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U.S. Department of Health and Human Services

Vaccines, Blood & Biologics

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Discipline Review Memo - RECOTHROM

Date:25 September 2007
To:Roman Drews, Ph.D. (HFM-392), Scientific Lead
for Stn.125248.0-ZymoGenetics
From:Eleanor Koo (HFM-340)
Subject:Discipline review memo for ZymoGenetics Inc.
Stn # 125248.0 (BLA)-Thrombin (Recombinant) (Human)
Through: Timothy Lee, Ph.D., Acting Lab. Chief Laboratory of Hemostasis/DH/OBRR/CBER (HFM-392)
CC: Mark Shields, RPM (HFM-380)

Background:

Zymo Genetics Inc. (ZGI) has submitted an original Biologics License Application (BLA) for Recombinant human Thrombin (rhThrombin).

Recombinant human Thrombin (rhThrombin) is identical in amino acid sequence to endogenous human α-thrombin. Recombinant human Thrombin is generated from a recombinant fragment of prothrombin called recombinant human prethrombin-1 (rh Prethrombin-1). The coded sequence for the rhPrethrombin-1 ---------------------------- truncated variant of the naturally occurring prothrombin.

Recombinant human Thrombin is indicated for use as a general adjunct to hemostasis when control of bleeding by conventional surgical techniques, including suture. Ligature and cautery is ineffective, insufficient or impractical. The product is indicated for topical use in conjunction with an absorbable gelatin sponge for hemostasis during surgery.

The commercial rhThrombin product is produced by changing its manufacturing process from ---------------------------- process to scale-up to commercial scale. The product has been extensively characterized by physicochemical methods; comparability of material from both processes has been demonstrated.

Additional long term stability data for qualification lots on 14 June 2007

Received qualification lots (----------------------------) with nine (9) months (-------------------), and six (6) months (-------) long term stability data at the recommended storage condition of 2-25ºC and ----------------------------------------------------. All test results met specification, and the drug product (Recombinant human Thrombin (rhThrombin)) is stable for up to 12 months at the recommended storage of 2-25ºC.

ZyniGentics submitted updated stability as the following on 18 July 2007:

  • Reference standards (rThrombin and rPrethrombin-1)
  • All --------------------------- lots listed in the BLA (from pilot and commercial processes)
  • All drug substance (BDS) lots listed in the BLA (from pilot and commercial processes)
  • All drug product (DP) lots listed in the BLA (made from pilot and commercial process BDS)

Conclusion/recommendation:

  1. Real-time long term stability data for Commercial process Qualification lots ----------------------------------- up to shelf life (Recommended 18 months) should be provided as they become available.
  2. Please consult a statistician for statistical valuation of the stability data.
  3. A shelf life of eighteen (18) is recommended.
  4. This submission is approvable

Summary of review:

  1. Container/Closure System for Bulk Intermediate drug Substance(3.2.S.6) and final drug Product (3.2.P.7)
  2. Bulk Intermediate drug substance Stability data (3.2.S.7.3)
  3. Final drug product Stability data (3.2.P.8.3)
  4. Post-approval stability Protocol and stability commitment for Bulk Drug Substance (3.2.S.7.2) and final drug Product (3.2.P.8.2)

Bulk drug substance (BDS) for rhThrombin:

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Final drug product Stability data (3.2.P.8.3):

Recombinant human Thrombin (rhThrombin) drug product is a sterile, lyophilized, and white to off-white solid and/or powder that contains no preservative and is reconstituted with 0.9% sodium chloride injection, USP. Upon reconstitution, rhThrombin drug product is a clear, colorless solution. It is intended for topical administration to bleeding surfaces. The quantitative composition for each vial is 5000-International unit (IU) of rhThrombin drug product.

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Comments:

Long-term Stability data submitted by the firm (ZymoGenetics) On June 14, 2007:

Received qualification lots ------------------------------ with nine (9) months ---------------------, and six (6) months ------------------------- long term stability data at the recommended storage condition of 2-25ºC and -----------------------------------------------------

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Results: All test results met specification limit.

Recommendation: This drug product can be stored at the recommended storage condition and stable up to twelve months. A twelve (18) months shelf life can be assigned.

  1. Please consult a statistician for statistical valuation of the stability data.
  2. Please submission commercial process qualification lots (3) samples for potency testing.

Comment: Three commercial process qualification lots -------------------------------samples with diluents had been submitted and potency assay has done, they are within the specification limit.

The following table showed the assay results:

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Reconstitution diluent and transfer devices:

The recommended reconstitution diluent for the lyophilized 5000-International unit (IU) rhThrombin drug product is 0.9% sodium chloride injection, USP. Use of the recommended diluent results in a solution containing a nominal potency of 1000 IU/mL.

The commercial 5000-IU rhThrombin drug product is co-package with a 5-mL pre-felled normal saline syringe (--------------------------------------------------------), a --------- needle-free multidose vial access device (-------------------------------------------) and a 5mL LuerLok tip syringe( ------- -------------------------------------------------,). The co-packaged components are intended to improve safety, aseptic technique, and ease of use. Inclusion of a pre-filled saline syringe and a needle-free transfer device is intended to ensure the following:

  • Use of the proper diluent (preservative-free, 0.9% sodium chloride injection, USP)
  • Safety to medical providers (i.e. eliminates potential for needle-sticks)
  • Safety to patients (i.e. prevents rhThrombin solutions from being inappropriately injected).

The empty sterile LuerLok tip syringe is provided for transfer of the reconstituted rhThrombi solution from the vial into the sterile basin in which the gelatin sponge(s) are immersed prior to administration.

Stability of Reconstituted Drug Product:

The stability of rhThrombin 5000-IU drug product following reconstitution with 0.9%sodium chloride injection, USP, from several sources that used various transfer devices is established (RES-10707), rhThrombin is stable for at least 24 hours at 2ºC to 25ºC following reconstitution with 5mL of 0.9% sodium chloride injection, USP.

The stability of reconstituted rhThrombin was evaluated with the co-packaged diluent, 5-mL pre-filled normal saline syringes (---------). The reconstituted stability studies were conducted with non-expired and expired (more than 3 year from manufacturing date) prefilled syringes.

The evaluations included stability assessments for reconstituted rhThrombin solution within the 5-mL LuerLok tip syringe that is co-packaged with the commercial product for transfer of the reconstituted solution. The stability was assessed under worst-case exposure. For instance, the reconstituted vials were stored inverted to maximize contact with the container closure. No differences in stability were observed when the 0.9% sodium chloride injection, USP, from the different sources or different transfer devices were used.

Additionally, no differences in stability were observed when pre-filled normal saline syringes (---------) that had exceeded the approved expiration date (more than 3 years from the manufacturing date) were used to reconstitute 5000-IU rhThrombin drug product. Similarly, no differences were observed for reconstituted rhThrombin solution stored in the 5-mL LuerLok tip syringe. These data establishing consistent in-use stability, regardless of the saline source/expiry dating or the transfer device used, indicates that reconstituted rhThrombin stability is not affected by silicone, elastomers or other potential leachables that may be present (but differ) amongst commercial saline products and transfer devices, including those co-packaged with the commercial 5000-IU rhThrombin drug product.

Compatibility of components Co-Packaged with 5000-IU rhThrombin Drug Product:

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C. ---- 5mL LuerLok Tip Syringe:

The 5mL LuerLok tip syringe provides a more efficient and safe means to transfer the reconstituted rhThrombin solution from the vial into the sterile basin in which the gelatin sponge(s) are immersed prior to administration. Using the syringe eliminates the requirement for removing the aluminum tear-off seal from the vial in order to transfer the rhThrombin solution into the sterile basin; the aluminum tear-off seal can potentially cut medical provider's surgical gloves, thereby compromising asepsis. A letter of authorization to cross reference 510(K) number --------------------. An overview of the suitability testing (including no clinical biocompatibility testing) that demonstrates the suitability of the ---- 5-mL LuerLok tip syringe materials is submitted.

The 5-mL LuerLok tip syringe meets the requirements specified by the tests. The tests selection and protocol design were performed in accordance with ISO 1993 guidelines for the Biological Evaluation of Medical Devices and FDA Blue Book Memorandum G95-1. All tests were conducted in compliance with Gook Laboratory Practice Regulations, U.S. Food and Drug Administration, Title 21, CFR Part 58.

Recombinant human Thrombin is indicated for topical administration in conjunction with an absorbable gelatin sponge as a general adjunct to homeostasis during surgery. The reconstituted rhThrombin solution is transferred from the vial into the sterile basin in which the gelatin sponge(s) are immersed prior to administration. Both Surgifoam (Ethicon, Inc; Sommerville, NJ) and Gelfoam (Pharmacia & Upjohn Co.; Kalamazoo, zmi) absorbable gelatin sponges, USP, were used in Phase 3 clinical trials. A gelatin sponge is not co-packaged with the 5000-IU rhthrombin drug product. Compatibility of reconstituted rhThrombin solution with Surgifoam and Gelfoam absorbable gelatin sponges, USP, was established (RES-10502, RES-10281). Briefly, portions of Surgifoam and Gelfoam absorbable gelatin sponges, USP, were soaked with reconstituted rhThrombin solution and then stored at 25ºC. Greater than 90% recovery of clotting activity (U/mL) and content (mg/mL) was observed after 24 hours of storage at 25ºC, representing worst-case conditions; no changes in specific activity (U/mg a-thrombin) were observed.

The use of surgical material other than absorbable gelatin sponges with rhThrombin is not recommended because potency may be affected.

Statistical assessment of stability data:

The purity graphs are generated by plotting all measured purity values (%) against time (months) at a given storage condition, while applying regression analysis and confidence intervals.

The 95% confidence interval (lines around the linear regression) represents the range of Y-values which encompass 95% of the sample points in normal statistical distribution.

As the regression line extends beyond real-time data points, it is considered a predicted estimate of the true mean at those future time points. The confidence interval reflects the prospective nature of this line by expanding as it extends through future time points, of which there is more uncertainty as to the true mean.

The results for the formal stability studies from the three lots --------------------------------- ------------ Commercial Process for Phase 3 clinical indicate that the rhThrombin drug product is stable to date (18 months) at the recommended storage condition of 2ºC to 25ºC.

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Comment: Please consult a statistician for statistical assessment of stability data.

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Conclusion/recommendation:

  1. Real-time long term stability data for Commercial process Qualification lots -------- -------------------- up to shelf life (recommended 18 months) should be provided as they become available.
  2. Please consult a statistician for statistical valuation of the stability data.
  3. A shelf life of eighteen (18) is recommended.
  4. This submission is approvable

 

 

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