Deciphera Pharmaceuticals, Inc. (NASDAQ: DCPH) announced the presentation today of updated data from its ongoing Phase 1 clinical trial of DCC-2618, the company’s broad-spectrum KIT and PDGFRα inhibitor, in patients with gastrointestinal stromal tumors (GIST) at the American Society of Clinical Oncology (ASCO) Annual Meeting 2018, in Chicago, Illinois and provided additional clinical and regulatory updates on DCC-2618.
Suzanne George, M.D. Assistant Professor of Medicine, Harvard Medical School and Clinical Director, Center for Sarcoma and Bone Oncology, Dana-Farber Cancer Institute presented the poster titled “Mutational Profile of Drug Resistant GIST Patients Enrolled in the Phase 1 Study of DCC-2618”. In addition to describing the mutational profile of KIT in GIST patients, the poster includes details of locally-read Objective Response Rates (ORR) and Disease Control Rates (DCR) as assessed by Response Evaluation Criteria in Solid Tumors (RECIST) in second, third, and fourth and fourth line plus GIST patients that received DCC-2618 at doses of ≥100mg daily for at least one 28-day cycle prior to February 2, 2018:
| Line of Therapy | GIST Patients (n) | DCR at 3 Months | ORR | |||
| 2nd Line1 | 25 | 79% | 24% | |||
| 3rd Line1 | 29 | 82% | 24% | |||
| ≥4th Line | 91 | 64% | 9% | |||
| Total | 145 | 70% | 15% |
1 46 of 54 second and third line patients received 150mg once daily dose.
The combined 24% ORR and 80% 3-month DCR in second and third line patients receiving DCC-2618 at doses of ≥100mg per day exceeds previously published results of registrational trials for the currently approved therapies for second line (sunitinib) and third line (regorafenib), which have reported ORRs of 7.0% and 4.5%, respectively, and levels of disease control of 60% and 53%, respectively.
“The preliminary data presented today on DCC-2618’s activity in second and third line GIST patients is very encouraging and supports the planned initiation later this year of our Phase 3 trial, INTRIGUE, in second line GIST patients,” said Michael D. Taylor, Ph.D., President and Chief Executive Officer of Deciphera. “The mutational profiling data across second, third and fourth line GIST patients observed in the Phase 1 study also demonstrates the need for the broadest spectrum of KIT inhibition in all GIST patients who previously received imatinib.”
“We are very pleased with the results presented today demonstrating DCC-2618’s potential to provide improved clinical benefit for not only heavily pre-treated patients, but also for second and third line GIST patients,” said Oliver Rosen, M.D. Chief Medical Officer of Deciphera. “Combined with the tolerability data presented at AACR in April 2018, these results demonstrate the potential of DCC-2618 as an effective and well tolerated therapy for a wide range of GIST patients.”
Highlights from the poster presentation include:
- Initial Objective Response Rates and Disease Control Rates with DCC-2618 at Doses of ≥100mg Daily in Second and Third Line GIST Patients Exceed Previously Published Results of Registrational Trials for Currently Approved Therapies, as well as the Results Observed in Heavily Pre-Treated GIST Patients Receiving DCC-2618:
- 24% ORR with DCC-2618 observed to date in second and third line GIST patients is higher than that reported for sunitinib in second line patients (7.0%) or regorafenib in third line patients (4.5%).
- These interim results show improved ORR and 3-month DCR in second line GIST patients treated with DCC-2618 compared to fourth and fourth line plus GIST patients treated with DCC-2618.
- Mutational Profiling Data Across Second, Third and Fourth Line GIST Patients Demonstrates the Breadth of KIT Mutations in GIST and the Ability of DCC-2618 to Reduce KIT Mutant Allele Frequency (MAF):
- Resistance mutations in KIT in exons 13, 14, 17 and 18, or a combination thereof, occurs in second, third and, fourth and fourth line plus patients.
- The KIT mutational profile in both tumors and plasma at baseline in GIST patient supports the need for a broad-spectrum KIT inhibitor in all post-imatinib lines of therapy.
- 57 of 73 patients (78%) receiving DCC-2618 at doses of ≥100 mg daily demonstrated reductions in KIT MAF of more than 50%.
In addition, the company is providing the following clinical and regulatory updates on DCC-2618:
- Planned Initiation of a Phase 3 Trial in Second Line GIST Patients in 2018
- Preliminary efficacy results in second line patients together with recently presented tolerability data at the recommended phase 2 dose (RP2D) of 150mg QD support the planned, randomized Phase 3 trial, INTRIGUE, in second line GIST.
- Following discussions with regulatory authorities in the United States and in Europe, the company has designed INTRIGUE as a randomized, multicenter, open-label, Phase 3 trial in second line GIST. This registration study is expected to enroll approximately 350 patients who will be randomized 1:1 to either DCC-2618 or sunitinib, the current standard of care in second line; with median progression free survival as the primary endpoint.
- Interim Results with DCC-2618 at Doses of ≥100mg Daily Demonstrate Robust Clinical Activity in Heavily Pretreated GIST Patients, Including Patients Previously Treated with the Investigational Agent avapritinib (BLU-285):
- 10 patients with KIT-driven GIST who previously received avapritinib were enrolled and treated with DCC-2618 as of January 31, 2018.
- 6 out of 10 (60%) of these patients achieved stable disease as best response by RECIST during treatment with DCC-2618. In addition, one patient achieved stable disease following intra-patient dose escalation to 150mg BID.
- 5 out of 10 (50%) of these patients were on study as of April 18, 2018.
- 3 out of 10 (30%) of these patients received DCC-2618 for more than six months. Two of these patients achieved continued stable disease and remain on study as of April 18, 2018. The third patient with progressive disease was dose escalated and was reported as off study as of April 18, 2018.
A copy of the poster presentation will be available on the Science section of the Deciphera website under “Presentations and Publications” at http://www.deciphera.com.
