                              In the

    United States Court of Appeals
                For the Seventh Circuit
                    ____________________
No. 17-3416
ISAAC OWENS,
                                                 Plaintiff-Appellant,

                                v.

AUXILIUM PHARMACEUTICALS, INC.,
                                                Defendant-Appellee.
                    ____________________

        Appeal from the United States District Court for the
          Northern District of Illinois, Eastern Division.
          No. 14 C 5180 — Matthew F. Kennelly, Judge.
                    ____________________

       ARGUED MAY 15, 2018 — DECIDED JULY 19, 2018
                    ____________________

   Before BAUER, KANNE, and HAMILTON, Circuit Judges.
    KANNE, Circuit Judge. Isaac Owens used Testim, a topical
gel containing 1% testosterone, sporadically for two years.
During this time, he developed deep vein thrombosis. He
sued Testim’s manufacturer, alleging that the drug caused the
condition. To show causation—a necessary element of all of
his claims—Owens planned to rely on the testimony of Dr. Ji-
had Abbas. The district court excluded Dr. Abbas's testimony
and, as a result, granted summary judgment in favor of the
2                                                    No. 17-3416

drug manufacturer. Owens appeals the district court’s deci-
sion to exclude his expert’s testimony and grant summary
judgment. We affirm.
                         I. BACKGROUND
    Owens developed deep vein thrombosis (“DVT”) while
using Testim, a drug manufactured by the defendant–Auxil-
ium Pharmaceuticals, LLC. He and other plaintiffs in a multi-
district litigation allege that they suffered injuries because
they took Testim and other testosterone-replacement-therapy
drugs. Owens’s case was selected for a bellwether trial in the
multidistrict litigation.
    Owens began using Testim in July 2011 when his doctor
diagnosed him with hypogonadism. Between July 2011 and
July 2013, Owens used the drug sporadically. He refilled his
prescription only three times, so he did not have enough of
the drug to take a full daily dose during the time period.
When Owens did use Testim, he did so incorrectly. Although
the medication guide directs users to apply a full tube of Tes-
tim to the shoulders and arms, Owens testified that he would
apply part of a tube to his thighs and stomach.
   On July 12, 2013, Owens was admitted to a hospital’s
emergency department for pain in his left leg. After an ultra-
sound revealed blood clots in his leg, he was diagnosed with
DVT. Owens was treated with blood thinners and released
from the hospital the following day.
    In his suit, Owens alleges that Testim caused the DVT and
asserts claims for strict liability, negligence, fraud, and negli-
gent misrepresentation under Kentucky law. Each of these
claims requires expert testimony to establish causation. In re
Testosterone Replacement Therapy Prod. Liab. Litig. Coordinated
No. 17-3416                                                      3

Pretrial Proceedings, No. 14 C 1748, 2017 WL 4772759, at *6
(N.D. Ill. Oct. 23, 2017) (citing Adams v. Cooper Indus., Inc., No.
CIV.A. 03-476-JBC, 2012 WL 2339741, at *1 (E.D. Ky. June 19,
2012)). For that, Owens planned to rely on the testimony of
Dr. Abbas. But Dr. Abbas’s testimony was problematic. Alt-
hough Dr. Abbas opined that Testim had caused Owens’s
DVT, he did so on the assumption that Owens was applying
the prescribed dose of the gel in the proper manner. Moreo-
ver, when asked during his deposition about hypothetical
cases that resembled Owens’s use of Testim, Dr. Abbas ex-
plained that he had no opinion.
    Auxilium moved to exclude Dr. Abbas’s testimony be-
cause it was not tied to the facts of the case. It also moved for
summary judgment because, without the expert testimony,
Owens could not show that Testim caused his injury. The dis-
trict court agreed and granted summary judgment to Auxil-
ium. Owens appealed.
                            II. ANALYSIS
    This appeal centers on the district court’s exclusion of Dr.
Abbas’s testimony, which Owens argues was improper. Fed-
eral Rule of Evidence 702 and Daubert v. Merrell Dow Pharma-
ceuticals, Inc., 509 U.S. 579 (1993) govern this decision. In rele-
vant part, they require that the expert’s testimony “assist the
trier of fact.” Ammons v. Aramark Unif. Servs., Inc., 368 F.3d
809, 816 (7th Cir. 2004) (quoting NutraSweet Co. v. X-L Eng'g
Co., 227 F.3d 776, 788 (7th Cir. 2000)). To do so, the testimony
must “fit the issue to which the expert is testifying and be tied
to the facts of the case.” Hartman v. EBSCO Indus., Inc., 758
F.3d 810, 819 (7th Cir. 2014) (quoting Deimer v. Cincinnati Sub-
Zero Prods., Inc., 58 F.3d 341, 345 (7th Cir. 1995)). When there
4                                                   No. 17-3416

is no question that the district court properly followed Daub-
ert’s framework—as is the case here—we consider whether
the district court abused its discretion by excluding the testi-
mony. Durkin v. Equifax Check Servs., Inc., 406 F.3d 410, 420
(7th Cir. 2005).
    Here, the district court properly exercised its discretion by
concluding that Dr. Abbas’s testimony did not fit the facts of
Owens’s case. Dr. Abbas testified that Testim caused Owens’s
DVT on the assumption that Owens used Testim as pre-
scribed. This in fact was not the case. Owens instead testified
that he used far less than the prescribed dose and that he did
not apply the medication as directed. When presented hypo-
theticals that more closely resembled the facts of Owens’s
case, Dr. Abbas conceded that he could not offer an opinion.
Because Dr. Abbas’s testimony did not fit the facts of the case,
it was not likely to “assist the trier of fact to understand the
evidence or to determine a fact in issue.” Ervin v. Johnson &
Johnson, Inc., 492 F.3d 901, 904 (7th Cir. 2007).
    Of course, some questions regarding an expert’s use of
faulty assumptions or data should be left to a jury. See, e.g.,
Stollings v. Ryobi Techs., Inc., 725 F.3d 753, 765–67 (7th Cir.
2013) (quality of testimony and soundness of factual basis are
questions for jury; debatable input to expert’s model was an
“arguable limitation” of his opinion, not an error rendering it
irrelevant). But whether an expert’s approach lines up with
the basic facts of the case goes to the relevance and admissi-
bility of the testimony itself. Gatekeeping of this sort is
properly left to the court. Dr. Abbas’s lack of familiarity with
the case did not simply affect the certainty of his conclusion.
It meant that he was giving an opinion about a hypothetical
high-risk patient using Testim as directed, not Owens who we
No. 17-3416                                                    5

know did not use it as directed. The district court therefore
did not abuse its discretion by excluding the testimony. Hart-
man, 758 F.3d at 819; Deimer, 58 F.3d at 345; Porter v. Whitehall
Labs., Inc., 9 F.3d 607, 616 (7th Cir. 1993).
    Owens takes issue with this analysis for two reasons. Nei-
ther is persuasive. First, he argues that the district court
should not have excluded Dr. Abbas’s testimony because—in
Owens’s view—deposition testimony suggests that he used
full doses of Testim in the days leading up to his DVT. By
Owens’s estimation, this inference is justified because:
   •   the prescribing doctor noted that Owens had not been
       using the full dose when filling the Testim prescription
       in July 2013;
   •   the doctor testified that he would have instructed a pa-
       tient using Testim incorrectly on how to use it cor-
       rectly; and
   •   Owens testified that he trusted the doctor and gener-
       ally followed his advice.
    This is hardly a set of facts that would lead us to conclude
that the district court abused its discretion. In fact, Owens put
the matter to rest during his deposition when he explained
that he continued to apply less than half a full dose per day
after his July appointment.
   Second, Owens argues that he at least used a “therapeutic
dose” and contends that Dr. Abbas’s testimony was not based
on the assumption that he used a full dose, but rather a “ther-
apeutic dose.” But Owens raises this argument for the first
time on appeal, so we do not consider it. Hale v. Chu, 614 F.3d
741, 744 (7th Cir. 2010) (“A party waives the right to argue an
6                                                  No. 17-3416

issue on appeal if he fails to raise that issue before the trial
court”).
                         III. CONCLUSION
    The district court properly applied the Daubert framework
when excluding Dr. Abbas’s testimony. It did not abuse its dis-
cretion by concluding that the testimony did not fit the facts
of Owens’s case. It also did not abuse its discretion by failing
to consider an argument Owens never presented. Without ex-
pert testimony on causation, Owens’s claims necessarily fail.
We therefore AFFIRM the judgment of the district court.
