacy of ipilimumab + nivolumab + external beam radiotherapy in patients with metastatic melanoma

TPS9591

Background: Immunotherapy (IMT) with checkpoint blocking antibodies has led to progress in metastatic melanoma with 3 FDA-approved drugs, including the combination of ipilimumab (IPI), a CTLA-4 antibody, and nivolumab (NIVO), a PD-1 antibody. Although radiotherapy (RT) is primarily used as local palliative therapy in metastatic melanoma, it also possibly affects systemic antitumor immunity. Preclinical data suggest RT alters the tumor microenvironment and renders tumor cells more susceptible to immunologically-mediated disease regression. These preclinical immunologic effects of RT have been shown to vary by RT dose and fractionation. We are now conducting the first clinical trial in patients to evaluate the triple combination of IPI + NIVO + RT using 2 different dose/fractionation schemes of RT. Methods: This ongoing Phase 1, open-label, multicenter study (NCT02659540) evaluates safety, efficacy, and immunologic effects of IPI + NIVO + RT in 18 patients with unresectable stage IV melanoma. Patients must have 1 melanoma metastasis that can be safely irradiated for palliative purposes and at least 1 measurable lesion that will not be irradiated. Patients receive concurrent IPI (3 mg/kg) and NIVO (1 mg/kg) every 3 weeks (Q3W) x 4, followed by NIVO monotherapy (240 mg Q2W), with RT initiated between the first and second doses of IPI + NIVO. In Cohort A, the irradiated metastasis receives a conventionally fractionated low dose of 30 Gy in 10 fractions of 3 Gy each over 2 weeks. If ≤7 of 9 patients (78%) in Cohort A have Grade 3/4 drug- or radiation-related adverse events, safety is deemed acceptable and Cohort B enrollment opens. In Cohort B, the irradiated metastasis receives a hypofractionated high dose of 27 Gy in 3 fractions of 9 Gy each over 2 weeks. The primary endpoint is safety. Secondary endpoints are objective response rate and disease control rate by RECIST and immune-related RECIST measured at Weeks 12 and 18, duration of response, progression-free survival, and overall survival. Exploratory endpoints include correlative studies of immunological effects. Enrollment opened on 05 Aug 2016. As of 31 Dec 2016, 4 patients are enrolled in Cohort A; enrollment is ongoing. Clinical trial information: NCT02659540.

Outcomes of patients with melanoma who discontinue immunotherapy

9548

Background: The question of when to discontinue (d/c) anti-program death-1 (PD-1) monotherapy (mono) or nivolumab in combination with ipilimumab (combo) immunotherapy (IT) is unknown. Methods: After IRB approval, a single center (Memorial Sloan Kettering Cancer Center), retrospective study was performed of 162 pts with unresectable stage III or IV melanoma treated with either mono (n = 106) or combo (n = 56) IT. Objective response rate (ORR), progression free survival (PFS), and overall survival (OS) were calculated for all pts from the 1stdose of IT. For pts (n = 40; mono and n = 40; combo) who d/c IT due to reasons (Table) other than progression or death, starting from the last date of IT, we then reported PFS, time to treatment failure (TTF) defined as any subsequent surgery/radiation/systemic therapy, and OS. Results: For pts that were alive at time of analysis, the median follow up was 28 mos. For all 162 pts (demographics in Table), ORR was 38.7% (mono) and 60.7% (combo); median PFS and OS were 12 months (mos) and 25 mos for mono; 34 mos and not reached (NR) for combo, respectively. From the last dose of IT, the PFS, TTF, and OS for 40 mono pts and 40 combo pts who d/c IT for reasons other than progression/death are shown in Table. Reasons included CR, toxicity, or other (most commonly protocol completion or prolonged PR). Conclusions: Outcomes in this cohort of pts with long follow-up treated with mono or combo IT are similar to results from other clinical trials. Pts who d/c IT for reasons other than progression/death were a highly selected group. Nonetheless, favorable PFS, TTF, and OS were seen after IT d/c, even in pts who did not obtain a CR. [Table: see text]

Phase 1b/2 trial of ribociclib+binimetinib in metastatic NRAS-mutant melanoma: Safety, efficacy, and recommended phase 2 dose (RP2D)

9519

Background: Simultaneous inhibition of MEK and CDK4/6 may suppress MAPK pathway activation and cell-cycle checkpoint dysregulation in NRAS-mutant melanoma, resulting in enhanced antitumor activity. Phase 1b data are reported. Methods: The phase 1b primary objective was to determine maximum tolerated dose (MTD)/RP2D. A 28-d cycle of oral ribociclib (RIBO) once daily (QD) for 21 d + oral binimetinib (BINI) twice daily (BID) for 28 d, and a 21-d cycle of RIBO QD + BINI BID, both for 14 d per cycle, were evaluated. Secondary objectives were to evaluate efficacy, safety and pharmacodynamics. Results: Based on dose escalation (van Herpen, ESMO 2015), MTD was 600mg RIBO/45mg BINI for the 21-d and 200/45 for the 28-d regimens. Due to promising activity, the 28-d cycle was selected as RP2D(unconfirmed partial response [PR] with limited follow-up occurred in 35% of pts). This finding was supported by comparable and manageable safety and the Bayesian logistic regression model.As of Jan 2017, the RP2D was received by 16 pts in phase 1b (ECOG PS 0/1/2, 63%/31%/6%; elevated lactate dehydrogenase, 44%; stage IVM1c disease, 50%; prior ipilimumab [ipi], 44%; prior anti–programmed death [PD]-1/PD-L1, 31%). Median (range) exposure was 4 (0–13) mo. Common adverse events (AEs) were increased blood creatine phosphokinase, elevated AST, peripheral edema, acneiform dermatitis, diarrhea and fatigue. Common grade 3/4 AEs were elevated AST and ALT (19%/6%), nausea (19%/0%), rash (19%/0%), vomiting (6%/6%) and neutropenia (12%/0%). Confirmed PR (cPR) occurred in 4 pts (25%; time to response, 48–168 d), stable disease in 7 pts (44%), disease progression in 3 pts (19%); 2 pts (12%) were not evaluable. Among cPR pts, 3 had prior ipi and/or anti–PD-1/PD-L1. Median progression-free survival (mPFS) was 6.7 (95% CI, 3.5–9.2) mo. Sequence analysis of synchronous non- RAS genetic alterations will be presented. Conclusions: Combined RIBO/BINI at the selected RP2D had a manageable safety profile and favorable efficacy (based on mPFS) for NRAS-mutant melanoma in phase 1b. Based on these promising data, the phase 2 expansion is underway to assess antitumor activity at the RP2D. Clinical trial information: NCT01781572.

Immune-related alopecia (areata and universalis) in cancer patients receiving immune checkpoint inhibitors

Cytotoxic T-lymphocyte-associated protein-4, programmed cell death protein and programmed cell death protein ligand 1 monoclonal antibodies (immune checkpoint inhibitors), are used to treat various malignancies. Their mechanism of action involves the inhibition of negative regulators of immune activation, resulting in immune-related adverse events (irAEs) including endocrinopathies, pneumonitis, colitis, hepatitis and dermatological events. Dermatological irAEs include maculopapular rash, pruritus, vitiligo, blistering disorders, mucocutaneous lichenoid eruptions, rosacea and the exacerbation of psoriasis. Alopecia secondary to immune checkpoint inhibitors has been reported in 1·0-2·0% of treated patients. Our objective is to characterize for the first time the clinicopathology of patients with alopecia areata (AA) secondary to immune checkpoint inhibitors, including the first report of anti-PD-L1 therapy-induced AA, and review of the literature. Four cases of patients who developed partial or complete alopecia during treatment with immune checkpoint inhibitors for underlying cancer were identified from our clinics. Methods include the review of the history and clinicopathologic features. Three patients (75%) had AA and one had universalis. Two patients had a resolution after topical, oral or intralesional therapies and one had a resolution after immunotherapy was discontinued; all regrown hair exhibited poliosis. One of the four patients had coincident onychodystrophy. This report describes a series of four patients who developed partial or complete alopecia (i.e. areata and universalis) during treatment with immune checkpoint inhibitor therapies for cancer. The recognition and management of hair-related irAEs are important for pretherapy counselling and interventions that contribute to maintaining optimal health-related quality of life in patients.

Clinical benefit and toxicity of nivolumab plus ipilimumab in patients with advanced melanoma previously treated with checkpoint blockade inhibitors

100

Background: The combination of nivolumab and ipilimumab (nivo+ipi) prolongs progression-free survival in treatment-naïve patients (pts) with advanced melanoma. However, the efficacy and tolerability of nivo+ipi in pts previously treated with checkpoint blockade inhibitors (CPI) are unknown. Methods: 19 pts previously treated with CPI (ipi or anti-PD-1 as single agents) were treated with nivo+ipi at MSKCC. Ipi (3mg/kg) and nivo (1mg/kg) were administered q3 weeks for 4 doses with the option to continue anti-PD1 maintenance. Pts were followed for time to treatment failure (TTF), defined as the time from the date of first nivo+ipi infusion to the date of one of the following: clinical progression, new locally-directed treatment (ie surgery or radiotherapy), new systemic treatment other than anti-PD-1 monotherapy, or death. Results: 15 pts (79%) had stage M1c disease and 12 (63%) had a cutaneous primary. Pts had received a median of 2 prior systemic treatments (range 1-7). 10 pts (53%) had received prior ipi and 17 pts (89%) had received prior anti-PD-1 treatment; 8 pts (42%) had received both. The median time between anti-PD-1 monotherapy and nivo+ipi was 51 days (range 20-385). Pts received a median of 3 doses of combination therapy; 9 of 19 pts (47%) received all 4 doses. With a median follow-up time of 210 days, 8 pts (42.1%) remained on combination immune therapy, 9 pts (47%) switched systemic treatments or had a local procedure and 6 pts (31.6%) died. Median time on immunotherapy for those still alive and without treatment failure was 105 days (range 26-343). The median TTF was 78 days (range 42-220). The most common systemic treatment after nivo+ipi failure was BRAF-targeted therapy (5/9 or 56.3%). The median number of immune related adverse events (irAEs) was 1 (range 0-3). Rash (26%), Hepatitis (16%) and Colitis (16%) were the most common irAEs. Conclusions: With a short median follow-up, administration of nivo+ipi in CPI-experienced patients with advanced melanoma was associated with a short TTF. 58% of patients died or had treatment failure within the follow-up period. More research is needed to guide the utilization of combination immunotherapy in this setting.

Clinical and immunologic variables associated with outcomes following combination ipilimumab and nivolumab immunotherapy in melanoma

55

Background: Prior studies have shown routine laboratory parameters such as lymphocytes (lymphs) and eosinophils (eos) are associated with outcome in patients (pts) treated with ipilimumab (ipi) or programmed death-1 (PD-1) agents as single drugs. Less is known about these parameters as potential biomarkers for pts treated with ipi + nivolumab (nivo) in combination. Methods: After IRB approval, a single institution, retrospective review was performed of pts with melanoma who received ipi + nivo on phase I-III clinical trials (n=122) as well as via commercial use (n=87). Prior to treatment initiation, routine laboratory parameters were investigated and correlated with overall survival (OS) and disease response by RECIST 1.1 (partial or complete response vs. stable/progressive disease). Absolute as well as relative frequencies of cell counts were examined. Kaplan-Meier estimators and Cox regression were performed. Results: 209 pts, 85 (41%) women and 124 (59%) men, with a median age of 60.5 years were analyzed. Median OS was 44.4 months, 95% CI (32.9, not reached). 23 pts had a complete response (CR) and 87 pts had a partial response (PR), while 39 pts had stable disease (SD) and 49 pts had progressive disease (PD). By univariate analysis, significant favorable factors for OS included: low absolute monocytes, low absolute/relative neutrophils, high relative eos, and high relative lymphs. Low LDH and the neutrophil to lymph ratio were also associated with better OS. None of these factors were significantly associated with response by RECIST 1.1. Conclusions: Routinely assessed laboratory parameters were associated with OS but not disease response among pts receiving ipi + nivo. Some of these factors were similar to those which previously correlated with OS after ipi or nivo as single-agents, suggesting they may be prognostic. Given the ongoing randomized phase III study of ipi + nivo and nivo vs. ipi, there is an opportunity to examine whether these factors are relevant in refining which pts obtain the greatest benefit from ipi + nivo vs. single agent therapy.

Recent advances in understanding antitumor immunity

The term "antitumor immunity" refers to innate and adaptive immune responses which lead to tumor control. Turning the immune system into a destructive force against tumors has been achieved in a broad range of human cancers with the use of non-specific immunotherapies, vaccines, adoptive-cell therapy, and, more recently with significant success, through blockade of immune checkpoints. Nevertheless, the efficacy of these approaches is not universal, and tools to identify long-term responders and primarily refractory patients are warranted. In this article, we review recent advances in understanding the complex mechanisms of antitumor immunity and how these developments can be used to address open questions in a setting of growing clinical indications for the use of immunotherapy.

Characterisation and management of dermatologic adverse events to agents targeting the PD-1 receptor

BACKGROUND

Dermatologic adverse events (AEs) are some of the most frequently observed toxicities of immune-checkpoint inhibitor therapy, but they have received little attention. The drugs, pembrolizumab and nivolumab are recently approved inhibitors of the programmed death (PD)-1 receptor that have overlapping AE profiles however, the incidence, relative risk (RR), and clinico-morphological pattern of the associated dermatologic AEs are not known.

METHODS

We conducted a systematic review of the literature, and performed a meta-analysis of dermatologic AEs observed with the use of pembrolizumab and nivolumab in cancer patients. An electronic search was conducted using the PubMed, and Web of Science, and on the American Society of Clinical Oncology and European Society for Medical Oncology meeting abstracts' libraries for potentially relevant oncology trials, that employed the drugs at Food and Drug Administration-approved doses and reported dermatologic AEs. The incidence, RR and 95% confidence intervals were calculated using either random- or fixed-effects models based on the heterogeneity of included studies. The clinical presentation, histology of affected skin areas, and management strategies (based on institutional experience), are also presented.

RESULTS

Rash, pruritus and vitiligo were found to be the most frequently reported dermatologic AEs. The calculated incidence of all-grade rash with pembrolizumab and nivolumab was 16.7% (RR = 2.6) and 14.3% (RR = 2.5), respectively. Other significant all-grade AEs included pruritus (pembrolizumab: incidence, 20.2% [RR = 49.9]; nivolumab: incidence, 13.2% [RR = 34.5]) and vitiligo (pembrolizumab: incidence, 8.3% [RR = 17.5]; nivolumab: 7.5% [RR = 14.6]). Interestingly, all the vitiligo events were reported in trials investigating melanoma. The RR for developing dermatologic AEs in general, was 2.95 with pembrolizumab, and 2.3 with nivolumab.

CONCLUSION

We found that pembrolizumab and nivolumab are both associated with dermatologic AEs, primarily low-grade rash, pruritus, and vitiligo, which are reminiscent of those seen with ipilimumab. Knowledge of these findings is critical for optimal care, maintaining dose intensity, and health-related quality of life in cancer patients receiving PD-1 inhibitors.

Toxicities of the anti-PD-1 and anti-PD-L1 immune checkpoint antibodies

Immune checkpoint antibodies that augment the programmed cell death protein 1 (PD-1)/PD-L1 pathway have demonstrated antitumor activity across multiple malignancies, and gained recent regulatory approval as single-agent therapy for the treatment of metastatic malignant melanoma and nonsmall-cell lung cancer. Knowledge of toxicities associated with PD-1/PD-L1 blockade, as well as effective management algorithms for these toxicities, is pivotal in order to optimize clinical efficacy and safety. In this article, we review selected published and presented clinical studies investigating single-agent anti-PD-1/PD-L1 therapy and trials of combination approaches with other standard anticancer therapies, in multiple tumor types. We summarize the key adverse events reported in these studies and their management algorithms.

Survival, response duration, and activity by BRAF mutation (MT) status of nivolumab (NIVO, anti-PD-1, BMS-936558, ONO-4538) and ipilimumab (IPI) concurrent therapy in advanced melanoma (MEL)

LBA9003^

Background: We report updated survival and clinical activity in initially enrolled cohorts and activity by BRAF MT status in a phase I trial of concurrent and sequenced NIVO + IPI. Methods: MEL pts (n=53, enrolled 2009-2012, data analysis Dec 2013) with ≤3 prior therapies received IV concurrent NIVO + IPI, Q3Wk × 4 doses, followed by NIVO Q3Wk × 4. At wk 24, NIVO + IPI continued Q12Wk × 8 in pts with disease control and no DLT. Tumor responses were evaluated by WHO and immune-related criteria. Results: Pt characteristics included stage M1c: 55% and prior systemic therapy: 40%. Across doses, 1- and 2-y OS rates were 82% and 75%. Clinical activity was similar to previous reports except CRs rose to 9/53 (17%). Pts with/without tumor BRAF MT (n=36) had similar activity (Table). By wk 36, 42% demonstrated ≥80% tumor reduction. Median duration of response (DOR) was not reached (NR). Of 22 pts with objective response, 14 (64%) had DOR ≥24 wk (range: 25+, 106+). Treatment-related adverse events were as reported previously: grade 3-4, 53% of pts; most common: ↑ lipase and AST (13% ea). Data for sequenced cohorts are shown (Table). Conclusions: Concurrent NIVO + IPI therapy showed encouraging survival and a manageable safety profile in advanced MEL pts. Responses were observed regardless of BRAF MT status and were durable in the majority of pts. Forty additional pts were enrolled (last pt: Nov 2013) on a cohort of NIVO 1 mg/kg + IPI 3 mg/kg Q3Wk × 4 doses, followed by NIVO 3mg/kg Q2Wk (the selected regimen for phase II/III trials). Clinical trial information: NCT01024231. [Table: see text]

Pretreatment levels of absolute and relative eosinophil count to improve overall survival (OS) in patients with metastatic melanoma under treatment with ipilimumab, an anti CTLA-4 antibody

9024

Background: Ipilimumab, a fully human monoclonal Ab directed against the CTLA-4 receptor on T-cells, has shown significant improvement in OS for patients with metastatic melanoma in randomized phase III trials. Eosinophilia in peripheral blood of those patients has been observed, but its clinical significance as a prognostic factor has not been assessed. Methods: We report on a retrospective multi-center analysis of 123 patients who received ipilimumab in three centers between 2010 and 2013. Patients treated had AJCC unresectable stage III or stage IV melanoma of any origin and received ipilimumab in first- and second-line setting at the approved standard dosage of 3mg/kg (4 times q21d). Four patients were excluded due to missing baseline values in eosinophil count (EC). Results: Median OS for patients in final analysis (n=119) was 9.57 months. Based on cut-offs assessed by ROC curves, OS was estimated by Kaplan-Meier curves. Baseline absolute eosinophil count (AEC) ≥ 0.1 (109/l) was significantly associated with improved OS (p= 0.002) with 6-, 12- and 18-month survival rates of 79%, 60% and 48% compared to rates of 48%, 37% and 19% for pts with baseline AEC below 0.1. Baseline relative eosinophil counts (REC) of ≥ 1.75% showed an even stronger significance (p<0.0001) with 6-, 12- and 18-months survival rates of 79% vs. 52%, 60% vs. 40% and 51% vs. 17.1% respectively. Conclusions: This retrospective analysis elucidates the possible association of baseline EC with OS of patients treated with Ipilimumab. Improvement of OS was highly significant in both analyses considering AEC (p= 0.002) and REC (p<0.0001). Since easily detectable biomarkers could be of great potential value, further effort on understanding the potential role of eosinophil granulocytes as possible effector cells in the immune-mediated response to anti CTLA-4 abs should be undertaken.

Safety and clinical activity of nivolumab (anti-PD-1, BMS-936558, ONO-4538) in combination with ipilimumab in patients (pts) with advanced melanoma (MEL)

9012^

Background: CTLA-4 and PD-1 are critical immune checkpoint receptors. In MEL pts, ipilimumab (anti-CTLA-4) prolonged survival in two phase III trials, and nivolumab (anti-PD-1) produced an objective response rate (ORR) of 31% (n=106) in a phase I trial. PD-1 is induced by CTLA-4 blockade, and combined blockade of CTLA-4/PD-1 showed enhanced antitumor activity in murine models. Thus, we initiated the first phase 1 study to evaluate nivolumab/ipilimumab combination therapy. Methods: MEL pts with ≤3 prior therapies received IV nivolumab and ipilimumab concurrently, q3 wk × 4 doses, followed by nivolumab alone q3 wk × 4 (Table). At wk 24, combined treatment was continued q12 wk × 8 in pts with disease control and no DLT. In two sequenced-regimen cohorts, pts with prior standard ipilimumab therapy were treated with nivolumab (q2 wk × 48). Results: As of Dec. 6, 2012, 69 pts were treated. We report efficacy data on 37 pts with concurrent therapy in completed cohorts 1-3 (Table); ORR was 38% (95% CI: 23-55). In cohort 2 (MTD), ORR was 47% and 41% of pts had ≥80% tumor reduction at 12 wk (Table) with some pts showing rapid responses, prompt symptom resolution, and durable CRs. Related adverse events (rAEs) for concurrent therapy were similar in nature with some higher in frequency than those typically seen for the monotherapies and were generally manageable using immunosuppressants. Cohort 3 exceeded the MTD (DLT: gr 3-4 ↑ lipase). At the MTD, gr 3-4 rAEs occurred in 59% of pts and included uveitis/choroiditis, colitis, and reversible lab abnormalities. Conclusions: Nivolumab and ipilimumab can be combined with a manageable safety profile. Clinical activity for concurrent therapy appears to exceed that of published monotherapy data, with rapid and deep tumor responses (≥80% tumor reduction at 12 wk) in 30% (11/37) of pts. A phase III trial is planned to compare concurrent combination dosing with each monotherapy. Clinical trial information: NCT01024231. [Table: see text]

Pharmacodynamic effect of ipilimumab on absolute lymphocyte count (ALC) and association with overall survival in patients with advanced melanoma

9052

Background: Ipilimumab (Ipi) is a fully human monoclonal antibody that augments antitumor T-cell responses. Ipi has been shown to improve overall survival (OS) in 2 phase (ph) III trials of advanced melanoma, as monotherapy at 3 mg/kg in previously treated patients (pts) (MDX010-20) or at 10 mg/kg with dacarbazine in previously untreated pts (CA184-024). In preclinical and clinical studies, inhibition of CTLA-4 by Ipi resulted in increases in activation and proliferation of peripheral T cells and increases in ALC. Baseline ALC may be a prognostic biomarker in several cancer types. The current analyses aim to increase understanding of changes in ALC with Ipi treatment and association of these changes with OS. Methods: Data were from 6 studies of Ipi with chemotherapy (CT) (ph I 078; N=59) or without CT (ph III MDX010-20; ph II trials 004, 007, 008, and 022; N=1203), and Ipi monotherapy in an Expanded Access Program (N=117) or with commercially available Ipi (N=71) or BRAF inhibitors (N=39). ALC was measured at baseline, prior to each dose during induction (weeks 1, 4, 7, and 10) and at the end of induction (week 13). Cox proportional hazards models were used to estimate and test associations between ALC measures and OS. Results: In all studies, mean ALC increased significantly over time in pts who received Ipi, with or without CT (P<.0001 to P=.03). There was no significant mean increase in ALC in pts who received gp100 or BRAF-inhibitor monotherapy. In study MDX010-20, pts with a greater rate of change in ALC from baseline to week 7 tended to have longer OS (P=.0003). A similar association was found between OS and ALC ≥1000/µL after 2 Ipi doses. However, pts in MDX010-20 had an OS benefit from Ipi relative to gp100, regardless of rate of change in ALC (P=.14). Conclusions: In these analyses, consistent with inhibition of CTLA-4, Ipi induced an increase in mean ALC, even with the addition of CT. A positive association between rate of ALC increase and OS was observed, but this was not specifically predictive of OS benefit from Ipi. Therefore, ALC cannot currently be used to guide clinical management with Ipi. However, further prospective investigation may be warranted.

Hypersensitivity skin reactions in melanoma patients treated with vemurafenib after ipilimumab therapy

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Background: Ipilimumab (IPI) and vemurafenib (VEM) each improve overall survival for patients (pts) with metastatic melanoma. Both are FDA-approved and are being used in pts with BRAFV600E-mutated metastatic melanoma. We previously described cases of prominent skin eruptions associated with VEM in pts who had previously received IPI. Methods: We have updated our experience of BRAFV600E-mutated melanoma pts treated with VEM who had previously received IPI. Pts were treated at our center from January 2007 to January 2012. Data were collected under an approved IRB waiver. Results: Sixteen melanoma pts were treated with VEM after having received IPI. The most common drug-related adverse event (AE) associated with VEM was rash, occurring in 13/16 patients (81.3%, 95% CI 56.5-93.2). Four pts developed a severe, Grade 3, maculopapular rash within 8 days of starting VEM. Biopsies in 2 pts revealed spongiotic and perivascular dermatitis with eosinophils consistent with a drug hypersensitivity reaction. Hypersensitivity reactions did not progress to life-threatening reactions such as anaphylaxis or Stevens-Johnson syndrome, nor did they result in VEM dose discontinuation. Reactions were managed with corticosteroids and dose modifications. Grade 3 rash strongly correlated with initiating VEM within one month of IPI (Fisher’s exact test, p = 0.007) and was not associated with the dose of prior IPI, the number of prior doses, or immune-related AEs. The incidence of Grade 3 rash in this pt cohort was significantly higher than in pts treated on the phase III trial of VEM (4/16, 25% versus 28/336, 8%; χ2 = 5.13, Df = 1, p = 0.02). The objective overall response for VEM was 50% (95% CI 26.5-73.4), which is similar to response rates seen on the phase II and III trials. Conclusions: In pts receiving VEM who have previously received IPI, dermatologic AEs appear to be more common. This effect seemed most pronounced if VEM was given within one month of completing IPI. Although more data are necessary to confirm this apparent association, we speculate that the release of immune checkpoint inhibition by IPI may predispose pts to hypersensitivity skin reactions to VEM.

Ipilimumab in the treatment of uveal melanoma: The Memorial Sloan-Kettering Cancer Center experience

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Background: Ipilimumab (ipi) is an antibody that blocks cytotoxic T-lymphocyte antigen-4 (CTLA-4) and improves overall survival in patients (pts) with metastatic melanoma. Uveal melanoma (UM) is a rare and biologically unique disease subtype with no known effective systemic therapy. Ipi has proven efficacy in cutaneous melanoma (CM), but limited data exists regarding its activity in UM. We reviewed our single-institutional experience with ipi in advanced UM. Methods: After IRB approval, the MSKCC melanoma database was queried for patients with metastatic UM treated with ipi between 03/08-01/12. Radiographic response by RECIST and immune-related response criteria (irRC) was assessed by a single radiologist blinded to clinical outcomes. Immune-related adverse events (irAEs), survival and absolute lymphocyte count (ALC) were also evaluated. Results: 20 pts were identified: the median age was 61yrs (range 46-83), 55% were male, 85% had liver metastases, 60% had elevated LDH, and pts reported a median of 1 prior therapies (range 0-5). Pts received a median of 4 doses (range 1-16) of ipi. Response rates (RR) by irRC at 12 and 24 wks are listed below. Among pts with stable disease (SD) at 12 wks, the median time to progression was 30.6 wks (range 19.6-83), with one partial response (PR) occurring after 24 wks (overall RR 10%). Responses were observed in lung, liver and peritoneal metastases. Pts with an ALC ≥ 1.0 at 7 wks had a trend toward a higher clinical benefit (CB= CR + PR + SD) than pts with ALC < 1.0 (5/12 [42%] vs 0/5 [0%]; p= .09), consistent with prior studies in CM. To date, median survival for the group is 8.6 mos (95% CI, 3.5-NR), with two ongoing PRs (3+ yrs and 24+ wks). Reported irAEs include rash/pruritis (10/20), hepatitis (1/20), colitis (1/20), pancreatitis (1/20) and uveitis (1/20). Conclusions: Ipi has potential for benefit in pts with advanced UM; RR and irAE rates are similar to those observed in pts with advanced CM. Further evaluation of ipi in the treatment of UM, including identification of potential biomarkers of CB, is warranted. [Table: see text]

Myeloid-derived suppressor cell quantity prior to treatment with ipilimumab at 10mg/kg to predict for overall survival in patients with metastatic melanoma

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Background: Ipilimumab, an antibody that blocks the function of the immune inhibitory molecule cytotoxic T lymphocyte antigen 4 (CTLA-4), significantly prolongs survival in patients with metastatic melanoma. Approximately 30% of patients derive clinical benefit from therapy. Defining biomarkers of response to ipilimumab therapy would enable selection of patients more likely to respond and is relevant for both practicing clinicians and for clinical trial design. We performed a pilot correlative study evaluating myeloid derived suppressor cells (MDSC), a population of immune suppressive monocytic cells, as a biomarker of clinical outcome. Methods: Peripheral blood from 26 patients with stage IV melanoma treated with ipilimumab 10mg/kg every 3 weeks for 4 doses at our center, as part of an expanded access program (BMS CA184-045) was assessed for MDSC quantity (%CD14+,HLA-DRlow/- cells) pre-treatment, at week 7, week 12, and week 24 by flow cytometry. MDSC ability to inhibit T cell proliferation was tested using an in vitro suppression assay. Results: We found that lower MDSC quantity pre-treatment predicted for improved overall survival (Hazard ratio 1.07 (1.03, 1.11) p=0.002) and trended toward associating with clinical benefit measured at week 24 imaging (p=0.09). This effect was independent of pre-treatment or week 7 absolute lymphocyte counts (ALC) and pre-treatment LDH when evaluated in a multivariate model with ALC and MDSC quantity HR 1.10; 95% CI 1.04, 1.17 p=0.0006 and LDH and MDSC quantity HR 1.06; 95% CI 1.01, 1.11 p = 0.013. Furthermore, a general trend of increasing MDSC number by week 24 from the pre-treatment baseline was associated with patients that did not achieve clinical benefit. MDSC suppressed peripheral blood T cell proliferation as measured by CFSE dilution in response to anti-CD3 antibody stimulation. Conclusions: Pre-treatment MDSC quantity may predict clinical response following ipilimumab therapy. Further studies evaluating MDSC as a biomarker of ipilimumab therapy are warranted both retrospectively and prospectively in a broader group of patients.

Evaluation of the absolute lymphocyte count as a biomarker for melanoma patients treated with the commercially available dose of ipilimumab (3mg/kg)

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Background: Ipilimumab (ipi) has demonstrated an overall survival (OS) benefit in 2 phase III trials. Only ~30% of patients (pts) achieve clinical benefit, and factors that determine which pts benefit are unclear. For pts treated with 10mg/kg of ipi, we previously reported that an absolute lymphocyte count (ALC) ≥1000/μL prior to dose 3 [week (wk) 7] was associated with improved OS. Since the mean increase in ALC during ipi treatment correlates with dose, we investigated if ALC is also associated with improved OS at 3mg/kg, the currently FDA approved, commercially available dose. Methods: In an IRB-approved analysis, we evaluated landmark survival data from 137 pts treated with 3mg/kg of ipi at Memorial Sloan-Kettering Cancer Center. 67 pts were treated on an expanded access protocol (CA 184-045). 70 pts were treated per FDA approval (commercial ipi) with 4 standard induction doses. These 2 groups were analyzed separately because some pts in CA 184-045 received re-induction ipi. ALC was determined at first ipi dose (baseline, wk 1) and at subsequent doses (wks 4, 7, and 10). Results: Pts treated with 3mg/kg on CA 184-045 with a wk 7 (prior to dose 3) ALC ≥1000/µL had significantly improved OS compared to pts with an ALC at wk 7 <1000/μL (Median OS: not reached vs. 4.24 mos, p<0.001). This OS difference was also seen for pts treated with commercial ipi (Median OS: not reached vs. 4.44 mos, p<0.01). This difference remained significant in a multivariable model accounting for Karnofsky performance score, LDH, M-stage, and number of prior therapies for pts in the CA 184-045 group and commercial ipi group (p=0.01 and p=0.05, respectively). Baseline ALC ≥1000/µL was associated with improved OS (p=0.02) for pts in the commercial ipi group, though follow-up is limited. Conclusions: At the FDA approved dose of ipi, 3mg/kg, ALC at wk 7 remains significantly associated with improved OS. Our preliminary finding of improved OS for pts treated with commercial ipi whose pre-treatment baseline ALC ≥1000/µL deserves confirmation with longer follow-up and prospective validation. Baseline or on treatment ALC may be a marker of overall prognosis, regardless of therapy.