sirpiglenastat (DRP-104)

This prodrug demonstrates superior safety compared to natural DON and greater antitumor activity against resistant tumors compared to the clinical phase II drug DRP104. These findings may address the clinical limitations of GLS1 allosteric inhibitors and underscore prodrug strategies in effectively treating Osimertinib-resistant lung cancer, providing a foundation for future clinical trials.

P1/2, N=27, Recruiting, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins | Trial completion date: Feb 2027 --> Aug 2029 | Trial primary completion date: Feb 2027 --> Aug 2028

Finally, our analysis demonstrated that GPX4 mediates the protection of HNSCC cells from accumulating toxic lipid peroxides; hence, glutamine blockade sensitizes HNSCC cells to ferroptosis cell death upon GPX4 inhibition. These findings demonstrate the therapeutic potential of sirpiglenastat in HNSCC and establish a novel link between glutamine metabolism and ferroptosis, which may be uniquely translated into targeted glutamine-ferroptosis combination therapies.

Using multimodal single-cell sequencing and ex vivo functional assays, we demonstrate that DRP-104 reverses T cell exhaustion, decreases Tregs, and enhances the function of CD4 and CD8 T cells, culminating in an improved response to anti-PD1 therapy. Our preclinical findings provide compelling evidence that DRP-104, currently in clinical trials, offers a promising therapeutic approach for treating patients with KEAP1 mutant lung cancer.

The glutamine antagonist DRP-104 blocks purine synthesis and combines with checkpoint inhibitors to promote antitumor immunity in KEAP1/NRF2-mutant lung cancers.

P1/2, N=27, Recruiting, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins | Phase classification: P1b/2 --> P1/2

P1/2, N=27, Recruiting, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins | Not yet recruiting --> Recruiting

P1/2, N=27, Not yet recruiting, Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins

Preclinical work from our laboratory and others has revealed that the DNAJB1-PRKACA fusion results in a metabolic rewiring of the tumor characterized by glutamine dependence. This study has been registered under NCT06027086 and is expected to begin enrollment in December 2023. Clinical trial information: NCT06027086.

P2a, N=61, Terminated, Dracen Pharmaceuticals, Inc. | N=246 --> 61 | Trial completion date: Dec 2023 --> Mar 2023 | Active, not recruiting --> Terminated; Company decision to closing study and discontinue further patient enrollment.

Overall, we find that DRP-104 impairs the growth of KEAP1 mutant tumors through both targeting of tumor intrinsic metabolic vulnerabilities and through tumor extrinsic immunostimulatory mechanisms such as promoting the expansion of functional anti-tumor T cell populations. This data provides additional rationale for the ongoing phase I/II clinical trial (NCT04471415) using DRP-104 in NSCLC with mutations in KEAP1 as well as for combining DRP-104 with checkpoint blockade.

P2a, N=246, Active, not recruiting, Dracen Pharmaceuticals, Inc. | Recruiting --> Active, not recruiting

Our data suggest that broad glutamine antagonism using sirpiglenastat (DRP-104) has therapeutic potential in HNSCC by dismantling cancer metabolism and sensitizing cells to additional perturbations leading to specific cell death. A clinical trial of sirpiglenastat (DRP-104) is currently ongoing (NCT04471415).

Our studies will provide a rationale for sub-stratification of KEAP1-mutant patients with hyperactivation of the NRF2 pathway, which is a genetic subset of NSCLC with great clinical need, as treatment candidates for sirpiglenastat. A first-in-human clinical trial of sirpiglenastat (DRP-104) is currently ongoing and will further explore this hypothesis in a LUAD cohort (NCT04471415).

However, less than 20% of HNSCC patients respond to FDA-approved anti-PD1 immune checkpoint blockade (ICB) (pembrolizumab and nivolumab), often not leading to durable responses. Our data suggest that broad glutamine antagonism using DRP-104 has therapeutic potential in HNSCC by both dismantling cancer metabolism and enhancing the anti-tumor immune response of immune checkpoint blockade. Clinical trials of DRP-104 are currently ongoing.

Importantly, this metabolic signature is predictive of either response or resistance to targeted therapies that inhibit glucose and glutamine metabolism that may be exploited in a clinical setting.We previously reported that combined targeting of glucose and glutamine metabolism with mTOR kinase inhibitor TAK228 or TKI in combination with the selective glutaminase (GLS) inhibitor CB-839 was required to significantly suppress glucose and glutamine metabolism in both LUSC and EGFR mutant LUADs resulting in metabolic crisis and tumor cell death3,5. Overall, DRP-104 showed great potential to treat hypermetabolic therapy-resistant LUSC and EGFR mutant LUAD as a single-agent therapy and in combination with immune CPI. Further clinical development of DRP-104 in this patient population is warranted and clinical trials are currently ongoing.

This unique and non-overlapping mechanism of action supports clinical development of DRP-104 alone and in combination with immune checkpoint inhibitors. The first in human clinical study of DRP-104 is ongoing.

P2a, N=246, Recruiting, Dracen Pharmaceuticals, Inc. | N=160 --> 246 | Trial completion date: Jul 2023 --> Dec 2023

P2a, N=160, Recruiting, Dracen Pharmaceuticals, Inc. | Not yet recruiting --> Recruiting

P2a, N=160, Not yet recruiting, Dracen Pharmaceuticals, Inc.

Combination therapy of DRP-104 with anti-PD-1/PD-L1 achieved significantly enhanced anti-tumor efficacy including long-term durable cures even in checkpoint inhibitor resistant models. This unique and non-overlapping mechanism of action supports clinical development of DRP-104 alone and in combination with PD-1/PD-L-1 checkpoint inhibitors.