Trial of Taselisib in Overgrowth (TOTEM)
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|ClinicalTrials.gov Identifier: NCT03290092|
Recruitment Status : Terminated (In accordance with the protocol, following the occurrence of two SUSARs, the TOTEM trial was stopped early for safety reasons.)
First Posted : September 21, 2017
Last Update Posted : November 12, 2019
Segmental overgrowth disorders are rare conditions characterised by abnormal growth which is usually asymmetric and confined to discrete parts of the body. We and others have identified mosaic activating mutations in the p110α catalytic subunit of phosphatidylinositol-3-kinase (PI3K; encoded by the PIK3CA gene) in a subset of overgrowth disorders. The PI3K-AKT-mTOR is a critical signalling pathway, which regulates cellular growth, proliferation and survival. Activating mutations in PIK3CA lead to increased activation of the PI3K-AKT-mTORC1 axis, which in turn promotes excessive growth in affected tissue.
The PIK3CA-related overgrowth spectrum is wide, and depends upon the timing of the founder mutation in embryogenesis, and potentially upon the exact mutation. Clinical presentation ranges from isolated enlargement of a digit, to extensive overgrowth of limbs, abdomen and in some cases the brain, and may be accompanied by vascular or lymphatic malformations. Associated morbidity can be profound, with functional impairment, debilitating haemorrhages and thromboses, coupled with neurological sequelae and, in some cases, death. At present, serial debulking surgery is the only available therapeutic option.
The identification of gain-of-function mutations in PI3K has raised the possibility of treatment with drugs that inhibit PIK3CA (the p110 alpha catalytic subunit of PI3K). Taselisib is a selective inhibitor of class I PI3Ks and has direct inhibitory activity of the p110α isoform with a Kiapp value of 0.29 nmol/l.
|Condition or disease||Intervention/treatment||Phase|
|PIK3CA-Related Overgrowth||Drug: Taselisib (GDC0032)||Phase 1 Phase 2|
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||19 participants|
|Intervention Model:||Single Group Assignment|
|Masking:||None (Open Label)|
|Official Title:||A Multi-Centre, Open Label, Single Arm, Phase IB/IIA, Trial of Taselisib (GDC0032) in PIK3CA-Related Overgrowth|
|Actual Study Start Date :||July 31, 2017|
|Actual Primary Completion Date :||February 14, 2019|
|Actual Study Completion Date :||November 4, 2019|
Drug: Taselisib (GDC0032)
The first six participants cohort receive a starting dose of 1mg once daily of taselisib during four weeks.
Drug: Taselisib (GDC0032)
The starting dose of the second cohort of 24 patients is 2 mg once daily. This dose may be adjusted down according to the pharmacokinetic data or tolerability data derived from the first cohort.
- Occurrence of dose limiting toxicities [ Time Frame: less than 24 hours ]
The dose limiting toxicity (DLT) is defined as a Grade 3 or more AE using the National Cancer Institute (NCI).
If two out of up to six participants at the same dose level experience a DLT as defined above, subsequent cohorts will be dosed at a lower level as illustrated in the flow-chart below. At least six evaluable participants are required to establish the MTD (Maximum tolerated dose) at a specific dose level for both combinations.
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03290092