Mesothelin-Targeted Immunotoxin LMB-100 Alone or in Combination With Nab-Paclitaxel in People With Previously Treated Metastatic and/or Locally Advanced Pancreatic Ductal Adenocarcinoma and Mesothelin Expressing Solid Tumors

Background:

- Pancreatic cancer is the fourth most common cause of cancer death in the United States,
claiming more than 40,000 lives each year.

- Incidence nearly equals mortality with just 6% of participants living five years beyond
their diagnosis. Most patients are diagnosed at an advanced stage, but even patients
with early stage disease have a long term survival of less than 20%.

- Mesothelin is specifically a marker of adenocarcinoma in the human disease and is not
expressed in preceding pre-malignant stages of tumor development

- Expression of mesothelin in pancreatic ductal adenocarcinoma (PDA) has been examined in
several published studies and ranges from 86 to 100%

- Recombinant immunotoxins (RITs) are antibody-based therapeutics that carry a toxin
payload. RITs that target mesothelin contain a genetically engineered variant of
Pseudomonas exotoxin A (PE) in which the native cell-binding domain of PE is replaced by
the mesothelin-binding antibody fragment. SS1P was the first mesothelin-targeted RIT
tested in patients.

- LMB-100 contains a newly engineered PE fragment that has improved activity against most
pancreatic cancer cell lines in vitro, and is also much less toxic than SS1P in
preclinical models. The new PE contains modifications specifically designed to reduce
immunogenicity of the molecule.

- Pre-administration of paclitaxel with SS1P was demonstrated to increase the amount of
immunotoxin internalized by tumor cells and to reduce levels of shed mesothelin in the
intra-tumoral environment so that more immunotoxin could bind tumor cells. The effect is
even more pronounced with NAB-paclitaxel in a pancreatic cancer model.

- Initial clinical testing of LMB-100 was performed by Roche in a multi-center
international first in human trial (NCT02317419). The agent was well tolerated and
appeared to have decreased immunogenicity compared to SS1P based on preliminary results.

- In initial and subsequent clinical testing, LMB-100 was found to have half-life of
approximately 60 mins. This is shorter then that measured for previous RITs used in the
clinical setting.

Primary Objectives:

- Arm A1 (Phase I, short infusion):

--To determine the maximum tolerated dose of short infusion LMB-100 in combination
nab-paclitaxel chemotherapy in participants with advanced pancreatic cancer

- Arm B1(Continous infusion single agent lead-in):

--To determine the maximum tolerated dose of LMB-100 given in a continuous infusion
format over 24 - 96 hours to patients with advanced solid tumors that express mesothelin

- Arm B2 (Continous infusion combination therapy)

--Establish a tolerated dose of LMB-100 given by continuous infusion in combination with
nab-paclitaxel chemotherapy in participants with advanced pancreatic cancer

- Arm A2(Phase II, short infusion):

- To determine the objective response rate (PR+CR) according to RECIST 1.1 criteria
of short infusion LMB-100 in combination with nab-paclitaxel chemotherapy in
participants with advanced pancreatic cancer

Eligibility:

- Age greater than or equal to18 years

- Histologically confirmed recurrent, metastatic and/or advanced pancreatic ductal
adenocarcinoma (Except for Arm B1 [B Single Agent Lead-in])

- For Arm B1 (Single Agent Lead-in), ONLY: Histologically confirmed solid tumor malignancy
for which no curative therapy exists with at least 25% of tumor cells expressing
mesothelin as determined by NCI Laboratory of Pathology. Determination can be made

using archival tumor tissue or fresh biopsy.

- Treatment must include at least one prior chemotherapy regimen

- No nab-paclitaxel or paclitaxel treatment in the last four months (Except for Arm B1
[Single Agent Lead-in])

- Adequate organ function

- Participants with HIV, active HBV or HCV infections are eligible only for the Arm B1
(Single Agent Lead-in)

Design:

- This study is a Phase I/II open label study to assess the safety and efficacy of LMB-100
in combination with the standard of care agent nab-paclitaxel in participants metastatic
and/or locally advanced pancreatic ductal adenocarcinoma

- Subjects will be treated for up to 2 cycles

- In Arm A1 (Phase I, short infusion) of the study, up to 3 dose levels will be evaluated.
LMB-100 will be administered on days 1, 3 and 5 of a 21 day cycle and nab-paclitaxel
will be administered on days 1 and 8

- Arm A2 (Phase II, short infusion), up to 20 evaluable participants (including those
treated at the short infusion MTD in the phase I study) will be enrolled.

- Arm B1 (Continous infusion single Agent Lead-in), escalating doses of single agent
LMB-100 will be administered. The study drug will be given as a continuous infusion for
the 1, 2, 3, or 4 days of a 21-day cycle.

- Arm B2 (Continous infusion, combination therapy) will be initiated after completion of
both Arm A1 and Arm B1 Single Agent Lead-in. It will test a single dose level of LMB-100
based on data from the Lead-in given in combination with nab-paclitaxel. LMB-100 will be
given as a continuous infusion for the 1, 2, 3 or 4 days of a 21-day cycle.
Nabpaclitaxel will be given on Day 1 and Day 8.

- The Arm A2 (Phase II, short infusion) portion of the study will be conducted in a Simon
Minimax two stage phase II design. The first stage will enroll 13 evaluable
participants, including the six participants treated at the short infusion MTD from
phase I. If 1 or more has a response, then accrual would continue until a total of 20
evaluable participants have been enrolled.

- INCLUSION CRITERIA:

- For participants who will be receiving nab-paclitaxel (all arms except Phase I Arm B
Single Agent Lead-in)

- Histologically confirmed recurrent, advanced or metastatic pancreatic ductal
adenocarcinoma as determined by NCI Laboratory of Pathology.

- No treatment with paclitaxel or nab-paclitaxel within 4 months prior to
initiation of study therapy

- ECOG performance p status (PS) 0-1.

- Adequate hematological function: neutrophil count of greater than or equal to 1.0
x 10(9) cells/L, platelet count of greater than or equal to 95,000/microliters,
hemoglobin greater than or equal to 9 g/dL

- Measurable disease as per the RECIST Criteria v 1.1

- For participants who will NOT receive nab-paclitaxel (Arm B1 Single Agent Lead-in
only)

- Histologically confirmed solid tumor malignancy for which no curative therapy
exists with at least 25% of tumor cells expressing mesothelin as determined by
NCI Laboratory of Pathology. Determination can be made using archival tumor
tissue or fresh biopsy. Subjects with epithelioid mesothelioma and pancreatic
adenocarcinoma are automatically eligible and are not required to have this test.

- ECOG performance status (PS) 0-2.

- Adequate hematological function: neutrophil count of greater than or equal to 1.0
x 10(9) cells/L, platelet count of greater than or equal to 85,000/microliters,
hemoglobin greater than or equal to 8.5 g/dL

- Measurable and/or evaluable disease as per the RECIST Criteria v 1.1

- For all arms of the protocol

- Participants must have received at least one prior chemotherapy regimen for their
disease.

- Age greater than or equal to 18 years. Because no dosing or adverse event data
are currently available on the use of LMB-100 in combination with nab-paclitaxel
in persons <18 years of age, children are excluded from this study.

- Participants must be more than 14 days removed from most recent minor surgical
procedure (such as biliary stenting), 28 days from most recent major surgical
procedure, 14 days removed from most recent radiation therapy, chemotherapy or
experimental drug treatment with published half-life known to be 72 hours or less
and 28 days removed from last experimental drug treatment with unpublished or
half-life greater than 72 hours.

- All acute toxic effects of any prior radiotherapy, chemotherapy, experimental
drug treatment or surgical procedure must have resolved to Grade less than or
equal to 1, except alopecia (any grade) and peripheral neuropathy.

- Serum albumin greater than or equal to 2.5 mg/dL without intravenous
supplementation

- Adequate liver function: Bilirubin, AST and ALT < 2.5 x ULN. AST and ALT up to 5x
ULN is permitted for patients with liver metastases.

- Adequate renal function: creatinine clearance greater than or equal to 50 mL/min.

- Must have left ventricular ejection fraction > 50%

- Must have an ambulatory oxygen saturation of > 88% on room air

- The effects of LMB-100 alone or in combination with nab-paclitaxel on the
developing human fetus are unknown. For this reason women of child-bearing
potential and men must agree to use adequate contraception (hormonal or barrier
method of birth control; abstinence) prior to study entry until 3 months the last
dose of study therapy. Should a woman become pregnant or suspect she is pregnant
while she or her partner is participating in this study, she should inform her
treating physician immediately.

- Ability of participant to understand and the willingness to sign a written
informed consent document.

EXCLUSION CRITERIA:

- Exclusion criteria for all study arms

- Known or clinically suspected CNS 2.1.2.1 primary tumors or metastases including
leptomeningeal metastases. History or clinical evidence of CNS metastases unless
they have been previously treated, are asymptomatic, and have had no requirement
for steroids or enzyme-inducing anticonvulsants in the last 14 days.

- Evidence of significant, uncontrolled concomitant diseases which could affect
compliance with the protocol or interpretation of results, including significant
pulmonary disease other than that related to the primary cancer, uncontrolled
diabetes mellitus, and/or significant cardiovascular disease (such as New York
Heart Association Class III or IV cardiac disease, myocardial infarction within
the last 6 months, unstable arrhythmias, unstable angina, or clinically
significant pericardial effusion)

- Any known diagnoses, metabolic dysfunction, physical examination finding, or
clinical laboratory finding giving reasonable suspicion of a disease or condition
(other than pancreatic adenocarcinoma) that would contraindicate the use of an
investigational drug, interfere with tumor measurement or lead to an expected
life expectancy of less than 6 months as judged by the investigator

- Active or uncontrolled infections.

- Live attenuated vaccinations within 14 days prior to treatment

- Dementia or altered mental status that would prohibit informed consent

- Pregnant women are excluded from this study because the effects of LMB-100 on the
developing fetus are unknown and may have the potential to cause teratogenic or
abortifacient effects. Because there is an unknown but potential risk for adverse
events in nursing infants secondary to treatment of the mother with LMB-100,
breastfeeding should be discontinued if the mother is treated with LMB-100. These
potential risks may also apply to other agents used in this study.

- Known hypersensitivity to any of the components of LMB-100

- Baseline QTcF interval of > 470 ms, participants with baseline resting
bradycardia < 45 beats per minute, or baseline resting tachycardia> 100 beats per
minute.

- Exclusion criteria specific to patients who will be receiving nab-paclitaxel (all arms
except Arm B1 Single Agent Lead-in)

- Participants with contra-indication and/or history of severe hypersensitivity
reactions to nab-paclitaxel

- Participants with baseline peripheral neuropathy greater than grade 2

- HIV or active HBV or HCV infection due to risk of progression while receiving
immunosuppressive chemotherapy