While the mechanism underpinning this discordant effect in vitro vs. in vivo is not clear, there was an association for greater sensitization in TP53 mutant lines. Transfection of a dominant-negative TP53 mutant in baseline TP53 wildtype GBM lines significantly delayed growth and decreased NHEJ efficiency (but not Homologous Recombination), after peposertib exposure.

We identified DNA-PK inhibitor (DNA-PKi) NU7441 as a promising immunomodulator that reduced immunosuppressive proteins while increasing MHC-I expression in a panel of human melanoma cell lines...In patients, PRKDC levels inversely correlated with MHC I expression and CD8 TILs but positively correlated with increased neoantigen loads and improved responses to ICB. These studies suggest that inhibiting DNA-PK activity can restore tumor immunogenicity by increasing neoantigen expression and presentation and broadening the neoantigen-reactive T cell population.

In vivo studies in an NSCLC xenograft model demonstrated that the Ku-DBi treatment blocked IR-dependent DNA-PKcs autophosphorylation, modulated DDR, and reduced tumor cell proliferation. This represents the first in vivo demonstration of a Ku-targeted DNA-binding inhibitor impacting IR response and highlights the potential therapeutic utility of Ku-DBis for cancer treatment.

P1, N=52, Completed, EMD Serono Research & Development Institute, Inc. | Phase classification: P1a/1b --> P1

To improve CFTR cDNA insertion in human airway basal stem cells (ABCs), we evaluated the use of the small molecules AZD7648 and ART558, which inhibit non-homologous end-joining (NHEJ) and micro-homology mediated end-joining (MMEJ). Adding AZD7648 did not increase off-target editing. Further studies are necessary to validate if AZD7648 treatment enriches cells with oncogenic mutations.

The interaction of Tip60 with ATM and DNA-PK was investigated using the specific inhibitors KU55933 and NU7441, respectively. Downregulation of Tip60 enhances the radiation sensitivity of both glioma cells and markedly elevates the radiation sensitivity when combined with DNA-PKi. Therefore, treatment with DNA-PK inhibitors represents a promising approach to augment the radiation sensitivity of glioma cell lines with deficient Tip60 activity in a synergistic manner.

P1/2, N=3, Completed, Valerio Therapeutics | Recruiting --> Completed | Phase classification: P1b/2 --> P1/2 | N=115 --> 3 | Trial completion date: Apr 2027 --> Oct 2023 | Trial primary completion date: Dec 2026 --> Oct 2023

NU7441 prevents DNA damage repair, leading to an increased concentration of free DNA fragments, while Mn2+ ions activate the cGAS-STING pathway, enhancing the systemic anti-tumor immune response. The orchestrated immune-boosting nanoplatform effectively inhibits tumor growth and lung metastasis, presenting a promising strategy for cancer treatment.

To improve CFTR cDNA insertion in human airway basal stem cells (ABCs), we evaluated the use of the small molecules AZD7648 and ART558 which inhibit non-homologous end joining (NHEJ) and micro-homology mediated end joining (MMEJ). Adding AZD7648 did not increase off-target editing. Further studies are necessary to validate if AZD7648 treatment enriches cells with oncogenic mutations.

P1, N=66, Recruiting, National Cancer Institute (NCI) | Trial completion date: Aug 2024 --> Aug 2026 | Trial primary completion date: Aug 2024 --> Aug 2026

P1/2, N=60, Recruiting, Chengdu Baiyu Pharmaceutical Co., Ltd.

Finally, patients with high CDCA3 expression in sarcoma were analyzed for resistance to NU7441 and others, while sensitive to Fulvestrant and Dihydrorotenone. These results suggest for the first time that knockdown of CDCA3 may inhibit sarcoma progression. CDCA3 may be an effective target for the treatment of sarcoma.

Using a kinome-wide CRISPR screen, we identified PRKDC as a critical determinant of doxorubicin (DOX) sensitivity in osteosarcoma. The PRKDC inhibitor AZD7648 and DOX synergized and strongly suppressed the growth of osteosarcoma in mouse xenograft models and human organoids. In conclusion, the PRKDC-GDE2-GNAS-AKT regulatory axis suppresses DOX sensitivity and comprises targetable candidates for improving the efficacy of chemotherapy in osteosarcoma.

A time-dependent shortening of telomere length was observed in both cell lines after combined treatment with AZD7648 and 8 Gy X-ray/C-ion IR. Our data suggest that the inhibition of DNA-PKcs may increase sensitivity to X-rays and C-ion IR by impairing its functional role in DNA repair mechanisms and telomere end protection.

Healthy fibroblasts tolerated AZD7648 alone extremely well, but irradiation-induced effects might occur. Our results justify in vivo studies.

P1, N=36, Recruiting, Chengdu Baiyu Pharmaceutical Co., Ltd.

AZD7648 possesses broad applications in augmenting nano-sized drug delivery and preventing DNA repair resistance. The promising efficacy and evident synergy underscore the potential of combining MPD1 with AZD7648 as a strategy for treating KRAS-mutant cancers.

P1, N=29, Active, not recruiting, National Cancer Institute (NCI) | Trial completion date: Jun 2024 --> Dec 2024 | Trial primary completion date: Jun 2024 --> Dec 2024

Using inhibitors targeting ATM (AZD1390), ATR (AZD6738) and DNA-Pkcs (AZD7648), we observed that this led to significantly decreased clonogenic survival of HNSCC cell lines following both X-ray and proton irradiation. We confirmed that the inhibitors in combination with X-rays and protons led to DSB persistence, and increased micronuclei formation. Cumulatively, our data suggest that targeting DSB repair, particularly via ATM and DNA-Pkcs inhibition, can exacerbate the impact of ionising radiation in sensitising HNSCC cell models.

P1, N=48, Suspended, National Cancer Institute (NCI) | Trial completion date: Dec 2024 --> Jun 2025 | Trial primary completion date: Dec 2024 --> Jun 2025

Targeting DNA-PKcs with the small molecule inhibitor NU7441 synergizes with temozolomide to reduce Ep-GBM tumorigenicity and prolong animal survival. These findings provide new insights into the epigenetic regulation of Ep-GBM-like transformation and suggest a potential therapeutic strategy for patients with Ep-GBM.

Similar effects were seen in the intestinal jejunum, tongue and FaDu tumor xenografts of mice assessed for proliferation rates at 3.5 days after treatment with etoposide or 5Gy whole body irradiation ± DNA-PK inhibitors AZD7648 or peposertib (M3814). DNA-PK inhibitor-mediated sensitization to radiation and DNA-damaging chemotherapy is not limited to tumor tissues, but also extends to normal tissues sustaining DNA damage. These data are useful for interpretation of the sensitizing effects of DNA damage repair inhibitors, where a therapeutic index showing greater cell-killing effects on cancer cells is crucial for optimal clinical translation.

Conversely, PARP inhibitors exhibit selective activity for proliferating cells, providing a mechanism for targeting activity to cancers, but due to poor activity in non-proliferating cells they have an overall reduced impact on tumor growth control. This study highlights the importance of creating a therapeutic ratio with DNA damage repair inhibition radiation sensitizing strategies.

P1/2, N=90, Recruiting, National Cancer Institute (NCI) | Suspended --> Recruiting

P1/2, N=98, Recruiting, National Cancer Institute (NCI) | Suspended --> Recruiting

A Phase Ia clinical trial (NCT05002140) with XRD-0394 in combination with RT has completed. These results provide a rationale for future clinical trials with XRD-0394 in combination with RT, PARP inhibitors and targeted delivery of topoisomerase I inhibitors.

Our findings demonstrate that ARF4-mediated retrograde trafficking contributes to the development of TMZ resistance, cementing this pathway as a viable strategy to overcome chemoresistance in GBM.

P1, N=29, Active, not recruiting, National Cancer Institute (NCI) | Recruiting --> Active, not recruiting

P1, N=30, Active, not recruiting, Boryung Pharmaceutical Co., Ltd | Recruiting --> Active, not recruiting

P1/2, N=90, Suspended, National Cancer Institute (NCI) | Trial completion date: Jan 2024 --> Jan 2025 | Trial primary completion date: Jan 2024 --> Jan 2025

The study suggests that simultaneous inhibition of telomerase and DNA-PK in pre-B ALL presents a novel targeted therapy approach.

P1, N=12, Completed, XRad Therapeutics Inc | Active, not recruiting --> Completed | Trial completion date: Dec 2023 --> Jul 2023 | Trial primary completion date: Dec 2023 --> Jul 2023

Moreover, BR101801 exerted robust synergistic effects on IR-induced cell cycle arrest, apoptosis, and tumor growth inhibition, even in radioresistant HCT116 p53 cells. Overall, these findings provide a scientific rationale for combining BR101801 with IR as a new therapeutic strategy to overcome radioresistance induced by p53 deficiency.

P1, N=48, Recruiting, National Cancer Institute (NCI) | Trial completion date: Dec 2023 --> Dec 2024 | Trial primary completion date: Dec 2023 --> Dec 2024

P1, N=36, Recruiting, National Cancer Institute (NCI) | Suspended --> Recruiting | Initiation date: May 2023 --> Feb 2024

P1/2, N=101, Recruiting, National Cancer Institute (NCI) | Trial completion date: Dec 2023 --> Dec 2024 | Trial primary completion date: Dec 2023 --> Dec 2024

P1, N=29, Recruiting, National Cancer Institute (NCI) | Phase classification: P1b --> P1

P1, N=66, Recruiting, National Cancer Institute (NCI) | Phase classification: P1b --> P1 | Initiation date: Nov 2023 --> Feb 2024

In conclusion, AZD7648 synergistically increased radiosensitivity through accumulating IR-induced G2/M arrest and further improved radioresistance via regulation of HIF-1α. The present data suggest that AZD7648 may be a strong radiosensitizer in radioresistant as well as radiosensitive cancers.

P1/2, N=90, Suspended, National Cancer Institute (NCI) | Phase classification: P2 --> P1/2

PRKDC inhibition with nedisertib sensitized glioblastomas to radiotherapy and extended survival in vivo, and single-cell RNA sequencing revealed hyperactivation of cell stress and cytokine signatures with combination treatment. In summary, we report in vivo perturb-seq as a platform for simultaneous discovery and functional interrogation of therapeutic vulnerabilities in glioblastoma, and show DNA-PK inhibition sensitizes glioblastomas to radiotherapy in vivo.

INSIGhT (NCT02977780) is an ongoing phase 2 adaptive platform trial in newly diagnosed MGMT unmethylated glioblastoma with a shared control arm of patients receiving radiation therapy with concurrent and maintenance temozolomide. In comparison to an ECA, there was no significant survival benefit with abemaciclib, neratinib and CC-115. Treatment effects estimates were similar to the primary analyses based on the original shared control arm of INSIGhT. The use of external control arms in early phase testing of new therapies is supported by our findings and could significantly reduce costs and time to conduct trials in newly diagnosed glioblastoma.