CA2244696A1 - Methods for retreatment of patients afflicted with hepatitis c using consensus interferon - Google Patents

Abstract

Methods for the retreatment, using a therapeutically effective amount of interferon consensus, of patients with HCV who exhibit serum ALT values above the upper limit of normal after previous treatment with interferon.

Description

~ W 0 97127866 PCT~US97/00340 METHODS FOR RETREATMENT OF PATIENTS AFFLICTED WITH
HEPATITIS C USING CONSENSUS INTERFERON

The present invention relates to methods of retreatment, using consensus interferon (IFN-con), of patients suffering ~rom Hepatitis C virus (HCV) who failed to respond to the initial course of treatment with interferon, or who, following cessation of interferon therapy, suffered relapse.
R~CKGROUND OF TH~ INVENTION

Hepatitis C virus (HCV) is one of five viral agents known to cause viral hepatitis. HCV is a small RNA virus that resembles the flavi- or pestiviruses in its nucleotide se~uence and genomic structure; Houghton et al., ~epatology, 1~:381, 1991. Patients actively infected with HCV have HCV-RNA in blood which can be detected using sensitive assays employing reverse transcription followed by polymerase chain reaction amplification (RT-PCR); Weiner et al., Lancet, 335 :1, lg90. HCV replicates largely, if not solely, in the liver and causes both acute and chronic hepatitis.
It is estimated by the Centers for Disease Control and Prevention that HCV is responsible for 160,000 new cases of acute hepatitis in the United States each year. While most patients are asymptomatic, approximately 25% of these patients may develop jaundice or other symptoms of hepatitis, and as many as 70% of these patients may progress to chronic liver disease as evidenced by persistent elevation of serum alanine aminotransferase (ALT~ levels as well as continual presence of circulating HCV-RNA. In addition, progression of HCV infection to hepatocellular carcinoma has been well documented; Tong et al , WJM, 160,2 :133-138, 1994. Epidemiolosy studies done ~y the Centers for W 097/27866 PCTrUS97/00340 Disease Control suggest that only 4% of HCV infections are transmitted by blood transfusions, 3~ by hemodialysis, 10% by sexual transmission, 35% by intravenous drug use, and in 48% of cases, the mechanism of HCV transmission is unknown.
Inter~erons are a subclass of cytokines that exhibit both antiviral and antiproliferative activity.
On the basis of biochemical and immunological properties, the naturally-occurring hu~an interferons are grouped into three classes: interferon-alpha ~leukocyte), interferon-beta (fibroblast) and interferon-gamma (immune). At least fourteen alpha interferons (grouped into subtypes A through H) having distinct amino acid sequences have been identified by isolating and sequencing DNA encoding these polypeptides. Alpha interferons have received considerable attention as potential therapeutic agents due to their antiviral and antitumor growth inhibition.
U.S. Patents Nos. 4,695,623 and 4,897,471 disclose novel human interferon polypeptides having amino acid sequences which include common or predom;n~nt amino acids found at each position among naturally-occurring alpha interferon subtype polypeptides and are referred to as consensus interferons ~IFN-con). The IFN-con amino acid sequences disclosed are designated IFN-con1, IFN-con2, and IFN-con3. The preparation of manufactured genes encoding IFN-con and the expression o~ said genes in E. ~Çl~ are also disclosed. In vitro studies comparing the relative antiviral, antiproliferative, and natural killer cell activities of recombinant IFN-con with either leukocyte or other recombinant type-one interferons demonstrate that IFN-con displays significantly higher activity when compared on a mass basis; Ozes et al., J Interferon Research, 1~:55-59, 1992.

W 097/27866 PCTfUS97100340 U.S. Patent No. 5,372,80~ discloses methods o~
treatment of diseases using consensus interferon. It is shown that IFN-con, when used in the treatment of diseases susceptible to treatment by alpha interferons, does not cause the same degree of side effects in patients as do the alpha interferons. It was ~urther shown that 3 to 5 times higher doses of IFN-con can be used, leading to enhanced therapeutic benefit, with substantially no corresponding increase in the fre~uency or severity of undesirable side ef~ects.
HCV is one of several clinical indications for which interferons have been approved by the Food and Drug Administration, and IFN-a is currentLy licensed for use in chronic HCV; Hoofnagle et al., Interferon:
Principles and Medical Applications, 1st Edition, Chap. 31, pgs 433-462, 1992. The types of responses that occur during IFN-a therapy can be characterized as:
(1) a sustained complete response (lldurableu), where patients serum ALT values begin to fall within the first months of treatment, are often normal by two to three months, and remain normal even after therapy is stopped.
(these patients may also become negative for serum HCV
RNA); (2) a transient complete response followed by relapse when therapy is stopped ("relapse"); (3) a partial or transient response, where patients serum ALT
values decrease but do not become normal or become normal transiently and then rise despite continuation of interferon therapy ("partial response"); and (4) no response, where patients serum ALT activities remain elevated during interferon treatment ("non-response~) Use of IFN-a in sufficient dosage to yield clinical efficacy (i.e. at amounts of about 1 x 106 units/treatment and a~ove) is usually associated with a "flu-like" syndrome characterized by fever, headache, lethargy, arthalgias and myalgias; Tyring et al., Interferon: Principles and Medical Applications, 1st W O 97~7866 PCTrUS97/00340 Edition, Section VIII., pgs 399-408, l9g2. At higher doses, i.e. 5-10 x 1O6 units/treatment and above, other toxicities become more fre~uent and may be dose-limiting. These effects include nausea, vomiting, diarrhea and anorexia; Id. at 403. Laboratory changes associated with high dose administration include relative leukopenia and thrombocytopenia and serum elevations in liver enzymes; Id.
The recommended IFN-atherapy for chronic ~CV
is 3-5 MU three times weekly either subcutaneously or intramuscularly for six to twelve months; see e.g., Davis et al., ~ Engl J Med., 321:1501-1506, 1989;
Marcellin et al., Hepatology, 1~ 3g3-397 , 1991; Causse et al., Gastroenterolo~y, 101:497-502, lg91i Linsey et 15 al ., Xepatology, ~:106a, 1993. Generally, approximately fifty percent of IFM-~ treated patients demonstrate normal serum ALT levels by the end of therapy. However, following cessation of ~FN-a treatment, between 50-100% of the responding patients relapsed, resulting in a 0-25% ~durable" ALT response rate, and a 0-25% "relapse~ response rate.
Unfortunately, there are no reliable means of predicting which patients are likely to respond to IFN-a and which of these will have a "durable" response.
In light of the shortcomings associated with IFN-a treatment of chronic HCV, investigators have set out to increase the response rate in chronic HCV, with several attempts focusing on the use of higher doses.
Reports from these studies suggest that higher doses of IFN-a, i.e., between 5 and 10 MU TIW to daily, may increase the long term ALT response rate; see e.g., Linsey et al., Hepato70~y, 1~:106a, 1993; Hoofnagle et al., N Engl J Med., 315:1575~1578, 1989; Ka~umu et al., Am J Gastroenterology, 85:655-659, 1990. However, because of the accompanying increase in toxicity, these higher doses are difficult to maintain and studies using W O 97127866 PCTrUS97/00340 doses up to 10 MU daily were only performed in patients who were hospitalized for this treatment; Iino et al., Dig Dis Sci., ~:612-618, 1993.
Other attempts have focused on IFN-a retreatment therapy. For example, Toyoda et al., ~ner. Jour. of Gastroent., 89:9:1453-1457, lg94, analyzed the retreatment of chronic HCV with IFN-a to get the standpoint for the selection o~ patients to receive it. Toyoda et al. retreated 23 patients (15 lQ relapses, 8 nonresponses) and reported that eight (34.8%) patients had normalized seru~n ALT values upon retreatment. All eight patients were patients from the "relapse" group who had had undetectable serum HCV-RNA
at the end of their initial IFN-a treatment period.
Based on their findings, Toyoda et al. concluded that selection of patients to receive retreatment re~uires careful consideration of genotype, HCV-RNA
concentration, and the clinical response on initial treatment, and that interferon retreatment may be effective in "relapse" cases where the patient has undetectable serum HCV-RNA at the end of initial treatment.
Weiland et al., Scand ~ Infect Dis., ~:25-30, l9g3, report the results of IFN-a retreatment of 1~
25 ~relapse~ patients (all 10 patients had normalization of serum ALT levels during the nine month initial treatment). Weiland et al. concluded that a 6-month course of retreatment induced a normalization of serum ALT levels once again in most patients (6/10~, and that HCV-~NA titers in serum fell to undetectable levels during retreatment, but that all patients relapsed again soon after treatment cessation, i.e., a second course of treatment fails to increase the number of patients with Udurable'' responses.
Marcellin et al., ~. Infect Dis., 167:780, 1993, describe a study to assess the efficacy of retreatment with IFN-~ in patients with chronic HCV who did not respond or who relapsed after an initial treatment. In the twelve patients retreated, retreatment with the same dose of the same interferon did not induce any "durable" responses. The overall rate of response to retreatment was not dif~erent ~rom that observed with first treatment, i.e., relapsers responded but then relapsed again, and nonresponders to initial treatment were nonresponders to retreatment.
Marriott et al., ~. In~ect Dis ., 166:1200-1201, 1992, evaluated the possible benefit o~ a second cycle of IFN administration in patients who were '~relapse" or "non-response" patients to one cycle o~ IFN
treatment. Of the retreated patients, 70% (14J20) had normalization o~ serum ALT values during retreatment, with 90~ of the "relapse" patients having normalization of serum ALT values, and only 28% of "non-response'~
patients having normalization during retreatment. Of the 14 patients who normalized during retreatment, only 1 had a "durable~ response. Marriott et al. conclude that a second cycle of therapy gave only a transitory bene~it and was not useful in improving the rate of "durable" serum ALT normalization.
Schvarcz et al., Scand J Infect Dis., 23:413-420, 1991, report on the outcome of treatment with increased doses of interferon in Unon-response~
patients. The six '~non-response~ patients had been treated with 3 MU alpha-2b interferon thrice weekly (t.i.w.), and were retreated with 6 MU t.i w. for at least 8 weeks. Schvarcz et al. report that none of the Unon-response" patients normalized the serum ALT levels during the retreatment with the higher doses.
Furthermore, with increased doses, side ef~ects were much more pronounced.

W O 97/27866 PCT~US97tOO340 Arase et al., J. of Gastroent., 29:299-304, 1994, studied the outcome of retreatment, using a human lymphoblastoid alpha interferon, of patients who failed to respond to initial interferon beta treatment.
Specifically, Arase et al. studied the outcome of retreatment in relation to serum ALT levels after the initial treatment and concluded that high-dose (6 MU) and prolonged readministration of IFN-a may be a worthwhile strategy in patients with HCV subtype III or in those showing transient normalization of serum ALT
levels and who are negative for serum HCV-RNA during or after their initial treatment. However, for those with HC~ subtype II or persistently positive serum HCV-RNA
and abnormal serum ALT levels during and after their initial treatment, retreatment with IFN-a is likely to fail.
Based on the teachings referenced above, it appears that retreatment with IFN-a has limited effectiveness in "relapse~ patients, and little, i~ any, effectiveness in Unon-response~ patients. More importantly, retreatment fails to be useful in improving t~e rate of sustained serum ALT normalization, i.e.
"durable" responses. It is clear then, that new approaches or modifications to IFN-a therapy of HCV are needed. Therefore, the ob~ect of this invention is a method for retreatment, using IFN-con, of patients suffering ~rom HCV, whereby the rate of "durable"
responses is increased.

SU~A~Y OF TH~ T~V~NTION

The invention encompasses methods of retreatment, using a therapeutically effective amount of IFN-con, for patients suffering from HCV who failed to respond to IFN-a therapy, or who, following cessation of IFN-a therapy, suffered relapse. The W O 97/27866 PCTrUS97/00340 invention is based on the discovery that retreatment of HCV patients with IFN-con elicits approximately a 46~ response rate for relapse and/or nonresponder patients, and that retreatment may be useful in improving the rate of durable ALT normalization.
IFN-con is a nonnaturally-occurring polypeptide having antiproliferative activity.
Preferably, IFN-con is a polypeptide having the amino acid se~uence of IFN-con1, IFN-con2, or IFN-con~. Most pre~erably, IFN-con has the amino acid sequence o~
IFN-conl .

DFTAIT~ D~SCRIPTION OF TH~ I ~ ~TION

As emp1oyed herein, human interferon consensus (IFN-con) means a nonnaturally-occurring polypeptide, which pre~omin~tly includes those amino acid residues that are common to a subset of IFN-~'s representative of the majority of the naturally-occurring human leukocyte interferon subtype sequences and which includes, at one or more of those positions where there is no amino acid common to all subtypes, an amino acid which predominantly occurs at that position and in no event includes any amino acid residue which is not extant in that position in at least one naturally-occurring subtype. IFN-con encompasses but is not limited to the amino acid sequences designated IFN-conl, IFN-con2 and IFN-con3 which are disclosed in commonly owned U.S.
Patents 4,6~5,623 and 4,897,471, the entire disclosures of which are hereby incorporated by reference. DNA
sequences encoding IFN-con may be synthesized as described in the above-mentioned patents or other standard methods.
IFN-con polypeptides are pre~erably the products of expression of manufactured DNA sequences transfonmed or transfected into bacterial hosts, - W O 97/27866 PCT~US97100340 _g _ especially E. coli. That is, IFN-con is recombinant IFN-con. IFN-con is preferably produced in E. coli and is purified by procedures known to those skilled in the art and generally described in Klein et al., J.
Chromatog. 454:205-215 ~1988) IFN-con1 purified in this manner is reported to have a specific activity of 3 x lOg unitsJmg protein as measured in the cytopathic ef~ect inhibition assay using the T98G human cell line;
Fish et al. J. Interferon Res. 9, 97-114 (1989).
The subject invention provides for a method of retreating, using a therapeutically effective amount of IFN-con, a patient suffering from HCV, who had previously failed to respond to IFN-a therapy or had previously responded to IFN-a therapy, but, upon cessation of therapy, suffered relapse. A preferred embodiment of the invention is a method of retreatment involving administering a therapeutically effective amount of IFN-conl, IFN-con2, or IFN-con3 More preferably, a therapeutically effective amount of IFN-con1 is administered. Most pre~erably 15 MU IFN-con is administered subcutaneously 3 times weekly for 24 or 48 weeks.
In Example 1 provided below, it is shown that IFN-con1 is ef~ective in eliciting approximately a 46%
response in patients who had previously failed to respond to IFN therapy, or who, upon cessation of IFN
therapy, suffered relapse. More importantly, it is shown that 27% of the retreated patients have a "durable" response. The example is offered to more ~ully illustrate the invention but is not to be - construed as limiting the scope thereof.

-W O 97127866 PCTrUS97/~U340 ~ffic~cv of IFN-conl A~m;nistere~ to P~tients with ~CV After Prior TreAtment With Interferon A randomized, open-label, multicenter study was undertaken to determine the efficacy of retreatment with IFN-con1 in patients with HCV who exhibit serum ALT
values above the upper limit o~ normal a~ter previous treatment with interferon, i.e. "relapse" or "non-response" patients. Efficacy of IFN-con1 was evaluated by measuring changes in serum ALT values during the course of retreatment. In addition, the study demonstrates the durability of response and the effects of IFN-conl retreatment on serum HCV RNA as measured by PCR analysis. The study was divided into two independent concurrent Cohorts: Cohort A ~retreatment) and Cohort B (observation only).

A. Product Description IFN-conl was produced in E. coli using methods described in U.S. Patent Nos. 4,695,623 and 4,897,471.
IFN-con1 was purified by procedures generally described in Klein et al., supra ~1988). For subcutaneous administration in the current study, IFN-conl was supplied as a clear, colorless, sterile protein solution free of particulates and formulated in an aqueous buffer before undergoing sterile filtration and filling the vials. Recombinant IFN-conl is not less than 95% pure.

B. Patient Selection The study included approximately 431 patients who had completed Amgen Inc. protocol CIFN-9210.
CIFN-9210 was a double-blind, randomized, positive-- WO 97127866 rCT/US97/00340 controlled, multi-center study to determine the efficacy o~ IFN-con1 administration at two dose Levels, 3 ~g (3 MU) and 9 ~g l9 MU) as compared to 1~ ~g (3 MU) Intron~ A (Schering-Plough). Durability of response, pre- and post-treatment intra-patient changes in serum HCV RNA, liver histology, formation of antibody to inter~eron, and quality o~ e were compared.
To be eligible for CIFN-9210, patients had to be at ~east 18 years old with chronic HCV, positive for HCV ~NA, with adequate bone marrow and organ function, and with ALT greater than 1.5 times the upper limit of normal. Eligible patients were randomly assigned to receive subcutaneous injections of 3 ~g IFN-con1, 9 ~g IFN-con1, or 15 ~g Intron~ A three times wee~ly for 24 weeks. Patients were then observed for 24 weeks.
Efficacy response criteria for ALT were as follows: ~1) a complete response (ALT-CR) was defined as a decrease in the monthly ALT values to less than or equal to the upper limit of normal any time during the double-blind treatment period that remains less than or equal to the upper limit of normal at the end of the double-blind treatment period; (2) a near-complete response (ALT-NCR) was defined as any decrease in the monthly ALT value to less than or equal to 1.5 times the upper limit of normal any time during the double-blind treatment period that r~inq less than or equal to 1.5 times the upper limit of normal at the end of the double-blind treatment period; (3) a partial response (ALT-PR) was defined as a decrease in ALT value to less than or equal to 50% of baseline but not less than or equal to 1.5 times the upper limit of normal any time during the double-blind treatment period. The decrease must remain less than or equal to 50% of baseline but not less than or equal to 1.5 times the upper limit of normal at the end of the double-blind treatment period to be classified as an ALT-PR; and (4) any response not W O 97/27866 PCTrUS97/00340 meeting the criteria speci~ied above was considered a non-response (ALT-NR).
Efficacy was assessed in patien~s who had serum ALT values above the upper limit of normal at the end of the 24-week post-treatment observation period in protocol CIFN-9210, and in patients whose serum ALT
values were within normal limuts at completion o~
protocol CIFN-9210 and subsequently increased above the upper limit of normal within approximately four years after completing protocol CIFN-9210.

C. Retreatment Procedures Treatment Cohort A
Eligible patients were enrolled within approximately 28 days of completing protocol CIFN-9210.
Patients who had serum ALT values above the upper limit of normal ~or two consecutive measurements at least two weeks apart were enrolled and randomized to receive treatment with 15 ~g of IFN-con1 in a 1:1 ratio for either 24 weeks or 48 weeks. Study drug was administered subcutaneously three times weekly at least 48 hours apart. Patients were monitored for safety, efficacy, and tolerability of study drug throughout the study. Response at the end o~ the 24- or 48-week treatment period and at the end of the 24-week post-treatment observation period was determined.
Patients who did not show a reduction in serum ALT values to less than 1.5 times the upper limit of normal or at least a 50% reduction from their baseline value at study entry within three months of starting retreatment were withdrawn from the study. Furthermore, for patients randomized to 48 weeks of retreatment, if, in the opinion of the investigator, no additional CA 02244696 l998-07-23 W O 97127866 PCTrUS97/0~34 benefit was seen by week 24, some of these patients were withdrawn from study.
Patients who experienced an intolerable Grade 2 toxicity, Grade 3 toxicity, or Grade 4 neutropenia ~criteria established by the World Health Organization and described ~urther in Miller et al., Cancer 47:
210-211, 1981) that was judged by the Investigator to be possibly, probably or definitely related to study drug had their dose of study drug withheld until the toxicity was judged by the Investigator to be a tolerable Grade 2 toxicity or less. Study drug was restarted at the next lower dose as shown in Table 1.

Table 1 Dose Reductions Due to Toxicity Toxicity**Dose (~g) Injection Volume TFN-con1 ~mL~
None 15 0.5 First 12 0.4 Second 9 0.3 Third 6 0.2 Fourth 3 0.1 **Patients who experienced more than four dose reductions were withdrawn from study.

Patients were withdrawn from study if they required more than four dose reductions, or if they experienced an intolerable Grade 2 toxicity, or Grade 3 toxicity (excluding neutropenia) thought to be related to study drug for greater than 14 days. Patients who experienced a Grade 4 toxicity (excluding neutropenia) were also withdrawn. Patients who completed the 24- or 48-week retreatment period will continue on to a post-treatment 3~ observation period ~or up to an additional four years.

CA 02244696 l998-07-23 W O 97/27866 PCTAUS97tOO34 Treatment Cohort B

Patients whose serum ALT values were less than or equal to the upper limit of normal within 28 days after the completion of protocol CIFN-9210 (week 60) were enrolled into Cohort B and followed for durability of response (time period in which serum ALT values remain within the normal range) and time to relapse (time point in which serum ALT values increase above the upper limit of normal) for up to four years. At the time of relapse, these patients will be given a new randomization number and assigned to a Cohort A
retreatment group as described above.

D. Results Ta~le 2 Percent~e of P~tients with Norm~l ATT Values After Retreatment with 15 llq IFN-Con1 Initial TreatmentTreatment Period Grou~* Week 24 Intron~ A (15 ~g)43% ~28~65) IFN-Con1 (3 ~g)42~ (25/59) IFN-Con1 (9 ~g)54% (26/48) * this represents the type and dose of interferon used to treat the group initially As illustrated by Table 2 above, patients retreated with IFN-conl at 15 ~g three times weekly ~or 24 weeks had complete ALT response rates that ranged from 42% to 54%. The above demonstrates that retreatment with IFN-con1 is effective in elicitin~ a complete response in patients who had previously failed CA 02244696 l998-07-23 - W O 97127866 PCTrUS97/00340 to respond to interferon therapy, or who, upon cessation of therapy, suffered relapse.

Table 3 Percenta~e of P~tients with "Durable" ResDonses Af~er Retreatmen~ with 15 ~ IFN-Con1 Initial Treatment Period After Treatment Stopped Grou~* Wee~ 12 Intron~ A (lS ~g) 25~ ~16/65 IFN-Conl (3 ~g) 25% (15/59) IFN-C~nl (9 ~g) 33% (16/48) * this represents the type and dose of interferon used to treat the group initially As illustrated by Table 3 above, retreatment with IFN-con1 at 15 ~g three times weekly for 24 weeks resulted in a "durable'l response rate that ranged from 25~ to 33%. This data demonstrates that retreatment with IFN-con1 increases the "durable" response rate in chronic HCV patients as compared to previously reported treatment and/or retreatment regimens.

While the present invention has been described in terms of the preferred embodiments, it is understood that variations and modifications will occur to those ~ skilled in the art. Therefore, it is intended that the appended claims cover all such equivalent variations ~ which come within the scope of the invention as claimed.

Claims (7)

WHAT IS CLAIMED IS:

1 A method for retreating HCV patients, said patients having been previously treated with an interferon, comprising administering to a patient a therapeutically effective amount of interferon consensus.

2. A method according to Claim 1, wherein said interferon consensus is selected from the group consisting of IFN-con1, IFN-con2, and IFN-con3.

3. A method according to Claim 2, wherein said interferon consensus is IFN-con1.

4. A method according to Claim 1 wherein said interferon consensus is a product of prokaryotic expression of an exogenous DNA sequence.

5. A method according to Claim 1, wherein the therapeutically effective amount is administered orally, intravenously, intramuscularly, subcutaneously, intranasally, or intralesionally.

6. A method according to Claim 1, wherein the therapeutically effective amount is 15 µg administered subcutaneously three times weekly for 24 weeks.

7. A method for obtaining normalized serum alanine aminotransferase (ALT) levels in a patient suffering from HCV and having been previously treated with interferon therapy, comprising administering to said patient a therapeutically effective amount of interferon consensus.