A phase 1, open-label, dose-escalation study of pralatrexate in combination with bortezomib in patients with relapsed/refractory multiple myeloma

Oncolytic adenoviruses expressing checkpoint inhibitors for cancer therapy

Despite the remarkable success of immune checkpoint inhibitors (ICIs), primary resistance to ICIs causes only subsets of patients to achieve durable responses due to the complex tumor microenvironment (TME). Oncolytic viruses (OVs) can overcome the immunosuppressive TME and promote systemic antitumor immunity in hosts. Engineered OVs armed with ICIs would likely have improved effectiveness as a cancer therapy. According to the diverse immune cell landscapes among different types of tumors, we rationally and precisely generated three recombinant oncolytic adenoviruses (OAds): OAd-SIRPα-Fc, OAd-Siglec10-Fc and OAd-TIGIT-Fc. These viruses were designed to locally deliver SIRPα-Fc, Siglec10-Fc or TIGIT-Fc fusion proteins recognizing CD47, CD24 or CD155, respectively, in the TME to achieve enhanced antitumor effects. Our results suggested that OAd-SIRPα-Fc and OAd-Siglec10-Fc both showed outstanding efficacy in tumor suppression of macrophage-dominated tumors, while OAd-TIGIT-Fc showed the best antitumor immunity in CD8+ T-cell-dominated tumors. Importantly, the recombinant OAds activated an inflammatory immune response and generated long-term antitumor memory. In addition, the combination of OAd-Siglec10-Fc with anti-PD-1 significantly enhanced the antitumor effect in a 4T1 tumor model by remodeling the TME. In summary, rationally designed OAds expressing ICIs tailored to the immune cell landscape in the TME can precisely achieve tumor-specific immunotherapy of cancer.

Results from a Phase I/II Open-Label, Dose-Finding Study of Pralatrexate and Oral Bexarotene in Patients with Relapsed/Refractory Cutaneous T-cell Lymphoma

Purpose: Pralatrexate is a folic acid analogue metabolic inhibitor similar to methotrexate, which has shown tolerability and efficacy with an overall response rate of 45% in a phase I dose deescalation study of patients with relapsed/refractory cutaneous T-cell lymphoma (CTCL).Experimental Design: The object of this phase I/II open-label, multicenter clinical trial was to determine the MTD and recommended dose of pralatrexate plus oral bexarotene in 34 patients with relapsed/refractory CTCL who had failed prior systemic therapies. Pralatrexate was administered by intravenous push at 15 mg/m² given weekly 3 weeks out of 4 weeks with daily oral bexarotene (150 or 300 mg/m²), levothyroxine, atorvastatin, folate, and with B12 every 2 months.Results: At the MTD of 15 mg/m² bexarotene and 15 mg/m² pralatrexate, the response rate was 60% [4 complete responses (CR), 14 partial responses (PR)], the maximum observed response duration was 28.9+ months, and duration of response for 4 CRs ranged from 9.0 to 28.3 months. The median progression-free survival was 12.8 months (0.5-29.9). Mucositis was the most common adverse event.Conclusions: The combination of pralatrexate (15 mg/m²) and oral bexarotene (150 mg/m²) is active with high response rates and minimal toxicity for cutaneous T-cell lymphomas. Clin Cancer Res; 23(14); 3552-6. ©2017 AACR.