Citations

60 Background: The activity of the anti-PD-1 antibody P in pts with advanced STS was evaluated in a prospective multicenter Phase II study conducted by the Sarcoma Alliance for Research through Collaboration (SARC). SARC028 enrolled 40 patients with advanced soft tissue sarcoma. Pembro had an ORR of 19% and PFS rate at 12 weeks of 55%, suggesting clinical activity. We investigated biomarkers of response to P. Methods: The primary endpoint was Objective Response Rate (ORR) by RECIST 1.1. Secondary endpoints included progression-free survival (PFS), overall survival, and biomarkers of response in blood and tumor. Pre- and on-treatment biopsies were required and obtained from over 90% and 72% of pts respectively. Serum was obtained from all pts at baseline and at multiple time points on therapy (pre-, week 8, and every 12 weeks). Sera were examined for candidate circulating biomarkers by Affymetrix Luminex platform array, including PD-L2. To determine whether there is a statistically significant difference between different conditions, we used Mann-Whitney and two-tailed t tests. Log-rank p-values in Kaplan-Meier survival analyses were calculated using the "survival" R package. Results: Forty pts with STS were enrolled into 4 cohorts (10 each) based on histological subtype including undifferentiated pleomorphic sarcoma (UPS), dedifferentiated liposarcoma (LPS), synovial sarcoma (SS), and leiomyosarcoma (LMS). 4 pts with UPS, 2 pts with LPS, and one pt with SS achieved a response. Six of seven responses were durable at the time of this analysis. Circulating levels at baseline or after therapy of PD-1, PD-L1, 4-1BB, IDO, BTLA, CTLA-4, LAG-3, and TIM-3 did not correlate with outcome. However, pre-treatment and week 8 PD-L2 levels correlated best with clinical outcome: high PD-L2 levels were associated with better PFS (p=0.019) in STS. Conclusions: P has clinical activity in specific histologic subtypes of STS, namely UPS and LPS. Pre-treatment circulating PD-L2 levels correlated with progression-free survival and is a novel and promising predictor of improved clinical outcome of PD-1 therapy in STS.

PURPOSE:Olaratumab is a human monoclonal immunoglobulin G1 antibody against platelet-derived growth factor receptor-α. We report the nature and frequency of infusion-related reactions (IRRs) with olaratumab in clinical trials and postmarketing reports.METHODS:Data from patients exposed to olaratumab across nine clinical trials were reviewed for IRRs. Blood samples were also analyzed for pre-existing immunoglobulin E anti–galactose-α-1,3-galactose (anti–α-Gal) antibodies.RESULTS:In the clinical trials, IRRs were identified in 70 of 485 patients (14.4%). The most frequent symptoms included flushing, fever or chills, and dyspnea. For 68 of 70 patients (97.1%), the first IRR occurred during the first two cycles of treatment. Grade 3 or worse IRRs were reported in 11 patients (2.3%), all during the first infusion and usually within 15 minutes of the start of the infusion. One IRR-related fatality (0.2%) occurred in a nonpremedicated patient with grade 3 or worse cardiac comorbidities. There was an association between grade 3 or worse IRRs and pre-existing anti–α-Gal antibodies, with a trend toward higher IRR rates in US geographies known to have a higher prevalence of anti–α-Gal antibodies. IRRs in postmarketing reports were consistent in nature and severity with those in the clinical trials.CONCLUSION:Premedication with corticosteroids and antihistamines should occur in all patients before olaratumab infusion, as indicated in labels in the United States and the European Union. Patients receiving olaratumab should be monitored for IRRs in a setting where resuscitation equipment is available for the treatment of IRRs.

Background Ontuxizumab, a humanized monoclonal antibody, targets endosialin (tumor endothelial marker 1 [TEM‐1] or CD248), which is expressed on sarcoma cells and is believed to be involved in tumor angiogenesis. This is the first trial to evaluate ontuxizumab in patients with sarcoma. Methods Part 1 was an open‐label, dose‐finding, safety lead‐in: 4, 6, or 8 mg/kg with gemcitabine and docetaxel (G/D; 900 mg/m 2 gemcitabine on days 1 and 8 and 75 mg/m 2 docetaxel on day 8). In part 2, patients were randomized in a double‐blind fashion in 2:1 ratio to ontuxizumab (8 mg/kg) or a placebo with G/D. Randomization was stratified by 4 histological cohorts. Results In part 2 with 209 patients, no significant difference in progression‐free survival between ontuxizumab plus G/D (4.3 months; 95% confidence interval [CI], 2.7‐6.3 months) and the placebo plus G/D (5.6 months; 95% CI, 2.6‐8.3 months) was observed ( P = .67; hazard ratio [HR], 1.07; 95% CI, 0.77‐1.49). Similarly, there was no significant difference in median overall survival between the 2 groups: 18.3 months for the ontuxizumab plus G/D group (95% CI, 16.2‐21.1 months) and 21.1 months for the placebo plus G/D group (95% CI, 14.2 months to not reached; P = .32; HR, 1.23; 95% CI, 0.82‐1.82). No significant differences between the treatment groups occurred for any efficacy parameter by sarcoma cohort. The combination of ontuxizumab plus G/D was generally well tolerated. Conclusions Ontuxizumab plus G/D showed no enhanced activity over chemotherapy alone in soft‐tissue sarcomas, whereas the safety profile of the combination was consistent with G/D alone.