**MEMORANDUM**

DATE: July 19, l999

TO: Antiviral Drugs Advisory Committee members

FROM: Rosemary Tiernan, M.D., Medical Officer

Cheryl Dixon, Ph.D., Statistician

VIA: Mark Goldberger, M.D., M.P.H., Director

Division of Special Pathogens and Immunologic Drug Products

SUBJECT: Clinical/Statistical Background Information for 27 July l999
Advisory Committee Meeting

Drug name: Rapamune® (sirolimus) Oral Solution

NDA-21-083

Indication: Prevention of acute rejection in renal transplantation

Applicant: Wyeth-Ayerst Laboratories

I.  **Introduction:**

> This section of the FDA briefing package will focus on several

specific safety issues that arose during the sirolimus Phase III trials
i.e. pivotal studies 301 and 302. Comments regarding the design and
conduct of the clinical studies will be rendered, and specific safety
issues will be addressed in order to assist in a final risk/benefit
analysis of the two proposed sirolimus doses.

Please refer to the Applicant's summary of safety data as presented in
their Advisory Committee briefing package. Please also refer to the FDA
Statistical Review which addresses the overall safety and efficacy of
sirolimus oral solution, when used in conjunction with cyclosporine
(CsA) and corticosteroids, to prevent acute rejection in the renal
transplant recipient.

The recommended fixed maintenance dose for sirolimus is 2 mg/day (SRL
2). In addition, the Applicant is recommending a fixed maintenance dose
of 5 mg/day (SRL 5) for patients with a "high risk for acute rejection"
such as African-American patients, highly HLA mismatched patients, those
with high panel reactive antibodies (PRA) and patients with a second
transplant.

# Design of Clinical Studies

The Applicant's briefing package summarizes the differences between
pivotal studies 301 and 302. It is important to note that both studies
were randomized, double-blind, controlled trials. The U.S. trial, study
301 (719 patients), utilized azathioprine as an active control. Study
302 (576 patients), which included sites in the U.S., Europe and Canada,
utilized a placebo control. The objective endpoints for both study 301
and 302 included a composite endpoint of acute rejection, graft loss
(defined as nephrectomy or dialysis for 56 or more consecutive days ) or
death at 6 months and patient and graft survival at 12 months.

***[Reviewer's Note:]{.underline} A strength of study 301 was its
enrollment of adequate numbers of African-American patients. The
African-American segment of the U.S. transplant population is 21.3%
according to 1998 UNOS data. In study 301, African-Americans comprised
23.1% of the study population.***

***One potential weakness of U.S. study 301 was that, although the
randomization at 48 hours post-transplant may have eliminated patients
who sustained surgical site complications, it also may have eliminated
"higher risk" patients such as those with "delayed graft function"
(maintained on dialysis for at least one week post-transplant). However,
study 302 randomized patients prior to transplantation and thus should
capture those with delayed graft function.***

Additional important points regarding studies 301 and 302:

[Trial Design]{.underline}

1)  Antibody induction was prohibited in study 301 and 302.

2\) Antibody therapy (OKT3 or Anti-thymocyte globulin) was used for
episodes of acute rejection, if the patient had failed an initial
steroid "pulse". No mycophenolate mofetil or tacrolimus was allowed.

3\) Study drug was administered as a loading dose of 15 mg and a fixed
dose of 5 mg/day or as a loading dose of 6 mg with a fixed dose of 2
mg/day. Refer to section 7.10.8 through 7.10.8.3 of the Applicant's
Advisory briefing package for a complete discussion of the issues
related to drug exposure, dose reduction and discontinuations for
Rapamune.

4\) In the initial NDA submission**,** fourteen patients had been
"lost-to follow-up" in study 301. However, over the past 6 months, the
Applicant was able to obtain follow-up data on all patients except 5 in
study 301: one in the SRL 2mg arm , two in the SRL 5 mg arm and one in
the azathioprine arm. If patients were lost to follow-up, they were
counted as efficacy failures. No patients were lost to follow-up in
study 302.

5\) The Division of Scientific Investigations inspected three U.S. study
sites and one overseas study site and found several minor problems with
the conduct of studies 301 and 302. No major protocol deviations or
violations were identified that would preclude accepting data from any
individual study site. However, it should be noted that one study 301
investigator had a high rate of discontinuations at his site because he
felt that when the patient's renal function began to worsen, it was
imperative to discontinue study drug and initiate an alternative
immunosuppressive regimen. There were also some difficulties in adhering
to the time of randomization in study 302. Consequently, 67 of the 576
(12%) study 302 patients were assigned to treatment at one or more days
after transplantation---as opposed to being randomized prior to
transplantation. The Applicant states that an analysis of the primary
endpoint, after these patients were excluded, did not show a difference
in the overall results. Consequently, it is doubtful that this will bias
the study results.

6\) Concomitant dosing for cyclosporine and corticosteroids was rendered
as outlined in the Applicant's briefing package. The target cyclosporine
troughs were slightly different for the first month in studies 301 and
302.

Target **cyclosporine** troughs were:

**[Study 301 Study 302]{.underline}**

Month 1 200-350 ng/ml 200-400 ng/ml

Month 2-3 200-300 ng/ml 200-300 ng/ml

[\>]{.underline}Month 3 150-250 ng/ml 150-250 ng/ml

**Corticosteroids** were dosed as :

pulse corticosteroids on days 1-4

tapering to 10mg/day by month 6

between 5-10 mg/day by month 12

**Azathioprine**, the active comparator in study 301, was dosed at
2-3mg/kg/day.

7\) Prophylaxis for *Pneumocystis carinii* pneumonia was mandated for
one year post- transplant during this trial. CMV prophylaxis for the
"high risk" patient i.e. the CMV negative recipient of a CMV positive
donor kidney, was mandated for 3 months post transplant (using
center-specific therapy such as ganciclovir or acyclovir) and was also
recommended for lower risk renal transplant recipients. Prophylaxis for
urinary tract infection was routinely utilized for 6 weeks
post-transplant and the study centers chose the antibiotic according to
their standard practice.

###### Demographics {#demographics .unnumbered}

1\) Multi-organ transplants and high risk patients, as defined by the
criteria of high PRA or second transplant were excluded from studies 301
and 302.

2)  Study 301 had 35.2% living related (LRT) and living unrelated donors
    (LURT).

Study 302 had 23% LRT and LURT.

3\) Studies 301 and 302 enrolled different ethnic populations and thus
there may be differences in dietary habits and reporting of adverse
events.

4\) A significantly higher proportion of African-Americans and females
was assigned to the azathioprine arm in study 301.

5\) The majority of renal allograft donors were of white ethnic
background and were CMV positive.

6\) Glomerulonephritis and hypertension were the most common etiologies
for end stage renal disease in renal tranplant recipients.

# EFFICACY ISSUES

***Please refer to the FDA statistical review on efficacy for further
discussion regarding the results presented in the tables outlined
below.***

**Table 2**

Efficacy Failure at 6 months (Study 301)

+-------------------------+----------------+----------------+----------+
|                         | **SRL 2        | **SRL 5        | **Azathi |
|                         | mg/day**       | mg/day**       | oprine** |
|                         |                |                |          |
|                         | **(n=284)**    | **(n=274)**    | **(      |
|                         |                |                | n=161)** |
+-------------------------+----------------+----------------+----------+
| Overall rate of         | 53 (18.7)      | 46 (16.8)      | 52       |
| efficacy failure, n(%)  |                |                | (32.3)   |
|                         | 47 (16.5)      | 31 (11.3)      |          |
| Acute rejection         |                |                | 47       |
|                         | 3 (1.1)        | 8 (2.9)        | (29.2)   |
| Graft loss              |                |                |          |
|                         | 2 (0.7)        | 5 (1.8)        | 4 (2.5)  |
| Death                   |                |                |          |
|                         | 1 (0.4)        | 2 (0.7)        | 0        |
| Lost to follow-up       |                |                |          |
|                         |                |                | 1 (0.6)  |
+-------------------------+----------------+----------------+----------+
| CMH p-value             | 0.002          | 0.001          |          |
+-------------------------+----------------+----------------+----------+
| Relative risk           | 0.61           | 0.58           |          |
| (stratified)            |                |                |          |
|                         | (0.42, 0.88)   | (0.39, 0.85)   |          |
| (97.5% CI)              |                |                |          |
+-------------------------+----------------+----------------+----------+
| Stratified differences  | -13.3          | -14.6          |          |
| in rates                |                |                |          |
|                         | (-23.2, -3.4)  | (-24.5, -4.7)  |          |
| (97.5% CI)              |                |                |          |
+-------------------------+----------------+----------------+----------+
| Breslow-Day p-value     | 0.290          | 0.310          |          |
+-------------------------+----------------+----------------+----------+

***[Reviewer's note:]{.underline}*** ***Sirolimus 2 mg/day and sirolimus
5 mg/day both significantly reduced the incidence of efficacy failure
compared to azathioprine and placebo during the first 6 months
post-transplant.***

**Table 3**

Efficacy Failure at 6 months Stratified by Race (Study 301)

+-------------------------+----------------+----------------+----------+
|                         | **SRL 2        | **SRL 5        | **Azathi |
|                         | mg/day**       | mg/day**       | oprine** |
|                         |                |                |          |
|                         | **(n=284)**    | **(n=274)**    | **(      |
|                         |                |                | n=161)** |
+-------------------------+----------------+----------------+----------+
| Overall rate of         | 53 (18.7)      | 46 (16.8)      | 52       |
| efficacy failure, n(%)  |                |                | (32.2)   |
|                         | 22/63 (34.9)   | 11/61 (18.0)   |          |
| Blacks                  |                |                | 14/42    |
|                         | 31/221 (14.0)  | 35/213 (16.4)  | (33.3)   |
| Non-blacks              |                |                |          |
|                         |                |                | 36/119   |
|                         |                |                | (30.3)   |
+-------------------------+----------------+----------------+----------+
| CMH p-value             | 0.002          | 0.001          |          |
+-------------------------+----------------+----------------+----------+
| Breslow-Day p-value     | 0.024          | 0.928          |          |
+-------------------------+----------------+----------------+----------+

***[Reviewer's note]{.underline}: The rate of efficacy failure is
slightly higher in African-American patients treated with sirolimus 2
mg/day ( 34.9%) when compared to azathioprine (33.3%).***

**Table 4**

Patient and Graft Survival at 12 months (Study 301)

+-------------------------+----------------+----------------+----------+
|                         | **SRL 2        | **SRL 5        | **Azathi |
|                         | mg/day**       | mg/day**       | oprine** |
|                         |                |                |          |
|                         | **(n=284)**    | **(n=274)**    | **(      |
|                         |                |                | n=161)** |
+-------------------------+----------------+----------------+----------+
| Patient and Graft       | 269 (94.7)     | 254 (92.7)     | 151      |
| survival, n(%)          |                |                | (93.8)   |
|                         | 8              | 12             |          |
| Graft loss              |                |                | 8        |
|                         | 7              | 8              |          |
| Death                   |                |                | 2        |
+-------------------------+----------------+----------------+----------+
| Fisher's exact p-value  | 0.674          | 0.845          |          |
+-------------------------+----------------+----------------+----------+
| Relative risk           | 0.85           | 1.175          |          |
|                         |                |                |          |
| (97.5% CI)              | (0.35, 2.07)   | (0.51, 2.72)   |          |
+-------------------------+----------------+----------------+----------+
| Differences in rates    | 0.9            | -1.1           |          |
|                         |                |                |          |
| (97.5% CI)              | (-4.8, 6.6)    | (-7.1, 4.9)    |          |
+-------------------------+----------------+----------------+----------+

**Table 12**

Patient and Graft Survival at 12 months (study 302)

+-------------------------+----------------+----------------+----------+
|                         | **Rapamune 2   | **Rapamune 5   | **P      |
|                         | mg/day**       | mg/day**       | lacebo** |
|                         |                |                |          |
|                         | **(n=227)**    | **(n=219)**    | **(      |
|                         |                |                | n=130)** |
+-------------------------+----------------+----------------+----------+
| Patient and Graft       | 204 (89.9)     | 199 (90.9)     | 114      |
| survival, n(%)          |                |                | (87.7)   |
|                         | 15             | 11             |          |
| Graft loss              |                |                | 9        |
|                         | 8              | 9              |          |
| Death                   |                |                | 7        |
+-------------------------+----------------+----------------+----------+
| Fisher's exact p-value  | 0.597          | 0.366          |          |
+-------------------------+----------------+----------------+----------+
| Relative risk           | 0.82           | 0.74           |          |
|                         |                |                |          |
| (97.5% CI)              | (0.41, 1.64)   | (0.37, 1.51)   |          |
+-------------------------+----------------+----------------+----------+
| Differences in rates    | 2.2            | 3.2            |          |
|                         |                |                |          |
| (97.5% CI)              | (-6.3, 10.7)   | (-5.2, 11.6)   |          |
+-------------------------+----------------+----------------+----------+

***[Reviewer's note:]{.underline}*** ***Sirolimus 2 mg/day demonstrated
equivalence to azathioprine and placebo controls in 1 year patient and
graft survival. However, please note in Table 4, that for study 301 in
the sirolimus 5 mg/day arm, the lower limit of the 97.5% confidence
interval is between a delta of --5 and --10 and not between the target 0
and --5 . In study 302, the lower limits of the 97.5 % confidence
intervals were --6.3 and***

***--5.2 for sirolimus 2mg and 5mg , respectively. Therefore, one can
exclude no more than a 7% overall decrease in survival for the
sirolimus. In addition, for sirolimus 5 mg in study 301, the relative
risk for efficacy*** ***failure is also slightly greater than 1.0
(1.175). Thus, the overall treatment effects observed on acute rejection
were not associated with a detectable improvement in patient or graft
survival at one year.***

**Table 7**

Efficacy Failure at 6 months

Selected subgroups (Study 301)

+---------------------+-----------------+-----------------+-----------+
| **Subgroup**        | **SRL 2         | **SRL 5         | **Azath   |
|                     | mg/day**        | mg/day**        | ioprine** |
|                     |                 |                 |           |
|                     | **(n=284)**     | **(n=274)**     | **        |
|                     |                 |                 | (n=161)** |
+---------------------+-----------------+-----------------+-----------+
| Recipient Gender    | 14/76 (18.4)    | 20/103 (19.4)   | 17/71     |
|                     |                 |                 | (23.9)    |
| Female              | 39 /208         | 26/171          |           |
|                     | (18.8)^c^       | (15.2)^c^       | 35/90     |
| Male                |                 |                 | (38.9)    |
+---------------------+-----------------+-----------------+-----------+
| Donor Source        | 39/180 (21.7)   | 28/167          | 34/119    |
|                     |                 | (16.8)^a^       | (28.6)    |
| Cadaver             | 10/86 (11.6)^c^ |                 |           |
|                     |                 | 15/83 (18.1)^b^ | 14/33     |
| Living Related      | 4/18 (22.2)     |                 | (42.4)    |
|                     |                 | 3/24 (12.5)     |           |
| Living Unrelated    |                 |                 | 4/9       |
|                     |                 |                 | (44.4)    |
+---------------------+-----------------+-----------------+-----------+
| Number of HLA       | 12/69 (17.4)    | 8/69 (11.6)     | 7/42      |
| mismatches          |                 |                 | (16.7)    |
|                     | 41/215          | 38/205          |           |
| 0 to 2              | (19.1)^c^       | (18.5)^c^       | 45/119    |
|                     |                 |                 | (37.8)    |
| 3 to 6              |                 |                 |           |
+---------------------+-----------------+-----------------+-----------+
| a: Comparison with  |                 |                 |           |
| azathioprine        |                 |                 |           |
| statistically       |                 |                 |           |
| significant at less |                 |                 |           |
| than 0.05.          |                 |                 |           |
|                     |                 |                 |           |
| b: Comparison with  |                 |                 |           |
| azathioprine        |                 |                 |           |
| statistically       |                 |                 |           |
| significant at less |                 |                 |           |
| than 0.01           |                 |                 |           |
|                     |                 |                 |           |
| c: Comparison with  |                 |                 |           |
| azathioprine        |                 |                 |           |
| statistically       |                 |                 |           |
| significant at less |                 |                 |           |
| than 0.001.         |                 |                 |           |
+---------------------+-----------------+-----------------+-----------+

**Table 15**

Efficacy Failure at 6 months

Selected subgroups (Study 302)

+---------------------+-----------------+-----------------+-----------+
| **Subgroup**        | **SRL 2         | **SRL 5         | **        |
|                     | mg/day**        | mg/day**        | Placebo** |
|                     |                 |                 |           |
|                     | **(n=227)**     | **(n=219)**     | **        |
|                     |                 |                 | (n=130)** |
+---------------------+-----------------+-----------------+-----------+
| Recipient Race      | 8/26 (30.8)     | 9/27 (33.3)     | 5/13      |
|                     |                 |                 | (38.5)    |
| Blacks              | 60/201          | 47/192          |           |
|                     | (29.9)^c^       | (24.5)^c^       | 57/117    |
| Non-blacks          |                 |                 | (48.7)    |
+---------------------+-----------------+-----------------+-----------+
| Recipient Gender    | 27/79 (34.2)    | 21/70 (30.0)    | 16/39     |
|                     |                 |                 | (41.0)    |
| Female              | 41/148          | 35/149          |           |
|                     | (27.7)^c^       | (23.5)^c^       | 46/91     |
| Male                |                 |                 | (50.6)    |
+---------------------+-----------------+-----------------+-----------+
| Donor Source        | 54/173          | 48/174          | 43/99     |
|                     | (31.2)^a^       | (27.6)^b^       | (43.4)    |
| Cadaver             |                 |                 |           |
|                     | 14/39 (35.9)    | 5/29 (17.2)^b^  | 16/27     |
| Living Related      |                 |                 | (59.3)    |
|                     | 0/15 (0.0)^b^   | 3/16 (18.8)     |           |
| Living Unrelated    |                 |                 | 3/4       |
|                     |                 |                 | (75.0)    |
+---------------------+-----------------+-----------------+-----------+
| Number of HLA       | 13/51 (25.5)    | 10/60 (16.7)    | 7/30      |
| mismatches          |                 |                 | (23.3)    |
|                     | 55/176          | 46/159          |           |
| 0 to 2              | (31.3)^c^       | (28.9)^c^       | 55/100    |
|                     |                 |                 | (55.0)    |
| 3 to 6              |                 |                 |           |
+---------------------+-----------------+-----------------+-----------+
| a: Comparison with  |                 |                 |           |
| azathioprine        |                 |                 |           |
| statistically       |                 |                 |           |
| significant at less |                 |                 |           |
| than 0.05.          |                 |                 |           |
|                     |                 |                 |           |
| b: Comparison with  |                 |                 |           |
| azathioprine        |                 |                 |           |
| statistically       |                 |                 |           |
| significant at less |                 |                 |           |
| than 0.01           |                 |                 |           |
|                     |                 |                 |           |
| c: Comparison with  |                 |                 |           |
| azathioprine        |                 |                 |           |
| statistically       |                 |                 |           |
| significant at less |                 |                 |           |
| than 0.001.         |                 |                 |           |
+---------------------+-----------------+-----------------+-----------+

######### Reviewer's note: Among women in study 301, there was not a statistically significant difference in efficacy failure between treatment groups. Though not statistically significant, a larger proportion of subjects in study 301 received organs from living donors in the sirolimus treatment groups compared to the azathioprine control group: sirolimus 2 mg (104/284 or 36.6%), sirolimus 5 mg (107/274 or 39.1%) and azathioprine (42 /161 or 26.1%) {#reviewers-note-among-women-in-study-301-there-was-not-a-statistically-significant-difference-in-efficacy-failure-between-treatment-groups.-though-not-statistically-significant-a-larger-proportion-of-subjects-in-study-301-received-organs-from-living-donors-in-the-sirolimus-treatment-groups-compared-to-the-azathioprine-control-group-sirolimus-2-mg-104284-or-36.6-sirolimus-5-mg-107274-or-39.1-and-azathioprine-42-161-or-26.1 .unnumbered}

######### Patients with \>3- 6 HLA mismatches had significant improvement with either dose of sirolimus when compared to azathioprine in study 301 or to placebo in study 302. Please see Table 15 which has the study 302 results. However, recipients at higher risk for acute rejection, including recipients of cadaveric kidneys and those with more than 2 HLA mismatches, did not significantly benefit from the 5 mg dose compared to the 2 mg dose of sirolimus. {#patients-with-3--6-hla-mismatches-had-significant-improvement-with-either-dose-of-sirolimus-when-compared-to-azathioprine-in-study-301-or-to-placebo-in-study-302.-please-see-table-15-which-has-the-study-302-results.-however-recipients-at-higher-risk-for-acute-rejection-including-recipients-of-cadaveric-kidneys-and-those-with-more-than-2-hla-mismatches-did-not-significantly-benefit-from-the-5-mg-dose-compared-to-the-2-mg-dose-of-sirolimus. .unnumbered}

Additional points regarding the efficacy of sirolimus include:

1\) Pharmacodynamic analysis does not demonstrate that African-American
patients had lower trough levels of either cyclosporine or sirolimus.
The Applicant proposes that there may be an efficacy benefit in
monitoring sirolimus blood levels and attempting to achieve a higher
trough i.e. closer to 20 ng/ml. The mean trough levels achieved with
sirolimus 2 mg/day were 8.59 ng/ml and with sirolimus 5 mg/day were 17.3
ng/ml. A trough level of 10 ng/ml may be necessary in order to attain a
significant efficacy benefit. This issue of how to optimally dose a
"high risk patient" requires further investigation especially since
studies 301 and 302 were not designed to address the issue of efficacy
in the "high risk population". Monitoring of sirolimus trough levels is
recommended for patients with hepatic disease, reduced or elevated
sirolimus clearance, pediatric age, necessity of cyclosporine dose
reduction or discontinuation or the need to administer concomitant
medications that may have a substantial effect on sirolimus metabolism.
Sirolimus trough levels greater than 30 ng/ml have been associated with
an increased rate of side effects.

2\) Sirolimus is a substrate for both cytochrome P450 IIIA4 (CYP3A4) and

p-glycoprotein. Please refer to the Applicant's briefing package for a
full description of the metabolism and drug interactions with this
product.

***[Reviewer's note:]{.underline} Additional studies are needed to
ascertain the factors that contribute to the higher rate of efficacy
failure in the black patients who received sirolimus 2 mg/day. The
Applicant is recommending that the higher dose of sirolimus 5 mg/day be
used in black patients as well as other "high risk" groups. However, the
factors that cause this reduced efficacy in black patients do not appear
to be related to differences in sirolimus pharmacokinetics.
Consequently, any recommendations for an increased sirolimus or
cyclosporine dose must be weighed against the side-effects of these
drugs i.e. the problems with "over-immunosuppression" and drug
toxicity.***

##   {#section .unnumbered}

3)  In studies 301 and 302, the use of anti-T-lymphocyte antibody
    therapies to treat the first biopsy-confirmed acute rejection during
    the first 6 months post-transplant was significantly reduced for
    sirolimus 5 mg compared to the control groups.

***[Reviewer's note:]{.underline} This decrement in the use of anti-
T-lymphocyte antibody preparations was a secondary study endpoint and
did not translate into improved survival, decreased rate of infection or
decreased rate of post-transplant lymphoproliferative disease (PTLD). In
fact, the incidence of PTLD was highest in the sirolimus 5 mg study
arm.***

# Safety

Of the 1295 patients enrolled in studies 301 and 302, 1260 patients
received randomized treatment and were considered evaluable for safety.

1.  **Please refer to the Applicant's briefing package for more detailed
    information regarding deaths and graft loss.**

The most common reasons for deaths were vascular (cardiovascular or
cerebrovascular) and infection. The overall death rate in study 301 and
302 was 3.7%. This included death rates of : 3.1% sirolimus 2 mg/day

4.5% sirolimus 5 mg/day

1.9% Azathioprine

> 5.4% Placebo

**[Table 3 Study 301]{.underline}**

Summary of Deaths, Graft Loss, Malignancy, Life-Threatening Adverse
Events

+------------------------------+------------+-----------+-------------+
| **Event**                    | **SRL**    | **SRL**   | ####        |
|                              |            |           | Aza {#aza . |
|                              | **2        | **5       | unnumbered} |
|                              | mg/day**   | mg/day**  |             |
|                              |            |           | (n=161)     |
|                              | (n=284)    | (n=274)   |             |
+------------------------------+------------+-----------+-------------+
| Death                        | 3 (1.1)    | 8 (2.9)   | 3 (1.9)     |
+------------------------------+------------+-----------+-------------+
| Graft Loss                   | 4 (1.4)    | 12 (4.3)  | 7 (4.3)     |
+------------------------------+------------+-----------+-------------+
| Malignancy                   | 1 (0.4)    | 2 (0.7)   | 3 (1.9)     |
+------------------------------+------------+-----------+-------------+
| Life-Threatening Adverse     | 6 (2.1)    | 4 (1.5)   | 0           |
| Event                        |            |           |             |
+------------------------------+------------+-----------+-------------+
|                              |            |           |             |
+------------------------------+------------+-----------+-------------+
|                              |            |           |             |
+------------------------------+------------+-----------+-------------+

**[Table 4 Study 302]{.underline}**

Summary of Deaths, Graft Loss, Malignancy, Life-Threatening Adverse
Events

+------------------------------+------------+-----------+-------------+
| **Event**                    | **SRL**    | **SRL**   | ###         |
|                              |            |           | #  Placebo  |
|                              | **2        | **5       | {#placebo . |
|                              | mg/day**   | mg/day**  | unnumbered} |
|                              |            |           |             |
|                              | (n=227)    | (n=219)   | (n=130)     |
+------------------------------+------------+-----------+-------------+
| Death                        | 5 (2)      | 8(4)      | 6 (5)       |
+------------------------------+------------+-----------+-------------+
| Graft Loss                   | 16 (7)     | 16 (7)    | 15 (12)     |
+------------------------------+------------+-----------+-------------+
| Malignancy                   | 3 (1)      | 2 (1)     | 1 (1)       |
+------------------------------+------------+-----------+-------------+
| Life-Threatening Adverse     | 1 (\<1)    | 2 (1)     | 1 (1)       |
| Event                        |            |           |             |
+------------------------------+------------+-----------+-------------+

2.  The most common etiology of graft loss was death with a functioning
    graft and the second most common etiology was acute rejection.
    Please refer to the Applicant's briefing package for a full
    discussion.

3.  The incidence of malignancy (post-transplant lymphoproliferative
    disease PTLD/lymphoma) during the first year post-transplant was
    higher in the sirolimus 5 mg/day group with an overall incidence of
    1.4%. The rates of PTLD in this trial were similar to that which has
    been reported in other trials of immunosuppressive agents.

***[Reviewer's note:]{.underline} Epstein-Barr virus (EBV) serologies
were not collected on patients at study onset and thus I can not comment
on whether the cases of PTLD were in "high risk" EBV-negative transplant
recipients of EBV-positive donor kidneys.***

## Please refer to the Applicant's briefing package regarding a discussion on discontinuation of study drug. The most frequent reason for discontinuation in the sirolimus 2 mg/day group was an unsatisfactory response and in the sirolimus 5 mg group it was an adverse event. Tables 5 and 6 below (and Tables 18 and 21 of the FDA statistical review) outline the clinically important treatment emergent adverse events (TEAE) that occur in studies 301 and 302 respectively. These tables also demonstrate the side effects that appear to be dose-dependent. Hypertension, diarrhea, anemia, leukopenia, thrombocytopenia and hyperlipidemia show an increased frequency at the higher dose of sirolimus. 

######## Table 5 {#table-5 .unnumbered}

Number (%) of **Study 301** Patients Reporting Clinically Important TEAE

Excluding Infection and Malignancy

+---------------------------+----------+----------+-----------+-------+
| **Body system**           | **SRL**  | **SRL**  | ##        | p-    |
|                           |          |          | ## Azathi | value |
| Event                     | **2      | **5      | o-prine { |       |
|                           | mg/day** | mg/day** | #azathio- |       |
|                           |          |          | prine .un |       |
|                           | (n=281)  | (n=269)  | numbered} |       |
|                           |          |          |           |       |
|                           |          |          | (n=159)   |       |
+---------------------------+----------+----------+-----------+-------+
| Body as a whole           | 44 (16)  | 50 (19)  | 12 (8)    | 0.00  |
|                           |          |          |           | 5^\*^ |
| Headache                  | 33 (12)  | 36 (13)  | 4 (3)     |       |
|                           |          |          |           | \     |
| Lymphocele                |          |          |           | <0.00 |
|                           |          |          |           | 1^\*^ |
+---------------------------+----------+----------+-----------+-------+
| Cardiovascular system     | 96 (34)  | 89 (33)  | 35 (22)   | 0.01  |
|                           |          |          |           | 7^\*^ |
| Hypertension              |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Digestive system          | 50 (18)  | 74 (28)  | 18 (11)   | \     |
|                           |          |          |           | <0.00 |
| Diarrhea                  | 24 (9)   | 26 (10)  | 14 (9)    | 1^\*^ |
|                           |          |          |           |       |
| Liver function tests      |          |          |           | 0.381 |
| abnormal                  |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Endocrine system          | 14 (5)   | 22 (8)   | 8(5)      | 0.256 |
|                           |          |          |           |       |
| Diabetes mellitus         |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Hemic and lymphatic       | 56 (20)  | 73 (27)  | 32 (20)   | 0.096 |
| system                    |          |          |           |       |
|                           | 14 (5)   | 28 (10)  | 17 (11)   | 0.02  |
| Anemia                    |          |          |           | 7^\*^ |
|                           | 25 (9)   | 47 (17)  | 9 (6)     |       |
| Leukopenia                |          |          |           | \     |
|                           | 2 (\<1)  | 4 (1)    | 0         | <0.00 |
| Thrombocytopenia          |          |          |           | 1^\*^ |
|                           |          |          |           |       |
| Thrombotic                |          |          |           | 0.283 |
| thrombocytopenia purpura  |          |          |           |       |
| (TTP)                     |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Metabolic and nutritional | 61 (22)  | 64 (24)  | 32 (20)   | 0.669 |
|                           |          |          |           |       |
| Creatinine increased      | 22 (8)   | 24 (9)   | 6 (4)     | 0.120 |
|                           |          |          |           |       |
| Healing abnormal          | 84 (30)  | 94 (35)  | 34 (21)   | 0.01  |
|                           |          |          |           | 2^\*^ |
| Hypercholesteremia        | 34 (12)  | 39 (14)  | 18 (11)   |       |
|                           |          |          |           | 0.581 |
| Hyperglycemia             | 34 (12)  | 22 (8)   | 30(19)    |       |
|                           |          |          |           | 0.00  |
| Hyperkalemia              | 83 (30)  | 103 (38) | 29 (18)   | 5^\*^ |
|                           |          |          |           |       |
| Hyperlipemia              | 137 (49) | 134 (50) | 68 (43)   | \     |
|                           |          |          |           | <0.00 |
| Peripheral edema          |          |          |           | 1^\*^ |
|                           |          |          |           |       |
|                           |          |          |           | 0.343 |
+---------------------------+----------+----------+-----------+-------+
| Musculoskeletal system    | 40 (14)  | 53 (20)  | 18 (11)   | 0.053 |
|                           |          |          |           |       |
| Arthralgia                |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Nervous system            | 14 (5)   | 14 (5)   | 1 (\<1)   | 0.02  |
|                           |          |          |           | 2^\*^ |
| Hypotonia                 | 28(10)   | 51 (19)  | 19 (12)   |       |
|                           |          |          |           | 0.00  |
| Insomnia                  | 60 (21)  | 64 (24)  | 25 (16)   | 8^\*^ |
|                           |          |          |           |       |
| Tremor                    |          |          |           | 0.136 |
+---------------------------+----------+----------+-----------+-------+
| Respiratory system        | 8 (3)    | 13 (5)   | 1 (\<1)   | 0.04  |
|                           |          |          |           | 3^\*^ |
| Epistaxis                 |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Skin and appendages       | 67 (24)  | 49 (18)  | 18 (11)   | 0.00  |
|                           |          |          |           | 4^\*^ |
| Acne                      | 14 (5)   | 32 (12)  | 3 (2)     |       |
|                           |          |          |           | \     |
| Hirsutism                 | 23 (8)   | 19 (7)   | 3 (2)     | <0.00 |
|                           |          |          |           | 1^\*^ |
| Rash                      |          |          |           |       |
|                           |          |          |           | 0.01  |
|                           |          |          |           | 6^\*^ |
+---------------------------+----------+----------+-----------+-------+
| \*Overall difference      |          |          |           |       |
| among treatment groups    |          |          |           |       |
| assessed by Fisher's      |          |          |           |       |
| exact test.               |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
|                           |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+

***[Reviewer's note:]{.underline} Some adverse events commonly
associated with cyclosporine such as hypertension, tremor, headache and
hirsutism were more frequently reported in the sirolimus treatment
groups in study 301.***

**Table 6**

Number (%) of **Study 302** Pts. Reporting Clinically Important TEAE

Excluding Infection and Malignancy

+---------------------------+----------+----------+-----------+-------+
| **Body system**           | **SRL**  | **SRL**  | ##        | p-    |
|                           |          |          | ##  Place | value |
| Event                     | **2      | **5      | bo {#plac |       |
|                           | mg/day** | mg/day** | ebo-1 .un |       |
|                           |          |          | numbered} |       |
|                           | (n=218   | (n=208)  |           |       |
|                           |          |          | (n=124)   |       |
+---------------------------+----------+----------+-----------+-------+
| Body as a whole           | 55 (25)  | 57 (27)  | 23 (19)   | 0.184 |
|                           |          |          |           |       |
| Headache                  | 20 (9)   | 25 (12)  | 6 (5)     | 0.091 |
|                           |          |          |           |       |
| Lymphocele                |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Cardiovascular system     | 80 (37)  | 84 (40)  | 51 (41)   | 0.611 |
|                           |          |          |           |       |
| Hypertension              |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Digestive system          | 36 (16)  | 50 (24)  | 17 (14)   | 0.03  |
|                           |          |          |           | 8^\*^ |
| Diarrhea                  |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Endocrine system          | 9 (4)    | 16 (8)   | 3 (2)     | 0.082 |
|                           |          |          |           |       |
| Diabetes mellitus         |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Hemic and lymphatic       | 36 (16)  | 56 (27)  | 16 (13)   | 0.00  |
| system                    |          |          |           | 3^\*^ |
|                           | 15 (7)   | 18 (9)   | 3 (2)     |       |
| Anemia                    |          |          |           | 0.069 |
|                           | 25 (11)  | 47 (23)  | 4 (3)     |       |
| Leukopenia                |          |          |           | \     |
|                           | 4 (2)    | 7 (3)    | 2 (2)     | <0.00 |
| Thrombocytopenia          |          |          |           | 1^\*^ |
|                           |          |          |           |       |
| Thrombic thrombocytopenia |          |          |           | 0.586 |
| purpura (TTP)^1^          |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+
| Metabolic and nutritional | 19 (9)   | 20 (10)  | 9 (7)     | 0.777 |
|                           |          |          |           |       |
| ALT increased             | 9 (4)    | 15 (7)   | 6 (5)     | 0.369 |
|                           |          |          |           |       |
| AST increased             | 56 (26)  | 65 (31)  | 40 (32)   | 0.295 |
|                           |          |          |           |       |
| Creatinine increased      | 15 (7)   | 22 (11)  | 7 (6)     | 0.224 |
|                           |          |          |           |       |
| Healing abnormal          | 81 (37)  | 91 (44)  | 25 (20)   | \     |
|                           |          |          |           | <0.00 |
| Hypercholesteremia        | 23 (11)  | 25 (12)  | 12 (10)   | 1^\*^ |
|                           |          |          |           |       |
| Hyperglycemia             | 29 (13)  | 23 (11)  | 28 (23)   | 0.786 |
|                           |          |          |           |       |
| Hyperkalemia              | 76 (35)  | 103 (50) | 22 (18)   | 0.01  |
|                           |          |          |           | 6^\*^ |
| Hyperlipemia              | 93 (42)  | 98 (47)  | 43 (35)   |       |
|                           |          |          |           | \     |
| Peripheral edema          |          |          |           | <0.00 |
|                           |          |          |           | 1^\*^ |
|                           |          |          |           |       |
|                           |          |          |           | 0.086 |
+---------------------------+----------+----------+-----------+-------+
| \*Overall difference      |          |          |           |       |
| among treatment groups    |          |          |           |       |
| assessed by Fisher's      |          |          |           |       |
| exact test.               |          |          |           |       |
|                           |          |          |           |       |
| ^1^All patiens with       |          |          |           |       |
| hemolytic uremic syndrome |          |          |           |       |
| (HUS) were coded to this  |          |          |           |       |
| term.                     |          |          |           |       |
+---------------------------+----------+----------+-----------+-------+

## The major toxicities that I will now focus on will include: infection, hyperlipidemia, post-transplant diabetes mellitus, elevated liver function tests , hematologic toxicity, HUS/TTP and renal function. 

*[Reviewer's note:]{.underline}* *The applicant recommends that "high
risk patients" be administered the sirolimus 5 mg/day dose. They infer
that the African-American population incurred less side effects/less
risk from sirolimus. Please keep in mind that there were only 166 black
patients in study 301. Regarding complications from cytomegalovirus
infection---the African-American patients may have been a lower risk
population to develop serious CMV infection and serious CMV disease.*

## INFECTION

1)  There was a decreased incidence of CMV in studies 301 and 302 that
    the Applicant partially attributed to the use of CMV prophylaxis.
    However, assessment of the degree of CMV donor and recipient
    mismatch for study 301 demonstrated that the majority of the black
    and non-black patients in study 301 were not at high risk to develop
    serious CMV infection or disease i.e. they were not CMV negative
    recipients (R-) of CMV positive donor kidneys (D+) i.e. (CMV D+R-).

[Reviewer's note:]{.underline} The applicant recommends that "high risk
patients" be administered the sirolimus 5 mg/day dose. They claim that
the black population incurred less side effects/less risk from
sirolimus. Please keep in mind that there were only 166 African-American
patients in study 301. Regarding complications from cytomegalovirus
infection---the African-American patients may have been a low risk
population to develop serious CMV infection and serious CMV disease.

[Table 7]{.underline} Analysis Black patients with "high risk" to
develop serious CMV infection and disease (CMV D+R-)

+-----------+---------------+--------------------+--------------------+
| **Study   | **Black**     | **Black patients** | **Black Pts. with  |
| 301**     |               |                    | unknown D/R        |
|           | **Pts. in     | **CMV D+/R-**      | serologic status   |
| **        | 301**         |                    | for CMV**          |
| Treatment |               | **"high risk"**    |                    |
| Arms**    |               |                    |                    |
+-----------+---------------+--------------------+--------------------+
| **AZA**   | **42**        | **5/42 (11.9%)**   | **4**              |
+-----------+---------------+--------------------+--------------------+
| **SRL 2** | **63**        | **4/63 (6.3%)**    | **4**              |
+-----------+---------------+--------------------+--------------------+
| **SRL 5** | **61**        | **2/61 (3.3%)**    | **3**              |
+-----------+---------------+--------------------+--------------------+
| **Total   | **166**       | **11/166 (6.6%)**  | **11 (6.6%)**      |
| Black     |               |                    |                    |
| p         |               |                    |                    |
| atients** |               |                    |                    |
+-----------+---------------+--------------------+--------------------+

> **[Table 8]{.underline}** **Analysis Non-Black patients with "high
> risk" to develop serious CMV infection and disease (CMV D+R-)**

+-----------+---------------+--------------------+--------------------+
| **Study   | **Non-Black   | **Non-Black        | **Non-Black with   |
| 301**     | Pts. in 301** | patients**         | unknown serologic  |
|           |               |                    | status for CMV**   |
| **Tr      |               | **CMV D+/R-**      |                    |
| eatment** |               |                    |                    |
|           |               | **"high risk"**    |                    |
| **Arms**  |               |                    |                    |
+-----------+---------------+--------------------+--------------------+
| **AZA**   | **119**       | **21/119 (17.6%)** | **0**              |
+-----------+---------------+--------------------+--------------------+
| **SRL 2** | **221**       | **55 /221          | **3**              |
|           |               | (25.0%)**          |                    |
+-----------+---------------+--------------------+--------------------+
| **SRL 5** | **213**       | **46 /213          | **5**              |
|           |               | (21.6%)**          |                    |
+-----------+---------------+--------------------+--------------------+
| **Total   | **553**       | **122/553          | **8 (1.5%)**       |
| Non-Black |               | (22.1%)**          |                    |
| p         |               |                    |                    |
| atients** |               |                    |                    |
+-----------+---------------+--------------------+--------------------+

**[*Reviewer's note*:]{.underline} *As one can see in the above tables,
the percentage of black patients in study 301, who were at high risk to
develop CMV infection and disease, was only 6.6%. The non-black patients
in study 301 carried a "high risk" of 22.1%. Study 302 enrolled less
black patients. However, once again, of the 66 black patients enrolled
in study302, only 2 were CMV negative recipients of CMV positive donor
kidneys. Many different host and epidemiologic factors, as well as the
level of immunosuppression, contribute to the development of
post-transplant infection. One must be careful not to overlook these
factors and falsely assume that the black population "better tolerated"
the sirolimus or that this population is "under-immunosuppressed"
because they developed fewer problems with CMV infection, opportunistic
infection and PTLD****.*

2)  There was no increase in the rates of sepsis, pyelonephritis, wound
    infection and pneumonia across treatment groups in studies 301 and
    302.

3)  There was no increase in the incidence of opportunistic infection in
    either of the sirolimus treatment groups compared to the control
    groups in studies 301 and 302, except for a higher incidence of
    mucosal *Herpes simplex* in the sirolimus 5 mg group.

4)  Despite differences between treatment groups, with respect to
    episodes of acute

> rejection requiring additional high doses of immunosuppression, there
> were no significant differences between treatment groups with respect
> to serious infection.

***[Reviewer's note:]{.underline}*** ***The increased incidence of
mucosal herpes simplex is quite unusual considering many of these
patients were receiving either acyclovir or ganciclovir prophylaxis for
CMV infection. Either of these two antiviral drugs has efficacy against
Herpes simplex virus. Please note that the diagnosis of Herpes simplex
infection can be problematic in that it was not confirmed by laboratory
tests such as culture.***

**B) HYPERLIPIDEMIA**

***[Reviewer's note:]{.underline}*** ***The following tables pertain to
an analysis of treatment emergent abnormalities in serum cholesterol and
triglycerides that developed in transplant recipients in Studies 301 and
302*** .***Data was not collected for HDL, LDL or apolipoproteins during
Studies 301 and 302. Consequently, the following analysis utilizes a
threshold for "normal cholesterol" as \< 200 mg/dl and "elevated
cholesterol" as [\>]{.underline}240 mg/dl. Keep in mind that the
National Cholesterol Education Program (NCEP) guidelines for
intervention utilizing lipid-lowering agents relies on data that was not
available for our review such as LDL values and cardiac risk factors.
The threshold values utilized for the triglyceride analysis include a
"normal triglceride" value of \<200 mg/dl and "elevated triglyceride"
value of [\>]{.underline}500 mg/dl.***

***The lipid analysis below differs from the Applicant's analysis in
that it evaluates a cohort of patients who had normal cholesterol and
triglyceride levels prior to initiation of study drug and who developed
hyperlipidemia while on study drug. Hyperlipidemia has been identified
as a major side-effect with sirolimus and has surfaced in all Phase II
and Phase III studies.***

**[TABLE 9 Study 301 patients who developed hypercholesterolemia on
study drug]{.underline}**

  --------------------- ------------------ ------------------ -----------------
  **\# study 301        **Azathioprine**   **Sirolimus 2mg**  **Sirolimus 5mg**
  patients**                                                  

  **Total \# study      **161**            **284**            **274**
  patients in each                                            
  treatment arm**                                             

  **Pts. with pre-study **116/161          **204/284          **195/274
  chol.\<200mg/dl**     (72.1%)**          (71.8%)**          (71.2%)**

  **Pts. with normal    **55/116 (47.4%)** **131/204          **133/195
  baseline cholesterol                     (64.2%)**          (68.2%)**
  who developed chol.                                         
  [\>]{.underline}240                                         
  mg/dl on study drug**                                       

  **Fisher's exact                         **0.005**          **0.0003**
  p-value**                                                   
  --------------------- ------------------ ------------------ -----------------

**[TABLE 10 Study 302 Patients who developed hypercholesterolemia on
study drug]{.underline}**

  --------------------- ----------------- ----------------- -----------------
  **\# study 302        **Placebo**       **Sirolimus 2     **Sirolimus 5
  patients**                              mg**              mg**

  **Total \# patients   **130**           **227**           **219**
  in each treatment                                         
  arm**                                                     

  **Pts. with pre-study **95/130          **163/227         **165/219
  chol.\<200mg/dl**     (73.1%)**         (71.8%)**         (75.3%)**

  **Pts. with normal    **39/95 (41.1%)** **123/163         **120/165
  baseline cholesterol                    (75.5%)**         (72.7%)**
  who developed chol.                                       
  [\>]{.underline}240                                       
  mg/dl on study drug**                                     

  **Fisher's exact                        **\<0.0001**      **\<0.0001**
  p-value**                                                 
  --------------------- ----------------- ----------------- -----------------

***[Reviewer's note:]{.underline} A significant risk to develop new
onset hypercholesterolemia , above and beyond the risk anticipated from
cyclosporine, exists in the sirolimus treatment arm and was identified
in both study 301 and 302.***

###### TABLE 11 Study 301 patients who developed hypertriglyceridemia on study drug {#table-11-study-301-patients-who-developed-hypertriglyceridemia-on-study-drug .unnumbered}

+-----------------------+------------+---------------+----------------+
| **Study 301**         | **AZA**    | **Sirolimus 2 | **Sirolimus 5  |
| **patients**          |            | mg**          | mg**           |
+-----------------------+------------+---------------+----------------+
| **Total \# patients   | **161**    | **284**       | **274**        |
| in each treatment     |            |               |                |
| arm**                 |            |               |                |
+-----------------------+------------+---------------+----------------+
| **Pts. with pre-study | **121/161  | **207/284     | **229/274**    |
| TG[\<]{               | (75.2%)**  | (72.9%)**     |                |
| .underline}200mg/dl** |            |               | **(83.6%)**    |
+-----------------------+------------+---------------+----------------+
| **Pts. with normal    | **6/121    | **30/207      | **4            |
| baseline TG who       | (5.0%)**   | (14.5%)**     | 1/229(17.9%)** |
| developed TG \>500    |            |               |                |
| mg/dl on study drug** |            |               |                |
+-----------------------+------------+---------------+----------------+
| **Fisher's exact      |            | **0.01**      | **0.0005**     |
| p-value**             |            |               |                |
+-----------------------+------------+---------------+----------------+

###### TABLE 12 Study 302 patients who developed hypertriglyceridemia on study drug {#table-12-study-302-patients-who-developed-hypertriglyceridemia-on-study-drug .unnumbered}

  ------------------------------ ------------- ---------------- ----------------
  **Study 302 patients**         **Placebo**   **Sirolimus 2    **Sirolimus 5
                                               mg**             mg**

  **Total \# patients in each    **130**       **227**          **219**
  treatment arm**                                               

  **Pts. with pre-study          **89          **168 (74.0%)**  **170 (77.6%)**
  TG[\<]{.underline}200mg/dl**   (68.5%)**                      

  **Pts. with normal baseline TG **2 (2.2)**   **26 (15.5)**    **40 (23.5)**
  who developed TG \>500 mg/dl                                  
  on study drug**                                               

  **Fisher's exact p-value**                   **0.0006**       **\<0.0001**
  ------------------------------ ------------- ---------------- ----------------

***[Reviewer's note:]{.underline} A significant risk to develop new
onset hypertriglyceridemia, above and beyond the risk anticipated from
cyclosporine, exists in the sirolimus treatment arms and has been
identified in both study 301 and 302.***

###### Table 13 Analysis of the use of lipid lowering agents Study 301 {#table-13-analysis-of-the-use-of-lipid-lowering-agents-study-301 .unnumbered}

  ----------------------------------- --------------- ----------- -------------
  **Study 301**                       **AZA**         **SRL 2     **SRL 5 mg**
                                                      mg**        

  **Patients with normal cholesterol  **116**         **204**     **195**
  pre-study**                                                     

  **Patients initiated on lipid       **25(21.6%)**   **93        **101
  -lowering drug**                                    (45.6%)**   (51.8%)**

  **Patients who continued on lipid   **23(20%)**     **59        **69 (35%)**
  lowering drug at 6-12 months**                      (29%)**     
  ----------------------------------- --------------- ----------- -------------

**[Table 14]{.underline} Analysis of the use of lipid lowering agents
Study 302**

  ---------------------------------- ------------- ----------- --------------
  **Study 302**                      **Placebo**   **SRL 2     **SRL 5 mg**
                                                   mg**        

  **Patients with normal cholesterol **95**        **163**     **165**
  pre-study**                                                  

  **Patients initiated on lipid      **15          **69        **77 (46.7%)**
  -lowering drug**                   (15.8%)**     (42.3%)**   

  **Patients who continued on lipid  **11 (12%)**  **47        **64 (39%)**
  lowering drug at 6-12 months**                   (29%)**     
  ---------------------------------- ------------- ----------- --------------

***[Reviewer's note:]{.underline} In study 301, approximately 22% of the
patients with normal cholesterol at study onset who developed
hypercholesterolemia on azathioprine as did 46 to 52 %. In study 302,
approximately 16% of the azathioprine patients were initiated on
lipid-lowering agents and 42-47% of the patients on sirolimus. Once
initiated on a lipid lowering agent, at least 60 % of the patients
continued on the lipid lowering agent at study's end. The majority of
the lipid- lowering agents used were HMG-CoA reductase inhibitors.***

**[Table 15]{.underline}**

Demographics for patients who developed elevated chol. while on study
301

+-------------+--------------------+--------------+-------------------+
|             | **Azathioprine**   | **Sirolimus  | **Sirolimus 5     |
|             |                    | 2 mg**       | mg**              |
|             | **N=55**           |              |                   |
|             |                    | **N=131**    | **N=133**         |
+-------------+--------------------+--------------+-------------------+
| **Black**   | **16 (29%)**       | **24         | **26 (19.5%)**    |
|             |                    | (18.3%)**    |                   |
+-------------+--------------------+--------------+-------------------+
| **          | **39 (71%)**       | **107        | **107 (80.5%)**   |
| Non-Black** |                    | (81.7%)**    |                   |
+-------------+--------------------+--------------+-------------------+
| **Male**    | **25 (45.5%)**     | **94 (72%)** | **77 (56%)**      |
+-------------+--------------------+--------------+-------------------+
| **Female**  | **30 (54.5%)**     | **37 (28%)** | **56 (42%)**      |
+-------------+--------------------+--------------+-------------------+

***[Reviewer's comment:]{.underline} As seen in the above tables, it is
obvious that a significant proportion of patients who entered these
trials with normal lipid profiles, and were treated with sirolimus,
developed a new problem with either elevated cholesterol and/or elevated
triglycerides. The Applicant states that this problem was manageable
with diet, exercise, lipid -lowering agents, reduction in
corticosteroids and cyclosporine and that there was no evidence of major
vascular disease at the end of one year. However, one year is too early
to assess the major sequelae of this hyperlipidemia. Please also keep in
mind that these patients may carry additional risk factors for heart
disease such as family history, diabetes and hypertension. Values for
HDL, LDL and the apolipoproteins were not collected during this trial
and consequently it was not possible to include these parameters in the
assessment of hyperlipidemia. We looked at the potential role of
elevated cyclosporine/sirolimus levels contributing to hyperlipidemia,
but found no data to substantiate a correlation. There was no
significant increase in hyperlipidemia, in this group of patients with
normal baseline lipid values, when the higher sirolimus dose was
utilized. The demographics showed that non-Black male patients tended
more often to develop hypercholesterolemia on sirolimus 2 mg and 5 mg.
Non-Black females developed more problems with hypercholesterolemia on
azathioprine. If a patient with a normal pre-study cholesterol developed
hypercholesterolemia on any study drug and was initiated on lipid
lowering therapy, greater than 60% of those patients continued to
require the lipid lowering agent at 6-12 months post- transplant.***

C.  **Post-transplant diabetes mellitus (PTDM)**

PTDM was defined as a patient, without a prior history of IDDM or NIDDM,
and who requires the use of insulin for 30 or more consecutive days with
less than 5 days of interruption to maintain a normal, fasting blood
glucose concentration.

Twenty seven patients fit the above criteria.

###### TABLE 16. 27 Patients who developed PTDM on study 301 & 302 {#table-16.-27-patients-who-developed-ptdm-on-study-301-302 .unnumbered}

+------------+---------+--------------+-------------+-----------------+
|            | **Pl    | **Az         | **Sirolimus | **Sirolimus 5   |
|            | acebo** | athioprine** | 2 mg**      | mg**            |
|            |         |              |             |                 |
|            | **N=    | **N= 98**    | **N= 334**  | **N= 327**      |
|            | 84**    |              |             |                 |
|            |         | **(23        | **(51       | **(52 Black**   |
|            |         | Black**      | Black**     |                 |
|            |         |              |             | **275           |
|            |         | **75         | **283       | Non-black)**    |
|            |         | Non-Black)** | Non-black   |                 |
|            |         |              | )**         |                 |
+------------+---------+--------------+-------------+-----------------+
|            |         |              |             |                 |
+------------+---------+--------------+-------------+-----------------+
| # Male     | 0       | **2**        | **9**       | **7**           |
|  {#male .u |         |              |             |                 |
| nnumbered} |         |              |             |                 |
+------------+---------+--------------+-------------+-----------------+
| **Female** | 0       | 0            | **1**       | **8**           |
+------------+---------+--------------+-------------+-----------------+
| **Black**  | 0       | **2**        | **3**       | **6**           |
+------------+---------+--------------+-------------+-----------------+
| **N        | 0       | 0            | **7**       | **9**           |
| on-Black** |         |              |             |                 |
+------------+---------+--------------+-------------+-----------------+
| **Total \# | 0       | **2**        | **10**      | **15**          |
| pts.**     |         |              |             |                 |
+------------+---------+--------------+-------------+-----------------+
| *          | **0%**  | **2%**       | **3%**      | **4.6%**        |
| *Incidence |         |              |             |                 |
| PTDM**     |         |              |             |                 |
+------------+---------+--------------+-------------+-----------------+

***[Reviewer's note]{.underline}*: *Overall, the incidence of PTDM was
uncommon in study 301 and 302. However, despite greater rates of acute
rejection and use of additional steroids to treat the episodes of
rejection in the control arms, there was no corresponding increase in
PTDM. In fact****,* ***the incidence of PTDM is greater in the sirolimus
5 mg study arm, noting that there were 8 patients whose status regarding
the use of insulin was unclear ( 2 in the azathioprine arm and 6 in the
sirolimus 5 arm).***

###### Liver function Tests (LFT's)

[Reviewer's note:]{.underline} Please note that information regarding
the serologic status of study patients for Hepatitis B or C was not
reported in this study. The LFT's that were assessed included alkaline
phosphatase, AST,and ALT . Bilirubin levels were not collected. Please
refer to table 8.71a in the Applicant's briefing package. Essentially
the percentage of patients who developed elevations of these LFT
parameters to 5 and 10 times the upper limit of normal were equally
distributed among the study drug groups in studies 301 and 302 . The
overall percentage of LFT elevations was small and no significant trends
were identified by race or gender.

#######  {#section-1 .unnumbered}

####### Renal Function as measured by Nankivell GFR and serum creatinine

**[*Reviewer's comment* :]{.underline} *Sirolimus is believed to lack
inherent nephrotoxicity as data indicates in animal models and in the
phase 2 trials in de novo renal transplants and in phase 2 monotherapy
psoriasis trials. In the following tables, one can see that in black and
non-black patients the GFR was better in the group on AZA at 12 months.
In the briefing package, the Applicant notes that patients on CsA and
sirolimus have higher creatinine levels over time vs patients treated
with full dose CsA in conjunction with placebo or azathioprine. These
creatinine levels show a dose relationship with higher levels of
creatinine found in patients treated with SRL 5 mg. The Applicant
believes that this is mainly due to CsA nephrotoxicity. Additional study
is needed to assess whether sirolimus will truly allowaa "cyclosporine
--sparing"regimen without incurring an increased risk of rejection. Our
analysis is different than that of the Applicant which was an "on
treatment" analysis. Rather, our study population encompasses both those
with and without rejection and patients both on and off study drug at 12
months. Our analysis includes patients similar to the general transplant
populations on study 301 and 302. Although patients on azathioprine had
an increased rate of rejection, we did not find a bias in our analysis
that could be ascribed to an increased number of azathioprine "dropouts"
with rejection which would have eliminated azathioprine patients with
poor renal function and thus led to a bias with retention of only
azathioprine patients with good renal function at 12 months.***

**[Table XII Study 301 GFR Results at 12months (337-393
days)]{.underline}**

+----------------+------------------------+----------------+----------+
| ## Treatm      | **N (observed) /N      | **Mean GFR**   | **p      |
| ent {#treatmen | (total)**              |                | -value** |
| t .unnumbered} |                        | **(cc/min)**   |          |
+----------------+------------------------+----------------+----------+
| **             | **127/161 (78.9%)**    | **65.9 +/-     | **\-\-\  |
| Azathioprine** |                        | 19**           | -\-\-\-\ |
|                |                        |                | -\-\--** |
+----------------+------------------------+----------------+----------+
| ## SRL         | **233/284 (82.0%)**    | **57.4 +/-     | *        |
| 2 mg {#srl-2-m |                        | 19.6**         | *0.001** |
| g .unnumbered} |                        |                |          |
+----------------+------------------------+----------------+----------+
| **SRL 5 mg**   | **226/274 (82.5%)**    | **55.1 +/-     | *        |
|                |                        | 19.3**         | *0.001** |
+----------------+------------------------+----------------+----------+

**[Table XIII Study 301 Creatinine at 12 months (337-393
days)]{.underline}**

  ----------------- ----------------- --------------------- ---------------
  Treatment         N(observed)       Mean creatinine mg/dl p-value

  Azathioprine      127               1.6 +/- 0.63          

  Sirolimus 2       233               2.17 +/- 1.49         0.0001

  Sirolimus 5       227               2.09 +/- 1.36         0.0002
  ----------------- ----------------- --------------------- ---------------

[Reviewer's note:]{.underline} In study 301 both GFR and serum
creatinine are significantly better in the azathioprine arm at 12
months.

###### Table XIV Study 301 Creatinine at 12 months by Race  {#table-xiv-study-301-creatinine-at-12-months-by-race .unnumbered}

+------------------+----------------+-----------+---------------------+
| **Treatment**    | **Race**       | ##        | **Mean creatinine   |
|                  |                |  N obs {# | (mg/dl)**           |
|                  |                | n-obs .un |                     |
|                  |                | numbered} |                     |
+------------------+----------------+-----------+---------------------+
| **Azathioprine** | Black          | 36        | 1.75 +/- 0.79       |
+------------------+----------------+-----------+---------------------+
|                  | Non-Black      | 91        | 1.54 +/- 0.55       |
+------------------+----------------+-----------+---------------------+
| **Sirolimus 2**  | Black          | 49        | 2.69 +/- 2.32       |
+------------------+----------------+-----------+---------------------+
|                  | Non-Black      | 184       | 2.04 +/- 1.15       |
+------------------+----------------+-----------+---------------------+
| **Sirolimus 5**  | Black          | 51        | 2.54 +/- 2.35       |
+------------------+----------------+-----------+---------------------+
|                  | Non-Black      | 176       | 1.96 +/- 0.87       |
+------------------+----------------+-----------+---------------------+

###### *Reviewer's note:* *The serum creatinine is better for both blacks and non-blacks in the azathioprine arm at 12 months.* *There is no statistical improvement in the serum creatinine with sirolimus 5 in the African-American population at 12 months.*  {#reviewers-note-the-serum-creatinine-is-better-for-both-blacks-and-non-blacks-in-the-azathioprine-arm-at-12-months.-there-is-no-statistical-improvement-in-the-serum-creatinine-with-sirolimus-5-in-the-african-american-population-at-12-months. .unnumbered}

######  {#section-2 .unnumbered}

Table XV Study 302 GFR results at 12 months (337-393 days)

  --------------- ------------------------ -------------------- ---------------
  **Treatment**   **N observed /N total**  **Mean GFR           **p-value**
                                           (cc/min)**           

  **Placebo**     **101/130 (77.7%)**      **61.7 +/- 18.18**   **\-\-\-\--**

  **SRL 2 mg**    **190/227 (83.7%)**      **54.9 +/- 17.36**   **0.0022**

  **SRL 5 mg**    **175/219 (79.9%)**      **52.9 +/- 18.29**   **0.001**
  --------------- ------------------------ -------------------- ---------------

[**Table XVI** **Study 302 Creatinine at 12 months **]{.underline}

  ----------------- ----------------- ---------------------- -------------
  **Treatment**     **N observed**    **Mean creatinine      **p-value**
                                      mg/dl**                

  **placebo**       102               1.96 +/- 1.77          

  **SRL 2**         191               2.11 +/- 1.65          0.4295

  **SRL 5**         180               2.11 +/- 1.32          0.4357
  ----------------- ----------------- ---------------------- -------------

***[Reviewer's note]{.underline}: The GFR was significantly better for
placebo vs sirolimus in study 302. However, the serum creatinine was not
significantly different in the treatment arms in study 302 at
12months.***

###### Table XVII Comparison of patients with rejection in the GFR analysis Study 301 {#table-xvii-comparison-of-patients-with-rejection-in-the-gfr-analysis-study-301 .unnumbered}

+----------------------+-----------------------+-----------------------+
| **Study 301**        | **Time to 1^st^       | **Time to 1^st^       |
|                      | rejection (days) in   | rejection (days) in   |
|                      | first 6 months post   | first 6 months post   |
|                      | transplant for pts.   | transplant for        |
|                      | in FDA GFR analysis** | overall study 301     |
|                      |                       | pts.**                |
+----------------------+-----------------------+-----------------------+
| **AZA**              | Mean 16.8             | Mean 13.0             |
|                      |                       |                       |
| N= 30 FDA            | Median 12.5           | Median 18.8           |
|                      |                       |                       |
| N= 47 study 301      |                       |                       |
+----------------------+-----------------------+-----------------------+
| **SRL 2**            | Mean 42.1             | Mean 43.3             |
|                      |                       |                       |
| N= 37 FDA            | Median 23.0           | Median 25.0           |
|                      |                       |                       |
| N = 47 study 301     |                       |                       |
+----------------------+-----------------------+-----------------------+
| **SRL 5**            | Mean 88.0             | Mean 67.3             |
|                      |                       |                       |
| N = 21 FDA           | **Median 77.0**       | Median 43.0           |
|                      |                       |                       |
| N= 35 study 301      |                       |                       |
+----------------------+-----------------------+-----------------------+

**[Table XVIII GFR analysis study 301 \@12 months (337-393 days post
transplant]{.underline}**)

+---------+--------+-----------+------------+-----------+-----------+
| **      | **\#   | **\#      | **\# pts.  | **        | **0verall |
| Study** | Pts.   | pts.with  | with first | Rejection | Study 301 |
|         | in 301 | first     | rejection  | rate at   | Rejection |
| **301** | GFR    | rejection | at 7-12    | 12 mos.   | Rate at   |
|         | anal   | at 0-6    | months**   | for pts.  | 12        |
|         | ysis** | months**  |            | in our 12 | months**  |
|         |        |           |            | mo. GFR   |           |
|         | **12   |           |            | a         |           |
|         | mos.** |           |            | nalysis** |           |
+---------+--------+-----------+------------+-----------+-----------+
| **AZA** | **127  | **30**    | **2**      | *         | *         |
|         | /161** |           |            | *32/127** | *49/161** |
| **      |        |           |            |           |           |
| N=161** | **(78  |           |            | **        | **        |
|         | .9%)** |           |            | (25.2%)** | (30.4%)** |
+---------+--------+-----------+------------+-----------+-----------+
| **SRL 2 | **233/ | **37**    | **9**      | *         | *         |
| N=      | 284(82 |           |            | *46/233** | *59/284** |
| 284**   | .0%)** |           |            |           |           |
|         |        |           |            | **        | **        |
|         |        |           |            | (19.9%)** | (20.8%)** |
+---------+--------+-----------+------------+-----------+-----------+
| **SRL   | **226  | **21**    | **6**      | *         | *         |
| 5**     | /274** |           |            | *27/226** | *38/274** |
|         |        |           |            |           |           |
| **      | **(82  |           |            | **        | **        |
| N=274** | .5%)** |           |            | (11.9%)** | (13.9%)** |
+---------+--------+-----------+------------+-----------+-----------+

**[Table XIV Analysis of population with rejection in the GFR analysis
for Study 302]{.underline}**

+-----------------------+-----------------------+-----------------------+
| **Study 302**         | Time to rejection     | Time to rejection     |
|                       | (days) in first 6     | (days) in first 6     |
|                       | months                | months                |
|                       | post-transplant for   | post-transplant for   |
|                       | pts. in our GFR       | pts. in overall study |
|                       | analysis              | 302                   |
+-----------------------+-----------------------+-----------------------+
| Placebo               | Mean 18.3             | Mean 21.4             |
|                       |                       |                       |
| N= 37 FDA             | Median 13.3           | Median 12.0           |
|                       |                       |                       |
| N= 54 overall         |                       |                       |
+-----------------------+-----------------------+-----------------------+
| SRL 2                 | Mean 31.0             | Mean 32.8             |
|                       |                       |                       |
| N=42 FDA              | Median 10.5           | Median 12.0           |
|                       |                       |                       |
| N = 56 overall        |                       |                       |
+-----------------------+-----------------------+-----------------------+
| SRL 5                 | Mean 32.7             | Mean 30.3             |
|                       |                       |                       |
| N = 31 FDA            | Median 14.0           | Median 12.5           |
|                       |                       |                       |
| N = 42 overall        |                       |                       |
+-----------------------+-----------------------+-----------------------+

**[Table GFR analysis study 302 \@12 months (337-393 days post
transplant]{.underline}**)

+--------+--------+------------+------------+------------+------------+
| **S    | **\#   | **\#       | **\# pts.  | *          | **0verall  |
| tudy** | Pts.   | pts.with   | with 1^st^ | *Rejection | Study 302  |
|        | in 302 | 1st        | rejection  | rate at 12 | Rejection  |
| *      | GFR    | rejection  | at 7-12    | mos. for   | Rate at 12 |
| *302** | anal   | at 0-6     | months**   | pts. in    | months**   |
|        | ysis12 | months**   |            | our 12 mo. |            |
|        | mos.** |            | **(N=4)**  | GFR        |            |
|        |        | **(N=      |            | analysis** |            |
|        |        | 110)**     | **our      |            |            |
|        |        |            | analysis** |            |            |
|        |        | **our      |            |            |            |
|        |        | analysis** |            |            |            |
+--------+--------+------------+------------+------------+------------+
| **Pla  | **101  | **37**     | **0**      | **37/101** | **54/130** |
| cebo** | /130** |            |            |            |            |
|        |        |            |            | *          | *          |
| **N    | **(77  |            |            | *(36.6%)** | *(41.5%)** |
| =130** | .7%)** |            |            |            |            |
+--------+--------+------------+------------+------------+------------+
| **SRL  | **190  | **42**     | **1**      | **43/190** | **58/227** |
| 2**    | /227** |            |            |            |            |
|        |        |            |            | *          | *          |
| **N=   | **(83  |            |            | *(22.6%)** | *(25.5%)** |
| 227**  | .7%)** |            |            |            |            |
+--------+--------+------------+------------+------------+------------+
| **SRL  | **175  | **31**     | **3**      | **34/175** | **47/219** |
| 5**    | /219** |            |            |            |            |
|        |        |            |            | *          | *          |
| **N    | **(79  |            |            | *(19.4%)** | *(21.5%)** |
| =219** | .9%)** |            |            |            |            |
+--------+--------+------------+------------+------------+------------+

***[Reviewer's note]{.underline}: In comparing the study populations for
the FDA GFR analysis with that of the overall study 301 and 302
population , for the patients who had rejection in the first year, the
mean and median times to first rejection for all groups were equivalent.
Consequently, we do not believe that an unfair bias was created whereby
patients with early rejection were excluded from the analysis and thus
the GFR would have been better than expected for any one study drug
group at one year.***

####### HUS/TTP

### There were 43 cases of HUS/TTP/ thrombotic microangiopathy in studies 301 and 302. {#there-were-43-cases-of-husttp-thrombotic-microangiopathy-in-studies-301-and-302. .unnumbered}

*Reviewer's note:* Rates for thrombotic microangiopathy are quoted in
the literature as being:

1 % for FK 506 and 3% for CsA.

The applicant believes that CsA is the major contributer to this
process, as no reports of

HUS/TTP have been reported in the sirolimus monotherapy trials. However
we don't

know the exact size of the entire sirolimus monotherapy trial safety
data base.

In the table below, please note that the rates of HUS are higher for SRL
5 mg and that

the rates for SRL 2mg approximates placebo but is greater than AZA.

No patient deaths occurred due to HUS and 3 patients (SRL 5 =2, SRL 2
= 1) lost grafts.

**[Rate(%) of HUS/TTP at \>12 months]{.underline}**

+-------------+--------------+----------------+----------+------------+
| study       | SRL 2 mg     | SRL 5 mg       | Placebo  | AZA        |
|             |              |                | n=130    |            |
|             | n=281 study  | n=269 study    |          | n=161      |
|             | 301          | 301            |          |            |
|             |              |                |          |            |
|             | n=218 study  | n=208 study    |          |            |
|             | 302          | 302            |          |            |
+-------------+--------------+----------------+----------+------------+
| 301         | 1.4          | 2.6            | \        | **1.9**    |
|             |              |                | -\-\-\-- |            |
+-------------+--------------+----------------+----------+------------+
| 302         | 2.7          | **8.2\***      | 3.2      | \-\        |
|             |              |                |          | -\-\-\-\-- |
+-------------+--------------+----------------+----------+------------+
| p-value\*   | \<0.05 SRL 5 |                |          |            |
|             | vs           |                |          |            |
|             |              |                |          |            |
|             | SRL 2        |                |          |            |
+-------------+--------------+----------------+----------+------------+

####### Hematologic

### Please refer to the Applicant briefing package for further discussion of this topic. {#please-refer-to-the-applicant-briefing-package-for-further-discussion-of-this-topic. .unnumbered}

Important points:

1)Thrombocytopenia was significantly higher in SRL 5 compared to SRL 2
and AZA and placebo. The thrombocytopenia is a dose-related reversible
decrease in platelet count---mean counts are still within the normal
range. The applicant states that there were no

platelet counts under 50 x 10^9^/L after month 3**.**.

Severe thrombocytopenia was rare (0.2%) and although epistaxis is
reported in this trial there was only one episodes of epistaxis
associated with thrombocytopenia.

2\) Leukopenia was significantly more frequent in the SRL 5 vs SRL 2
group but lower than in AZA. There were no cases of neutropenia.
Leukopenia resolved with discontinuation of study medication . No white
blood cell count was less than 1x 10^9^/L (1000 mm^3^).

[**Reviewer's note***:*]{.underline} ***Leukopenia was not associated
with an increased risk of infection. Neutropenia was not an adverse
event noted in the sirolimus arms.***

**V. SUMMARY OF MAJOR SAFETY ISSUES**

1)  **Hyperlipidemia is a major issue and will need to be closely
    followed. It is difficult to ascertain exactly what proportion of
    patients can be successfully treated with diet and exercise vs
    lipid-lowering therapy. It is difficult to make any specific
    recommendations regarding management since treatment decisions will
    depend on LDL values that we didn't have and risk factor
    stratification/modification.**

2)  **The elevated GFR and serum creatinine at the end of 12 months in
    the sirolimus groups is of concern. The Applicant ascribes this to
    cyclosporine toxicity however, there was no evidence of elevated
    cycosporine troughs in this population. Studies are planned to
    assess outcomes utilizing sirolimus in a cyclosporine sparing
    regimens.**

3)  **It would be risky to conclude that 166 black patients encountered
    less difficulty with infectious disease complications in this study
    and had decreased efficacy with SRL 2 mg/day because they are
    "under-immunosuppressed". Factors that predispose immunosuppressed
    transplant patients for infection are multi-factorial and encompass
    more than just the type of immunosuppressive agent that they are
    receiving. To suggest merely that "more sirolimus" is better for
    this subset of patients is concerning and decisions on the use of
    the sirolimus 5 mg/day dose must be weighed against the price of
    hyperlipidemia and vascular disease. The answer may be to monitor
    trough levels more stringently---further study is warranted.**

4)  **The number of African-American patients in Study 301 may be too
    small to exclude an unacceptable increase in less common adverse
    events associated with a 5 mg maintenance dose of sirolimus over the
    long term.**