                                                                               FILED
                                                                  United States Court of Appeals
                                                                          Tenth Circuit

                                                                          July 12, 2011
                       UNITED STATES COURT OF APPEALSElisabeth A. Shumaker
                                                                           Clerk of Court
                                    TENTH CIRCUIT




HOPE HUERTA, as Next Friend and
Parent of Blanca M. Valdez-Huerta, a
minor,

         Plaintiff-Appellant,                                 No. 10-2203
                                                  (D.C. No. 1:09-CV-00485-RHS-LFG)
v.                                                             (D. N.M.)

BIOSCRIP PHARMACY SERVICES,
INC.,

        Defendants-Appellees.



                                ORDER AND JUDGMENT*


Before O’BRIEN, HOLLOWAY, and GORSUCH, Circuit Judges.


       Following a catastrophic rejection of her transplanted kidney in May of 2006,

plaintiff-appellant Blanca Valdez-Huerta, by and through her mother, Hope Huerta,

(collectively, “Huerta”), brought this diversity jurisdiction action against BioScrip

Pharmacy Services, Inc. (“BioScrip”) in the District of New Mexico. Huerta asserted

claims under New Mexico law for strict products liability, negligence, negligent


*
  This order and judgment is not binding precedent, except under the doctrines of law of
the case, res judicata, and collateral estoppel. This court generally disfavors the citation
of orders and judgments; nevertheless, an order and judgment may be cited under the
terms and conditions of 10th Cir. R. 36.3.
misrepresentation, deceptive trade practices, breach of express and implied warranties,

and punitive damages. All of Huerta’s claims were premised on the theory that BioScrip

dispensed subpotent tacrolimus1 to her, eventually resulting in her kidney rejection.

       The district court2 granted summary judgment in favor of BioScrip after striking

Huerta’s experts’ testimony on causation. Final judgment was entered on August 19,

2010 and Huerta timely filed her notice of appeal. We have jurisdiction pursuant to Title

28, United States Code, Section 1291. For the reasons stated below, we AFFIRM.

                                           I. Facts

       A. Huerta’s Kidney Transplant and Rejection

       In August of 2003, Huerta, seven years old at the time, received a kidney

transplant. As part of her medication regime, she took immunosuppressants, including

tacrolimus and Cellcept, to help prevent her body from rejecting the transplanted kidney.

In February of 2006, Huerta was hospitalized after she suffered a series of pneumonias


1
       Tacrolimus is an immunosuppressant that was prescribed to Blanca to prevent her
body from rejecting the kidney transplant. A body’s immune system normally attacks
foreign tissues, including transplants, resulting in the body’s rejecting the organ
transplant. Paul S. Russell, M.D., Transplantation, in THE MERCK MANUAL OF MEDICAL
INFORMATION 1076 (2d ed. 2003). Immunosuppressants can usually control rejections by
suppressing the immune system and therefore the body’s ability to recognize and destroy
foreign substances, such as transplant tissue. Id. Potency refers to the amount of a drug
needed to produce an effect. G. Victor Rossi, PhD, Drug Dynamics, in THE MERCK
MANUAL, supra, at 73. “Subpotent tacrolimus” thus refers to a preparation of tacrolimus
that contained less than the prescribed amount of tacrolimus.
2
       The parties consented to Magistrate Judge Robert Hayes Scott’s serving as the
presiding judge and entering final judgment in this action pursuant to Title 28, United
States Code, Section 636(c) and Federal Rule of Civil Procedure 73(b). Accordingly, the
references in this order to the “district court” refer to Magistrate Judge Scott.

                                            -2-
that did not clear with antibiotics. On March 8, 2006, Huerta’s treating nephrologists

replaced Cellcept with a weaker immunosuppressant, Imuran, because they believed that

Cellcept over-suppressed her immune system and may have increased her risk of

infection. Huerta continued to take tacrolimus.

       On May 15, 2006, Huerta was admitted to the University of New Mexico Hospital

(UNMH) after she had been vomiting for three nights. Physicians at UNMH determined

that Huerta was suffering an acute, severe, and sudden rejection of her kidney transplant.

Dr. John Brandt, one of Huerta’s treating nephrologists, reduced Huerta’s tacrolimus

dosage on May 15 because he was concerned that she might have too much tacrolimus in

her system. Huerta’s tacrolimus level on May 15th was not measured and the experts

appear to agree that without a measurement, there is no way to know what Huerta’s

tacrolimus level was on that day. On May 17, 2006, lab reports showed that Huerta’s

tacrolimus level was 2.5. Before Huerta’s kidney rejection, her last tacrolimus level was

measured at 5.4 on April 12, which is apparently considered normal.

       Huerta partially recovered from the May 2006 rejection episode but suffered

another rejection episode in May 2007. The treatment notes from Huerta’s May 2007

rejection episode showed that “she had undetectable levels” of tacrolimus and her doctors

were concerned “that her mother wasn’t dosing her properly.” Mem. Order and Op.

Granting BioScrip’s Motion to Exclude Proposed Testimony of Doctors Craig Wong,

Bruce Morgenstern, and Loyd Alexander, August 13, 2010 (“Aug. 13, 2010 Op.”) at 8 &

nn. 6 & 7. Only Huerta’s 2006 rejection is at issue in this case.



                                            -3-
       Just prior to Huerta’s 2006 kidney rejection, a distributor of tacrolimus issued a

recall for its tacrolimus which was found to be subpotent. It is undisputed that the

BioScrip tacrolimus was not subject to the recall.

       B. BioScrip’s Tacrolimus Suspension

       Huerta had her tacrolimus prescription filled by BioScrip in April of 2006.

BioScrip had compounded, or mixed, the liquid form of tacrolimus (called a

“suspension”) by crushing tacrolimus capsules and mixing the resulting powder with a

syrup according to recipes in the National Children’s Hospital Pharmacy Guide. The

tacrolimus capsules were manufactured and distributed by Astellas Pharma U.S., Inc., a

party dismissed from the instant case because there was no evidence that the tacrolimus

Astellas manufactured and supplied to BioScrip was subpotent or had been the subject of

a recall.

       BioScrip filled Huerta’s tacrolimus prescription from its Batch No. 37. Three

other individuals also had their prescriptions filled from Batch No. 37. BioScrip did not

receive any reports of error or of adverse reactions from those other three individuals.

       C. Proceedings Below

       Both parties filed Daubert3 motions to exclude the other party’s expert testimony.

After the district court granted BioScrip’s motions and denied Huerta’s motions, BioScrip

moved for summary judgment on all claims. The district court granted BioScrip’s

motion, finding that without her experts, Huerta could not establish to a reasonable degree


3
       Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993).

                                            -4-
of medical probability that BioScrip’s tacrolimus suspension was subpotent or that it

caused her kidney rejection.

                                            II. Discussion

       A. Huerta’s Expert Witnesses

       The Supreme Court has explained that when a trial court is “[f]aced with a proffer

of expert scientific testimony . . . the trial judge must determine at the outset . . . whether

the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of

fact to understand or determine a fact in issue.” Daubert v. Merrell Dow Pharm., Inc.,

509 U.S. 579, 589-93 (1993) (citing Fed. R. Evid. 104(a), footnotes omitted).

Accordingly, the district court must “[first] determine if the expert's proffered testimony .

. . has ‘a reliable basis in the knowledge and experience of his [or her] discipline.’”

Norris v. Baxter Healthcare Corp., 397 F.3d 878, 883-884 (10th Cir. 2005) (quoting

Bitler v. A.O. Smith Corp., 400 F.3d 1227, 1232 (10th Cir. 2004)). “In making this

determination, the district court must decide ‘whether the reasoning or methodology

underlying the testimony is scientifically valid.’” Id. at 884 (same). Next, “the district

court must further inquire into whether proposed testimony is sufficiently ‘relevant to the

task at hand.’” Id. (quoting Daubert, 509 U.S. at 597) (footnote omitted).

       The Supreme Court has articulated four non-exclusive considerations to aid in

assessing the reliability of an expert’s testimony: (1) whether the expert’s theory can be

tested or falsified; (2) whether the theory or technique has been subject to peer review and

publication; (3) whether there are known or potential rates of error with regard to specific



                                              -5-
techniques; and (4) whether the theory or approach has general acceptance. Daubert, 509

U.S. at 593-94. The district court must “make certain that an expert . . . employs in the

courtroom the same level of intellectual rigor that characterizes the practice of an expert

in the relevant field.” Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137, 152 (1999).

        We review a district court’s decision to admit or exclude expert testimony for an

abuse of discretion. Id. Under this deferential standard of review, we reverse a district

court’s decision only if it is “arbitrary, capricious, whimsical or manifestly unreasonable,”

or if “we are convinced that the district court made a clear error of judgment or exceeded

the bounds of permissible choice in the circumstances.” Norris, 397 F.3d at 883 (citing

Dodge v. Cotter Corp., 328 F.3d 1212, 1223 (10th Cir. 2003)). This standard “applies as

much to the trial court’s decisions about how to determine reliability as to its ultimate

conclusion.” Kumho Tire, 526 U.S. at 152; see Goebel v. Denver and Rio Grande W.

R.R. Co., 346 F.3d 987, 990 (10th Cir. 2003) (“The trial court’s broad discretion applies

both in deciding how to assess an expert’s reliability, including what procedures to utilize

in making that assessment, as well as in making the ultimate determination of

reliability.”).

        1. District Court’s Orders

        The district court struck portions of the testimony of Huerta’s four experts, Dr.

Craig Wong, Dr. Steven Alexander, Dr. Bruce Morgenstern, and Dr. Randall Tackett, as

unreliable and therefore inadmissible under Daubert and Federal Rule of Evidence 702.4

4
        Federal Rule of Evidence 702 provides the following:
        If scientific, technical, or other specialized knowledge will assist the trier of

                                               -6-
First, the district court held that Dr. Wong, Dr. Alexander, and Dr. Morgenstern were all

“well qualified to give an opinion stating that, based on (1) the severity, (2) the type, and

(3) abruptness of Blanca’s rejection when she had been doing well the month before, (4)

the extremely high creatinine4 levels in her blood on May 15, 2006, and the fact that (5)

tacrolimus is the most powerful and the most critical immunosuppressant medication

Blanca was taking . . . Blanca’s rejection was most likely caused by insufficient levels of

tacrolimus and/ or other immunosuppressants in her system.” Aug. 13, 2010 Op. at 10.

The district court found, however, that “[w]hat [wa]s not supported by any medical

evidence in the record . . . [is] their opinions regarding the cause of the insufficient

tacrolimus level.” Id. (emphasis in original).

       As for Dr. Tackett, the district court held that he could testify to a potential

relationship between sloppy pharmaceutical record-keeping and sloppy compounding, as

well as to the most common types of compounding errors made when capsules are used to

compound a suspension. However, the district court held that Dr. Tackett’s ultimate


        fact to understand the evidence or to determine a fact in issue, a witness
        qualified as an expert by knowledge, skill, experience, training, or education,
        may testify thereto in the form of an opinion or otherwise, if (1) the testimony
        is based upon sufficient facts or data, (2) the testimony is the product of
        reliable principles and methods, and (3) the witness has applied the principles
        and methods reliably to the facts of the case.
4
        Creatinine is a metabolic waste product generated by the body. DORLAND’S
ILLUSTRATED MEDICAL DICTIONARY 390 (28th ed. 1994). Normally functioning kidneys
filter creatinine from the bloodstream and the body then excretes it in urine. Ralph E.
Cutler, MD, Kidney Failure, in THE MERCK MANUAL, supra note 1, at 828. When a
kidney fails and is therefore unable to filter creatinine, “[a] progressive daily rise in the
creatinine indicates acute kidney failure.” Id. at 829. “[T]he higher the level [of
creatinine], the more severe the failure is likely to be.” Id.

                                              -7-
causation testimony that subpotent tacrolimus caused Huerta’s kidney rejection was

insufficiently reliable to be admissible.

       Stated differently, the district court found that the experts were qualified to opine

on general causation, or what might cause a kidney rejection. See Norris, 397 F.3d at

881 (“General causation is whether a substance is capable of causing a particular injury or

condition in the general population.”). However, the district court held that the experts

could not render their specific causation opinions that Bioscrip’s tacrolimus suspension

was subpotent or that subpotent tacrolimus caused Huerta’s kidney rejection because

their methodologies were insufficiently reliable. See id. (“[S]pecific causation is whether

a substance caused a particular individual's injury.”). We address the contentions

regarding each of the experts in further detail below.

       2. Testimony of Dr. Craig Wong

       According to Huerta, Dr. Craig Wong was prepared to testify that, to a reasonable

degree of medical certainty, subpotent tacrolimus dispensed by BioScrip caused Huerta’s

kidney rejection. The district court, however, found that Dr. Wong’s testimony was

unreliable because it was not supported by any direct evidence that the BioScrip

tacrolimus suspension was actually subpotent and because Dr. Wong’s testimony was

based on the erroneous assumption that Huerta had taken the recalled tacrolimus, which

she had not. Aug. 13, 2010 Op. at 11; see Goebel, 346 F.3d at 991.

       Insofar as Dr. Wong reached his causation opinion by rendering a “differential

diagnosis,” the district court also found that Dr. Wong’s methodology fell short. A



                                             -8-
“differential diagnosis” is one rendered by a physician who first “‘rule[s] in’ all

scientifically plausible causes of the plaintiff’s injury. The physician then ‘rules out’ the

least plausible causes of injury until the most likely cause remains.” Hollander v. Sandoz

Pharm. Corp., 289 F.3d 1193, 1209 (10th Cir. 2002) (quoting Glasteter v. Novartis

Pharm., Corp., 252 F.3d 986, 989 (8th Cir. 2001)). Then, “[t]he remaining cause is the

expert’s conclusion.” Id. (citing same).

       Our circuit has recognized that a differential diagnosis can be admissible if the

district court concludes that it is reliable and if general causation has been established.

Goebel, 346 F.3d 987 (citing Hollander, 89 F.3d at 1210). As the Sixth Circuit has

explained, however,

       Calling something a ‘differential diagnosis’ . . . does not by itself answer the
       reliability question but prompts three more: (1) Did the expert make an
       accurate diagnosis of the nature of the disease? (2) Did the expert reliably rule
       in the possible causes of it? (3) Did the expert reliably rule out the rejected
       causes? If the court answers “no” to any of these questions, the court must
       exclude the ultimate conclusion reached.


Pluck v. BP Oil Pipeline Co., --- F.3d ----, 2011 WL 1794293, 5 (6th Cir. 2011) (citing

Tamraz v. Lincoln Elec. Co., 620 F.3d 665, 674 (6th Cir.2010) (cert. denied,

--- S. Ct. ----, 2011 WL 863879 (May 16, 2011) (Nos. 10-1122, 10A744)). To that end,

the district court answered “no” to the last two questions.

       The district court found that Dr. Wong “ruled in” subpotent tacrolimus as a

potential cause of Huerta’s kidney rejection because of the severity of Huerta’s rejection

and the concurrent tacrolimus recall when she was hospitalized. Although Dr. Wong did



                                              -9-
not know which manufacturer issued the recall, “he assigned a ‘blanket blame on every

liquid [tacrolimus] preparation.’” Aug. 13, 2010 Op. at 6 (quoting R., Vol. I at 72).

Because it turned out that Huerta had not taken the recalled tacrolimus, and because there

was no direct evidence of the potency of the tacrolimus suspension or of Huerta’s

tacrolimus levels when she was admitted to the hospital, the district court found that there

was no way to “test” Dr. Wong’s hypothesis that subpotent tacrolimus caused Huerta’s

kidney rejection. Id.; see also Daubert, 509 U.S. at 593-94.

       The district court also found that Dr. Wong’s testimony was based on Huerta’s

attorneys’ erroneous representations that test results showed that the tacrolimus

suspension was subpotent when such test results did not exist. Aug. 13, 2010 Op. at 6-7.

When he was informed that the purported test results did not actually exist, Dr. Wong

conceded that “if there [wa]s ‘no evidence to show that [Bioscrip’s tacrolimus

suspension] was subpotent, then I don’t think anybody can say what caused the rejection,

and that’s just history.’” Id. at 7 (quoting R., Vol. II at 489).

       The district court also found that Dr. Wong’s “ruling out” Huerta’s non-

compliance with her medication regime as a potential cause of her kidney rejection was

wanting. It was based only on “knowing” Huerta’s family, without any investigation into

whether Huerta’s family had properly administered her medication in the weeks before

the rejection and without examining the suspension bottles to determine how much of the

suspension had been used. Id. at 11-12.




                                              -10-
       Given these deficiencies, the district court found that Dr. Wong’s opinion was “not

‘supported by appropriate validation – i.e., ‘good grounds,’ based on what is known.’”

Id. at 11 (quoting Daubert, 509 U.S. at 590).

       As a significant matter, we find telling Dr. Wong’s concession that he would only

be speculating as to the cause of Huerta’s kidney rejection when it was revealed to him

that there was no direct evidence measuring the potency of Huerta’s tacrolimus

suspension. Our court has previously stated that “[t]o be reliable under Daubert, an

expert’s scientific testimony must be based on scientific knowledge . . . and not mere

‘subjective belief or unsupported speculation.’” Goebel, 346 F.3d at 991 (quoting

Daubert, 509 U.S. at 590); see Mitchell v. Gencorp Inc., 165 F.3d 778, 780 (10th Cir.

1999). This indicates that the district court did not abuse its discretion in excluding Dr.

Wong’s testimony as unreliable.

       Moreover, given Dr. Wong’s concession, his final testimony and the evidence and

methodology upon which he relied are unclear to us. See Mitchell, 165 F.3d at 781 (“At a

minimum, the expert testimony should include a description of the method used to arrive

at the level of exposure and scientific data supporting the determination. The expert’s

assurance that the methodology and supporting data [are] reliable will not suffice.”)

(citing Moore v. Ashland Chem., Inc., 151 F.3d 269, 276 (5th Cir. 1998) (en banc)). Only

piecemeal excerpts of Dr. Wong’s deposition testimony are provided to us, and Huerta’s

briefing does not articulate his final proffer. On this record, we cannot find that the




                                            -11-
district court was manifestly unreasonable in excluding Dr. Wong’s testimony as

unreliable.

       None of Huerta’s arguments persuades us otherwise. Huerta argues that Dr.

Wong’s testimony was supported by his observation that her kidney rejection was one of

the most severe and catastrophic rejection episodes he had seen. The district court,

however, held only that Dr. Wong could testify that Huerta’s kidney rejection was severe

and catastrophic. What the district court found lacking, however, was the causal link

between the severity of the rejection and the potency of BioScrip’s tacrolimus suspension.

And we find that the district court was within its discretion to so conclude. See Goebel,

346 F.3d at 992 (“‘A court may conclude that there is simply too great an analytical gap

between the data and the opinion proferred.’”) (quoting General Elec. Co. v. Joiner, 522

U.S. 136, 146 (1997)).

       Our court has stated that “a differential diagnosis is most useful when ‘the party

relying on the diagnosis has offered independently reliable evidence that the allegedly

dangerous drug or substance had harmful effects.’” Goebel, 346 F.3d at 999 (quoting

Hollander, 289 F.3d at 1210). Here, the evidence appears to be weak or entirely missing

to show that the tacrolimus suspension administered to Huerta was subpotent. See, e.g.,

Nelson v. Tenn. Gas Pipeline Co., 243 F.3d 244, 253 (6th Cir. 2001) (“Without any

factual basis from which a jury could infer that the plaintiffs were in fact exposed to

PCBs from Station 79, the reasoning and methodology underlying the testimony is not

scientifically valid.”). Huerta’s argument that her other experts’ differential diagnoses



                                            -12-
constituted “direct evidence,” even though they had been excluded as unreliable, is

clearly unpersuasive. Aplt’s Br. 17-18.

       Huerta next argues that contrary to the district court’s findings, Dr. Wong properly

ruled out non-compliance with the prescribed treatment as a possible cause of Huerta’s

kidney rejection. The district court found that Dr. Wong summarily ruled out non-

compliance based only on “knowing” Huerta’s family. Dr. Wong did so even though he

acknowledged that Huerta’s physicians were concerned that non-adherence may have led

to her subsequent kidney rejection episode in May of 2007 when she was taking a

different form of tacrolimus. Aug. 13, 2010 Op. at n.6. Huerta argues that Dr. Wong

properly based his “ruling out” of non-adherence on his seeing non-adherence in patients

“on a quite regular basis.” Aplt’s Br. 16 (quoting R., Vol. I at 112). Dr. Wong also

testified that non-adherence would not have caused the type of rejection he saw in Huerta.

Id. (citing same). Dr. Wong also testified that some teenagers fail to take their medicine

“10 to 25 percent of the time and they still kind of manage to do okay.” Id. (citing R.,

Vol. I at 120). Despite Huerta’s arguments, we cannot conjecture about the viability of

Dr. Wong’s conclusion in view of his concession that he would be speculating as to the

cause of Huerta’s kidney rejection in the absence of evidence. On the record submitted to

us, we are unpersuaded that the district court was unreasonable in finding that Dr. Wong

did not properly rule out non-adherence as a potential cause of Huerta’s kidney rejection.

       Huerta next argues that the district court abused its discretion by faulting her for

not providing direct evidence of the potency of the tacrolimus suspension when



                                            -13-
insufficient tacrolimus remained for testing. To the contrary, the district court did not

require direct evidence as a baseline to sustain Dr. Wong’s testimony, but found that in

this case, no other evidentiary link could reliably connect the tacrolimus suspension with

Huerta’s rejection. Aug. 13, 2010 Op. at 6-7; see also Kumho Tire, 526 U.S. at 153

(“[W]hether Daubert's specific factors are, or are not, reasonable measures of reliability

in a particular case is a matter that the law grants the trial judge broad latitude to

determine.”) (quoting Joiner, 522 U.S. at 143). By conceding that he could not say what

caused Huerta’s kidney rejection without evidence that the tacrolimus was subpotent, Dr.

Wong appears to agree with the district court’s assessment. R., Vol. II at 489.

       Lastly, Huerta argues that the district court mischaracterized Dr. Wong’s testimony

as “ruling in” subpotent tacrolimus solely on the assumption that Huerta was administered

the recalled tacrolimus. However, Huerta’s argument fails for two reasons. First, the

district court recognized that Dr. Wong’s testimony was based on both the severity of

Huerta’s rejection and also on the recall. Aug. 13, 2010 Op. at 6. As discussed above,

the district court found that while Dr. Wong could testify to the severity of Huerta’s

rejection, that testimony fell short of establishing subpotent tacrolimus as a cause for

Huerta’s kidney rejection. Second, as to the recall, Dr. Wong testified that at the time of

Huerta’s 2006 hospitalization, he hypothesized that subpotent tacrolimus could have

caused Huerta’s kidney rejection by assigning a “blanket blame on every liquid

[tacrolimus] preparation and, you know, guilty unless proven innocent.” Id. (quoting R.,

Vol. I at 72). Whether Dr. Wong continued to rely on this in his final testimony given his



                                              -14-
prior concession is unclear to us from the record, and on this we also decline to speculate.

Accordingly, this last argument clearly fails.

       For all the foregoing reasons, we find that the district court did not abuse its

discretion in excluding Dr. Wong’s testimony.

       3. Testimony of Dr. Steven Alexander

       Like Dr. Wong, Dr. Steven Alexander was prepared to testify that to a reasonable

degree of medical certainty, the cause of Huerta’s kidney rejection was inadequate

immunosuppression resulting from “a preparation of [t]acrolimus that was insufficient.”

R., Vol. I at 130. The district court held that Dr. Alexander’s testimony was unreliable

because it was based on the erroneous assumption that Blanca’s tacrolimus suspension

was subpotent even though that had not yet been established, Aug. 13, 2010 Op. at 11; R.,

Vol. I at 74, and because it was not based on any known facts.

       The district court found that Dr. Alexander’s differential diagnosis fell short of

reliability. For example, Dr. Alexander testified that almost nothing would cause

Huerta’s creatnine level to go from 0.6 to 9 except nonadherence. Id. at 80 (testifying

that of the six different suspected explanations for creatinine levels spiking in kidney

transplant patients when they have been stable for two years, nonadherence is considered

numbers one, two, and three). Yet, Dr. Alexander ruled out “non-adherence” based on

“knowing” Huerta’s family. Id. at 87, 90. Dr. Alexander, however, was not aware that

following Huerta’s 2007 kidney rejection, “one of the concerns was that multiple family

members were providing Blanca with her oral medications, and that they were concerned



                                             -15-
she wasn’t being dosed sufficiently.” Id. at 88.5

       When Dr. Alexander was informed that Huerta’s treating physicians suspected

non-compliance as a cause of her 2007 kidney rejection, he maintained that compliance

was not an issue in the May 2006 rejection because he “ha[d] no reason to doubt that

[Huerta’s] mother was giving her her medications.” Id. at 90. The district court’s finding

this to fall short of reliable testimony was not an abuse of discretion because Dr.

Alexander did not “provide reasons for rejecting alternative hypotheses ‘using scientific

methods and procedures.’” Clausen v. M/V NEW CARISSA, 339 F.3d 1049, 1058 (9th Cir.

2003) (quoting Claar v. Burlington N. R.R. Co., 29 F.3d 499, 502 (9th Cir.1994)). Dr.

Alexander’s ruling out of non-adherence in view of contradictory evidence should have

been “founded on more than ‘subjective beliefs or unsupported speculation.’” Id. (same).

Although “‘[t]rained experts commonly extrapolate from existing data[,] . . . nothing . . .

requires a district court to admit opinion evidence which is connected to existing data

only by the ipse dixit of the expert. ’” Mitchell, 165 F.3d at 782 (quoting Joiner, 522 U.S.

at 146).




5
        In her reply brief, Huerta argues for the first time that the district court could not
properly consider her May 2007 rejection as evidence of whether she took her medicine
as prescribed in the time leading to her May 2006 rejection. Reply Br. 13. Huerta argues
that this was “wholly irrelevant, constitute[d] improper character evidence, [was] more
prejudicial than probative,” and was reversible error. Id. (citing Fed. R. Evid. 402, 403,
and 404). By not raising this issue in her opening brief, however, Huerta has forfeited her
right to appellate review of it. See Bronson v. Swensen, 500 F.3d 1099, 1104 (10th Cir.
2007) (explaining that “the omission of an issue in an opening brief generally forfeits
appellate consideration of that issue”).

                                             -16-
       Dr. Alexander’s belief that he had no reason to doubt that Huerta was being dosed

properly despite squarely contradictory evidence indicates that the district court was

within its discretion to find his testimony unreliable. As our court has previously stated,

“‘scientists whose conviction about the ultimate conclusion of their research is so firm

that they are willing to aver under oath that it is correct prior to performing the necessary

validating tests [may] properly be viewed by the district court as lacking the objectivity

that is the hallmark of the scientific method.’” Id. at 783 (quoting Claar, 29 F.3d at 503).

       The district court also found that Dr. Alexander relied at least in part on Huerta’s

attorneys’ representations that the tacrolimus suspension was subpotent. The district

court found that this rendered his methodology unreliable because it was “derived from

erroneous facts or assumptions.” Aug. 13, 2010 Op. at 11. We find that the district court

was acting within its discretion in excluding Dr. Alexander’s testimony on this ground.

C.f. In re Paoli R.R. Yard PCB Litig., 35 F.3d 717, 762 (3d Cir. 1994) (“We do not doubt

the propriety of a medical report prepared just for litigation, but a physician who

evaluates a patient in preparation for litigation should seek more than a patient’s self-

report of symptoms or illness . . . in order to determine that a patient is ill and what illness

the patient has contracted.”).

       Huerta argues that Dr. Alexander’s testimony was based on his experience with

other children who had undetectable levels of tacrolimus even though they were very

compliant. Huerta also argues that Dr. Alexander based his testimony on his observations

that Huerta had shown no prior problems and that her age group was the best in terms of



                                              -17-
compliance. Moreover, Dr. Alexander also observed that improper compounding rather

than improper dosing caused problems similar to those experienced by Huerta in children

who took liquid tacrolimus. Even taking all of these observations as true for the sake of

argument, however, we do not find that the district court abused its discretion. The

district court was concerned with Dr. Alexander’s own characterization of non-adherence

as comprising the top three of six explanations6 for severe kidney rejections in previously-

stable patients, and then his summary rejection of “non-adherence” as a cause of Huerta’s

kidney rejection in the face of contradictory evidence. Aug. 13, 2010 Op. at 8, 11-13. It

was within the district court’s discretion to find Dr. Alexander’s testimony unreliable for

this reason. See Bitler, 391 F.3d at 1124 (“[A]n inference to the best explanation for the

cause of an accident must eliminate other possible sources as highly improbable, and

must demonstrate that the cause identified is highly probable.”); see also Kumho Tire,

526 U.S. at 152.

       4. Testimony of Dr. Bruce Morgenstern7

6
        A. (Dr. Alexander)           “[T]here is almost nothing that will basically have the
kidney go from .6 to a creatinine of 9, except nonadherence. And that is, for us, the main
number, 1, 2, and 3, of the differential diagnosis when someone’s kidney that’s been
stable for two years, no rejection prior to that time, suddenly fails.
        Q.     So nonadherence would be the first thing you would look at when
somebody comes in with a spiking creatinine level; correct?
        A.     A very high creatinine.
        Q.     What’s the second thing you look at?
        A.     Nonadherence.
        Q.     Well, I thought that was No.1.
        A.     It’s No. 1, 2, and 3.
R., Vol. I at 80 (Deposition of Dr. Steven Alexander, Feb. 11, 2010).
7
        The parties and the district court differ in their spelling of Dr. Morgenstern’s name
and also spell it “Morganstern.” For consistency, we will use the spelling of the title of

                                            -18-
       Dr. Bruce Morgenstern was prepared to testify that it was “highly probable” that

the reason for Huerta’s low tacrolimus levels in May of 2006 was the subpotency of

BioScrip’s tacrolimus suspension. Aug. 13, 2010 Op. at 9-10. Yet, the district court

found that Dr. Morgenstern’s testimony was based on the erroneous assumptions that the

other physicians had definitively established that the tacrolimus suspension was subpotent

when they had not, id. at 9, 11, and that other likely causes of Huerta’s kidney rejection

had been ruled out because of their absence from the medical records. Id. at 9.

       Huerta argues that Dr. Morgenstern in fact reached his conclusions “given his

experience as a pediatric nephrologist and statistical data,” Aplt’s Br. 21, citing only Dr.

Morgenstern’s ultimate causation testimony which does not mention any actual statistical

data. Id. On this record and on our affirming the district court’s exclusion of Dr. Wong’s

and Dr. Alexander’s testimony, we are unconvinced that the district court made a clear

error of judgment by excluding Dr. Morgenstern’s testimony.

       5. Testimony of Dr. Randall Tackett

       Dr. Tackett was prepared to testify that “reduced levels of tacrolimus resulted in

Huerta’s kidney rejection and it was caused by a compounding error.” Mem. Order and

Op. Granting BioScrip’s Motion to Exclude Proposed Testimony of Randall L. Tackett,

PhD, August 18, 2010 (“Aug. 18, 2010 Op.”) at 9. Dr. Tackett was also prepared to

testify that “his ‘guess’ was that, when BioScrip pharmacists were compounding the April




the appellant’s Daubert motion, “Dr. Morgenstern.” See R., Vol. I at 42.

                                             -19-
or May 2006 suspension, either ‘the wrong number of capsules were counted or emptied

improperly.’” Id. (quoting R., Vol. I at 37).

       The district court admitted Dr. Tackett’s testimony relating sloppy pharmaceutical

record-keeping with sloppy compounding. The district court also found that Dr. Tackett

was qualified to testify regarding the most common type of compounding errors when

capsules are used as an ingredient in the compound, and that BioScrip’s compounding

task was straightforward instead of complicated. Id. at 10. The district court, however,

excluded Dr. Tackett’s testimony on the standard of care for keeping pharmacy records,

the actual potency or adequacy of the tacrolimus suspension dispensed to Huerta, and the

cause of Blanca’s kidney rejection being subpotent tacrolimus compounded by BioScrip.

       Huerta argues that the district court erred in faulting Dr. Tackett’s reliance on the

findings of other experts as hearsay, and insists that Dr. Tackett “was able to conclude,

based on all the evidence before him, from a pharmacological and toxicological

standpoint . . . that the only cause not completely ruled out was a compounding error.”

Aplt’s Br. 24-25. Huerta’s arguments, however, fall short.

       Huerta is correct to say that experts may offer opinions based on hearsay or other

inadmissible evidence if experts in the field reasonably rely on such evidence in forming

their opinions. See Fed. R. Evid. 703; United States v. Posey, 647 F.2d 1048, 1051 n.2

(10th Cir. 1981) (“If of a type reasonably relied upon by experts in the particular field in

forming opinions or inferences upon the subject, the facts or data [in the particular case

upon which an expert bases an opinion or inference] need not be admissible in



                                            -20-
evidence.”); see also United States v. Mulder, 273 F.3d 91, 102 (2d Cir. 2001). However,

in this case, the district court also pointed out inconsistencies in Dr. Tackett’s testimony,

Aug. 18, 2010 Op. at 11-12, and Dr. Tackett’s “dodg[ing] the issue” of Huerta’s 2007

kidney rejection where non-compliance was suspected. Id. at 11. Huerta does not

address either of these issues, which are alternative grounds upon which we could affirm

the district court’s order. See Murrell v. Shalala, 43 F.3d 1388, 1389 (10th Cir. 1994)

(stating that an independently sufficient alternative basis for the district court’s holding

that is unchallenged forecloses success on appeal).

       We note that this case presents difficult questions that a different district judge

may have resolved differently. As this judge pointed out, all of Huerta’s experts are well-

qualified to testify on a variety of the underlying issues in this case. However, “when

coupled with [the abuse of discretion] standard of review, Daubert’s efforts to safeguard

the reliability of science in the courtroom may produce a counter-intuitive effect: different

courts relying on [] essentially the same science may reach different results.” Hollander,

289 F.3d at 1206-07 (citing Federal Judicial Center, Reference Manual on Scientific

Evidence 27 (2d ed. 2000)). For the reasons stated above, we find that the district court

did not abuse its discretion by excluding the testimony of Dr. Wong, Dr. Alexander, Dr.

Morgenstern, and Dr. Tackett as unreliable.

       B. Whether the District Court Abused its Discretion in Admitting the Opinions of

Bioscrip’s Experts




                                             -21-
       Huerta next argues that the district court erred by admitting the testimony of two of

BioScrip’s experts. The district court granted summary judgment to BioScrip on the

ground that BioScrip had admissible expert testimony that, more likely than not, factors

other than subpotent tacrolimus8 caused Huerta’s kidney rejection. Aug. 19, 2010 Op. at

8-9. Because the district court held that Huerta did not have admissible expert testimony

on causation, the district court also held that Huerta could not rebut the testimony of

BioScrip’s experts. Id. Thus, assuming without deciding that it was necessary for the

district court to reach this issue given its exclusion of Huerta’s experts’ testimony, we

address Huerta’s arguments and reject them for the reasons stated below.

       1. Dr. Chris Clardy

       Huerta argues that the testimony of Dr. Chris Clardy should have been stricken

because it was based on the wrong legal standard. According to Huerta, Dr. Clardy

rendered the opinion that “‘it is not certain that [Huerta’s] low level [of tacrolimus]

resulted from using an inadequate preparation of tacrolimus.’” Aplt’s Br. at 34 (quoting

R., Vol. I at 36) (emphasis from the appellant’s brief). Because the proper standard under

New Mexico law is whether something is true “to a reasonable degree of medical

probability” rather than “certainty,” Huerta argues that the district court abused its




8
       These causes included the change in Huerta’s prescription from Cellcept to Imuran
(a weaker immunosuppressant), Huerta’s vomiting for three days before she was
hospitalized and her creatinine levels were checked, that Huerta was vomiting for five
days before her tacrolimus levels were checked, and the possibility of non-adherence to
her medication regime. Aug. 19, 2010 Op. at 8 (citing R., Vol. II at 392-93).

                                             -22-
discretion by admitting Dr. Clardy’s testimony. Id. at 35 (quoting Baca v. Bueno Foods,

108 N.M. 98, 100 (N.M. App. 1988)).

       When Huerta advanced these arguments before the district court, the district court

found that they mischaracterized Dr. Clardy’s opinion. The district court explained Dr.

Clardy’s actual proffer, citing Dr. Clardy’s written report and his deposition testimony.

Finding that Dr. Clardy’s opinions were based upon correct legal standards and

methodologies, the district court held that his opinions were admissible. Mem. Order and

Op. Granding BioScrip’s Mot. to Exclude Proposed Testimony of Chris Clardy and Lloyd

Vernon Allen, August 9, 2010 (“Aug. 9, 2010 Op.”) at 5.

       Huerta’s brief fails to address the district court’s thorough analysis. Based on our

review of the briefing, the record, and the district court’s reasoning, we are unpersuaded

that the district court abused its discretion in admitting Dr. Clardy’s testimony.

       2. Dr. Lloyd Vernon Allen

       Huerta sought to exclude the testimony of Dr. Lloyd Vernon Allen on the ground

that Dr. Allen’s retention as an expert created a gross conflict of interest because of

Huerta’s retention also of Dr. Tom Kupiec. Huerta retained Dr. Kupiec as an expert

witness in a prior action and also listed Dr. Kupiec in her initial disclosures in the instant

action. Aplt’s Br. 35-36. BioScrip subsequently retained Dr. Allen as an expert

pharmacologist. Huerta argues that there is a close personal relationship between Dr.

Allen and Dr. Kupiec, that they communicate frequently both in person and by e-mail,

that they discussed this case briefly on at least one occasion, that Dr. Allen has worked



                                             -23-
with Dr. Kupiec on a number of projects, and that Dr. Allen selects Dr. Kupiec’s lab for

quality assurance testing for pharmaceutical companies. Id. Thus, Huerta argues that

there is an apparent conflict of interest between Dr. Allen and Dr. Kupiec and the failure

to exclude Dr. Allen’s testimony is an abuse of discretion. Id.

       The district court found that Blanca’s arguments mischaracterized Dr. Allen’s

testimony. The “frequent communication” between Dr. Allen and Dr. Kupiec was once

every week or two, and at the time of Dr. Allen’s deposition, the two doctors did not have

any concurrent projects ongoing. Their “discussion” of the instant case was only a single

instance when Dr. Allen mentioned to Dr. Kupiec that he had been retained in “a

tacrolimus case.” Dr. Kupiec mentioned that he had “a contact about that case,” and

immediately the two stopped talking about it. Aug. 9, 2010 Op. at 7-8. Ultimately, the

district court found that “[Huerta] ha[s] failed to allege facts showing any conflict of

interest, much less the ‘gross conflict’ that [she] contend[s] exists.” Id. at 8.

       Without citing a single case in support of her position, or identifying any error in

the district court’s reasoning, Huerta reiterates the arguments made before the district

court and then insists that the district court abused its discretion. Based on the district

court’s thoughtful analysis and the facts found on the record before it (again, none of

which Huerta’s brief addresses), we are unpersuaded. See also Habecker v. Town of

Estes Park, Colo., 518 F.3d 1217, 1223 n.6 (10th Cir. 2008) (stating on appeal that the

trial court erred without advancing reasoned argument as to the grounds for the appeal is




                                             -24-
insufficient appellate argument). In sum, we find no error in the district judge’s refusing

to exclude Dr. Allen’s testimony.

       C. Whether the District Court Erred in Granting Summary Judgment in Favor of

Bioscrip

       We now turn to the district court’s grant of summary judgment in favor of

BioScrip, which we review de novo. Garrison v. Gambro, Inc., 428 F.3d 933, 935 (10th

Cir. 2005). We apply de novo review with application of the principle that “we view the

evidence and draw reasonable inferences therefrom in the light most favorable to the

nonmoving party.” Id. Summary judgment “‘necessarily implicates the substantive

evidentiary standard of proof that would apply at the trial on the merits.’” Burlington N.

& Santa Fe Ry. Co. v. Grant, 505 F.3d 1013, 1023 (10th Cir. 2007) (quoting Anderson v.

Liberty Lobby, Inc., 477 U.S. 242, 253 (1986)).

       Huerta asserted claims for strict products liability, negligence, negligent

misrepresentation, a violation of the New Mexico Unfair Trade Practices Act, breach of

express and implied warranty, and for an award of punitive damages. In New Mexico, “a

tort plaintiff must demonstrate the defendant’s actions caused the plaintiff’s injury.”

Wilcox v. Homestake Mining Co., 619 F.3d 1165, 1166 (10th Cir. 2010). “[F]ailure of

proof of an essential element renders all other facts immaterial.” Koch v. Koch Indus.,

Inc., 203 F.3d 1202, 1212 (10th Cir. 2000). When “the moving party does not bear the

ultimate burden of persuasion at trial, it may satisfy its burden at the summary judgment

stage by identifying a lack of evidence for the nonmovant on an essential element of the



                                            -25-
nonmovant’s claim.” Cassara v. DAC Serv., Inc., 276 F.3d 1210, 1212 (10th Cir. 2002)

(internal quotation marks omitted). The burden then shifts to the opposing party to come

forward with admissible evidence to create a genuine issue of material fact on that

element. See Bacchus Indus., Inc. v. Arvin Indus., Inc., 939 F.2d 887 891 (10th Cir.

1991).

         Accordingly, after excluding Huerta’s experts’ causation testimony, the district

court found that “BioScrip has demonstrated that there is no direct evidence that the

tacrolimus suspension it compounded for Huerta was subpotent or otherwise defective,

and that there were several other undisputed factors that could have contributed to

Huerta’s transplant rejection.” Mem. Order and Op. Granting BioScrip’s Motion for

Summary Judgment, August 19, 2010 (“Aug. 19, 2010 Op.”) at 7.

         The district court held that the testimony of BioScrip’s expert, Dr. Chris Clardy,

was admissible, which we affirm as discussed above. Dr. Clardy was prepared to testify

that while it was theoretically “possible” that BioScrip’s tacrolimus suspension was

subpotent and caused Huerta’s kidney rejection, “there was a 75 to 80 percent

‘probability’ that the cause of Blanca’s rejection was a combination of non-adherence or

some other reason for insufficient levels of tacrolimus in her system other than

subpotency, plus the change from Cellcept to Imuran.” Id. at 8. With Dr. Clardy’s

testimony and “the undisputed fact that the other three patients taking BioScrip’s

tacrolimus suspension from the same batch as Blanca did not report any issues with the




                                              -26-
tacrolimus BioScrip compounded,” the district court found that “no reasonable jury could

find that the tacrolimus was defective or caused Blanca’s rejection.” Id. at 8-9.

       The district court then reasoned that “the continuing vitality of this case . . .

depend[ed] upon a single issue: whether Plaintiffs [sic] have met their [sic] burden to

come forward with sufficient, admissible, medical evidence to show that BioScrip

compounded and dispensed subpotent tacrolimus that caused Blanca [sic] kidney-

transplant rejection such that a reasonable jury could return a verdict in favor of the

Plaintiffs [sic].” Id. at 7. Without admissible expert testimony to rebut Dr. Clardy’s

testimony on the issue of causation, the district court concluded that Huerta could not

establish any of the following facts:

       (1) [that] the tacrolimus BioScrip marketed and dispensed was subpotent or
       defective; (2) [that] BioScrip’s compounding of the tacrolimus suspension
       failed to meet the standard of care [to prove negligence]; (3) [that] BioScrip
       made any misrepresentations [sic] or concealed any information about the
       quality and efficacy of the tacrolimus it dispensed; (4) [that] BioScrip’s
       tacrolimus was not fit for human consumption; (5) [that] Blanca’s low levels
       of tacrolimus on May 17, 2006 were caused by BioScrip’s marketing or
       dispensing of a defective product; or (6) [that] Blanca’s transplant rejection
       and resulting injuries were caused by ingestion of subpotent tacrolimus.

Aug. 19, 2010 Op. at 9. Finding that Huerta did not meet her burden to demonstrate a

genuine issue of material fact on causation, the district court granted summary judgment

in BioScrip’s favor. Id.

       Huerta argues that genuine issues of material fact exist regarding causation, citing

the testimony of her experts which we have held was within the district court’s discretion

to exclude. Aplt’s Br. 26; Reply Br. 15. Aside from stating the elements of the strict



                                             -27-
products liability tort in New Mexico, Huerta offers no argument as to how those

elements have been met in this case, Aplt’s Br. 30-31, and we decline to make them for

her here. See Fed. R. App. P. 28(a)(9)(A) (“The appellant’s brief must contain . . .

appellant’s contentions and the reasons for them, with citations to the authorities and parts

of the record on which the appellant relies.”).

       On her negligence claim, Huerta argues that a jury is entitled to weigh the

testimony given by the experts, and that contrary to BioScrip’s arguments, she does not

have to show that subpotent tacrolimus was the cause of her kidney rejection to avoid

summary judgment. Aplt’s Br. 31-32. Given that we hold that her experts’ testimony

was properly excluded, Huerta’s first argument fails. Huerta’s second argument

mischaracterizes BioScrip’s position. Nowhere does BioScrip argue that Huerta must

show that subpotent tacrolimus must be the sole cause of her injury. Rather, BioScrip

argues that given the variety of other potential causes of Huerta’s kidney rejection,

without her experts’ testimony, Huerta could not show that more likely than not, the

tacrolimus suspension dispensed was subpotent, that it was a but-for cause of Huerta’s

kidney rejection, or that it was a proximate cause of Huerta’s kidney rejection. Aplee’s

Br. 52-54. To that end, the only case Huerta cites supports BioScrip’s position: to sustain

a negligence claim, “[p]laintiff . . . must prove that the act characterized as negligence

more probably than not was a contributing cause of the injury.” Tafoya v. Seay Bros.

Corp., 119 N.M. 350, 351 (N.M. 1995) (first emphasis added).




                                             -28-
       Next, Huerta summarily argues that BioScrip violated the New Mexico Unfair

Trade Practices Act, Section 57-21-1 NMSA (1978), by selling subpotent medication and

by failing to warn of the medication’s subpotency. Aplt’s Br. 32. As the district court

held, however, Huerta cannot establish to a reasonable degree of medical probability that

the BioScrip tacrolimus was subpotent without the testimony of her experts. Huerta’s

summary reliance on her experts’ testimony to sustain her failure to warn and unfair trade

practices claims, therefore fails. The same is true for her breach of express and implied

warranty claims.

       Because the district court properly granted summary judgment in favor of

BioScrip, we need not address Huerta’s claim for punitive damages.

                                     III. Conclusion

       For the foregoing reasons, we affirm the district court’s granting of summary

judgment in favor of BioScrip.


                                          Entered for the Court



                                          William J. Holloway, Jr.
                                          Circuit Judge




                                           -29-
