(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2012/0022157 A1
`Scharschmidt
`(43) Pub. Date:
`Jan. 26, 2012
`
`US 20120022157A1
`
`(54) DOSING AND MONITORING PATIENTS ON
`NITROGEN-SCAVENGING DRUGS
`
`(75) Inventor:
`
`(73) Assignee:
`
`(21) Appl. No.:
`
`Bruce Scharschmidt, South San
`Francisco, CA (US)
`s
`UCYCLYD PHARMA, INC,
`Scottsdale, AZ (US)
`13/061509
`
`Publication Classification
`
`(51) Int. Cl.
`A6II 3L/26
`A6IP3/00
`GOIN 33/00
`A6IPI3/2
`
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`
`(52) U.S. Cl. ......................... 514/533; 514/532; 73/6141
`
`Aug. 27, 2009
`PCT/USO9/55256
`
`(22) PCT Filed:
`(86). PCT No.:
`S371 (c)(1),
`Jun. 15, 2011
`(2), (4) Date:
`Related U.S. Application Data
`(63) Continuation-in-part of application No. PCT/US09/
`30362, filed on Jan. 7, 2009, Continuation-in-part of
`a lication No. 1273 50 111 filed on Jan. 7, 2009
`pp
`s u u us
`•
`s
`(60) Provisional application No. 61/093,234, filed on Aug.
`29, 2008, provisional application No. 61/093,234,
`filed on Aug. 29, 2008.
`
`ABSTRACT
`(57)
`The invention provides a method for determining a dose and
`dosing schedule, and making dose adjustments of patients
`taking PBA prodrugs as nitrogen Scavengers to treat nitrogen
`retention states, including ammonia accumulation disorders
`as well as chronic renal failure, by measuring urinary excre
`tion of phenylacetylglutamine and/or total urinary nitrogen.
`The invention provides methods to select al appropriate dos
`age of a PBA prodrug based on the patient's dietary protein
`intake, or based on previous treatments administered to the
`patient. The methods are applicable to selecting or modifying
`a dosing regimen for a subject receiving an orally adminis
`tered waste nitrogen scavenging drug, and to monitoring
`patients receiving Such drugs.
`
`Page 1 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 1 of 17
`
`US 2012/0022157 A1
`
`
`
`
`
`?lapinsig ?aAIT
`
`
`
`
`
`
`
`
`Page 2 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 2 of 17
`
`US 2012/0022157 A1
`
`Sodium Phenlybutyrate
`t
`NH 4
`-Katoglu'arate
`NH+4 N. Glutamates - Glutamine
`Phenylacetate
`HCO
`AP
`Y
`CPS
`Phenylacetylglutamine
`.
`.
`.
`.
`Urine ExCretion
`A. A
`f :
`/
`i
`
`Carbamyl Phosphate
`
`OTC
`
`Citruline ---
`
`Y
`
`Orithine
`
`Urea
`
`Aspartate
`
`?
`
`ASS
`
`?
`
`Supplemented-Arginine
`Arginine
`Fumarate
`
`ASL
`
`Figure 1b
`
`Page 3 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 3 of 17
`
`US 2012/0022157 A1
`
`
`
`
`
`
`
`
`
`
`
`Page 4 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 4 of 17
`
`US 2012/0022157 A1
`
`TOENEVAT
`
`
`
`
`
`
`
`
`
`
`
`Page 5 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 5 of 17
`
`US 2012/0022157 A1
`
`Buphenyl(3g/m2)
`
`5000
`
`20
`15
`10
`Time (Hours)
`HPN-100(3g/m2)
`
`25
`
`30
`
`O
`
`5
`
`
`
`5000
`
`500
`
`Time (Hours)
`Figure 4
`
`Page 6 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 6 of 17
`
`US 2012/0022157 A1
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`*w.… ---- - - - - - - - - - -
`
`Page 7 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 7 of 17
`
`US 2012/0022157 A1
`
`UP1204-00: Blood Metabolite Concentrations
`Vs. Time in Healthy Adults
`Analyte=PBA
`
`* Shows BD dosing from days 8-15.
`Plasma PBA levels returned to near predose
`level between doses On each day during
`multiple dosing for healthy individuals. .
`PAA levels increase, but reach a steady
`state after 3 days of BID dosing
`
`s
`
`10D
`
`50
`
`
`
`
`
`10
`
`s
`5
`e
`s
`s 5
`used
`
`Analyte=PAGN
`
`200 250 3DO 350 400
`Time (Hours)
`
`Analytes FAA
`k
`
`OO
`
`50
`
`s
`
`S.
`
`.
`
`5 E 10
`
`al
`
`S 5
`r
`
`OO
`
`50
`
`S.
`
`s
`f
`E
`
`S 10
`
`S 5
`r
`
`200 250 300 350 400
`Time (Hours)
`
`Figure 6
`
`200 250 300 350 400
`Time (Hours)
`
`Page 8 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 8 of 17
`
`US 2012/0022157 A1
`
`UP1204-00: Blood Metabolite ConCentrations
`Vs. Time in Palients With Cirrhosis (Childs-Pugh C)
`Analyte=PBA
`
`* Shows BD dosing from days 8-15.
`Plasma PBA levels returned to near predose
`level between doses On each day during
`multiple dosing in cirrhotics. PAA levels
`increase and require 4 days to reach
`steady-state with BID dosing
`
`s
`
`
`
`100
`
`E 50
`s
`
`
`
`E. 10
`G
`5
`
`-
`
`200 250 300 350 400
`Time (Hours)
`
`Analyte=PAA
`
`Analyte=PAGN
`
`She
`
`As
`
`100
`
`s
`E 50
`an
`E
`e
`s
`10-
`s
`e 5
`
`is
`
`100
`
`S
`L
`-S 50
`S.
`E
`s
`3.
`
`10
`5
`
`t
`
`-
`
`200 250 300 350 400
`Time (Hours)
`
`Figure 7
`
`200 250 300 350 400
`Time (Hours)
`
`Page 9 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 9 of 17
`
`US 2012/0022157 A1
`
`PBA CInax and AUC and HPN Dose
`AUC0-24-200
`-C)- ClaxSS
`
`150
`
`100 S
`
`50
`
`O
`
`
`
`HPN Dose
`PBA AUC and HPN Dose
`--KX- PBA AUC0-24
`- A - CmaxSS
`-H HPN DOSB
`
`Page 10 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 10 of 17
`
`US 2012/0022157 A1
`
`2O
`
`5
`
`O
`
`5
`
`O
`
`PAA AUC and HPN Dose
`
`
`
`HPN-100 3500
`- 3000
`
`2500
`
`2000
`
`1500
`
`1000
`
`500
`
`O
`
`Figure 8b
`
`Page 11 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 11 of 17
`
`US 2012/0022157 A1
`
`U-PAGN and HPN Dose
`
`
`
`2D-
`18
`
`HPN-PBA 16000000
`U-PAGN-14000000
`12OOOOOO
`
`100OOOOO
`
`80OOOOO
`
`6000000
`
`4000000
`
`2OOOOOO
`
`O
`
`Page 12 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 12 of 17
`
`US 2012/0022157 A1
`
`TN-AUC
`BUPHENYLHPN-100
`- Mean
`- - - Median
`
`
`
`Cmax
`BUPHENYLHPN-100
`
`
`
`
`
`HPN-100
`BUPHENYLo
`38.4 / 19.6 26. --/- 10.3
`79.it/- 40.1 56.3 +/- 27.9
`Figure 9
`
`
`
`Page 13 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 13 of 17
`
`US 2012/0022157 A1
`
`40
`3 5
`
`3 5O
`
`2
`
`Cumulative Ammonia Concentration TN-AUC
`-- HPN
`SBUP
`
`Ns
`
`3.
`
`SS
`O-12-r
`
`Figure 10
`
`mid
`
`12-24Hr
`
`Page 14 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 14 of 17
`
`US 2012/0022157 A1
`
`
`
`Page 15 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 15 of 17
`
`US 2012/0022157 A1
`
`
`
`80 -
`
`g 60
`
`C)
`S.
`S 40
`S
`
`sc 20-
`
`Ammonia(TI-AUC) After 7 Days of Treatment
`with BUPHENY and HPN-100
`
`HPN-100
`Mean
`26.1 +/- 0.3
`
`BUPHENYL
`
`HPN-100
`
`Figure 12
`
`Page 16 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 16 of 17
`
`US 2012/0022157 A1
`
`
`
`)
`
`i
`
`HNonVNL
`
`Page 17 of 48
`
`LUPIN EX. 1014
`
`

`

`Patent Application Publication
`
`Jan. 26, 2012 Sheet 17 of 17
`
`US 2012/0022157 A1
`
`
`
`
`
`Page 18 of 48
`
`LUPIN EX. 1014
`
`

`

`US 2012/0022157 A1
`
`Jan. 26, 2012
`
`DOSING AND MONITORNG PATIENTS ON
`NITROGEN-SCAVENGING DRUGS
`
`CROSS-REFERENCE TO RELATED
`APPLICATIONS
`0001. This application is a continuation in part of U.S.
`Nonprovisional patent application Ser. No. 12/350,111, filed
`Jan. 7, 2009 which is pending, and a continuation in part of
`International Application No. PCT/US08/30362, filed Jan. 9,
`2009, each of which claims benefit of priority to U.S. Provi
`sional Application Ser. No. 61/093,234, filed Aug. 29, 2008,
`each of which is incorporated herein by reference in its
`entirety. This application is also related to the U.S. provi
`sional patent application entitled "Treating special popula
`tions having liver disease with nitrogen-Scavenging com
`pounds.” naming Sharron Gargosky as inventor, Ser. No.
`61/048.830, filed on Apr. 29, 2008.
`
`TECHNICAL FIELD
`0002 This invention relates to treatment of patients with
`nitrogen retention states, including urea cycle disorders
`(UCDs), cirrhosis complicated by hepatic encephalopathy
`(HE) and chronic renal failure (CRF), using administered
`compounds that assist in elimination of waste nitrogen from
`the body. The compounds can be orally administered small
`molecule drugs, and the invention provides methods for
`delivering Such compounds and selecting Suitable dosages for
`a patient as well as adjusting dosages and monitoring effec
`tiveness of a treatment. As depicted in FIG. 1a, inherited
`disorders (e.g., UCDs) and acquired disorders (e.g. cirrhosis,
`typically with portal systemic shunting, complicated by HE)
`involving the liver which impair the normally efficient clear
`ance of ammonia from the portal circulation and conversion
`to urea via the urea cycle, depicted in FIG. 1b, result in
`elevated levels in the blood of ammonia, a potent neurotoxin.
`CRF, while associated in some instances with mildly elevated
`levels of ammonia, (Deferrari, Kid Int. 1980; 20:505), results
`in retention of other nitrogenous waste products normally
`excreted in the urine, in particular urea, the blood levels of
`which are commonly used to assess renal function.
`0003 Restriction of dietary protein (i.e. intake of dietary
`nitrogen) is commonly used in the management of each of
`these nitrogen retention states, to avoid accumulation of
`ammonia or metabolic products containing ammonia, e.g.,
`urea. References herein to ammonia and ammonia Scaveng
`ing refer primarily to treating UCDs and HE and conditions
`that emulate UCDs, although the terms ammonia Scavenging
`and waste nitrogen Scavenging are used interchangeably.
`
`BACKGROUND ART
`0004 Drug dosing is usually based upon measurement of
`blood levels of the active drug species in conjunction with
`clinical assessment of treatment response. However, the
`present invention is based on evidence that for certain pro
`drugs of phenylacetic acid (PAA), measuring the blood level
`of the prodrug (e.g. PBA) or of PAA formed from it is unre
`liable in assessing drug effect: drug levels in the blood do not
`correlate with efficacy in this case. In addition, assessment of
`treatment effect by measuring levels of ammonia in the blood
`in UCD patients is also potentially unreliable. Individual
`ammonia level measurements vary several-fold over the
`course of a day for a given patient, and withdrawing multiple
`blood samples under carefully controlled conditions over an
`
`extended period of time is clinically impractical as a way to
`monitor a treated patient. The variability in blood ammonia
`levels reflects the fact that ammonia levels in UCD patients
`are affected by various factors including dietary protein and
`timing in relation to meals. Such that any individual value fails
`to provide a reliable measure of how much ammonia the drug
`is mobilizing for elimination; i.e. drug effect. The invention
`demonstrates that prodrugs of phenylbutyric acid (PBA)
`behave similarly to sodium PBA, in that measuring PBA
`levels is unreliable for assessing their effectiveness. This
`invention provides a novel method for dosing in patients with
`nitrogen retention states, in particular patients with liver dis
`ease and clinical manifestations of hepatic encephalopathy
`and patients with UCDs. It is particularly applicable to pro
`drugs that liberate or are metabolized to form phenylacetic
`acid, i.e., prodrugs of PAA, and those prodrugs that are
`metabolized to form PBA.
`0005 Hepatic encephalopathy (HE) refers to a reversible
`spectrum of neurologic signs and symptoms which frequently
`occur in patients with cirrhosis or certain other types of liver
`disease.
`0006 Urea cycle disorders (UCDs) comprise several
`inherited deficiencies of enzymes or transporters necessary
`for the synthesis of urea from ammonia. The urea cycle is
`depicted in FIG.1b, which also illustrates how certain ammo
`nia-Scavenging drugs act to assist in elimination of excessive
`ammonia. UCDs include inherited conditions associated with
`insufficient function of any one of several ammonia-process
`ing enzymes. Individuals born with no meaningful residual
`urea synthetic capacity typically present in the first few days
`of life (neonatal presentation). Individuals with residual func
`tion typically present later in childhood or even in adulthood,
`and symptoms may be precipitated by increased dietary pro
`tein or physiological stress (e.g. intercurrent illness.) Some
`enzymes whose deficient functioning causes UCDS include
`the following:
`0007 Carbamyl phosphate synthetase (CPS),
`0008 ornithine transcarbamylase (OTC),
`0009 argininosuccinate synthetase (ASS),
`0.010
`argininosuccinate lyase (ASL),
`0.011
`arginase (ARG; EC Number 3.5.3.1: autosomal
`recessive), (ARG) and
`0012 N-acetylglutamine synthetase (NAGS)
`0013 Mitochondrial transporter deficiency states which
`mimic many features of urea cycle enzyme deficiencies, and
`thus emulate UCDs and are treatable by the methods
`described herein for treating UCDs, include the following:
`0.014. Ornithine translocase deficiency (hyperorni
`thinemia, hyperammonemia, homocitrullinuria or HHH
`Syndrome)
`0.015
`Citrin (aspartate glutamate transporter) defi
`ciency
`0016. The common feature of UCDs and similar condi
`tions and hepatic encephalopathy that render them treatable
`by methods of the invention is an accumulation of excess
`waste nitrogen in the body, and hyperammonemia. CRF is
`similarly characterized by build-up of excessive waste nitro
`gen in the blood in the form urea, and the ammonia Scaveng
`ing drugs described herein are likewise effective to prevent
`accumulation of excess levels of urea. In normal individuals,
`the body's intrinsic capacity for waste nitrogen excretion is
`greater than the body's waste nitrogen production, so waste
`nitrogen does not accumulate and ammonia does not build up
`to harmful levels. For patients with nitrogen retention states
`
`Page 19 of 48
`
`LUPIN EX. 1014
`
`

`

`US 2012/0022157 A1
`
`Jan. 26, 2012
`
`such as UCD or HE, the body's intrinsic capacity for waste
`nitrogen excretion is less than the body's waste nitrogen
`production based on a normal diet that contains significant
`amounts of protein. As a result, waste nitrogen builds up in the
`body of a patient having a nitrogen retention disorder, which
`usually results in excess ammonia in the blood. This has
`various toxic effects; drugs that help eliminate the excess
`ammonia are an important part of an overall management
`strategy for Such disorders.
`0017. To avoid build-up of ammonia to toxic levels in
`patients with nitrogen retention States, dietary intake of pro
`tein (a primary source of exogenous waste nitrogen) must be
`balanced by the patient’s ability to eliminate excess ammonia.
`Dietary protein can be limited, but a healthy diet requires
`Sufficient protein to support normal growth (i.e. in growing
`children) and repair, thus in addition to controlling dietary
`protein intake, drugs that assist with elimination of nitrogen
`are used to reduce ammonia build-up (hyperammonemia).
`The capacity to eliminate excess ammonia in treated patients
`can be considered the sum of the patient's endogenous capac
`ity for nitrogen elimination (if any) plus the amount of addi
`tional nitrogen-elimination capacity that is provided by a
`nitrogen Scavenging drug. The methods of the invention use a
`variety of different drugs that reduce excess waste nitrogen
`and ammonia by converting it to readily-excreted forms. Such
`as phenylacetyl glutamine (PAGN). In some embodiments,
`the invention relates to methods for determining or adjusting
`a dosage of an oral drug that forms PAA in vivo, which is
`converted into PAGN, which is then excreted in urine and thus
`helps eliminate excess nitrogen.
`0018 Based on prior studies in individual UCD patients
`(e.g. Brusilow, Pediatric Research, vol. 29, 147-50 (1991);
`Brusilow and Finkelstien, J. Metabolism, Vol. 42, 1336-39
`(1993)) in which 80-90% of the nitrogen scavenger sodium
`phenylbutyrate (a PAA prodrug) was reportedly excreted in
`the urine as PAGN, current treatment guidelines typically
`either assume complete conversion of sodium phenylbutyrate
`or other PAA prodrugs to PAGN (e.g. Berry et al., J. Pediat
`rics, vol. 138, S56-S61 (2001)) or do not comment on the
`implications of incomplete conversion for dosing (e.g. Singh,
`Urea Cycle Disorders Conference Group Consensus State
`ment from a Conference for the Management of Patients with
`Urea Cycle Disorders, Suppl to J Pediatrics, Vol. 138(1),
`S1-S5 (2001)). Based on what is known, one expects essen
`tially complete conversion of these drugs into urinary PAGN.
`0019 PBA is currently the preferred nitrogen scavenging
`drug for UCD patients in need of substantial nitrogen elimi
`nation capacity. Current treatment guidelines recommend 4
`times per day dosing with PBA, based on the fact that PBA is
`absorbed rapidly from the intestine when administered in the
`form of sodium PBA and exhibits a short half life in the
`bloodstream (Urea Cycle Disorders Conference Group Con
`sensus Statement 2001). Current recommendations for
`sodium phenylbutyrate dosing in UCD patients indicate that
`dosage should not exceed 600 mg/kg (for patients weighing
`up to 20 kg) or in any case 20 grams total per day. Frequent
`dosing helps minimize the peak levels of ammonia, which can
`be very harmful, and it minimizes buildup of high concentra
`tions of PAA as well.
`0020 CRF (chronic renal failure) resulting from a variety
`of causes (e.g. diabetes, hypertension, glomerular disease,
`etc.) is associated with diminished excretion from the body of
`water soluble waste products normally present in the urine,
`including nitrogenous waste Such as urea. While the contri
`
`bution of increased blood levels of urea, perse, to the clinical
`manifestations of CRF and end-stage renal disease (ESRD)
`known as uremia is uncertain, urea levels in the blood are
`commonly used as one measure of renal function and the need
`for and frequency of renal replacement therapy Such as dialy
`sis. As a corollary of the findings noted above in UCD patients
`(e.g. Brusilow, Pediatric Research, vol. 29, 147-50 (1991);
`Brusilow and Finkelstien, J. Metabolism, Vol. 42, 1336-39
`(1993)), increased waste nitrogen excretion in the form of
`PAGN resulting from administration of PAA prodrugs
`decreases urea synthesis and therefore can serve as an alter
`native to urea excretion. Consistent with this, Brusilow (U.S.
`Pat. No. 4,284,647) has demonstrated that administration of
`Sodium benzoate, which increases waste nitrogen excretion in
`the form of hippuric acid, lowered blood urea levels in a
`patient with renal failure (FIG. 14). Accordingly, PAA pro
`drugs, including PBA and HPN-100 can be used to treat CRF
`as well as UCDs and HE, and methods for determining and
`adjusting dosage of these PAA prodrugs and monitoring treat
`ment efficacy are among the inventions disclosed herein. In
`general, and without being limited by theory, prodrugs of
`PAA which do not contain sodium would be preferred for
`treatment of treatment of those nitrogen retention states,
`including CRF as well as cirrhosis and HE, which are also
`known to be associated with sodium and fluid retention mani
`fested, for example, as ascites and or peripheral edema. HPN
`100 is one such sodium-free PAA prodrug.
`
`DISCLOSURE OF EMBODIMENTS OF THE
`INVENTION
`0021. The invention provides a novel approach for deter
`mining and adjusting the schedule and dose of orally admin
`istered nitrogen Scavenging drugs, including sodium phenyl
`butyrate and glyceryl tri-4-phenylbutyrate (HPN-100),
`based upon the urinary excretion of the drug metabolite phe
`nylacetylglutamine (PAGN) and/or total urinary nitrogen. It
`is based in part on the discovery that bioavailability of these
`drugs as conventionally assessed based on systemic blood
`levels of the drugs themselves or of the active species pro
`duced in vivo from these drugs does not accurately predict
`removal of waste nitrogen or reduction of plasma ammonia in
`healthy human volunteers, adults with liver disease, or
`patients with UCDS receiving ammonia Scavenging drugs as
`defined below. Conversion of orally administered sodium
`phenylbutyrate (NaPBA, or sodium PBA) to urinary PAGN
`(uPAGN) is now shown to be incomplete: conversion is typi
`cally about 40-70%, or about 54% on average. (A preliminary
`analysis suggested the range would be around 60-75%, but
`final analysis shows the average is about 54%.) The average
`value of about 54% conversion was determined experimen
`tally for orally administered HPN-100 or PBA converting into
`urinary PAGN, and a range of about 40-70% represents the
`average plus or minus approximately one standard deviation
`for this data set. By comparison, correlating urinary PAGN
`with drug dosage using information available in the art would
`have provided substantially different results, since the prior
`art Suggests a much higher conversion, e.g., 90% or more. As
`used in this context, “about 54%' refers to a value between
`50% and 60%, and the urinary PAGN output refers to a
`measure of urinary PAGN output for a subject receiving
`ongoing stable daily dosages of the nitrogen scavenging drug.
`0022. Urinary PAGN can be measured in various ways; in
`Some embodiments, as described herein, it is a 24-hour mea
`surement, which means measurement of total urinary PAGN
`
`Page 20 of 48
`
`LUPIN EX. 1014
`
`

`

`US 2012/0022157 A1
`
`Jan. 26, 2012
`
`output for a period of 24 hours following the first dose of the
`day of a nitrogen scavenging drug. In other embodiments, a
`12-24 hour urinary PAGN level is used, which is the total
`amount of urinary PAGN excreted over the time period 12-24
`hours after the first dose of the day. As an alternative, as
`described herein, spot testing of urinary PAGN levels can be
`used, by normalizing the value as a ratio to urinary creatinine
`output. Daily creatinine output is relatively stable for most
`subjects, and this has been found to be true even in the UCD,
`HE, and CRF patients receiving the nitrogen scavenging
`drugs described herein. Because creatinine output is rela
`tively stable, it can be used to normalize urinary PAGN output
`levels: from a spot test of a partial sample, the ratio of
`uPAGN to urinary creatinine can be used to estimate a total
`daily urinary PAGN output. These values may be used in
`calculations of dosages or protein intake based on urinary
`PAGN output as well as for determining initial drug dosage
`for a patient taking a given amount of protein.
`0023 The invention further provides methods to easily
`monitor treated patients to determine from urinary PAGN
`output whether their overall treatment program (diet and
`medication) is working, and when the patient needs a modi
`fied treatment program or adjusted drug dosage. These meth
`ods comprise monitoring urinary PAGN output, either as a 24
`hour output, or as a 12-24 hour total urinary PAGN output, or
`as an estimated value from a spot test, where the urinary
`output is normalized to urinary creatinine and converted to an
`estimated 24-hour (or 12-24 hour) output. In one embodi
`ment, the method comprises comparing that value for urinary
`PAGN to a cut-off value that distinguishes patients likely to
`have normal ammonia levels from patients likely to have high
`ammonia levels.
`0024 Prodrugs of phenylbutyrate (PBA, the active ingre
`dient in BUPHENYL(R) (sodium phenylbutyrate), which is
`the sodium salt of PBA along with small amounts of inert
`ingredients), which is itself a prodrug of phenylacetic acid
`(PAA), are especially subject to the effects described herein.
`
`CONa"
`
`phenylbutyrate
`OH
`
`O
`
`Phenylacetic acid
`O
`NH2
`
`Phenylacetylglutamine
`
`0025. As used herein "ammonia scavenging drugs” is
`defined to include all orally administered drugs in the class
`which contain or are metabolized to phenylacetate. Thus, the
`
`term includes at least phenylbutyrate, BUPHENYL(R) (so
`dium phenylbutyrate), AMMONAPSR), butyroyloxymethyl
`4-phenylbutyrate, glyceryl tri-4-phenylbutyrate (HPN
`100), esters, ethers, and acceptable salts, acids and derivatives
`thereof. These drugs reduce high levels of endogenous
`ammonia by providing phenylacetic acid in vivo, which is
`metabolized efficiently to form phenylacetyl glutamine
`(PAGN). PAGN is efficiently excreted in urine, carrying away
`two equivalents of nitrogen per mole of PAA converted to
`PAGN. References herein to sodium phenylbutyrate are
`understood to include reference to the drug product BUPHE
`NYL(R), and BUPHENYL(R) was used for the Examples herein
`wherever test subjects were treated with sodium phenylbu
`tyrate. Thus the sodium PBA dosages used in the Examples
`generally refer to a dosage of BUPHENYL(R), and the
`amounts of sodium phenylbutyrate in those Examples should
`be interpreted accordingly. Note that the terms ammonia
`Scavenger and nitrogen scavenger are used interchangeably
`in this invention, reflecting the fact that the drugs described
`herein lower blood ammonia and/or urea levels through
`elimination of waste nitrogen in the form of PAGN.
`0026. In some embodiments, the invention uses prodrugs
`that can be converted into PAA within the body. Sodium
`phenylbutyrate (sodium PBA) is one such drug; it is converted
`by oxidative mechanisms into PAA in the body. HPN-100 is
`another such drug: it can behydrolyzed to release PBA, which
`in turn can be converted to PAA. Thus, HPN-100 is a prodrug
`of PBA, and also a pre-prodrug of PAA. Clinical evidence
`demonstrates that HPN-100 is converted into PAA in the body
`as expected, and that PAA is then linked to a molecule of
`glutamine and converted into PAGN, which is eliminated in
`the urine as predicted. This process can be summarized as
`follows:
`
`HPN-100-s3PBA-3PAA
`
`PAA+glutamine->PAGN.
`0027 PAGN is mainly excreted in the subject's urine, and
`removes two molecules of ammonia per molecule of excreted
`PAGN. Each HPN-100 molecule forms three PAA molecules,
`so each molecule of HPN-100 can promote excretion of six
`molecules of ammonia. The clinical results suggest that con
`version of HPN-100 into PBA and PAA is efficient, in that
`HPN-100 is generally not detectable in blood, but surpris
`ingly suggest that some PBA derived from HPN-100 is con
`verted to PAGN before the HPN-100 (or PBA, or PAA derived
`from PBA) enters systemic circulation. As a result, systemic
`levels of PAA or PBA are not reliably correlated with the
`efficacy of HPN-100 as an ammonia scavenger.
`0028. In some embodiments, the invention uses a prodrug
`of PBA, including HPN-100 and other esters of phenylbu
`tyrate. The PBA prodrug is thus a prodrug of a prodrug, since
`PBA acts to scavenge ammonia after it is converted to PAA
`and is thus considered a prodrug of PAA. In some embodi
`ments, the PBA prodrug is an ester of phenylbutyrate, such as
`those described below; a preferred PBA prodrug for use in the
`invention is HPN-100. These compounds can be made and
`used by methods disclosed in U.S. Pat. No. 5,968,979, which
`is incorporated herein by reference for its description of these
`compounds and methods for their administration.
`0029 Where an equal molar or equimolar amount of a
`second drug is to be used along with or instead of a certain
`amount of a first drug, the amount of each drug is calculated
`on a molar basis, and the equimolar amount of the second
`drug is the amount that produces an equal molar amount of
`active drug in vivo. Where one of the drugs is a prodrug, the
`amount of prodrug will typically refer to the molar amount of
`the active species formed from that prodrug. That active spe
`
`Page 21 of 48
`
`LUPIN EX. 1014
`
`

`

`US 2012/0022157 A1
`
`Jan. 26, 2012
`
`cies is usually PAA for the prodrugs described herein, and the
`molar amount of a prodrug corresponds to the amount of PAA
`that would form in the body from that amount of the prodrug,
`assuming complete conversion into PAA occurs in vivo.
`Thus, for example, a molecule of HPN-100 can be metabo
`lized by ester hydrolysis followed by oxidation to form three
`molecules of PAA, so a mole of HPN-100 would be consid
`ered equimolar to three moles of PAA. Similarly, since HPN
`100 hydrolyzes to form three molecules of PBA (and one
`molecule of glycerol), an equimolar amount of HPN-100
`would be one-third of the molar amount of PBA.
`0030. The following Table sets forth amounts of HPN-100
`that correspond to equimolar amounts of certain relevant
`doses of BUPHENYL(R) (sodium phenylbutyrate). Note that
`the conversion of the dose of sodium PBA to the dose of
`HPN-100 involves correction for their different chemical
`forms i.e. HPN-100 consists of glycerol in ester linkage with
`3 molecules of PBA and contains no sodium; (sodium PBA
`gx0.95=HPN-100g) as well as correction for the specific
`gravity of HPN-100, which is 1.1 g/mL.
`
`embodiment is the same, i.e., R, R2, and R are all the same.
`The advantage over the prior art of decreased dosage is
`greater with Such triesters, and having all three acyl groups
`the same reduces issues related to mixtures of isomers. More
`over, the triol backbone liberated by hydrolysis of the esters is
`glycerol, a normal constituent of dietary triglyceride which is
`non-toxic.
`0034. The present invention also utilizes phenylbutyrate
`and phenylacetate prodrugs of the formula II:
`
`(II)
`
`R-o- R4
`
`0035 wherein R is a C-C alkyl group,
`0036 R is
`
`TABLE 1.
`
`Conversion Factors.
`
`(CH2)
`
`O
`
`HPN-100 PBA
`Equivalent Dose (mg)
`
`BUPHENYL (R)
`(sodium PBA)
`450-600 mg/kg/day 428-570 mg/kg/day
`(patients is 20 kg)
`9.9-13.0 g/m2/day
`(patients > 20 kg)
`Maximum Daily
`Dose: 20 g
`
`9.4-12.4 g/m2/day
`
`Maximum Daily
`Dose: 19 g
`
`HPN-100
`PBA Equivalent Dose (mL)
`0.39-0.52 mL/kg/day
`
`8.6-11.2 mL/m2/day
`
`17.4 mL
`
`0037 and n is zero or an even number, and m is an even
`number.
`0038. In Formula II, R can be, for example, ethyl, propyl,
`isopropyl. n-butyl, and the like.
`0039. The compounds of the invention are esters of the
`congeners of phenylalkanoic and phenylalkenoic acids hav
`ing an even number of carbon atoms in the alkanoic acid
`portion, which include phenylacetic acid esters and those of
`phenylbutyric acid, etc., which can be converted by efficient
`beta-Oxidation processes to phenylacetic acid in the body.
`They are thus prodrugs for phenylacetic acid. Where n is 2 or
`4, the esters are also prodrugs for phenylbutyric acid. Prefer
`ably the alkylene oralkenylene carboxylate group contains 24
`or fewer carbon atoms, so n or m is less than 24. In some
`embodiments, n and mare 0, 2, 4 or 6, and in Some preferred
`embodiments in or m is 2.
`0040 Certain preferred embodiments of the invention use
`HPN-100 (Formula III):
`
`0031. The present invention can use prodrugs of the for
`mula (I):
`
`(I)
`
`H
`
`H
`
`H
`
`H
`
`H
`
`O-R
`
`O-R
`
`O-R
`
`0032 wherein R. R. and R are independently, H.
`
`(III)
`
`O
`
`O
`
`O
`
`(CH2)
`
`(CnH2n-2)
`
`0033 andnis Zero oran even number, misan even number
`and at least one of R. R. and R is not H. For each R. R. or
`R., n or m is independently selected, so the R, R2, and R
`groups in a compound of formula I do not have to be identical.
`The preferred compounds are those wherein none of R. R.
`and R is H. and frequently each n or m for a particular
`
`O
`
`O
`
`H
`
`H
`
`H
`
`H
`
`O
`
`O
`
`O
`
`O
`
`H
`
`Page 22 of 48
`
`LUPIN EX. 1014
`
`

`

`US 2012/0022157 A1
`
`Jan. 26, 2012
`
`0041. Total daily dosage of prodrugs like sodium PBA can
`often be selected according to the amount needed to provide
`an appropriate amount of the active species, if that amount is
`known or can be determined. PBA is a prodrug for PAA:
`therefore, an initial dose of PBA could be selected if an
`effective dosage of PAA were known, taking into account the
`fraction of PBA that is converted into PAA and ultimately into
`PAGN. If a subject has been treated with PAA or a prodrug
`that forms PAA in the body, the amount of the previously used
`drug that was effective provides a possible starting point for
`selecting a dosage of a new prodrug of PAA. In this same
`patient, after the new prodrug is administered at the expected
`PAA dose equivalence, the PAA levels in the subject could be
`monitored and the dose of the prodrug adjusted until the same
`plasma level of PAA that was effective with the previous
`treatment is achieved. However, the current invention is based
`in part on finding that plasma PAA and PBA levels are not
`well correlated with the dose of a PBA prodrug administered
`or with ammonia elimination; for monitoring a dosing level of
`a PBA prodrug, one should not rely upon these parameters to
`assess the effectiveness of the prodrug. While not bound by
`the underlying theory, explanations for this effect (i.e. the
`inconsistent relationship between ammonia Scavenging and
`PBA and/or PAA blood levels) are provided herein.
`0042. The following Tables provides data from three clini
`cal test groups showing the inconsistent relationship between
`plasma PAA and PBA levels among healthy volunteers,
`patients with cirrhosis and UCD patients, despite th