PUBLISHED

UNITED STATES COURT OF APPEALS
                FOR THE FOURTH CIRCUIT


AMERICAN CYANAMID COMPANY,            
                Plaintiff-Appellee,
                 v.                             No. 02-1235
ST. LOUIS UNIVERSITY,
               Defendant-Appellant.
                                      
           Appeal from the United States District Court
            for the District of Maryland, at Baltimore.
                 J. Frederick Motz, District Judge.
                        (CA-99-1316-JFM)

                      Argued: January 22, 2003

                       Decided: July 16, 2003

  Before NIEMEYER, LUTTIG, and TRAXLER, Circuit Judges.



Affirmed by published opinion. Judge Traxler wrote the majority
opinion, in which Judge Niemeyer joined. Judge Luttig wrote a con-
curring opinion.


                            COUNSEL

ARGUED: Marc Simon Moller, KREINDLER & KREINDLER,
New York, New York, for Appellant. David Patrick Donovan, WIL-
MER, CUTLER & PICKERING, McLean, Virginia, for Appellee.
ON BRIEF: Mark R. Dunn, HERZOG, CREBS & MCGHEE,
L.L.P., St. Louis, Missouri; Stanley P. Kops, Bala Cynwyd, Pennsyl-
vania; Rex Carr, CARR, KOREIN, TILLERY, KUNIN, MONTROY
2             AMERICAN CYANAMID CO. v. ST. LOUIS UNIV.
& GLASS, East St. Louis, Missouri, for Appellant. Roger W. Yoer-
ges, WILMER, CUTLER & PICKERING, Washington, D.C., for
Appellee.


                              OPINION

TRAXLER, Circuit Judge:

   St. Louis University ("SLU") paid a $16 million Missouri state-
court judgment to the family of a boy who became paralyzed after
receiving Orimune, an oral polio vaccine, and SLU now seeks contri-
bution from American Cyanamid Company, the parent company of
the vaccine manufacturer. The district court granted summary judg-
ment in favor of Cyanamid, and SLU appeals. We affirm.

                                   I.

  Much of the factual and procedural background relevant to this
case is set out in our opinion in St. Louis University v. United States,
No. 02-1351, which is also filed today. To the extent possible, we will
not repeat that information in this opinion.

   After SLU paid the judgment in the state court case, it filed various
federal and state-court actions against Cyanamid. These actions were
dismissed for procedural reasons. SLU ultimately filed a contribution
action against the United States government in federal district court
in Maryland (the "Government Contribution Action"). The district
court in that action granted summary judgment in favor of the govern-
ment in 1999. Cyanamid thereafter filed a declaratory judgment
action in the same federal district court, seeking a declaration that the
summary judgment order in the Government Contribution Action col-
laterally estopped SLU from seeking contribution against Cyanamid.
The district court agreed with Cyanamid, gave collateral estoppel
effect to its order in the Government Contribution Action, and granted
summary judgment in favor of Cyanamid. SLU appealed the rulings
in the declaratory judgment action and the Government Contribution
Action. This court reversed and remanded both cases for further pro-
ceedings. See St. Louis Univ. v. United States, No. 99-2227 (4th Cir.
              AMERICAN CYANAMID CO. v. ST. LOUIS UNIV.                  3
March 1, 2001); American Cyanamid v. St. Louis Univ., No. 99-2224
(4th Cir. March 1, 2001). On remand, the district court concluded that
the government could be held liable in contribution to SLU, but that
Cyanamid was not liable in contribution.1

                                   II.

   The district court concluded that SLU failed to establish that a
defect in the vaccine proximately caused the injuries in the underlying
state-court case. SLU’s arguments on appeal largely track those it
made in response to the government’s appeal in St. Louis University
v. United States, No. 02-1351. That is, SLU contends that the opin-
ions of the district court and this court in the Sabin cases2 are determi-
native of this case. The Sabin courts concluded that the government
violated the neurovirulence regulations and that the government’s
actions proximately caused the injuries suffered by the Sabin plain-
tiffs, and SLU contends that the "rationale" of the Sabin opinions
applies to Cyanamid as well as the government. Reply Brief at 6. SLU
also contends that Cyanamid bears ultimate responsibility for the reg-
ulatory violations found in Sabin, and that these regulatory violations
alone make Cyanamid liable in contribution to SLU.

   As to SLU’s reliance on the Sabin cases, we again find it to be mis-
placed. As we explained in our decision in No. 02-1351, the Sabin
  1
     SLU’s argument that there is no live case or controversy involving
Cyanamid because Cyanamid did not amend its complaint after our
remand is wholly without merit. The post-remand conduct of the parties
clearly indicated the question of whether Cyanamid could be held liable
in contribution was tried by consent. See People for the Ethical Treat-
ment of Animals v. Doughney, 

, 367 (4th Cir. 2001) ("A
party’s failure to amend will not affect a final judgment if the issues
resolved were tried by express or implied consent of the parties. Even
without a formal amendment, a district court may amend the pleadings
merely by entering findings on the unpleaded issues." (citations and
internal quotation marks omitted)).
   2
     In re Sabin Oral Polio Vaccine Prods. Liab. Litig., 

(D. Md. 1990); In re Sabin Oral Polio Vaccine Prods. Liab. Litig., 

(D. Md. 1991); In re Sabin Oral Polio Vaccine Prods. Liab.
Litig., 

(D. Md. 1991), aff’d In re Sabin Oral Polio Vac-
cine Prods. Liab. Litig., 

(4th Cir. 1993) (per curiam).
4                AMERICAN CYANAMID CO. v. ST. LOUIS UNIV.
cases involved questions of Maryland and Florida law. Because this
case is governed by Missouri law, the Sabin decisions are not control-
ling. Thus, the issue we must resolve is whether, without regard to the
Sabin decisions, SLU has carried its burden of demonstrating that
Cyanamid can be held responsible for the injures suffered by Danny
Callahan. We agree with the district court that SLU did not carry this
burden.
   Under Missouri law, SLU is entitled to contribution from Cya-
namid only if Cyanamid can be held liable for Danny’s injuries. See
Gramex Corp. v. Green Supply, Inc., 

, 442 (Mo. 2002)
(en banc). Liability is grounded in Missouri’s product liability law,
which follows the approach set forth in the section 402A of the
Restatement (Second) of Torts. See Keener v. Dayton Elec. Mfg. Co.,

, 364 (Mo. 1969).
        The essential elements of a strict product liability claim are
        (1) the defendant sold a product in the course of its business;
        (2) the product was then in a defective condition, unreason-
        ably dangerous when put to a reasonably anticipated use; (3)
        the product was used in a manner reasonably anticipated;
        and (4) the plaintiff was damaged as a direct result of such
        defective condition as existed when the product was sold.
Lay v. P & G Health Care, Inc., 

, 325 (Mo. Ct. App.
2000); see Restatement (Second) of Torts § 402A(1) (1965) ("One
who sells any product in a defective condition unreasonably danger-
ous to the user or consumer or to his property is subject to liability
for physical harm thereby caused to the ultimate user or consumer
. . . ."). Assuming that the first three elements are satisfied, SLU has
not satisfied the fourth element, causation.
   SLU has simply failed to present any competent evidence showing
that the defect in the vaccine — excessive neurovirulence — proxi-
mately caused Danny’s injuries.3 SLU insists, however, that the mere
    3
    The record does include an article discussing a particular genetic
mutation in the vaccine that might be connected to cases of vaccine-
associated poliomyelitis, but SLU offered no expert testimony to inter-
pret the findings and explain the relevance of the findings to this case.
The article, therefore, is insufficient to satisfy SLU’s burden of showing
proximate cause. The expert testimony in the record is likewise insuffi-
cient. As explained in our opinion in 02-1351, none of SLU’s experts tes-
tified that increased neurovirulence led to increased incidence of
vaccine-associated polio, nor were any qualified to render such an opin-
ion.
              AMERICAN CYANAMID CO. v. ST. LOUIS UNIV.                     5
fact that the neurovirulence regulations were violated entitles it to
recovery. As we explained in No. 02-1351, SLU is simply wrong on
this point. Even in cases where the violation of a statute amounts to
negligence per se, Missouri law is unambiguous in its requirement
that the plaintiff must still prove that the violation proximately caused
his injuries. See Sill v. Burlington No. R.R., 

, 392 (Mo.
Ct. App. 2002) ("If a submissible case is made under a negligence per
se cause of action, a plaintiff could recover if a jury concluded that
a statute was violated and the violation was the proximate cause of
the injury."); Friend v. Yokohama Tire Corp., 

, 579
(Mo. Ct. App. 1995) ("One of the elements of a negligence per se
action is that the violation of a statute was the proximate cause of the
injury.").
   SLU presented no expert testimony showing that Danny Callahan
would not have contracted polio or would have contracted a less
severe case of polio had he been given a vaccine complying with the
neurovirulence regulations. The district court, therefore, properly
rejected SLU’s claim against Cyanamid. See Klein v. General Elec.
Co., 

, 900 (Mo. Ct. App. 1986) ("To prevail under the
doctrine of strict liability in tort, the plaintiffs must prove that the
product was defective and dangerous . . . that the plaintiff sustained
damage as a direct result of the defect.").
  Accordingly, for the foregoing reasons, the district court’s grant of
summary judgment in favor of Cyanamid is hereby affirmed.4
                                                               AFFIRMED
  4
    Proximate cause is an element of the plaintiff’s cause of action.
Because SLU failed to establish this essential element of its claim, SLU’s
argument that Cyanamid failed to prove its entitlement to the affirmative
defense set forth in comment K to section 402A of the Restatement is
irrelevant. See, e.g., Farm Bureau Town & Country Ins. of Missouri v.
Hilderbrand, 

, 948 (Mo. Ct. App. 1996) ("An affirmative
defense seeks to defeat or avoid the plaintiff’s cause of action. It avers
that even if the petition is true, the plaintiff cannot prevail because there
are additional facts that permit the defendant to avoid legal responsibil-
ity." (citation omitted)). Also irrelevant is SLU’s pre-emption argument.
The district court did not reject SLU’s claim on pre-emption grounds, nor
do we. Instead, the district court held, and we agree, that SLU failed to
prove proximate cause, as required by Missouri law.
6            AMERICAN CYANAMID CO. v. ST. LOUIS UNIV.
LUTTIG, Circuit Judge, concurring:

   I concur in the judgment of the court. I do not fully join the major-
ity opinion, however, for the same reasons that I dissent from the
companion case in 02-1351. Again, the majority would have it that
Sabin IV does not present binding law for this appeal. Again, I dis-
agree. However, I join the judgment of the court in this case for the
straightforward reason that SLU failed to proffer evidence of proxi-
mate causation sufficient to satisfy the Missouri tort standards.

   In contrast to the companion case, the defendant here is being sued
not for its conduct as an alleged defective product-approver, but for
its conduct as an alleged defective product manufacturer. The
straightforward defective product manufacturing proximate cause
analysis therefore applies to this case. See Nesselrode v. Executive
Beechcraft, Inc., 

, 375-76 (Mo. 1986) (en banc)
(holding that the plaintiff in a product manufacturing defect case must
prove the defect caused his injuries by proving that had the product
been defect-free he would not have been injured).

   Here, the defect in question is the defective manufacture of the vac-
cine. As the majority well points out, SLU proffered no evidence that
the vaccine, had it been defect-free, would not have caused Danny
Callahan’s injuries. As such, SLU failed to create a genuine issue as
to that central proximate cause question, without which it cannot sur-
vive appellee’s summary judgment motion.

   For these reasons I too would affirm the district court’s judgment
in this case.