A phase Ib/II dose expansion study of subcutaneous sasanlimab in patients with locally advanced or metastatic non-small-cell lung cancer and urothelial carcinoma

BACKGROUND

Sasanlimab is an antibody to the programmed cell death protein 1 receptor. We report updated data of subcutaneous sasanlimab in non-small-cell lung cancer (NSCLC) and urothelial carcinoma dose expansion cohorts from a first-in-human phase Ib/II study.

PATIENTS AND METHODS

Patients were ≥18 years of age with NSCLC or urothelial carcinoma, and no prior immunotherapies, who progressed on or were intolerant to systemic therapy, or for whom systemic therapy was refused or unavailable. Patients received subcutaneous sasanlimab at 300 mg every 4 weeks (q4w). Primary objectives were to evaluate safety, tolerability, and clinical efficacy by objective response rate (ORR).

RESULTS

Sixty-eight and 38 patients with NSCLC and urothelial carcinoma, respectively, received subcutaneous sasanlimab. Overall, sasanlimab was well tolerated; 13.2% of patients experienced grade ≥3 treatment-related adverse events. Confirmed ORR was 16.4% and 18.4% in the NSCLC and urothelial carcinoma cohorts, respectively. ORR was generally higher in patients with high programmed death-ligand 1 (PD-L1) expression (≥25%) and high tumor mutational burden (TMB; >75%). In the NSCLC and urothelial carcinoma cohorts, median progression-free survival (PFS) was 3.7 and 2.9 months, respectively; corresponding median overall survival (OS) was 14.7 and 10.9 months. Overall, longer median PFS and OS correlated with high PD-L1 expression and high TMB. Longer median PFS and OS were also associated with T-cell inflamed gene signature in the urothelial carcinoma cohort.

CONCLUSIONS

Subcutaneous sasanlimab at 300 mg q4w was well tolerated with promising clinical efficacy observed. Phase II and III clinical trials of sasanlimab are ongoing to validate clinical benefit. Subcutaneous sasanlimab may be a potential treatment option for patients with NSCLC or urothelial carcinoma.

Tumor mutational burden is predictive of response to immune checkpoint inhibitors in MSI-high metastatic colorectal cancer

BACKGROUND

Microsatellite instability (MSI) is a biomarker for response to immune checkpoint inhibitors (ICPIs). PD-1 inhibitors in metastatic colorectal carcinoma (mCRC) with MSI-high (MSI-H) have demonstrated a high disease control rate and favorable progression-free survival (PFS); however, reported response rates to pembrolizumab and nivolumab are variable and often <50%, suggesting that additional predictive biomarkers are needed.

METHODS

Clinicopathologic data were collected from patients with MSI-H mCRC confirmed by hybrid capture-based next-generation sequencing (NGS) treated with PD-1/L1 inhibitors at five institutes. Tumor mutational burden (TMB) was determined on 0.8-1.1 Mb of sequenced DNA and reported as mutations/Mb. Potential biomarkers of response and time to progression were analyzed by univariate and multivariate analyses. Once TMB was confirmed as a predictive biomarker, a larger dataset of 18 140 unique CRC patients was analyzed to define the relevance of the identified TMB cut-point.

RESULTS

A total of 22 patients were treated with PD-1/L1 inhibitors including 19 with pembrolizumab monotherapy. Among tested variables, TMB showed the strongest association with objective response (OR; P < 0.001) and PFS, by univariate (P < 0.001) and multivariate analysis (P < 0.01). Using log-rank statistics, the optimal predictive cut-point for TMB was estimated between 37 and 41 mutations/Mb. All 13 TMBhigh cases responded, while 6/9 TMBlow cases had progressive disease. The median PFS for TMBhigh has not been reached (median follow-up >18 months) while the median PFS for TMBlow was 2 months. A TMB of 37.4 mutations/Mb in a large MSI-H mCRC population (821/18, 140 cases; 4.5%) evaluated by NGS corresponded to the 35th percentile cut-point.

CONCLUSIONS

TMB appears to be an important independent biomarker within MSI-H mCRC to stratify patients for likelihood of response to ICPIs. If validated in prospective studies, TMB may play an important role in guiding the sequencing and/or combinations of ICPIs in MSI-H mCRC.

Cabozantinib in hepatocellular carcinoma: results of a phase 2 placebo-controlled randomized discontinuation study

Background

Cabozantinib, an orally bioavailable inhibitor of tyrosine kinases including MET, AXL, and VEGF receptors, was assessed in patients with hepatocellular carcinoma (HCC) as part of a phase 2 randomized discontinuation trial with nine tumor-type cohorts.

Patients and methods

Eligible patients had Child-Pugh A liver function and ≤1 prior systemic anticancer regimen, completed ≥4 weeks before study entry. The cabozantinib starting dose was 100 mg daily. After an initial 12-week cabozantinib treatment period, patients with stable disease (SD) per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.0 were randomized to cabozantinib or placebo. The primary endpoint of the lead-in stage was objective response rate (ORR) at week 12, and the primary endpoint of the randomized stage was progression-free survival (PFS).

Results

Among the 41 HCC patients enrolled, the week 12 ORR was 5%, with 2 patients achieving a confirmed partial response (PR). The week 12 disease control rate (PR or SD) was 66% (Asian subgroup: 73%). Of patients with ≥1 post-baseline scan, 78% had tumor regression, with no apparent relationship to prior sorafenib therapy. Alpha-fetoprotein (AFP) response (>50% reduction from baseline) occurred in 9 of the 26 (35%) patients with elevated baseline AFP and ≥1 post-baseline measurement. Twenty-two patients with SD at week 12 were randomized. Median PFS after randomization was 2.5 months with cabozantinib and 1.4 months with placebo, although this difference was not statistically significant. Median PFS and overall survival from Day 1 in all patients were 5.2 and 11.5 months, respectively. The most common grade 3/4 adverse events, regardless of attribution, were diarrhea (20%), hand-foot syndrome (15%), and thrombocytopenia (15%). Dose reductions were utilized in 59% of patients.

Conclusions

Cabozantinib has clinical activity in HCC patients, including objective tumor responses, disease stabilization, and reductions in AFP. Adverse events were managed with dose reductions.

Trial registration number

NCT00940225.

Combination of 5-azacytidine (5-AZA) and valproic acid (VPA) in advanced solid cancers: A phase I study

3547

Background: 5-AZA is a DNA hypomethylating agent. VPA is a histone deacetylase inhibitor (HDACI). The combination of hypomethylating agents and HDACI has synergistic anticancer activity in vitro and in vivo. Based on this, we conducted a phase I study of the combination of 5-AZA and VPA in patients with advanced solid cancers. Methods: 5-AZA was administered SQ daily for 10 days. VPA was given orally daily titrated to 75–100 mcg/ml. Cycles were 28 days long. 5-AZA was started at 20 mg/m2 and escalated using an adaptive algorithm based on toxicity in the prior cohort. Each cohort included 6 patients (pts). Global DNA methylation was estimated with the LINE pyrosequencing assay in peripheral blood mononuclear cells on days 1 and 10 of each cycle. Histone H3 and H4 acetylation was assessed with western blots. Results: Forty seven patients were evaluable. Median age was 60 years (15–77). 5- AZA dose levels included 20, 25, 37.5, 47, 59, 75 and 94 mg/m2. One DLT occurred at 37.5 (Neutropenic fever (NF)). At 75 mg/m2, 1 grade 3 NF and at 94 mg/m2, 3 DLTs (2 NF and 1 thrombocytopenia) were observed. The MTD was 75 mg/m2 SQ daily for 10 days. Other toxicities included drowsiness (N=6), tremor (N=6), hypomagnesemia (N=1), anemia (N=2) and vomiting (N=1). Stable disease (SD) was observed in 16 pts (34%). One pt with rapidly progressive renal cell carcinoma had SD for 6 months (mos). Two pts with leiomyosarcoma of the uterus had SD for 8 and 6 mos. One pt with melanoma and two pts with uveal melanoma had SD for 4 mos. One pt with sinus adenoid cystic carcinoma and 1 with thymic carcinoma had SD for 4 mos. SD was also observed in pts with colon (N=3), sarcoma (N=2), papillary thyroid (N=2) and breast cancer (N=1). Global DNA hypomethylation was demonstrated in all of the doses of 5- AZA. Median LINE methylation pretreatment was 65% (59–70%), it declined to 61% (53–63%) by day 10 (p=0.001) and returned to baseline by day 0 of the next cycle. Histone acetylation was observed in 53% of the pts. Conclusions: The combination of 5-AZA and VPA in patients with advanced solid tumors is safe. The MTD of 5-AZA in combination with VPA was 75 mg/m2 SQ daily for 10 days. DLTs were neutropenic fever and thrombocytopenia. Clinical benefit (SD) was observed in 16 pts (34%). Transient global hypomethylation and histone acetylation were demonstrated.

No significant financial relationships to disclose.

Phase I study of low-dose hypomethylating agent azacitidine (5-AC) combined with the histone deacetylase inhibitor valproic acid (VPA) in patients with advanced cancers

3060

Background: By inhibiting DNA methyltransferase, 5-azacytidine (5-AC) reverses epigenetic silencing of aberrantly hyper-methylated genes restoring activity of tumor suppressor and pro-apoptotic genes. In leukemia, the responses achieved with the hypomethylating agent decitabine are considerably greater at low doses than at high dose levels. We explored the tolerance to a combination of valproic acid (VPA), a histone deacetylase inhibitor, given together with low-dose 5-AC and the ability of this combination to induce DNA hypomethylation. Methods: Every 28-day cycle, 5-AC was givenSC daily for 10 days, and VPA was administered orally daily in doses titrated up to therapeutic levels (75–100 mcg/mL). Planned dose-levels of 5-AC (6-patients/cohort) were determined per an adaptive algorithm based on toxicity in the previous cohort (toxicity-based adaptive dosing model (TAD model) with a starting dose of 20 mg/m2. The methylation status of long interspersed nuclear elements (LINE) was used as a surrogate marker of global methylation, and was performed on peripheral blood mononuclear cells on day 1 and 10 of the first 4 cycles for each patient. Results: To date, twenty-two patients have enrolled at 20, 25, 37.5 and 47 mg/m2 dose-levels. The VPA dose was titrated up to 18.8 ± 6.9 mg/kg. Side effects include mainly drowsiness (N = 5), tremor (N = 4), hypomagnesemia (N = 2), grade 1–2 anemia (N = 2), and neutropenia (N = 2). One DLT (neutropenic fever) occurred at a dose of 37.5 mg/m2. One patient with rapidly progressive disease (renal cell carcinoma) experienced stable disease (6 months), and three patients (adenocystic carcinoma = 1, leiomyosarcoma of the uterus = 2) experienced stable disease for 4 months. Eighty-two blood samples were obtained. Median LINE methylation pretreatment was 65% (range 59–70%, it declined to 61% (range 53–63%) by day 10 (p = 0.001)and returned to baseline by day 0 of the following cycle. Conclusions: Our preliminary data suggest that low-dose 5-AC combined with VPA (median = 17 mg/kg) is well tolerated and exhibits biological activity in patients with advanced cancer. Western blot assays for histone acetylation are in process. The trial is currently accruing at dose-level 47 mg/m2.

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