RE: SDC-1801 into Phase 1 trials2 Oct 2022 11:29
https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet
PARP is approved for use as a cancer treatment. It is more effective when used with CHK1
From 2011 .
Clinical development of UCN-01 has overcome many initial obstacles, but the drug has nevertheless failed to show a high level of clinical activity when combined with chemotherapeutic agents. One very likely reason for the lack of clinical efficacy of Chk1 inhibitors may be that the inhibition of Chk1 causes the compensatory activation of ATM and ERK1/2 pathways. Indeed, inhibition of many enzyme activities, not necessarily components of cell cycle regulation, may block Chk1 inhibitor-induced ERK1/2 activation and enhance the toxicity of Chk1 inhibitors.
Difficulties here due to CHK1 inhibition resistance identified.
however by 2021 sept
Checkpoint kinase 1 (CHK1) plays a central role in the response to replication stress through modulation of cell-cycle checkpoints and homologous recombination (HR) repair. In BRCA-deficient cancers with de novo or acquired PARP inhibitor resistance, the addition of the CHK1 inhibitor prexasertib to the PARP inhibitor olaparib compromises replication fork stability, as well as HR proficiency, allowing for sensitization to PARP inhibition.
full info in link below.
https://aacrjournals.org/clincancerres/article/27/17/4710/671668/Phase-1-Combination-Study-of-the-CHK1-Inhibitor
Taken from the research paper by Michelle Garrett from May 2021.
'The data reveals an NF-kB regulated pathway controlling CHk1 activity in cancer cells and identifies a potential mechanism for both acquiring and overcoming CHK1 inhibitor resistance in cancer patients'
Note carefully the excerpt. :-
' The dramatic loss of CHK1 signalling we observed in the C- Rel Eu-Myc lymphoma cells raised the question of how these cells were surviving and coping with ongoing DNA replication stress. Especially given our previous observation that lymphomas in these mice arise earlier than in wild type controls.
The activation of compensatory signalling pathways is a major contributing factor in the development of resistance to kinase inhibitors and often goes hand in hand with the tumour cell having bypassed the need for the drug target, which we observed in our models of both de novo and acquired resistance.'
'Our data implies that a treatment with P13K or AKT pathway inhibitor could be an invaluable strategy either in the treatment of patients whose tumours develop resistance to CHK1 inhibition or potential as a combination therapy to enhance the effectiveness of the initial treatment'
P13K or an AKT inhibitor ( both which exist)!
I
Chk 1 inhibition it is envisaged, can be overcome when used in combo. Vital for HGSOC, Breast cancer and pancreatic cancer. This is a huge market. Sierra had patents for SRA737put in place.
The science has evolved.
Regards