First-in-Human Dose Escalation Study of XMT-1536 in Cancers Likely to Express NaPi2b

A Phase 1b/2, First-in-Human, Dose Escalation and Expansion Study of XMT-1536 In Patients With Solid Tumors Likely to Express NaPi2b

First-in-human, Phase 1b/2 safety study of the antibody-drug conjugate (ADC) XMT-1536 (upifitamab rilsodotin) administered as an intravenous infusion once every four weeks. Patients with tumor types likely to express NaPi2b were enrolled in dose escalation. Patients with platinum-resistant ovarian cancer and non-small cell lung cancer (adenocarcinoma subtype) were enrolled in the expansion segment of this study. In addition to safety assessments, the pharmacokinetics of the drug were assessed along with ADC activity.

Study Overview

• Status: Completed
• Conditions: Platinum Resistant Ovarian Cancer; Non Small Cell Lung Cancer Metastatic
• Intervention / Treatment: Drug: upifitamab rilsodotin

Detailed Description

This is a multi-center study of XMT-1536 (upifitamab rilsodotin) in patients with tumors likely to express NaPi2b, focusing on patients with platinum-resistant ovarian cancer and non-small cell lung cancer, adenocarcinoma subtype. XMT-1536 (upifitamab rilsodotin) was administered as an intravenous infusion once every four weeks. The DES segment studied small groups of patients who received increased doses. A Safety Review Committee was established to review the data from each dose level before moving to the next higher dose. The dose escalation cohort has ended and is no longer enrolling patients. All adverse events were graded according to the National Cancer Institute (NCI) Common Terminology Criteria version (CTCAE v5.0). Throughout the study, pharmacokinetics were measured using proprietary assays developed by Mersana. Anti-cancer activity were measured via RECIST.

• Study Type: Interventional
• Enrollment (Actual): 62
• Phase: Phase 1

Contacts and Locations

Study Locations

• United States
  • Oklahoma
    • Oklahoma City, Oklahoma, United States, 73104
      • University of Oklahoma

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

General Inclusion Criteria (for Dose Escalation, Expansion, and UPLIFT):

• ECOG performance status 0 or 1
• Measurable disease as per RECIST, version 1.1
• Resolution of all acute toxic effects of prior therapy or surgical procedures to ≤Grade 1 (except alopecia, stable immune-related toxicity such as hypothyroidism on hormone replacement, adrenal insufficiency on ≤10 mg daily prednisone [or equivalent], chronic Grade 2 peripheral sensory neuropathy after prior taxane therapy).
• Cardiac left ventricular ejection fraction (LVEF) ≥50% or ≥ the institution's lower limit of normal by either Echo or MUGA scan

• Adequate organ function as defined by the following criteria:

  1. Absolute neutrophil count (ANC) ≥1500 cells/mm3
  2. Platelet count ≥100,000/mm3
  3. Hemoglobin ≥9 g/dL
  4. In patients not on anticoagulation therapy: INR, activated partial thromboplastin time (aPTT), and prothrombin time (PT) all within 1.2 times the institution's upper limit of normal (ULN). Patients on anticoagulation therapy are allowed if their relevant laboratory values are within the therapeutic window.
  5. Estimated glomerular filtration rate (GFR) ≥45 mL/min
  6. Total bilirubin ≤ULN
  7. g. Patients with asymptomatic elevations in unconjugated bilirubin due to Gilbert syndrome or stable chronic hemolytic anemia (e.g., hereditary spherocytosis, sickle cell disease, thalassemia intermedia) may be eligible after discussion with the Sponsor Medical Monitor.
• Aspartate aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT) ≤1.5 times the institutional ULN.
• Albumin ≥3.0 g/dL
• Able to provide informed consent.

General Exclusion Criteria (for Dose Escalation, Expansion, and UPLIFT) :

• Major surgery within 28 days of starting study treatment, systemic anti-cancer therapy within the lesser of 28 days or 5 half-lives of the prior therapy before starting study treatment, or recent radiation therapy with unresolved toxicity or within a time window of potential toxicity.
• Patients with untreated CNS metastases (including new and progressive brain metastases), history of leptomeningeal metastasis or carcinomatous meningitis.
• Current known active infection with HIV, hepatitis B virus, or hepatitis C virus.
• Prior history of liver disease such as liver cirrhosis, hepatic fibrosis
• Current severe, uncontrolled systemic disease (e.g., clinically significant cardiovascular, pulmonary, or metabolic disease) or intercurrent illness that could interfere with per-protocol evaluations.
• Current use of either constant or intermittent supplementary oxygen therapy.
• History of suspected pneumonitis or interstitial lung disease.
• Pregnant or nursing women.
• History of other malignancy within the last 2 years, except for appropriately treated carcinoma in situ of the cervix, non-melanoma skin carcinoma, or other malignancy with a similar expected curative outcome.
• Active corneal disease, or history of corneal disease within 12 months prior to enrollment
• Use of strong CYP450 3A inhibitors or inducers that cannot be discontinued while receiving study treatment
• Oxygen saturation on room air <93%

Ovarian Cancer Inclusion Criteria for UPLIFT:

• Histological diagnosis of high grade serous ovarian cancer, which includes fallopian tube, or primary peritoneal cancer, that is metastatic or recurrent.

• Platinum-resistant disease

  1. Patients who have only had 1 line of platinum-based therapy must have received at least 4 cycles of platinum, must have had a response [complete response/remission (CR) or partial response/remission (PR)], and then progressed between 3 months and ≤ 6 months after the date of the last dose of platinum
  2. Patients who have received 2 to 4 lines of prior therapy must have received at least 4 cycles of platinum and then progressed within 6 months after the date of the last dose of platinum

• One to 4 prior lines of systemic therapy for ovarian cancer

  a. Prior treatment with bevacizumab is required for patients with 1 to 2 prior lines of therapy

• Patients must be willing to provide an archival tumor tissue block or slides or if not available, undergo procedure to obtain a new tumor biopsy using a low-risk, medically routine procedure

Ovarian Cancer Exclusion Criteria for UPLIFT:

• Low-grade, clear cell, endometrioid, mucinous, carcinosarcoma, germ-cell, mixed histology, or stromal tumors
• Prior treatment with mirvetuximab soravtansine or another ADC containing an antitubulin payload
• Primary platinum-resistant disease, defined by a lack of response or by progression within 3 months after completing front-line, platinum-containing therapy.
• Participation in DES or EXP segments of this study

Ovarian Cancer Inclusion Criteria for QTc sub-study:

Note: patients must meet all UPLIFT cohort inclusion criteria in order to participate in the QTc sub-study

• Study patient has agreed to remain in the clinic for the additional QTc related study activities on the Day 1 of Cycle 1 and Cycle 3.

Ovarian Cancer Exclusion Criteria for QTc sub-study:

• Use of strong CYP450 3A inducers.
• Uncontrolled cardiac arrhythmias, for example, atrial fibrillation with a ventricular response at rest > 100 beats per minute. left bundle branch block (LBBB)
• Known abnormality of any cardiac valve (either stenosis or regurgitation) that is greater than moderate in severity.
• Subjects not in sinus rhythm at screening with HR >45- <100
• Any ECG abnormality that can interfere with the measurement of the QT interval

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Dose Escalation; XMT-1536 (upifitamab rilsodotin) treatment is administered in groups of patients who will receive doses that increase over time. This cohort is closed to enrollment.

Drug: upifitamab rilsodotin; XMT-1536 will be administered once every 28 days until disease progression, unacceptable toxicity, or either the patient or study physician determines it is in the best interest of the patient to discontinue participation in the study. For sites participating in the sub-study, patients with platinum -resistant ovarian cancer will have the option to enroll in this sub-study to evaluate potential changes in the QTc interval following administration of XMT-1536; Other Names: XMT-1536; UpRi

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
DES: Maximum tolerated dose or recommended Phase 2 dose	Evaluate adverse events and concomitant medication use after XMT-1536 (upifitamab rilsodotin) doses	Up to 36 weeks, from the date of first dose until unacceptable side effects or a dose-limiting toxicity is met
DES and EXP: Safety and Tolerability	Evaluate incidence and severity of adverse events	First dose up until 30 days after study termination

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
DES: Anti-neoplastic effects of XMT-1536 (upifitamab rilsodotin)	Monitor tumor size	Every 6 weeks for up to 36 weeks

Collaborators and Investigators

• Sponsor: Mersana Therapeutics
• Investigators: Study Director: Robert Burger, MD, Mersana Therapeutics

Study record dates

Study Major Dates

• Study Start (Actual): December 12, 2017
• Primary Completion (Actual): July 9, 2021
• Study Completion (Actual): July 9, 2021

Study Registration Dates

• First Submitted: July 18, 2024
• First Submitted That Met QC Criteria: July 18, 2024
• First Posted (Actual): July 24, 2024

Study Record Updates

• Last Update Posted (Actual): July 24, 2024
• Last Update Submitted That Met QC Criteria: July 18, 2024
• Last Verified: September 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: MER-XMT-1536-1 DES

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No