This page is dedicated to research that has been undertaken in to PROS.

Explanations of PROS:

Research papers in to PROS (PIK Related Overgrowth Spectrum)

Drug Trials for PROS (PIK Related Overgrowth Spectrum)

  • The various cells in our bodies usually follow a particular lifespan, this is the same for the growth gene PIK3CA. A normal cell will undergo a rapid death should anything become altered or damaged.
  • However, if through mutation this PIK3CA gene does not die or “switch off” they become known as “oncogenes.”
  • This means that the gene has the potential to cause cancer & tumour progression. however, this does not seem to be common place in PROS patients.
  • This link to cancer has led to an increase in research to find potential (non-invasive) treatment for cancer patients, but which could also benefit PROS patients.

2016: Cancer drug could treat blood vessel deformities

  • Conclusion of the study suggests that “Rapamycin is a drug that blocks a signalling process that happens downstream of PIK3CA, so it stops one of PIK3CA’s effects but does not block it at source,” explains lead author Dr Sandra Castillo (UCL Cancer Institute). “When we gave rapamycin to the mice, it showed clinical benefit, but in patients it can have serious side-effects and compromise the immune system”.

2017: ArQule Announces First Patient Dosed in Company Sponsored Phase 1/2 Trial of AKT Inhibitor, ARQ 092, for Rare Overgrowth Diseases

  • ArQule announced that the first patient has been dosed in a company sponsored phase 1/2 trial with its AKT inhibitor, ARQ 092, in patients with Overgrowth Diseases driven by genetic alterations of the PI3K/AKT1 pathway. ARQ 092 is an orally available, selective pan-AKT inhibitor. 

2017: Study of ARQ 092 in Subjects With PIK3CA-related Overgrowth Spectrum and Proteus Syndrome (MOSAIC)

  • Details of the study: “this is an open label, Phase 1/2 study of oral ARQ 092 (Miransertib) administered to subjects at least 2 years of age with PIK3CA-related Overgrowth Spectrum (PROS) and Proteus syndrome (PS) (MOSAIC)”.

2017/2018: Severe PI3Kinase Overgrowth Syndrome Treated with the AKT Inhibitor Miransertib

  • Results indicated as follows: “calculated volumes of fatty overgrowth declined by approximately 15% on treatment. The patient has now completed 25 months of therapy with clinically stable disease and clear radiological improvement. Miransertib was well tolerated with no significant toxicities other than hyperlipidaemia comparable to lipid profile derangement previously noted on sirolimus therapy”.

2017: Trial of Taselisib in Overgrowth (TOTEM)

  • “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”. Unfortunately the trial was: “Terminated (In accordance with the protocol, following the occurrence of two SUSARs, the TOTEM trial was stopped early for safety reasons.)”

2018: In vitro efficacy of ARQ 092, an allosteric AKT inhibitor, on primary fibroblast cells derived from patients with PIK3CA-related overgrowth spectrum (PROS)

  • Results from the trial suggest: “we demonstrated the following: (a) that PROS cells are dependent on AKT; (b) the advantage of inhibiting the pathway immediately downstream of PI3K to circumventing problems depending on multiple classes a PI3K kinases; and (c) that PROS patients benefit from inhibition of AKT rather than mTOR. Clinical development of ARQ 092 in PROS patients is on going in these patients.”
  • Results showed: “BYL719 was used to treat nineteen patients with PROS. The drug improved the disease symptoms in all patients. Previously intractable vascular tumours became smaller, congestive heart failure was improved, hemihypertrophy was reduced, and scoliosis was attenuated. The treatment was not associated with any substantial side effects. In conclusion, this study provides the first direct evidence supporting PIK3CA inhibition as a promising therapeutic strategy in patients with PROS.
  • Results from this study offer the following thoughts: “This study suggests that low-dose sirolimus can modestly reduce overgrowth, but cautions that the side-effect profile is significant, mandating individualized risk–benefit evaluations for sirolimus treatment in PROS.”
  • As a side note, I (Mandy Sellars) began taking Rapamycin a number of years ago with amazing results. Along with a combination of exercise & healthy eating, my overgrowth stopped & began to shrink. I lost around 4/5 stone in weight from my affected areas. Unfortunately my body became tolerant of the dosage I was taking & it was recommended not to increase the dose. Therefore, sadly I had to stop taking the medication & my overgrowth started to increase again.
  • An overview of research in the UK from Professor R Semple.

2019: Managed Access Program (MAP) to Provide Alpelisib (BYL719) for Patients With PIK3CA-Related Overgrowth Spectrum (PROS)

    • The purpose of the study is “to allow access to alpelisib for patients diagnosed with PIK3CA-Related Overgrowth Spectrum (PROS) who fulfill certain eligibility criteria as specified in this document. The patient’s Treating Physician should follow the suggested treatment guidelines and comply with all local health authority regulations.”
    • To reiterate, this drug is available on “compassionate use” only. Please speak to your specialist/consultant who will hopefully be able to help you with this.

2020: Retrospective Chart Review Study of Patients With PIK3CA-Related Overgrowth Spectrum Who Have Received Alpelisib (EPIK-P1)

  • This retrospective study aims to determine the effectiveness & safety of the drug Alpelisib. This was administered to patients through the “compassionate use” scheme for the treatment of PROS (PIK Related Overgrowth Spectrum)
  • Results of this study should be available July/August 2020. Should the results be favourable, this could hopefully lead to medical trials of Alpelisib for PROS patients.


  • PIK3CA-related overgrowth spectrum is characterized by increased cell proliferation.
  • Strong activation of HSF1 is found in PIK3CA-related overgrowth spectrum fibroblasts.
  • AKT inhibitors reduces HSF1 activation and HSF1-dependent gene transcription.
  • HSF1 inhibition blocks the PIK3CA-related overgrowth spectrum proliferation.
  • As there is currently no curative treatment for PIK3CA-related overgrowth spectrum, our results identify HSF1 as a new potential therapeutic target.

2020: Novartis receives Piqray approval in Europe – the first and only targeted medicine for HR+/HER2- advanced breast cancer with a PIK3CA mutation

  • Piqray (alpelisib) is the only treatment approved specifically to address PIK3CA mutation
  • This is very promising for those living with a PIK3CA mutation that is causes overgrowth, trials are in the pipeline.


  • Novartis has an ambitious development plan for the drug going forward. It’s preparing to file for approval in patients with a rare disorder called PIK3CA overgrowth syndrome.