A Dose Escalation, Dose Expansion Study to Evaluate the Safety, Tolerability, and Antitumor Activity of MEDI-575, in Subjects With Advanced Tumors.

An adverse event (AE) is any unfavorable and unintended sign, symptom, or disease temporally associated with the use of study drug, whether or not considered related to the study drug. Treatment-emergent AEs (TEAEs) are events present at baseline that worsened in intensity after administration of study drug or events absent at baseline that emerged after administration of study drug, for the period extending to 30 days after the last dose of study drug. Participants were counted only once for each event and by the highest event severity, regardless of how many events the participant experienced. The AEs were summarized using Medical Dictionary for Regulatory Activities (MedDRA) version 14.1.

A serious AE (SAE) is any AE that results in death, is immediately life threatening, require (or prolong) inpatient hospitalization, results in persistent or significant disability/incapacity, is a congenital anomaly or birth defect, or is an important medical event that may jeopardize the participant or may require medical intervention to prevent one of the outcomes listed above. Treatment-emergent SAEs that emerged after start of study drug were reported. Participants were counted only once for each event and by the highest event severity, regardless of how many events the participant experienced. The SAEs were summarized using MedDRA version 14.1.

Laboratory evaluations of blood and urine samples were performed, including hematology (complete blood count, differential, and platelet count); serum chemistry (SrChem) aspartate transaminase (AST), alanine transaminase, total bilirubin, creatinine, alkaline phosphatase, sodium, potassium, chloride, phosphorus, calcium, glucose, magnesium, albumin, and lactate dehydrogenase); and routine urinalysis. Number of participants with TEAEs related to laboratory evaluations were reported.

All 12-lead electrocardiograms (ECGs) performed during the study were obtained in triplicate (ie, 3 ECGs were obtained within a 5-minute time interval) and analyzed. ECG parameters included heart rate (high and low), QT interval, QTcB (corrected QT interval per Bazett's formula), and QTcF (corrected QT interval per Fridericia's formula). Number of participants with TEAEs related to ECG after the start of study drug were reported.

Vital signs (temperature, blood pressure, pulse rate, and respiratory rate) were performed throughout the study. The TEAEs related to vital signs in participants were reported.

For the dose escalation phase, a minimum of 21 evaluable participants (3 participants each in Dose Cohorts 1 through 7) were required for this study if Dose Limiting Toxicities (DLTs) do not occur. If a DLT does occur among the first 3 participants in a cohort, 3 additional participants were to be added to the cohort; 3 more participants were to be added to a cohort to determine the MTD if only 3 participants have been previously treated at that dose. The MTD is the maximum dose at which no more than 1 out of 6 participants experienced a DLT. A DLT is defined as any grade 3 or higher hematologic toxicity or any grade 3 or higher non-hematologic toxicity except grade 3 fever (in the absence of neutropenia) or grade 3 rigors/chills.

The concentration of MEDI-575 quantitatively determined in serum samples using a validated electrochemiluminescence (ECL) PK assay. The Cmax after the first dose was obtained directly from the measured concentration-time curves. The concentration-time curve is the result of blood sampling at specified time points and its measured concentration of MEDI-575.

The time to reach maximum serum concentration after the first dose of MEDI-575 was obtained directly from the measured concentration-time curves. The concentration-time curve is the result of blood sampling at specified time points and its measured concentration of MEDI-575.

The Cmax/dose after the first dose of MEDI-575 was obtained directly from the measured concentration-time curves. The concentration-time curve is the result of blood sampling at specified time points and its measured concentration of MEDI-575.

The Ctrough ie, measured concentration at the end of a dosing interval (taken directly before next dose administration) of MEDI-575 was obtained directly from the measured concentration-time curves. The concentration-time curve is the result of blood sampling at specified time points and its measured concentration of MEDI-575.

The AUCτ was obtained directly from the measured concentration-time curves. The concentration-time curve is the result of blood sampling at specified time points and its measured concentration of MEDI-575.

The AUCτ/dose was obtained directly from the measured concentration-time curves. The concentration-time curve is the result of blood sampling at specified time points and its measured concentration of MEDI-575.

Blood samples for immunogenicity assessments were collected from participants prior to the initiation of infusion of each treatment cycle of MEDI-575. Anti-MEDI-575 antibodies were analyzed using the electro-chemiluminescence (ECL) based method. Only the number of participants positive for anti-MEDI-575 antibodies at any visit are presented.

Objective response rate is defined as the proportion of participants with confirmed complete response (CR) or confirmed partial response (PR) according to Response Evaluation Criteria in Solid Tumors (RECIST) guidelines. Confirmed responses are those that persist on repeat imaging study at least 4 weeks after the initial documentation of response. The CR is defined as disappearance of all target and non-target lesions, and normalization of tumor marker level. The PR is defined as at least a 30% decrease in the sum of the longest diameter (LD) of target lesions, taking as reference the baseline sum LD.

Time to response was measured from the start of treatment with MEDI-575 to the first documentation of objective response (confirmed CR or PR). The time to response is assessed only for the participants who have achieved the objective response.

Duration of response is defined as the duration from the first documentation of objective response to the first documented disease progression. Disease progression is defined according to RECIST guidelines (ie, at least a 20% increase in the sum of the LD of target lesions, taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions). The duration of response was censored on the date of last tumor assessment documenting absence of disease progression for participants who have no documented progression prior to data cutoff, dropout, or the initiation of alternate anticancer treatment. Duration of response was calculated for the subgroup of participants with an objective response.

Time to progression (TTP) is defined as time from the start of treatment with MEDI-575 until the documentation of disease progression. Disease progression is defined according to RECIST guidelines (ie, at least a 20% increase in the sum of the LD of target lesions, taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions). The TTP was censored on the date of last tumor assessment documenting absence of tumor progression for participants who have no documented progression prior to data cutoff, dropout, or the initiation of alternate anticancer treatment. TTP was censored on the first date of treatment for the participants with no tumor assessments after the start of MEDI-575 treatment.

Progression-free survival (PFS) is defined as time from the start of treatment with MEDI-575 until the documentation of disease progression or death due to any cause, whichever occurred first. Disease progression is defined according to RECIST guidelines (ie, at least a 20% increase in the sum of the LD of target lesions, taking as reference the smallest sum LD recorded since the treatment started or the appearance of one or more new lesions). PFS was censored on the date of last tumor assessment documenting absence of tumor progression for participants who have no documented progression and were still alive prior to data cutoff, dropout, or the initiation of alternate anticancer treatment. PFS was censored on the first date of treatment for the participants with no tumor assessments after the start of MEDI-575 treatment.

Overall survival (OS) is defined as the time from the start of treatment with MEDI-575 until death. For the participants who were alive at the end of study or lost to follow-up, OS was censored on the last date when participants were known to be alive.