Phase 1 Study of SL-172154 (SIRPα-Fc-CD40L) in Subjects With Ovarian Cancer

NCT04406623CompletedPHASE1INTERVENTIONAL

Summary

Key Facts

Lead Sponsor

Shattuck Labs, Inc.

Enrollment

27

Start Date

2020-06-29

Completion Date

2023-02-02

Study Type

INTERVENTIONAL

Official Title

Phase 1 Dose Escalation Study of the Agonist Redirected Checkpoint, SL-172154 (SIRPα-Fc-CD40L) Administered Intravenously in Subjects With Ovarian Cancer

Interventions

SL-172154

Conditions

Ovarian CancerFallopian Tube CancerPrimary Peritoneal Carcinoma

Eligibility

Age Range

18 Years+

Sex

FEMALE

Inclusion Criteria:

Participants are eligible to be included in the study only if all the following criteria apply:

1. Subject has voluntarily agreed to participate by giving written informed consent in accordance with ICH/GCP guidelines and applicable local regulations.
2. Subject must have a histologically confirmed diagnosis of an unresectable, locally advanced or metastatic ovarian cancer, or primary peritoneal cancer or fallopian tube cancer.
3. Subjects must be refractory or intolerant to existing therapy(ies) known to provide clinical benefit for their condition. Subject must have received platinum-based therapies, and should not be eligible for further platinum therapy, or should be intolerant to such therapy. Subjects with HRD positive disease may participate if they have received prior polyadenosine diphosphate ribose polymerase (PARP) inhibitor therapy given alone or with bevacizumab.
4. Subjects should not be primary platinum refractory as defined by progressing during or within 1 month of upfront platinum therapy.
5. Has measurable disease by RECIST v1.1 using radiologic assessment.
6. Subject age is 18 years and older.
7. Has an Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1.
8. Has life expectancy of greater than 12 weeks.
9. Has adequate organ function.
10. Females of childbearing potential (FCBP) must have a negative serum or urine pregnancy test within 72 hours of D1 of IP.
11. Recovery from prior anti-cancer treatments including surgery, radiotherapy, chemotherapy or any other anti-cancer therapy to baseline or ≤ Grade 1.
12. Willing to consent to mandatory pre-treatment and on-treatment tumor biopsy(ies), unless there is excessive risk as determined by the investigator.

Exclusion Criteria:

Participants are excluded from the study if any of the following criteria apply:

1. Prior treatment with an anti-CD47 or anti-SIRPα targeting agent or a CD40 agonist.
2. Any anti-cancer therapy within the washout period prior to first dose (D1) of SL-172154.
3. Concurrent chemotherapy, immunotherapy, biologic or hormonal/hormonal suppression therapy for cancer treatment is prohibited. Concurrent use of hormones for non-cancer related conditions is acceptable.
4. Use of corticosteroids or other immunosuppressive medication, current or within 14 days of D1 of SL-172154 treatment.
5. Receipt of live attenuated vaccine within 28 days of D1 of IP.
6. Active or documented history of autoimmune disease. Exceptions include controlled Type I diabetes, vitiligo, alopecia areata or hypo/hyperthyroidism.
7. Hypersensitivity to the active drug substance or to any of the excipients for the agent to be administered or subjects with known hypersensitivity to Chinese hamster ovary cell products.
8. Active pneumonitis (i.e. drug-induced, idiopathic pulmonary fibrosis, radiation-induced, etc.).
9. Ongoing or active infection (e.g., no systemic antimicrobial therapy for treatment of infection within 5 days of D1 of IP).
10. Symptomatic peptic ulcer disease or gastritis, active diverticulitis, other serious gastrointestinal disease associated with diarrhea within 6 months of D1 of IP.
11. Clinically significant or uncontrolled cardiac/thromboembolic disease.
12. Untreated central nervous system or leptomeningeal metastases.
13. Women who are breast feeding.
14. Psychiatric illness/social circumstances that would limit compliance with study requirements and substantially increase the risk of AEs or compromised ability to provide written informed consent.
15. Another malignancy that requires active therapy and that in the opinion of the investigator and Sponsor would interfere with monitoring of radiologic assessments of response to IP.
16. Has undergone allogeneic stem cell transplantation or organ transplantation.
17. Known history or positive test for human immunodeficiency virus, or positive test for hepatitis B.

Outcome Measures

Primary Outcomes

Safety Profile of SL-172154

Number of participants with treatment emergent adverse events

Time frame: From Day 1 to 90 days after Last Dose of SL-172154

Maximum Tolerated Dose (MTD) of SL-172154

Number of participants with dose limiting toxicities (DLTs)

Time frame: From Day 1 to 90 days after Last Dose of SL-172154

Secondary Outcomes

Recommended Phase 2 Dose (RP2D) for SL-172154

Based on review of all data, including safety, tolerability, PK, antitumor activity, and PD effects

Time frame: Approximately 24 months

Assess Preliminary Evidence of Anti-tumor Activity of SL-172154

Number of participants with an objective response per investigator assessment according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v 1.1). Objective response includes complete response (disappearance of all target lesions) and partial response (\>/= 30% decrease in the sum of the longest diameter of target lesions).

Time frame: Approximately 24 months

Immunogenicity to SL-172154

Number of participants with positive anti-drug antibody (ADA) titer, sustained ADA response (positive ADA in \>/= 2 samples without reverting to negative ADA or positive ADA in the last sample), or persistent ADA response (positive ADA in \>/= 2 samples where the first and last samples are \>/= 16 weeks apart, or positive ADA in the last sample, or only one sample but \< 16 weeks before a negative last sample).

Time frame: Approximately 24 months

Maximum Serum Concentration (Cmax) of SL-172154

The Cmax is the maximum observed serum concentration of SL-172154 following single and multiple doses

Time frame: Cycle 1 Day 1, Cycle 1 Day 15, and Cycle 2 Day 1 (each cycle = 28 days)

Minimum Serum Concentration (Cmin) of SL-172154

The Cmin is the minimum observed serum concentration of SL-172154 following at least one dose

Time frame: Cycle 1 Day 15 and Cycle 2 Day 1 (each cycle = 28 days)

Time at Which Maximum Concentration of SL-172154 is Observed (Tmax)

The Tmax is the time at which the maximum concentration of SL-172154 is observed following single and multiple doses

Time frame: Cycle 1 Day 1, Cycle 1 Day 15, and Cycle 2 Day 1 (each cycle = 28 days)

Area Under the Serum Concentration-time Curve (AUC)

The AUC is the area under the serum concentration time curve following single and multiple doses of SL-172154. AUC (0-last; from time 0 to the last quantifiable concentration) is reported for C1D1 and AUC (tau; over a dosing interval) is reported for C1D15 and C2D1.

Time frame: Cycle 1 Day 1, Cycle 1 Day 15, and Cycle 2 Day 1 (each cycle = 28 days)

Terminal Elimination Half-life (t1/2)

Terminal elimination half-life (t1/2) of SL-172154

Time frame: Cycle 1 Day 1, Cycle 1 Day 15, and Cycle 2 Day 1 (each cycle = 28 days)

Clearance (CL)

Clearance of SL-172154

Time frame: Cycle 1 Day 1, Cycle 1 Day 15, and Cycle 2 Day 1 (each cycle = 28 days)

Volume of Distribution

Volume of distribution of SL-172154

Time frame: Cycle 1 Day 1, Cycle 1 Day 15, and Cycle 2 Day 1 (each cycle = 28 days)

Locations

City of Hope, Duarte, United States

START Midwest, Grand Rapids, United States

University of North Carolina at Chapel Hill, Chapel Hill, United States

Stephenson Cancer Center at Oklahoma University, Oklahoma City, United States

Sarah Cannon Research Institute, Nashville, United States

START Mountain Region, West Valley City, United States

Linked Papers

2025-01-11

First-in-human phase I trial of the bispecific CD47 inhibitor and CD40 agonist Fc-fusion protein, SL-172154 in patients with platinum-resistant ovarian cancer

Background SL-172154 is a hexameric fusion protein adjoining the extracellular domain of SIRPα to the extracellular domain of CD40L via an inert IgG4-derived Fc domain. In preclinical studies, a murine equivalent SIRPα-Fc-CD40L fusion protein provided superior antitumor immunity in comparison to CD47- and CD40-targeted antibodies. A first-in-human phase I trial of SL-172154 was conducted in patients with platinum-resistant ovarian cancer. Methods SL-172154 was administered intravenously at 0.1, 0.3, 1.0, 3.0, and 10.0 mg/kg. Dose escalation followed a modified toxicity probability interval-2 design. Objectives included evaluation of safety, dose-limiting toxicity, recommended phase II dose, pharmacokinetic (PK) and pharmacodynamic (PD) parameters, and antitumor activity. Results 27 patients (median age 66 years (range, 33–85); median of 4 prior systemic therapies (range, 2–9)) with ovarian (70%), fallopian tube (15%), or primary peritoneal (15%) cancer received SL-172154. Treatment-emergent adverse events (TEAEs) were reported for 27 patients (100%), with 24 (88.9%) having a drug-related TEAE and infusion-related reactions being the most common. 12 patients (44.4%) had grade 3/4 TEAEs, and half of these patients (22.2%) had a drug-related grade 3/4 TEAE. There were no fatal adverse events, and no TEAEs led to drug discontinuation. SL-172154 Cmax and area under the curve increased with dose with greater than proportional exposure noted at 3.0 and 10.0 mg/kg. CD47 and CD40 target engagement on CD4+ T cells and B cells, respectively, approached 100% by 3.0 mg/kg. Dose-dependent responses in multiple cytokines (eg, interleukin 12 (IL-12), IP-10) approached a plateau at ≥3.0 mg/kg. Paired tumor biopsies demonstrated a shift in macrophages from an M2- to an M1-dominant phenotype and increased infiltration of CD8 T cells. PK/PD modeling showed near maximal margination of B cells and a dose-dependent production of IL-12 nearing a plateau at &gt;3.0 mg/kg. The best response was stable disease in 6/27 (22%) patients. Conclusions SL-172154 was tolerable as monotherapy and induced, dose-dependent, and cyclical immune cell activation, increases in multiple serum cytokines, and trafficking of CD40-positive B cells and monocytes following each infusion. The safety, PK, and PD activity support 3.0 mg/kg as a safe and pharmacologically active dose. Trial registration number NCT04406623.