Document Type

Abstract

Publication Date

10-2018

Abstract

Background: The NCI-MATCH trial is the largest national study (1173 sites) for ptswith relapsed/ refractory solid tumors, lymphomas and myeloma, which assigns tar-geted therapies based on individual tumor molecular alterations detected using theadapted Oncomine AmpliSeq panel (143 genes) and immunohistochemistry (IHC).We hypothesized that patients with PTEN-deficient cancers enrolled to Arms N and Pmay benefit from treatment with the PI3K beta-selective inhibitor GSK2636771.

Methods: Eligibility: relapsed/refractory ca, good end-organ function, and ECOG PS ≤ 1. Pts were screened for molecular alterations by centralized testing on fresh tumor biopsy and had deleterious PTEN mut/del without loss of expression (Arm N) or complete loss of cytoplasmic and nuclear PTEN staining on IHC (Arm P), and no other aberrations activating the PI3K/MTOR and MAPK pathways (mut in PIK3CA, PIK3R1, BRAF, KRAS, AKT1, TSC1/2, mTOR, RHEB, NF2, NRAS, HRAS). Pts received GSK2636771 400mg/day (28-days cycles). RECIST 1.1 overall response rate (ORR) was the primary endpoint.

Results: Of 59 enrolled pts, 56 were eligible and received treatment. Of 22 pts with PTEN mut/del (Arm N: 6 uterine, 2 breast, 2 prostate, 2 head/neck ca, 10 other), all are off treatment as of analysis (14 disease progression, 4 for adverse events [AEs], 4 other). One pt (4.5%) with prostate ca (PTEN deletion, MPRSS2-ERG fusion) attained a partial response (-42%). Of 7 (32%) pts with stable disease (SD), 2 had SD > 6 months (uterine leiomyosarcoma; endometrial carcinoma). Of 34 pts with loss of PTEN protein by IHC (Arm P: 7 prostate, 6 breast, 3 squamous anal ca, 2 cholangiocarcinoma, 16 other), all are off treatment as of analysis (26 disease progression, 4 for AE, 4 other). Of 9 (37.5%) pts with SD, 3 had SD > 6 months (prostate cancer; squamous bladder cancer, squamous anal cancer). Median progression-free survival was 1.8 months for both arms. Gr ≥ 3 treatment-related (tr) reversible toxicities were experienced by 30% (7) and 20% (7) of pts in arms N and P, respectively. No tr Gr 5 toxicities were observed in either arm.

Conclusions: Single agent GSK2636771 has very modest activity in ca with PTEN gene mutation/deletion and/or PTEN protein loss.

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Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

PubMed ID

32136211

Language

English

Included in

Oncology Commons

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