Continuous vs intermittent adenosine 2A receptor (A2AR) inhibition in preclinical colon cancer (CC) models and in a Phase (Ph) II study of taminadenant (NIR178) + spartalizumab (PDR001) in patients (pts) with non-small cell lung cancer (NSCLC)

CD39 - A bright target for cancer immunotherapy

The ATP-adenosine pathway functions as a key modulator of innate and adaptive immunity within the tumor microenvironment, and cancer immune evasion largely involves the generation of high amounts of immunosuppressive extracellular adenosine (eADO). Consequently, inhibition of eADO-generating enzymes and/or eADO receptors can effectively restore the antitumor immunity of multiple immune cells. With several clinical strategies currently being explored to modulating the eADO pathway in patients with cancer, recent clinical data with antagonists targeting CD73 and A_2A receptor have demonstrated a promising therapeutic potential in cancer. Recent findings reveal that the ectonucleotidase CD39, the limiting enzyme been viewed as "immunological switch", converts ATP-driven pro-inflammatory milieu to an anti-inflammatory state mediated by adenosine. Owing to its superior feature of CD39 antagonism that rely not only on preventing the accumulation of adenosine but also on the stabilization of extracellular ATP to restore antitumor immunity, several inhibitors and clinical trials based on CD39 are being evaluated. Consequently, there is currently a focus on understanding the role of CD39 in governing immunity and how therapeutic strategies targeting this pathway alter the antitumor potential. We herein review the impact of CD39 on tumor microenvironment with a focus on treatment preference. Additionally, we also discuss the implication for rational combination therapies, molecular regulation, as well as potential limitations.

Phase I study of taminadenant (PBF509/NIR178), an adenosine 2A receptor antagonist, with or without spartalizumab, in patients with advanced non-small cell lung cancer

PURPOSE

The adenosine 2A receptor (A2AR) mediates the immunosuppressive effects of adenosine in the tumor microenvironment and is highly expressed in non-small cell lung cancer (NSCLC). Taminadenant (PBF509/NIR178) is an A2AR antagonist able to reactivate the antitumor immune response.

EXPERIMENTAL DESIGN

In this phase I/Ib, dose-escalation/expansion study, patients with advanced/metastatic NSCLC and {greater than or equal to}1 prior therapy received taminadenant (80-640 mg; orally; twice-daily) with or without spartalizumab (anti-programmed cell death-1; 400 mg; intravenously; every four weeks). Primary endpoints: safety, tolerability, and feasibility of the combination.

RESULTS

During dose escalation, 25 patients each received taminadenant alone or with spartalizumab; 19 (76.0%) and 9 (36.0%) had prior immunotherapy, respectively. Dose-limiting toxicities (all Grade 3) with taminadenant alone were alanine/aspartate aminotransferase increase and nausea (n=1 [4.0%] each; 640 mg) and in the combination group were pneumonitis (n=2 [8.0%]; 160 and 240 mg), fatigue and alanine/aspartate aminotransferase increase (n=1 [4.0%] each; 320 mg); pneumonitis cases responded to steroids rapidly and successfully. Complete and partial responses were observed in one patient each in the single-agent and combination groups; all immunotherapy-naive. In the single-agent and combination groups, seven and 14 patients experienced stable disease; seven and six patients were immunotherapy-pretreated, respectively.

CONCLUSIONS

Taminadenant, with and without spartalizumab, was well tolerated in patients with advanced NSCLC. The maximum tolerated dose of taminadenant alone was 480 mg twice-daily, and 240 mg twice-daily plus spartalizumab. Efficacy was neither a primary or secondary endpoint; however, some clinical benefit was noted regardless of prior immunotherapy or programmed cell death ligand-1 status.