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MO09 - Mesothelioma I (ID 120)
- Event: WCLC 2013
- Type: Mini Oral Abstract Session
- Presentations: 1
- Moderators:K. Suzuki, S.G. Armato III
- Coordinates: 10/28/2013, 16:15 - 17:45, Bayside 204 A+B, Level 2
MO09.01 - Evaluation of tolerability and anti-tumor activity of GDC-0980, an oral PI3K/mTOR inhibitor, administered to patients with advanced malignant pleural mesothelioma (MPM) (ID 1712)
16:15 - 17:45 | Author(s): L. Delasos
The PI3K-AKT-mTOR signaling pathway is dysregulated in a wide variety of cancers. Pathway activation in mesothelioma may occur through diverse cellular mechanisms, including activation of receptor tyrosine kinases that signal through Ras and PI3K/Akt/mTOR, and loss of PTEN expression. GDC-0980 is a potent and selective oral dual inhibitor of class I PI3K and mTOR kinases that has demonstrated broad activity in various xenograft cancer models.
A phase I dose-escalation study was conducted in 2 Stages: Stage 1 evaluated oral, daily (QD) doses of 2-70 mg GDC-0980 given 21/28 or 28/28 days in a 3+3 dose escalation design. Stage 2 evaluated disease specific cohorts at the recommended phase 2 dose (RP2D), including a MPM cohort at 30 mg GDC-0980 QD 28/28 days. Safety and tolerability of GDC-0980 was assessed as well as pharmacokinetics (PK) and pharmacodynamics (PD) assessment of PI3K pathway inhibition by FDG-PET. Anti-tumor activity was assessed by modified RECIST; CT scans were centrally reviewed retrospectively by a radiologist with MPM expertise. Archival tumor tissue was evaluated for PIK3CA mutation by allele specific PCR or Sanger sequencing and PTEN expression was assessed by immunohistochemistry.
33 MPM patients were enrolled: 6 in Stage 1 at 8-70 mg and 27 in Stage 2 at 30mg GDC-0980. Safety and tolerability of GDC-0980 in Stage 1 was similar in MPM compared to other solid tumor patients, with the exception of a Grade 5 pneumonitis that occurred in a MPM patient at 40 mg GDC-0980 QD. Based on Stage 1 tolerability data, a RP2D of 30 mg QD was evaluated in Stage 2 for MPM patients. The most frequent Grade ≥3 drug-related adverse events (AEs) at 30 mg GDC-0980 were rash (19%), with one patient (4%) having to discontinue GDC-0980. Other AEs were fatigue (15%), and hyperglycemia, diarrhea, and colitis (7% each). Reversible Grade 2 pneumonitis was reported for 2 patients (7%). Population PK analysis was used to assess the behavior of GDC‑0980 in MPM patients. Additionally, PK/PD relationships will be discussed for efficacy and safety, including exposure‑response, where appropriate. Archival tissue was analyzed for 29 MPM patients. Two samples had PIK3CA mutations (R88Q and E545G) and one sample showed loss of PTEN expression. PI3K pathway inhibition by FDG-PET responses was observed in 8 of 24 MPM patients with available scans. Anti-tumor activity was observed in both stages. Two patients achieved a partial response (PR) in Stage 1, one patient at 50 mg and one patient with the PIK3CA mutation R88Q at 8 mg GDC-0980. Two PRs were observed at the RP2D of 30 mg in Stage 2. Eleven (41%) MPM patients at the RP2D remained on study for >6 months, and 2 (7%) patients remained on study >12 months.
GDC-0980 was generally well tolerated in MPM patients at the RP2D. Anti-tumor activity, evidenced by tumor regression and prolonged disease control, has been observed. PIK3CA mutations and PTEN loss were uncommon.
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P3.13 - Poster Session 3 - SCLC (ID 202)
- Event: WCLC 2013
- Type: Poster Session
- Track: Medical Oncology
- Presentations: 1
- Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level
P3.13-007 - Pilot trial of an adjuvant pentavalent vaccine for patients with small cell lung cancer (SCLC) (ID 2830)
09:30 - 16:30 | Author(s): L. Delasos
Despite initial responses to chemotherapy, SCLC typically progresses within a few months. Targeting residual disease has the potential to improve outcomes. A number of tumor specific glycolipid antigens have been identified and are potential targets for immune therapies. In a series of phase I clinical trials, vaccination with each of these antigens individually was safe and induced antibody responses in the majority of patients. Preclinical data indicate that combining these antigens will expand the immunogenicity across a broader array of SCLC tumor cells. We conducted this pilot trial to determine the safety and immunogenicity of a vaccine combining five of these antigens.
Patients with limited or extensive stage SCLC who have completed initial chemotherapy +/- thoracic or cranial irradiation with a maintained response are eligible. Vaccinations must start within 3-8 weeks of the last chemotherapy, and at least 1 week after radiation. Patients receive KLH-conjugates of GD2L, GD3L, Globo H, fucosyl GM1, and N-propionylated polysialic acid (30mcg each) plus OPT-821 adjuvant (150mcg) subcutaneously on weeks 1, 2, 3, 9, 20, and 32. One cycle of etoposide/platinum chemotherapy was administered in week 6. A significant immune response is defined as an antibody titer of ≥ 1:80 by ELISA against a given antigen or a ≥ 8 fold increase over baseline for patients with a detectable baseline titer. The vaccine would be deemed worthy of further study if >5 patients had an immune response to 3 or more antigens.
Ten patients were treated, including 9 with extensive stage, 4 women, 7 with prior brain radiation. The number of vaccinations administered was: 1 (1pt), 3 (2), 4 (3), 5 (2), and 6 (2). Toxicity was limited to mild skin reactions. One patient was taken off study after he developed aphasia the day after the first vaccination; MRI brain was unremarkable and symptoms resolved spontaneously. No patients met the predefined criteria for immune response. Six patients had increases in IgM titers to 1-2 antigens. The median time to progression was 4 months. The two patients with the strongest IgM responses to Globo H and fucosyl GM1, and also the only IgG responses to fucosyl GM1, had progression of disease 7 and 9 months after starting the vaccines, and both progressed initially in the brain only.
The polyvalent vaccine is safe, but fewer patients than expected had a significant immune response, Two patients with immune responses experienced a longer than expected time to progression. A second cohort of patients is now receiving the vaccinations over a shorter period of time and without the added cycle of chemotherapy. Five out of 10 of those patients have been enrolled, and preliminary data will be available on those patients for the meeting. Following completion of this pilot trial, a multicenter randomized trial is planned. Supported by MabVax Therapeutics’s NIH grant R41 CA128363 and a grant from FAMRI.