Phase I study to evaluate toxicity and feasibility of intratumoral injection of α-gal glycolipids in patients with advanced melanoma

Abstract

Effective uptake of tumor cell-derived antigens by antigen-presenting cells is achieved pre-clinically by in situ labeling of tumor with α-gal glycolipids that bind the naturally occurring anti-Gal antibody. We evaluated toxicity and feasibility of intratumoral injections of α-gal glycolipids as an autologous tumor antigen-targeted immunotherapy in melanoma patients (pts). Pts with unresectable metastatic melanoma, at least one cutaneous, subcutaneous, or palpable lymph node metastasis, and serum anti-Gal titer ≥1:50 were eligible for two intratumoral α-gal glycolipid injections given 4 weeks apart (cohort I: 0.1 mg/injection; cohort II: 1.0 mg/injection; cohort III: 10 mg/injection). Monitoring included blood for clinical, autoimmune, and immunological analyses and core tumor biopsies. Treatment outcome was determined 8 weeks after the first α-gal glycolipid injection. Nine pts received two intratumoral injections of α-gal glycolipids (3 pts/cohort). Injection-site toxicity was mild, and no systemic toxicity or autoimmunity could be attributed to the therapy. Two pts had stable disease by RECIST lasting 8 and 7 months. Tumor nodule biopsies revealed minimal to no change in inflammatory infiltrate between pre- and post-treatment biopsies except for 1 pt (cohort III) with a post-treatment inflammatory infiltrate. Two and four weeks post-injection, treated nodules in 5 of 9 pts exhibited tumor cell necrosis without neutrophilic or lymphocytic inflammatory response. Non-treated tumor nodules in 2 of 4 evaluable pts also showed necrosis. Repeated intratumoral injections of α-gal glycolipids are well tolerated, and tumor necrosis was seen in some tumor nodule biopsies after tumor injection with α-gal glycolipids.

Keywords: Cancer vaccines; Immunotherapy; Melanoma; α-Gal glycolipids.

Fig. 1

Tumor biopsy histology. Representative histological analyses (H&E) from UW002 (×10 magnification). Target lesion, panels (a–c): a pre-treatment; nests of tumor cells with foamy, gray cytoplasm (black arrow). Lymphocytic inflammation is primarily at the edge of the tumor, but also infiltrates within the tumor cells (red arrows). b 2 weeks post-first injection; melanoma cells exhibit ballooning of their cytoplasm which now appears “foamy” (black arrow). A small patch of lymphoid cells is present in the tumor (red arrows). c 4 weeks post-second injection; Tumor cells with atypical ballooned, foamy appearance in the absence of inflammation or necrosis. d Non-target lesion, 4 weeks post-second injection; the tumor cells are necrotic (black arrows) with an area of collagenous fibrous tissue infiltrated by lymphocytes (red arrow)

Fig. 2

Tumor antigen-specific T cells pre- and post-treatment. Pre-treatment (Pre-trt.) and Day 57 post-treatment (Post-trt.) PBMC from indicated patients were stained and gated as described in “Materials and methods” section. Values in plots are MFI of pentamer⁺ T cells, and % pentamer⁺ of CD8⁺ T cells after background subtraction